My dad had a sample for each of his glass types that looked like a set of stairs. He cut strips that were 5 inches wide at 25" 20", 15", 10", 5" then did the layers to make something he could keep and show to clients for each glass weave. He also did some combinations in a stairstep manner for combinations of glass fabric that he recommended. He drilled a hole in each one and hung it on the wall so people could see them and measure themselves with a set of calipers.
Great information! Good stuff. In the Age of UA-cam when people do the same old unoriginal boat/fiberglass/reality TV… your content is original, truly informative, and a cut above. Two thumbs up 😁👍 👍
This was a great real-world test for the hand build garage set up of building a major part for a boat. Nominally 'back in the day' a square foot of fiberglass laminate 1\8" thick was 1 lbs. This became the standard thickness for fiberglass parts ( not necessarily boats ). This was a simple way to price out a product too as you could compare to 1 lbs of steel or aluminum when costing out a job. Obviously there are many ways to make it more complicated now! Cheers warren
It was very enlightening to see first hand how my work measures up. I was then able to extrapolate that data and apply it to the build. It’s how I knew I only needed 8 layers instead of 9. Saved me about 3 hours of labor!
Hi I'm in the UK I need some advice I need to make fiberglass sheets there about 2m x 1m and have to be pretty thick as the side to a pond project I'm doing and the pond is in panels for easy to put to gether and dismantle could you advise me on how many sheets you would recommend to use and the grade of fiberglass to use please meny thanks Richard from the UK
There are a bunch of factors that need to be addressed: how big is the pond (what is the total weight of all that water) as well as what is going to be on the other side of the panel? If this is an above ground pond with air on the other side, then this needs to be treated like a water tank and sized accordingly. If it is in the ground, then the ground will take the strain and the fiberglass simply needs to “seal” so that water can’t escape. In the states, I have seen garbage bags cut open and laid down in sheets to hold water in to make a pond so in ground setups don’t really need strength.
I’m planning to replace the top of an aluminum tube frame “hardtop” with fiberglass (has a stretched vinyl of sorts now). I’m very experienced with polyester resins from doing custom autobody, and interested in your use of same. Would polyester be better than epoxy for my hardtop project? Plan is to use the existing top as a sort of “mold” and remove from underneath. Thanks!
That’s what I would use. Epoxy is so much more expensive and not that much better for boat building than polyester. If polyester wasn’t good for large projects, then boat builders wouldn’t use it to build entire boats! Epoxy is really good for select projects, but everything else can be done successfully with polyester.
Verbally at least, you often are conflating stiffness (resistance to deflection) with strength (tensile or compression load before destructive failure). This is very much not the case.
Very true. Stiffness is resistance to bending, strength is compression and tension forces applied to the material. For this video, I’m only looking at stiffness.
I also vacuum bag glass with a core material to get the most stiffness out of the material. You broke it down to measuring the glass to get the right number of layers well down I learned something every day!
Great how-to video, really really informative. One quick question - Why aren't you using a vacuum bagging technique? Even with big areas this can help control the amount of resin and get rid of excessive voids.
That was a reallly interesting test Herby. Like you, I switch between metric and imperial according to which is the most convenient. Of course, the uk didn't go fully metric until I was an adult so Imperial is in my blood so to speak.
Puerto Rico went metric but then partially went back to the imperial. Speed limit in miles, distance markers in km Milk by the gallon, fuel by the liter It’s a jumbled mix in my head as well
I was wrong, guess 8 layers isn't half an inch lol! However...I think 10 layers will be good for building a hard bimini on my boat. Hey while you're building it are you going to install the backing plates for any kind of sampson post or attachment point for a drogue system?
SI is soooooo easy to use. I started off schooling in British Imperial and all this messing around with fractions of an inch is crazy. 1/64, 1/16, 1/32, why when the metric sizes are all so consistent. 1000 micron = 1mm, 1000mm = 1m, 1000m = 1km
With metric it just goes 1,2,3,4,5,6,7,8 all the way up to 999 If whole units are too much than any fraction that is decimal. What could be simpler?@@RiggingDoctor
@@jonathanwetherell3609The lower set of numbers in his example are metric. You do realize not everything you can measure will fall in a whole number in either system. Hence the decimal points in his metric example. Now figure in your head quickly what comes next like he asked.
Accuracy required varies with the application. Brick layers work to the nearest half brick. Working to a base 10 is the basis of metric. Imperial switches bases all the time base 12, base 3, base 8 (for fractions of an inch). Add in chains, furlongs and miles, perches and poles and we only have linear measure. @@timothyrepp4259
Generally, this is really good information to have but I am missing some important things to this video. What weight of fiberglass material are you using? I've used 3, 4, 5, 7, and 10 oz. material with very different results, especially with the layers you're talking about. Also if one is picky, one needs to add an equally consistent amount of poly or epoxy resin to the layers for that weight. I guess the main thing to get from this video is to run your own tests first, with your material (whatever it is) before embarking on a larger project.
You got it! I used 1708 from Totalboat. I definitely use too much resin but I did the test pieces the same way I did the hull of the transom extension that way it would be an accurate representation of the weight of my work. Doing the test yourself is a great way to corroborate how well you are doing when compared to the standards.
Its actually even easier, West has information on the types of glass and thickness wetted out. E.G. 3 layers of 1708 is almost 1/8" One layer os 0.042" been pretty consistent for me.
I wanted to know how thick my actual work was so I did the test even though I found this kind of information online. I just wanted to make sure that my results match what I found online.
There are simple techniques to calculate the amount of materials required to achieve a prescribed thickness regardless what type of cloth or resin is used. All very basic stuff, but critical to safety in fibreglass repair and fabrication. For structural fibreglass advice / instruction, consult a "qualified person". (This applies to the video producer too.)
Thanks for letting me know about the Amazon links, I removed them since they don’t work. The glass is 1708 from Totalboat and the resin is Polyester from Totalboat as well.
Professional wharves often use a vacuum to compress a fiberglas construction while curing. Does this compression affect the thickness and density of the final product? And how on earth are imperial measurements practial. I am and always will be a metric boy. Also, I hate to be a pedant but what you were testing was not strength but stiffnes. The two are related but by no means the same.
You are correct in my misuse of strength and stiffness interchangeably. I was only measuring stiffness here and calling it strength. Vacuum bagging would (I believe) make it a thinner layup because it is compressing the fibers down onto each other. I don’t have the equipment to vacuum bag, so I’m building with hand layup. I did this test to see with the materials I am using and the technique I employ, what are my actual thickness results. The metric system is great for measuring everything relative to water, but the imperial system is handy when it lines up perfectly with the task at hand.
@@RiggingDoctor Lets agree to disagree on the imperial thing. I don't think that 0.8 of a mm is too hard to multiply, especially for someone raised in the imperial system. Good luck with the build, I am eagerly following your progress.
25oz per yard. The answer to your question is: I have no idea. I’m not an expert in this and I’m doing this test to see how heavy and how thick does my work come out to be. I definitely use too much resin so I come out on the heavy side but I still ended up at 6% lighter than the textbook weight.
A "qualified person" would know that the "experiment" was flawed because the laminate was not properly consolidated, and the cloth / resin ratio unknown.
Good idea for a test! You could as easily use 12/10 mm as 3/64 inches - given this is to the nearest 10th of a mm, as opposed to the nearest 0.2 mm. I wonder if this is a kind of a conformation bias in seeking the US imperial measuring system as the canonical measuring system. :)
I normally use my calipers on metric because it’s easier to follow the decimals, but then I flipped it over to imperial and quickly saw the sequence in the fractions. This time, the imperial system matched up with the job perfectly!
Ah, forgive my implicitness - it's a bad habit of mine. What I meant was - surely choosing y=6x/5 (representing 1.2 mm) or y=3x/64 (3/64 inches) makes no odds?
Love that you're collecting empirical data to verify this. Just wondering if the hull thickness should be specified in number of layers to begin with, since that's what gives the strength.
I’m using only 1708 for my buildup so the number of layers is straight forward. For big projects, they will use a thicker type of cloth called Roving which will add a lot of bulk with each layer. This is why the thickness is dictated and then it’s up to the builder to achieve that thickness.
Most videos I have seen show a roller is used to eliminate air bubbles. Just guessing, but I think air bubbles would reduce strength of the end product. Also, it seems the roller would also roll out excessive resin. So, I am thinking that using a roller would add strength and reduce weight. the roller may also reduce thickness but the reduction would be so small it would not be a consideration. Is this thinking correct, or not? Oh, this is not how I smear cream cheese on my breakfast onion bagel with lox! :¬) Webhead USA
I have experienced if your making a "patch" backing of this size to help fix a hole in your boat, for example. The size of a patch this size would only need what he used to move all the bubbles out between each layer bc it's not that big in size, and you can visible see if there are bubbles. That was my experience. Just trying to help.😊
Thanks for the reply. His 6" x 12" patch size was a test for dimension and weight he could apply to his larger size project. I can't recall if I saw him use the roller on his bigger project. But my question was a general question for the process of glassing. :¬) Webhead USA@@melinda5777
I try to avoid using the roller because it’s a pain to clean afterwards. The brush is disposable so I just squeeze out the excess that way. I have needed to use the roller a few times because I couldn’t get the bubbles out with the brush, but for the most part I have made due with the brush and scraper. My weight came in 6.25% lighter than textbook, so I’m good on weight, just need to get the layer count in for the stiffness.
IMHO, you are absolutely correct. The lamination techniques used in this video were severely flawed. This may have corrupted the results of the "experiment". The techniques shown should not be followed for any structural fibreglass repair or fabrication. Always consult a "subject matter expert" or "qualified person" for instruction how to perform work that can be critical to safety.
You still refuse to use a roller. You can change the thickness by rolling more or less especially when there are more layers. I remember a boat for racing. There, almost half of the polyester was saved with the same amount of fiberglass. The laminate in the hull became lighter and stronger but it was extreme. If you want a stiffer laminate, balsa wood or Divinycell can be used. The fiberglass mats are packed into each other and become more homogeneous through rolling, and the risk of delamination also decreases. When performing, add polyester to the first two layers and roll in the third and possibly the fourth layer without more polyester. On the other hand, epoxy and fiberglass require significantly less rolling. I wish you the best!
I did this with a brush because I did the rest with a brush and wanted to see what my brush results yield. It turns out that my work with a brush is still 6.25% lighter than the textbook standard for fiberglass density. Imagine how light I could make it with a roller!
This was a real-world test of what could be achieved in a garage or backyard build . if you wanted a very specific 'strength to weight ratio' you would do different tests.
Indeed! This is how I built the piece and I want to see how it measures up on this test. If I did the test differently from how I did the work on the piece, it wouldn’t be a very helpful or useful test for me.
I became the owner of a 1977 Pearson 365 back in July 2023. I'm enjoying your channel and videos as I plan my refit to help get my thoughts and plan together! I'm hoping to start a discussion and in no way intend this as a flame and I am not an expert and the years of experience that I had working in the marine realm was also decades ago. I built skiffs for the commercial salmon fishermen for a few years and then worked in both in yards doing repair and some new construction for a few more years while I got an engineering degree. I speak from this experience. I know this comment is long, but the resin, fiberglass and layup schedule are all pertinent and interwoven (yeah, a bad pun.) I didn't see you mention the resin type used, I assume polyester. I also didn't notice the weight of the cloth used. Polyester resin is not a super adhesive, IMO, nor is vinyl ester. Both are good, but not great, depending on the substrate being bonded to. Vinyl ester is a better adhesive than polyester, but not as good as epoxy. Polyester is far and away the most cost effective, but you have to weigh the benefits of the resin choice with the job and you need to make every effort to ensure the resin choice is compatible with the substrate. Neither poly nor vinyl are should be used on an existing epoxy laminate. >> If choosing epoxy, make sure the sizing on the mat, cloth, roving is compatible with epoxy and not only poly or vinyl ester resins.
Thank you for your comment. The main reason for polyester is the Alberg is polyester so we are bonding like to like. Polyester is not a good adhesive which is why we will be creating a massive and drawn out mating surface to bring the two pieces together. The cloth is 1708. I didn’t use any CSM in the test because I wanted to figure out the thickness of the 1708 as it stacked up in the part I’m building. On the actual piece, it goes gelcoat->CSM->1708. There are parts where I added CSM to help with air bubbles that were not leaving or to help soak up resin rich areas, also to smooth the surface if the edges of the 1708 were a bit abrupt. In the part layup, I didn’t count the layers of CSM because I want the thickness to be “greater than” the minimum. By knowing that the minimum is now 8 layers of 1708, having 8 layers of 1708 plus a few layers of CSM means that I’m in the clear and can pop it out of the mold. This is by far the biggest fiberglass project I have ever undertaken and has been a learning experience for me every step of the way. The way I do things now might be different from how I will do things later as I get better or know better. I appreciate your input on the matter :)
If a cubic foot of fiberglass is 96 lbs, a board foot would be 1/12 of that, or 8 lbs. This is really convenient math, so the 96 lbs/sf is most likely an approximation. 16/64 thick fiberglass should weigh around 2 lbs. For you metric people: 1 inch = 2.54 centimeters.
After doing the test, my work came out to be 90 pounds per square foot, about 6.25% lighter than the documentation. The important part is I’m not too worried about the weight, more the thickness per layer.
What thickness do I use? "It depends". Re: metric vs: imperial vs: US. I have come to the conclusion that Metric measurements are designed to "dehumanize" measurements. As you have figured out, metric units don't relate to anything. They especially don't relate to anything human or in a way that humans think. It is possible recognize various metric measurements or sizes. For example just know "that is a 10mm nut". But the more use metric gets the more obscure it gets. Why do we measure snow fall in 100s of mm instead of 10s cm? It seems various official sources use the unit that is the hardest to visualize for any one measurement. Another thing to go away officially soon is the nautical mile. Despite the fact that we all have ten fingers, we do not think in 10ths but rather halfs, quarters, thirds and eights. Funny thing, so do computers which have to do an extra conversion from base 10 to binary and back for every calculation. As for US units, where did the US gallon come from? A gallons is 10 pounds of water but in the US it seems to have been taxed to 8.something or other pounds. Someone is picken someones pocket... It is funny that even looking at the standards metric units are based on, a standard meter is based on light traveling 299 792 458 meters per second.... say what? It couldn't have been 300million meters/second? As if anyone can see how fast light travels or can visualize 300 million meters anyway. I will note that somehow we got people on the moon with only 3 digits resolution, do we really need 9 or more? Yes I live in a "metric" country but we still measure flour in cups or ounces, use "2X4" to build things in 4 inch multiples, talk about how much we weigh in pounds and realize 100mm of snow is about 4 inches or a hand width... A distance is how many steps we take or how many minutes (or hours or months) it takes to get there.... humans don't care how fast we got somewhere or how far away it is so much as the time taken
The US gallon is 8 pounds of water. I noticed that there was a difference when I bought a fuel can in Spain from a British chandler. The jug has L and Gal on it but the marks don’t line up the same as they do on my US jugs. In the US, a 5 gallon fuel jug says 18L on it. The British 5 gallon fuel jugs have the 5 gal line a smidge above the 20L mark because it’s 22L to 5 imperial gallons. Metric makes sense for science reasons since it’s based on water. Volume, weight, lengths, all stem from water. 1g = 1mL = 1cm^3 1cal is the energy to raise 1mL of water 1°C Water freezes 0°C, boils 100°C Then you get into the imperial system and it seems so whacky but it is really practical if you are using the right units for the job. I’m sad to hear that the nm is going away. 6076.12ft = 1nm is such an easy conversion 🤣 The link between 1nm and 1’ of latitude was very useful. 60nm per degree N-S and a fraction thereof for the E-W. It made plotting easier as you could quickly figure your distance and time to arrive with these units. As you said, we don’t care how far it is as much as we care how long it will take to get there.
One small detail to be aware of, Herbie. You made your test pieces by wetting all the layers at once, as opposed to sequentially allowing each layer to polimerize before wetting the next layer . So you used up less resin, meaning your test pieces will be thinner and lighter compared to what you will end up with your project.
This is probably how he achieved 6% lower weight than,spec . but he was also looking to produce a given thickness and he now,know the max layers to achieve the,minimum thickness by this,layup method.
This is the funniest justification of the imperial system i ever heard 😂😂😂. Instead of multiplying the thickness for the number of layers you are going 15 32conds and divide by 3 etc 😅😅😅😅 sorry, maybe its just funny to me. Cheers
@@RiggingDoctor you got me there😅 wait No you didn't lol... because there's nothing wrong with calling an arc degree a Mile its a nice name. The problem arises when a Nautical mile is exactly 1852 meters an English mile is 1,609.3426 a us mile is 1,609.3472 and a Scott mile is 1,807. So, if I'm told without context that something is 10 miles away, i will need to ask, which Mile ? On the other hand a meter is a meter everywhere. 😁 Cheers mate
The metric values are merely *25.4 for mm. I normally use metric but as I said the imperial system lined up perfectly with this test so I used that system instead.
@@RiggingDoctor when I was fourteen I made a nine foot hydroplane from design sold from an ad in the back of a Mechanics Illustrated magazine. I used fiberglass to cover up my very poor carpentry skills. With a ten horse power outboard it would achieve approximately 25 mph. I developed a hate for fiberglass from the itch from sanding.
Haha! It’s a spa/resort in West Virginia that I love going to. It’s called Capon Springs and Farms. If you are ever in the area, I highly recommend going there for a few days. It’s the best!
I didn't weigh my layup using Totalboat 2 to one. Epoxy and bydrectonal 1708 on my half. Inch. Thick. Layups. I did discover. In cooler Wether you can lay up a half inch thickness without. Overhearing. As far as number of layers I lost. Count. But somewhere around 13. I also discovered that it gets a little spongy so perhaps. If you. Break it up into a few. Session with. Cure Time I actually. I think it would. Take fewer layers of glass. just. My observation. All the penetrations.topside.are through. Solid half inch glass Even the port lights. So nothing is going through the plywood core. In fact no penetration is within an inch of the core. Stronger and hopefully no future core. Issues. Time will tell.
Sounds like you are building it the right way. The Landing School in Maine teaches this style of construction. Everything that gets through bolted has the region of the boat converted into a compression ring that will take the load and protect the core.
@@RiggingDoctor I'll be following your build closely. It's funny, when I started doing my refit videos on UA-cam, There was only a few. channels. Now there's quite a few. And people are showing interest. I need to get back to editing I've got. Lots of footage but I've been slacking on getting the videos out.
All you need to do is sand the previous layer to remove any irregularities or strands sticking up and the next layer will go on over it as long as it’s just laminating resin. If you have finishing resin, you will need to scuff it up a bit more to give it more tooth.
I was being funny a bit. But I just did work on the top of my cabin and only put one layer of glass over most of the repair. I was very sick and was rushed at the time. But your whole episode on "layers" has me fearing now. @@RiggingDoctor
To the audience, please be advised that structural fibreglass fabrication and repair can be critical to the safety of the vessel, skipper, crew, and boating community. In my opinion, this video (and series) is riddled with errors, omissions, and flawed technique, that could be harmful to the audience if followed. For your personal safety and the safety of others, please consult a "Subject Matter Expert" or "Qualified Person" before attempting structural fibreglass repair or fabrication.
As I have said in many of these videos, I’m just a cruiser doing work on my own boat, not a professional shipwright! These videos are showing how I have done it so that you can learn from my mistakes and improve the product that you make by doing better than I did.
Please stop presenting your videos as an expert tutorial ("you can", "you should", "it is done like this"). Even your channel titles / branding seems to be presenting your videos as some kind of expert authority. At the very least, start every video with, "I am not qualified in any way to teach others how to do this. What I am doing is could be harmful to me and my loved ones, and you and your loved ones if you try to do it like this. If you are not trained, skilled, and experienced in this type of critical to safety boat fabrication or repair, consult a qualified person before lifting a tool."
@@rodbrandon8598 he has always been that way. not just with fiberglass work, but with other projects and 'advice' videos, even the rigging videos contain misinformation. it is always better to read the instructions or read a textbook than to trust UA-cam. it is likewise just as easy to get absolute crap advice-as-gospel from numerous Old Guys on the dock, or in my case horrible paid work and horrible advice from paid boat mechanics working in the nearby yard (one yard employee even suggested to me, that if I had trouble fitting a hose over a bronze seacock fitting's end barb, that I should simply file the barb down! ludicrous and definitely unsafe! so f*** those "Subject Matter Experts" too!). regardless this channel is still better content than numerous other sailing channels who claim to be college degreed architects or engineers or whatever else, or the numerous other channels who feature bikinis more than brains.
Hi guys long time viewer. You skimmed over the metric & focused on the imperial. Which I see why (because you miss being English 😂) No the formula makes sense but we might of miss another formula. The main thing is you have viewer through out UK Europe & the rest of the world
I normally do my work in metric, but each layers was averaging 1.19mm thick. It wasn’t exact as the test pieces were 1.35mm, 2.54mm, 3.68mm, 5.71mm, and 11.82mm. The imperial system was very helpful as the layers were exactly 3/64, 3/32 (6/64), 9/64, 15/64, 15/32 (30/64). Each layer of cloth added 3/64 of an inch, so the math became much easier to do. From this fraction, you can then switch to mm by *25.4. (3/64)*25.4= thickness in mm I went with imperial because the pattern really showed itself clearly.
I noticed as you were laying up the glass, the resin was greenish, then oranges, then greenish again. Did you use different resins, or was it just lighting?
I had to rebuild my deck because the builder did not use enough cloth when they built my boat because it was built when fibreglass was first being used for boats. When I replaced my balsa core I was told to use 2 layers of (cloth with woven roving bound together). This was 20 years ago and there has been no signs that this was incorrect. My resin & cloth supplier was my source of information for the above. I don't know how this applies to your situation since all your calculations don't involve using a core for additional stiffness without the weight. Have fun laminating 9 layers of cloth.
![Is My Boat Strong Enough to Become Bigger? | Windpuff's Rebuild [S1 Ep 8]](http://i.ytimg.com/vi/CHLfsuOMekA/mqdefault.jpg)
![Is My Boat Strong Enough to Become Bigger? | Windpuff's Rebuild [S1 Ep 8]](/img/tr.png)
My dad had a sample for each of his glass types that looked like a set of stairs. He cut strips that were 5 inches wide at 25" 20", 15", 10", 5" then did the layers to make something he could keep and show to clients for each glass weave. He also did some combinations in a stairstep manner for combinations of glass fabric that he recommended. He drilled a hole in each one and hung it on the wall so people could see them and measure themselves with a set of calipers.
It makes a difference to have a sample that you can touch and feel instead of just looking up information in a table
Great information! Good stuff. In the Age of UA-cam when people do the same old unoriginal boat/fiberglass/reality TV… your content is original, truly informative, and a cut above. Two thumbs up 😁👍 👍
Thank you very much! I can’t say many other channels are undergoing a project like this!
This was a great real-world test for the hand build garage set up of building a major part for a boat.
Nominally 'back in the day' a square foot of fiberglass laminate 1\8" thick was 1 lbs. This became the standard thickness for fiberglass parts ( not necessarily boats ).
This was a simple way to price out a product too as you could compare to 1 lbs of steel or aluminum when costing out a job.
Obviously there are many ways to make it more complicated now!
Cheers warren
It was very enlightening to see first hand how my work measures up. I was then able to extrapolate that data and apply it to the build. It’s how I knew I only needed 8 layers instead of 9. Saved me about 3 hours of labor!
to simplify 1 layer = 0.047 inch OR 1.19mm
Hi I'm in the UK I need some advice I need to make fiberglass sheets there about 2m x 1m and have to be pretty thick as the side to a pond project I'm doing and the pond is in panels for easy to put to gether and dismantle could you advise me on how many sheets you would recommend to use and the grade of fiberglass to use please meny thanks Richard from the UK
There are a bunch of factors that need to be addressed: how big is the pond (what is the total weight of all that water) as well as what is going to be on the other side of the panel?
If this is an above ground pond with air on the other side, then this needs to be treated like a water tank and sized accordingly. If it is in the ground, then the ground will take the strain and the fiberglass simply needs to “seal” so that water can’t escape. In the states, I have seen garbage bags cut open and laid down in sheets to hold water in to make a pond so in ground setups don’t really need strength.
I’m planning to replace the top of an aluminum tube frame “hardtop” with fiberglass (has a stretched vinyl of sorts now). I’m very experienced with polyester resins from doing custom autobody, and interested in your use of same. Would polyester be better than epoxy for my hardtop project? Plan is to use the existing top as a sort of “mold” and remove from underneath. Thanks!
That’s what I would use. Epoxy is so much more expensive and not that much better for boat building than polyester. If polyester wasn’t good for large projects, then boat builders wouldn’t use it to build entire boats!
Epoxy is really good for select projects, but everything else can be done successfully with polyester.
Next I have to determine thickness… 2-3 layers likely should work. Thanks! Keep up the great work!
Verbally at least, you often are conflating stiffness (resistance to deflection) with strength (tensile or compression load before destructive failure). This is very much not the case.
Very true. Stiffness is resistance to bending, strength is compression and tension forces applied to the material.
For this video, I’m only looking at stiffness.
I also vacuum bag glass with a core material to get the most stiffness out of the material. You broke it down to measuring the glass to get the right number of layers well down I learned something every day!
Great info - thanks for sharing!!
It’s a great product to work with!
Great how-to video, really really informative. One quick question - Why aren't you using a vacuum bagging technique? Even with big areas this can help control the amount of resin and get rid of excessive voids.
I don’t have the equipment for it.
That was a reallly interesting test Herby. Like you, I switch between metric and imperial according to which is the most convenient. Of course, the uk didn't go fully metric until I was an adult so Imperial is in my blood so to speak.
Puerto Rico went metric but then partially went back to the imperial.
Speed limit in miles, distance markers in km
Milk by the gallon, fuel by the liter
It’s a jumbled mix in my head as well
Great tutorial
Thank you
It's a very valuable information! Thanks for sharing!
Glad it was helpful!
I was wrong, guess 8 layers isn't half an inch lol! However...I think 10 layers will be good for building a hard bimini on my boat. Hey while you're building it are you going to install the backing plates for any kind of sampson post or attachment point for a drogue system?
10 layers will be really strong, but you should also include some stringers to add additional stiffness to the hardtop.
@@RiggingDoctor good idea
I would consider using a 1\2 or 3\4" foam core between 2 layers of 1708 fiberglass unless you want to have a dance party on top!
Cheers warren
@@Cheers_Warren Cheers!
A "Qualified Person" would likely recommend a cored composite to achieve required strength while reducing weight high in the vessel structure.
SI is soooooo easy to use. I started off schooling in British Imperial and all this messing around with fractions of an inch is crazy. 1/64, 1/16, 1/32, why when the metric sizes are all so consistent. 1000 micron = 1mm, 1000mm = 1m, 1000m = 1km
3/64, 6/64, 9/64, …
1.19, 2.38, 3.57, …
What is the next number for each series? One of these is obvious, the other needs a calculator.
With metric it just goes 1,2,3,4,5,6,7,8 all the way up to 999 If whole units are too much than any fraction that is decimal. What could be simpler?@@RiggingDoctor
@@jonathanwetherell3609The lower set of numbers in his example are metric. You do realize not everything you can measure will fall in a whole number in either system. Hence the decimal points in his metric example. Now figure in your head quickly what comes next like he asked.
Accuracy required varies with the application. Brick layers work to the nearest half brick. Working to a base 10 is the basis of metric. Imperial switches bases all the time base 12, base 3, base 8 (for fractions of an inch). Add in chains, furlongs and miles, perches and poles and we only have linear measure. @@timothyrepp4259
Exactly.
Generally, this is really good information to have but I am missing some important things to this video. What weight of fiberglass material are you using? I've used 3, 4, 5, 7, and 10 oz. material with very different results, especially with the layers you're talking about. Also if one is picky, one needs to add an equally consistent amount of poly or epoxy resin to the layers for that weight. I guess the main thing to get from this video is to run your own tests first, with your material (whatever it is) before embarking on a larger project.
You got it!
I used 1708 from Totalboat. I definitely use too much resin but I did the test pieces the same way I did the hull of the transom extension that way it would be an accurate representation of the weight of my work.
Doing the test yourself is a great way to corroborate how well you are doing when compared to the standards.
Its actually even easier, West has information on the types of glass and thickness wetted out. E.G. 3 layers of 1708 is almost 1/8" One layer os 0.042" been pretty consistent for me.
I wanted to know how thick my actual work was so I did the test even though I found this kind of information online. I just wanted to make sure that my results match what I found online.
There are simple techniques to calculate the amount of materials required to achieve a prescribed thickness regardless what type of cloth or resin is used.
All very basic stuff, but critical to safety in fibreglass repair and fabrication.
For structural fibreglass advice / instruction, consult a "qualified person". (This applies to the video producer too.)
Type and thickness was the fiberglass? The Amazon link dont work anymore.
Thanks for letting me know about the Amazon links, I removed them since they don’t work.
The glass is 1708 from Totalboat and the resin is Polyester from Totalboat as well.
can you test in situ with ultrasound or other non-destructive testing?
That would be cool to do but I don’t have the equipment. I still have the pieces if you happen to have access to an ultrasound device.
Professional wharves often use a vacuum to compress a fiberglas construction while curing. Does this compression affect the thickness and density of the final product?
And how on earth are imperial measurements practial. I am and always will be a metric boy.
Also, I hate to be a pedant but what you were testing was not strength but stiffnes. The two are related but by no means the same.
You are correct in my misuse of strength and stiffness interchangeably. I was only measuring stiffness here and calling it strength.
Vacuum bagging would (I believe) make it a thinner layup because it is compressing the fibers down onto each other. I don’t have the equipment to vacuum bag, so I’m building with hand layup. I did this test to see with the materials I am using and the technique I employ, what are my actual thickness results.
The metric system is great for measuring everything relative to water, but the imperial system is handy when it lines up perfectly with the task at hand.
@@RiggingDoctor
Lets agree to disagree on the imperial thing. I don't think that 0.8 of a mm is too hard to multiply, especially for someone raised in the imperial system.
Good luck with the build, I am eagerly following your progress.
👍
How much resin is there supposed to be; how hard are you supposed to press to leave the right amount of resin?
25oz per yard.
The answer to your question is: I have no idea. I’m not an expert in this and I’m doing this test to see how heavy and how thick does my work come out to be. I definitely use too much resin so I come out on the heavy side but I still ended up at 6% lighter than the textbook weight.
A "qualified person" would know that the "experiment" was flawed because the laminate was not properly consolidated, and the cloth / resin ratio unknown.
Is there a control amount ,Oz of resin per area that is constant .
The cloth is 1708 and it does state its resin amount to be 25oz per yard. I just wet it until it’s all wet and squeeze out the excess.
Ok ,I was thinking did you use a controlled amount per layer that was constant during the whole process.
That would be a better control but not real world conditions.
Good idea for a test! You could as easily use 12/10 mm as 3/64 inches - given this is to the nearest 10th of a mm, as opposed to the nearest 0.2 mm. I wonder if this is a kind of a conformation bias in seeking the US imperial measuring system as the canonical measuring system. :)
I normally use my calipers on metric because it’s easier to follow the decimals, but then I flipped it over to imperial and quickly saw the sequence in the fractions.
This time, the imperial system matched up with the job perfectly!
Ah, forgive my implicitness - it's a bad habit of mine. What I meant was - surely choosing y=6x/5 (representing 1.2 mm) or y=3x/64 (3/64 inches) makes no odds?
Love that you're collecting empirical data to verify this. Just wondering if the hull thickness should be specified in number of layers to begin with, since that's what gives the strength.
I’m using only 1708 for my buildup so the number of layers is straight forward. For big projects, they will use a thicker type of cloth called Roving which will add a lot of bulk with each layer. This is why the thickness is dictated and then it’s up to the builder to achieve that thickness.
Most videos I have seen show a roller is used to eliminate air bubbles. Just guessing, but I think air bubbles would reduce strength of the end product. Also, it seems the roller would also roll out excessive resin. So, I am thinking that using a roller would add strength and reduce weight. the roller may also reduce thickness but the reduction would be so small it would not be a consideration. Is this thinking correct, or not? Oh, this is not how I smear cream cheese on my breakfast onion bagel with lox! :¬) Webhead USA
I have experienced if your making a "patch" backing of this size to help fix a hole in your boat, for example. The size of a patch this size would only need what he used to move all the bubbles out between each layer bc it's not that big in size, and you can visible see if there are bubbles. That was my experience. Just trying to help.😊
Thanks for the reply. His 6" x 12" patch size was a test for dimension and weight he could apply to his larger size project. I can't recall if I saw him use the roller on his bigger project. But my question was a general question for the process of glassing. :¬) Webhead USA@@melinda5777
I try to avoid using the roller because it’s a pain to clean afterwards. The brush is disposable so I just squeeze out the excess that way. I have needed to use the roller a few times because I couldn’t get the bubbles out with the brush, but for the most part I have made due with the brush and scraper.
My weight came in 6.25% lighter than textbook, so I’m good on weight, just need to get the layer count in for the stiffness.
IMHO, you are absolutely correct. The lamination techniques used in this video were severely flawed. This may have corrupted the results of the "experiment". The techniques shown should not be followed for any structural fibreglass repair or fabrication. Always consult a "subject matter expert" or "qualified person" for instruction how to perform work that can be critical to safety.
I figured it out
this guys just here to fill up psych wards
Boaters are crazy!
You still refuse to use a roller. You can change the thickness by rolling more or less especially when there are more layers. I remember a boat for racing. There, almost half of the polyester was saved with the same amount of fiberglass. The laminate in the hull became lighter and stronger but it was extreme. If you want a stiffer laminate, balsa wood or Divinycell can be used. The fiberglass mats are packed into each other and become more homogeneous through rolling, and the risk of delamination also decreases. When performing, add polyester to the first two layers and roll in the third and possibly the fourth layer without more polyester. On the other hand, epoxy and fiberglass require significantly less rolling. I wish you the best!
I did this with a brush because I did the rest with a brush and wanted to see what my brush results yield. It turns out that my work with a brush is still 6.25% lighter than the textbook standard for fiberglass density. Imagine how light I could make it with a roller!
This was a real-world test of what could be achieved in a garage or backyard build . if you wanted a very specific 'strength to weight ratio' you would do different tests.
Indeed! This is how I built the piece and I want to see how it measures up on this test. If I did the test differently from how I did the work on the piece, it wouldn’t be a very helpful or useful test for me.
I became the owner of a 1977 Pearson 365 back in July 2023. I'm enjoying your channel and videos as I plan my refit to help get my thoughts and plan together! I'm hoping to start a discussion and in no way intend this as a flame and I am not an expert and the years of experience that I had working in the marine realm was also decades ago.
I built skiffs for the commercial salmon fishermen for a few years and then worked in both in yards doing repair and some new construction for a few more years while I got an engineering degree. I speak from this experience. I know this comment is long, but the resin, fiberglass and layup schedule are all pertinent and interwoven (yeah, a bad pun.)
I didn't see you mention the resin type used, I assume polyester. I also didn't notice the weight of the cloth used. Polyester resin is not a super adhesive, IMO, nor is vinyl ester. Both are good, but not great, depending on the substrate being bonded to. Vinyl ester is a better adhesive than polyester, but not as good as epoxy. Polyester is far and away the most cost effective, but you have to weigh the benefits of the resin choice with the job and you need to make every effort to ensure the resin choice is compatible with the substrate. Neither poly nor vinyl are should be used on an existing epoxy laminate. >> If choosing epoxy, make sure the sizing on the mat, cloth, roving is compatible with epoxy and not only poly or vinyl ester resins.
Thank you for your comment. The main reason for polyester is the Alberg is polyester so we are bonding like to like. Polyester is not a good adhesive which is why we will be creating a massive and drawn out mating surface to bring the two pieces together.
The cloth is 1708. I didn’t use any CSM in the test because I wanted to figure out the thickness of the 1708 as it stacked up in the part I’m building. On the actual piece, it goes gelcoat->CSM->1708.
There are parts where I added CSM to help with air bubbles that were not leaving or to help soak up resin rich areas, also to smooth the surface if the edges of the 1708 were a bit abrupt.
In the part layup, I didn’t count the layers of CSM because I want the thickness to be “greater than” the minimum. By knowing that the minimum is now 8 layers of 1708, having 8 layers of 1708 plus a few layers of CSM means that I’m in the clear and can pop it out of the mold.
This is by far the biggest fiberglass project I have ever undertaken and has been a learning experience for me every step of the way. The way I do things now might be different from how I will do things later as I get better or know better. I appreciate your input on the matter :)
👍👍👍
😁
If a cubic foot of fiberglass is 96 lbs, a board foot would be 1/12 of that, or 8 lbs. This is really convenient math, so the 96 lbs/sf is most likely an approximation.
16/64 thick fiberglass should weigh around 2 lbs.
For you metric people: 1 inch = 2.54 centimeters.
After doing the test, my work came out to be 90 pounds per square foot, about 6.25% lighter than the documentation. The important part is I’m not too worried about the weight, more the thickness per layer.
I worked out when we were doing our boat 677 grams was equal to 1 mm. I don’t know what that is in ancient measurements.
😂
What thickness do I use? "It depends". Re: metric vs: imperial vs: US. I have come to the conclusion that Metric measurements are designed to "dehumanize" measurements. As you have figured out, metric units don't relate to anything. They especially don't relate to anything human or in a way that humans think. It is possible recognize various metric measurements or sizes. For example just know "that is a 10mm nut". But the more use metric gets the more obscure it gets. Why do we measure snow fall in 100s of mm instead of 10s cm? It seems various official sources use the unit that is the hardest to visualize for any one measurement. Another thing to go away officially soon is the nautical mile. Despite the fact that we all have ten fingers, we do not think in 10ths but rather halfs, quarters, thirds and eights. Funny thing, so do computers which have to do an extra conversion from base 10 to binary and back for every calculation. As for US units, where did the US gallon come from? A gallons is 10 pounds of water but in the US it seems to have been taxed to 8.something or other pounds. Someone is picken someones pocket... It is funny that even looking at the standards metric units are based on, a standard meter is based on light traveling 299 792 458 meters per second.... say what? It couldn't have been 300million meters/second? As if anyone can see how fast light travels or can visualize 300 million meters anyway. I will note that somehow we got people on the moon with only 3 digits resolution, do we really need 9 or more? Yes I live in a "metric" country but we still measure flour in cups or ounces, use "2X4" to build things in 4 inch multiples, talk about how much we weigh in pounds and realize 100mm of snow is about 4 inches or a hand width... A distance is how many steps we take or how many minutes (or hours or months) it takes to get there.... humans don't care how fast we got somewhere or how far away it is so much as the time taken
The US gallon is 8 pounds of water. I noticed that there was a difference when I bought a fuel can in Spain from a British chandler. The jug has L and Gal on it but the marks don’t line up the same as they do on my US jugs. In the US, a 5 gallon fuel jug says 18L on it. The British 5 gallon fuel jugs have the 5 gal line a smidge above the 20L mark because it’s 22L to 5 imperial gallons.
Metric makes sense for science reasons since it’s based on water. Volume, weight, lengths, all stem from water. 1g = 1mL = 1cm^3
1cal is the energy to raise 1mL of water 1°C
Water freezes 0°C, boils 100°C
Then you get into the imperial system and it seems so whacky but it is really practical if you are using the right units for the job. I’m sad to hear that the nm is going away. 6076.12ft = 1nm is such an easy conversion 🤣
The link between 1nm and 1’ of latitude was very useful. 60nm per degree N-S and a fraction thereof for the E-W. It made plotting easier as you could quickly figure your distance and time to arrive with these units. As you said, we don’t care how far it is as much as we care how long it will take to get there.
No chopped strand layers?
1708 has CSM on the underside. Each “layer” is actually 1 CSM, 1 unidirectional fiber, 1 perpendicular direction unidirectional fiber.
One small detail to be aware of, Herbie.
You made your test pieces by wetting all the layers at once, as opposed to sequentially allowing each layer to polimerize before wetting the next layer . So you used up less resin, meaning your test pieces will be thinner and lighter compared to what you will end up with your project.
This is probably how he achieved 6% lower weight than,spec . but he was also looking to produce a given thickness and he now,know the max layers to achieve the,minimum thickness by this,layup method.
This is the funniest justification of the imperial system i ever heard 😂😂😂. Instead of multiplying the thickness for the number of layers you are going 15 32conds and divide by 3 etc 😅😅😅😅 sorry, maybe its just funny to me. Cheers
The imperial system is very quirky while the metric system is completely based around the properties of water.
@@RiggingDoctor and we all love water, based on this alone all sailors should be Metric 😁
Until they want to know how many miles are in a degree of latitude, then they will gladly resort to nautical miles ;)
@@RiggingDoctor you got me there😅 wait No you didn't lol... because there's nothing wrong with calling an arc degree a Mile its a nice name. The problem arises when a Nautical mile is exactly 1852 meters an English mile is 1,609.3426 a us mile is 1,609.3472 and a Scott mile is 1,807. So, if I'm told without context that something is 10 miles away, i will need to ask, which Mile ? On the other hand a meter is a meter everywhere. 😁 Cheers mate
It would be great if you would also write the metric values on the screen so that the rest of the world would also know of what you are talking.
The metric values are merely *25.4 for mm. I normally use metric but as I said the imperial system lined up perfectly with this test so I used that system instead.
I would have performed this the lazy way: fiberglass two sheets, then multiplied.
I wanted to see the difference in stiffness too
@@RiggingDoctor when I was fourteen I made a nine foot hydroplane from design sold from an ad in the back of a Mechanics Illustrated magazine. I used fiberglass to cover up my very poor carpentry skills. With a ten horse power outboard it would achieve approximately 25 mph. I developed a hate for fiberglass from the itch from sanding.
Great job, Master Obi-Wan Kenobi!!! Perfect DIY instructor!! BTW, Congratulations on your RAVENS last night!!! 🤣 ✝️🙏❤️🇺🇸⛵️👣🍍😊
They played amazingly!
Interesting. But, Capon? Castrated rooster? Why?
Haha! It’s a spa/resort in West Virginia that I love going to. It’s called Capon Springs and Farms. If you are ever in the area, I highly recommend going there for a few days. It’s the best!
I didn't weigh my layup using Totalboat 2 to one. Epoxy and bydrectonal 1708 on my half. Inch. Thick. Layups. I did discover. In cooler Wether you can lay up a half inch thickness without. Overhearing. As far as number of layers I lost. Count. But somewhere around 13. I also discovered that it gets a little spongy so perhaps. If you. Break it up into a few. Session with. Cure Time I actually. I think it would. Take fewer layers of glass. just. My observation. All the penetrations.topside.are through. Solid half inch glass Even the port lights. So nothing is going through the plywood core. In fact no penetration is within an inch of the core. Stronger and hopefully no future core. Issues. Time will tell.
Sounds like you are building it the right way. The Landing School in Maine teaches this style of construction. Everything that gets through bolted has the region of the boat converted into a compression ring that will take the load and protect the core.
@@RiggingDoctor I'll be following your build closely. It's funny, when I started doing my refit videos on UA-cam, There was only a few. channels. Now there's quite a few. And people are showing interest. I need to get back to editing I've got. Lots of footage but I've been slacking on getting the videos out.
A qubic foot is 12 inches wide.
Yes it is.
This is 12x6, so all the values get doubled to make it a square foot, then furthered to make it the full cubic foot.
Imperial units is for nerds, the whole world uses de metric system, so much easier!
😂
:)
👍
You can add layers to fiberglass? Oh no.
All you need to do is sand the previous layer to remove any irregularities or strands sticking up and the next layer will go on over it as long as it’s just laminating resin. If you have finishing resin, you will need to scuff it up a bit more to give it more tooth.
I was being funny a bit. But I just did work on the top of my cabin and only put one layer of glass over most of the repair. I was very sick and was rushed at the time. But your whole episode on "layers" has me fearing now. @@RiggingDoctor
One will keep the water out until you feel better and can finish the job :)
lol…. One only need to look at your work to see your full of glass dust.
That’s why I shower after every working period. If not the dust, the smell of the vapors that gets in your hair is aweful
To the audience, please be advised that structural fibreglass fabrication and repair can be critical to the safety of the vessel, skipper, crew, and boating community.
In my opinion, this video (and series) is riddled with errors, omissions, and flawed technique, that could be harmful to the audience if followed.
For your personal safety and the safety of others, please consult a "Subject Matter Expert" or "Qualified Person" before attempting structural fibreglass repair or fabrication.
As I have said in many of these videos, I’m just a cruiser doing work on my own boat, not a professional shipwright! These videos are showing how I have done it so that you can learn from my mistakes and improve the product that you make by doing better than I did.
Please stop presenting your videos as an expert tutorial ("you can", "you should", "it is done like this").
Even your channel titles / branding seems to be presenting your videos as some kind of expert authority.
At the very least, start every video with, "I am not qualified in any way to teach others how to do this. What I am doing is could be harmful to me and my loved ones, and you and your loved ones if you try to do it like this. If you are not trained, skilled, and experienced in this type of critical to safety boat fabrication or repair, consult a qualified person before lifting a tool."
@@rodbrandon8598 he has always been that way. not just with fiberglass work, but with other projects and 'advice' videos, even the rigging videos contain misinformation. it is always better to read the instructions or read a textbook than to trust UA-cam. it is likewise just as easy to get absolute crap advice-as-gospel from numerous Old Guys on the dock, or in my case horrible paid work and horrible advice from paid boat mechanics working in the nearby yard (one yard employee even suggested to me, that if I had trouble fitting a hose over a bronze seacock fitting's end barb, that I should simply file the barb down! ludicrous and definitely unsafe! so f*** those "Subject Matter Experts" too!).
regardless this channel is still better content than numerous other sailing channels who claim to be college degreed architects or engineers or whatever else, or the numerous other channels who feature bikinis more than brains.
Hi guys long time viewer. You skimmed over the metric & focused on the imperial. Which I see why (because you miss being English 😂) No the formula makes sense but we might of miss another formula. The main thing is you have viewer through out UK Europe & the rest of the world
I normally do my work in metric, but each layers was averaging 1.19mm thick. It wasn’t exact as the test pieces were 1.35mm, 2.54mm, 3.68mm, 5.71mm, and 11.82mm. The imperial system was very helpful as the layers were exactly 3/64, 3/32 (6/64), 9/64, 15/64, 15/32 (30/64).
Each layer of cloth added 3/64 of an inch, so the math became much easier to do. From this fraction, you can then switch to mm by *25.4. (3/64)*25.4= thickness in mm
I went with imperial because the pattern really showed itself clearly.
I noticed as you were laying up the glass, the resin was greenish, then oranges, then greenish again. Did you use different resins, or was it just lighting?
@@kennethzielinski6233 the resin was ageing and turning brown as it was getting close to setting.
I had to rebuild my deck because the builder did not use enough cloth when they built my boat because it was built when fibreglass was first being used for boats. When I replaced my balsa core I was told to use 2 layers of (cloth with woven roving bound together). This was 20 years ago and there has been no signs that this was incorrect. My resin & cloth supplier was my source of information for the above. I don't know how this applies to your situation since all your calculations don't involve using a core for additional stiffness without the weight. Have fun laminating 9 layers of cloth.