I used butyl tape to bed all the deck fittings / windows / hatches ( hundreds of bolts) when I refitted my Sealord 39. It does work very well but you do have to go back around and give everything an extra tighten after a while & clean up the excess again. Worth the bit of extra work for a dry boat ! 👌⛵️ Good luck with it
Butyl tape needs compression so is great for hatches, portlights etc where the screws give this compression. Nothing beats butyl for this; it’s cheap, FAR easier to work with than any silicone and lasts…. Not sure, but a LONG time!
100% agree Butyl tape, easy to use, no goey mess and any excess that gets squeezed out you trim off and squash it all into a ball and can use it on the next job, and dose not leak if you tighten everything properly. I use it for everything now, fixings, stanchions, under cleats anywhere that you put a hole in the fibreglass basically.
I’ve done all of my 23 port lights in butyl tape and have no leaks in a heavy blue water ketch. It makes it a dream to repair or replace anything in the future and at $20 per 10 meter roll it is the cheapest sealant that you will find, but it takes technique to properly apply but not rocket science.
Sealants are probably one of the most controversial topics. So far the best sealant I have used is 100% neutral cure silicone. It is durable, bonds well but not too aggressively, does not attack plastics, will not depassivate stainless steel and stays flexible for a long time. I bonded polycarbonate windows to aluminium frames using neutral cure silicone 20 years ago and they have not leaked. I avoid 291i because it is for interior use. I avoid cheap bathroom sealants because they shrink dry, crack and debond easily. I now hate butyl tape as it squeezes out and horribly gums up anything it comes in contact with. For permanent bonding I use any of the high quality polymers suitable for exterior use. These modern polymers however need to be used with care because they will not release.
Sounds like you have tried everything. Thanks for adding your experience. I was under the impression 291i could be used interior and above waterline exterior, as long as there is no UV exposure?
I’ve researched the shit out of this topic 😂 and about to do the same job on our boat. The unequivocal champion per feedback and sciencey tests is to use Dow Corning 795 or 791. It’s a structural building sealant used the world over for glazing. Now called Dowsil. Pain in the arse to get in Gibraltar, but so is everything. I will hang on to get some before doing our fixed windows as I don’t want to be doing the job again anytime soon. Also highly recommended for this job is to use VHB tape to hold the glass/acrylic in place, if you don’t have screws in play.
Was taught to stay away from any silicone sealants when sealing on fiberglass as it contaminates the fiberglass. I use either 3m's 4200 (as for portlights) or 5200 for items of more permanent installs.
Butyl IS the best sealant as far as I`ve experienced. All car winshields use butyl, Even as a loadcarrying part of the body. You can Get it both in a canister for the caulking gun, and in various types of tape. On this type of window I`ll recommend using a tape for instance the with of the glass Renate, and 2-3 mm trick. Rubb the rebate with 80 grit, and wash rebate and glass with acetone. Do not use acetone on acrylics, as this will crack the plastic. Also chamfer all screw holes a little, this will squeze the butyl or mastic around the screw, and make it nice and water tight. Enter the screw without tightening the, and press the window will against the butyl. Press until all the airpockets disappear. Then tighten the screws lightly. You can also use a caulking gun type of butyl, but that takes a lot of masking tape and cleaning. Excess butyl can be removed by carefully cutting along the window Edge with a knife, and pulling the butyl off. It`s easier if you pull «backwards» on the tape, not as when you`re peeling off masking tape. Butyl is the best sealant for all hardware on deck, but should never be left «open,» as it will never harden. I`ve ben using butyl for years, and it has never let me down. With acrylic Windows I use a mastic named CT-1, with Even bones to West surfaces. You should never use silocone products anywhere but in bathrooms!Best of luck, and thanks for a really nice channel!
I have been using Selleys N-Mastic, I'd want to do a test on wood first, it may stain. It's been fantastic on fiberglass and metal fittings, bolt/screw holes, etc. Wipes off easily with white spirit.
Thanks for the suggestion. I've now done the reseal but its great to have suggestions people can see in the comments when they come to do their own. :)
I started but have been rained off. Pouring down the last couple of days (nothing but flood warnings) but getting some interior work done. Its a good thing I'm delayed too, its given a chance on some input. Glad your enjoying it!
Classic case of ‘is the more expensive product actually better??’ I usually err on the side of using the more expensive one because I don’t want to save $10 just to have to re-do the job AND spend the amount for the original product in the end if the cheaper product fails.
I like non-acid tar with filaments mixed in. On land, I'd use plaster of Paris. Silicone will rot any adjacent wood. I don't even use it for bathtub tiles.
Hey I have had problems with aluminum with acrylic hatches 3 goes at one, but now fixed it Silicon was not sticking to acrylic, I found a windscreen kit resealing windscreen that had a primer with matching silicon Works perfectly
There are butyl based sealants available and I rebedded a deck hatch on an old f/g boat. It's a bit messy because it's a lower viscosity to butyl tape, but it will continue to flex with the boat. I find butyl tape is great if it's a fitting held in compression, like the leg of a pushpit. I'd prob bed with butyl sealant then use Evostik silicon frame sealer to cover the outside joint, because the butyl will remain tacky.
Thanks for the advice. I have not come across butyl sealants in tubes or similar over here but think I have enough compression to keep the glass watertight. we will see.
@@theincompetentcrew I've put off refurbishing my window frames and put a fresh coat of clear silicon frame sealer on the outside each spring. Use a plastic blade/profile, not your finger, to give a deeper seal.
When we built boats. We used MMM UV4200 (Not 5200) for hardware. Tried everything on the windows. They were lexan glued in place, no hardware. The best we could find was marine silicon. Sika for windows, fancy multi part process, just failed all over. The marine silicon held. For wood trim to fiberglass? A woodworker used Dolfinite when rebuilding the companionway on my boat. It's not leaked a drop in nearly 20 years now. We had butyl in cases at the boat shop for doing vacuum infusion. Everyone called it Monkey poop. I always wanted to try it for bedding hardware, but didn't feel right experimenting on customer's boats. I guess I should have.
While several commenters suggest butyl, couple things to consider... Is your teak bezel more a decorative trim or does it actually hold the glass firmly and evenly in place? I doubt it'll apply enough even pressure for a good seal with butyl. Also, there's butyl tape and there's butyl tape, if you're not familiar with it, then perhaps best to avoid. Butyl's great for big hatches with screws every few inches that'll be removed and rebedded occasionally. Use a proper marine grade sealant designed for the elements for your job. Please don't cheap out and use silicone on a boat.
Hi, thanks for the advice. A few years ago in the USA we learned there is 'Butyl tape' and there is 'Butyl Tape' with an RV when redoing the roof and window. The cheaper was garbage and in the end thrown away, the latter premium brand worked well. The teak frame clamps the glass into place, but I would be hesitant to overtighten the screws to apply a lot of pressure as its quite a delicate frame with screws around every 8".
@@theincompetentcrew that's kinda what I figured and you'll need sealant for the trim screws. The teak should be adequate to hold the glass in place until she cures it also shields the sealant from UV damage. Remember, silicone sealant requires oxygen and moisture to kick off, so don't be so quick to jam the portlight on
I'm also in the butyl camp- if you can get it. I really have a hard time with adhesive sealants when I have to do a modification or repair. That being said, I've just about anything non silicone that a local hardware store had on hand. I just try to avoid adhesives as sealants.
Possible aspect to consider: use a material with anti-bacterial content, regardless of which product. Normal household silicon doesn't have that, whereas silicon for wet-rooms/bathrooms usually does. My current information: Sikaflex does, Dow Corning does, don't know about butyl or butyl tape, I suspect not, but I personally would check the component/ingredient list to make sure. If not, I personally would stay away from it, unless you're boat is only on the water for a few months in the summer. Even minimal bacteria buildup, especially on the inside of windows, hatches etc, can be a health risk. To be clear, that's a tip I got from someone I trust (a professional carpenter who, believe it or not, also has a degree in biology which she decided not to pursue). I am not a doctor, so can't claim to know how accurate that information is, but sounds right to me and influenced my personal choice.
@ 5200 is fantastic if you want to permanently glue something in place. But once glued, you will never be able to get it off without destroying it. You can try heating it with a heat gun, which helps, but. If you glue your port lights in with that stuff, be prepared to replace them if they ever start to leak again. The nickname for 5200 is the Devil’s glue.
Hi Steve, I have heard a lot of people talk of the 3M 5200. Never Owned any / used myself. I've been told it is about as permanent an adhesive as you can get, but don't use it if there is a chance you will have to remove the thing again. I will have a look at SV Seeker. Thanks
5200 is very similar to sika 291, they are both good at first but as the solvent dries over time and the silicone shrinks it splits off from the surface allowing water to seep in
As a non-boater/sailor, just an electrical engineer/romantic boat observer, I was thinking there was something less hard core than the 5200, so perhaps Ben can give the 4200 a go. Looks like butyl could be a winner, but I am curious, this boat is what, 30-40 years old plus - so how did the original sealant last so long? What was the original method?
Thats something I'd be interested to know myself. As the teak expands and contracts a little and with its oiliness, my worry would be it failing earlier. So far I have used stronger sealants (Sika 291 and deck caulk) to get a more adhesive grip under deck fittings.
I used butyl tape to bed all the deck fittings / windows / hatches ( hundreds of bolts) when I refitted my Sealord 39. It does work very well but you do have to go back around and give everything an extra tighten after a while & clean up the excess again. Worth the bit of extra work for a dry boat ! 👌⛵️ Good luck with it
Thanks for your input.
Butyl tape is probably the best sealant for windows. Bill
Probably the best suggestion I had forgotten about the existence of. Easier to remove the next time around as well.
@@WilliamBell-t8k use both!
Butyl tape needs compression so is great for hatches, portlights etc where the screws give this compression. Nothing beats butyl for this; it’s cheap, FAR easier to work with than any silicone and lasts…. Not sure, but a LONG time!
@@sailinghjem I am being swayed to the Butyl. :)
@@theincompetentcrewon my way to the chandlery this arvo to get me some of this Butyl stuff having seen this 😂 🤝 good luck with it all brother
100% agree Butyl tape, easy to use, no goey mess and any excess that gets squeezed out you trim off and squash it all into a ball and can use it on the next job, and dose not leak if you tighten everything properly. I use it for everything now, fixings, stanchions, under cleats anywhere that you put a hole in the fibreglass basically.
Seems I may be going for butyl
I’ve done all of my 23 port lights in butyl tape and have no leaks in a heavy blue water ketch. It makes it a dream to repair or replace anything in the future and at $20 per 10 meter roll it is the cheapest sealant that you will find, but it takes technique to properly apply but not rocket science.
thanks for your input. :)
Sealants are probably one of the most controversial topics. So far the best sealant I have used is 100% neutral cure silicone. It is durable, bonds well but not too aggressively, does not attack plastics, will not depassivate stainless steel and stays flexible for a long time. I bonded polycarbonate windows to aluminium frames using neutral cure silicone 20 years ago and they have not leaked. I avoid 291i because it is for interior use. I avoid cheap bathroom sealants because they shrink dry, crack and debond easily. I now hate butyl tape as it squeezes out and horribly gums up anything it comes in contact with. For permanent bonding I use any of the high quality polymers suitable for exterior use. These modern polymers however need to be used with care because they will not release.
Sounds like you have tried everything. Thanks for adding your experience. I was under the impression 291i could be used interior and above waterline exterior, as long as there is no UV exposure?
Butyl tape is my 1st choice, its dry and can even be reused if compromised. Ive also used seal leaky pipes
another vote on butyl. Thanks :)
I’ve researched the shit out of this topic 😂 and about to do the same job on our boat. The unequivocal champion per feedback and sciencey tests is to use Dow Corning 795 or 791. It’s a structural building sealant used the world over for glazing. Now called Dowsil. Pain in the arse to get in Gibraltar, but so is everything. I will hang on to get some before doing our fixed windows as I don’t want to be doing the job again anytime soon. Also highly recommended for this job is to use VHB tape to hold the glass/acrylic in place, if you don’t have screws in play.
Was taught to stay away from any silicone sealants when sealing on fiberglass as it contaminates the fiberglass. I use either 3m's 4200 (as for portlights) or 5200 for items of more permanent installs.
Good rec!
Butyl IS the best sealant as far as I`ve experienced. All car winshields use butyl, Even as a loadcarrying part of the body. You can Get it both in a canister for the caulking gun, and in various types of tape. On this type of window I`ll recommend using a tape for instance the with of the glass Renate, and 2-3 mm trick. Rubb the rebate with 80 grit, and wash rebate and glass with acetone. Do not use acetone on acrylics, as this will crack the plastic. Also chamfer all screw holes a little, this will squeze the butyl or mastic around the screw, and make it nice and water tight. Enter the screw without tightening the, and press the window will against the butyl. Press until all the airpockets disappear. Then tighten the screws lightly. You can also use a caulking gun type of butyl, but that takes a lot of masking tape and cleaning. Excess butyl can be removed by carefully cutting along the window Edge with a knife, and pulling the butyl off. It`s easier if you pull «backwards» on the tape, not as when you`re peeling off masking tape.
Butyl is the best sealant for all hardware on deck, but should never be left «open,» as it will never harden.
I`ve ben using butyl for years, and it has never let me down.
With acrylic Windows I use a mastic named CT-1, with Even bones to West surfaces.
You should never use silocone products anywhere but in bathrooms!Best of luck, and thanks for a really nice channel!
A lot of butyl recommendations! Trying to locate it in southern Spain is a different issue, apparently :) but I’m in search now. Thanks for the input!
I have been using Selleys N-Mastic, I'd want to do a test on wood first, it may stain. It's been fantastic on fiberglass and metal fittings, bolt/screw holes, etc. Wipes off easily with white spirit.
Thanks for the suggestion. I've now done the reseal but its great to have suggestions people can see in the comments when they come to do their own. :)
I’m literally about to attempt this myself on my lil 5 meter Yorkshire Pebble! 😅 man I’m loving my new favourite channel 🤗✊🤝
I started but have been rained off. Pouring down the last couple of days (nothing but flood warnings) but getting some interior work done. Its a good thing I'm delayed too, its given a chance on some input. Glad your enjoying it!
@ shame about the weather brother- we have a fortnight of dry weather down ere in Cornwall ( apparently 😅 )
Classic case of ‘is the more expensive product actually better??’ I usually err on the side of using the more expensive one because I don’t want to save $10 just to have to re-do the job AND spend the amount for the original product in the end if the cheaper product fails.
Can I not just be cheap though?
I like non-acid tar with filaments mixed in. On land, I'd use plaster of Paris. Silicone will rot any adjacent wood. I don't even use it for bathtub tiles.
Thanks for the input 😁
Hey
I have had problems with aluminum with acrylic hatches
3 goes at one, but now fixed it
Silicon was not sticking to acrylic, I found a windscreen kit resealing windscreen that had a primer with matching silicon
Works perfectly
Thats a nice little tip. Good work around.
There are butyl based sealants available and I rebedded a deck hatch on an old f/g boat. It's a bit messy because it's a lower viscosity to butyl tape, but it will continue to flex with the boat. I find butyl tape is great if it's a fitting held in compression, like the leg of a pushpit. I'd prob bed with butyl sealant then use Evostik silicon frame sealer to cover the outside joint, because the butyl will remain tacky.
Thanks for the advice. I have not come across butyl sealants in tubes or similar over here but think I have enough compression to keep the glass watertight. we will see.
@@theincompetentcrew I've put off refurbishing my window frames and put a fresh coat of clear silicon frame sealer on the outside each spring. Use a plastic blade/profile, not your finger, to give a deeper seal.
When we built boats. We used MMM UV4200 (Not 5200) for hardware. Tried everything on the windows. They were lexan glued in place, no hardware. The best we could find was marine silicon. Sika for windows, fancy multi part process, just failed all over. The marine silicon held. For wood trim to fiberglass? A woodworker used Dolfinite when rebuilding the companionway on my boat. It's not leaked a drop in nearly 20 years now. We had butyl in cases at the boat shop for doing vacuum infusion. Everyone called it Monkey poop. I always wanted to try it for bedding hardware, but didn't feel right experimenting on customer's boats. I guess I should have.
Thanks for your input, I hadn't come across Dolfinite before, or hadn't noticed it. Either way, another compound worth looking into. thanks
While several commenters suggest butyl, couple things to consider... Is your teak bezel more a decorative trim or does it actually hold the glass firmly and evenly in place? I doubt it'll apply enough even pressure for a good seal with butyl. Also, there's butyl tape and there's butyl tape, if you're not familiar with it, then perhaps best to avoid. Butyl's great for big hatches with screws every few inches that'll be removed and rebedded occasionally. Use a proper marine grade sealant designed for the elements for your job. Please don't cheap out and use silicone on a boat.
Hi, thanks for the advice. A few years ago in the USA we learned there is 'Butyl tape' and there is 'Butyl Tape' with an RV when redoing the roof and window. The cheaper was garbage and in the end thrown away, the latter premium brand worked well. The teak frame clamps the glass into place, but I would be hesitant to overtighten the screws to apply a lot of pressure as its quite a delicate frame with screws around every 8".
@@theincompetentcrew that's kinda what I figured and you'll need sealant for the trim screws. The teak should be adequate to hold the glass in place until she cures it also shields the sealant from UV damage. Remember, silicone sealant requires oxygen and moisture to kick off, so don't be so quick to jam the portlight on
I have used CT one £14 it hasn't shrunk, works below the waterline and cures at a lower temperature than silicone
Thats a second mention for CT1
I'm interested to see what you find works best, I'll be watching the next vid for sure
I might split the sealants over a few different windows and see what happens. Thanks for commenting.
I'm also in the butyl camp- if you can get it. I really have a hard time with adhesive sealants when I have to do a modification or repair. That being said, I've just about anything non silicone that a local hardware store had on hand. I just try to avoid adhesives as sealants.
Butyl is a popular recommendation for sure! We’re having a hard time finding it in southern Spain. Wonder how resistant to heat it is..
@@theincompetentcrew 300F is the spec. I haven't used it for engine stuff, but most everything. the cleanup and prep are also pretty nice
Possible aspect to consider: use a material with anti-bacterial content, regardless of which product. Normal household silicon doesn't have that, whereas silicon for wet-rooms/bathrooms usually does. My current information: Sikaflex does, Dow Corning does, don't know about butyl or butyl tape, I suspect not, but I personally would check the component/ingredient list to make sure. If not, I personally would stay away from it, unless you're boat is only on the water for a few months in the summer. Even minimal bacteria buildup, especially on the inside of windows, hatches etc, can be a health risk.
To be clear, that's a tip I got from someone I trust (a professional carpenter who, believe it or not, also has a degree in biology which she decided not to pursue). I am not a doctor, so can't claim to know how accurate that information is, but sounds right to me and influenced my personal choice.
Seems sound to me too!
Butyl tape is best. Silicone will always fail and nothing will stick where it used to be. 5200 has no place on a boat.
Sounds like you had a bad experience with 5200. Can you elaborate?
@ 5200 is fantastic if you want to permanently glue something in place. But once glued, you will never be able to get it off without destroying it. You can try heating it with a heat gun, which helps, but. If you glue your port lights in with that stuff, be prepared to replace them if they ever start to leak again.
The nickname for 5200 is the Devil’s glue.
@@rickedwards7276 Thanks for the reply. Probably saved me from an expensive mistake.
Hi Ben, no experience of this, but the SV Seeker fellow once recommended using "3m marine adhesive sealant 5200" on his boat
Hi Steve, I have heard a lot of people talk of the 3M 5200. Never Owned any / used myself. I've been told it is about as permanent an adhesive as you can get, but don't use it if there is a chance you will have to remove the thing again. I will have a look at SV Seeker. Thanks
5200 is very similar to sika 291, they are both good at first but as the solvent dries over time and the silicone shrinks it splits off from the surface allowing water to seep in
As a non-boater/sailor, just an electrical engineer/romantic boat observer, I was thinking there was something less hard core than the 5200, so perhaps Ben can give the 4200 a go. Looks like butyl could be a winner, but I am curious, this boat is what, 30-40 years old plus - so how did the original sealant last so long? What was the original method?
I like 3M 5200
I can recommend Butyl tape….ive gained some instant wisdom by reading the comments 😉
You and us both 😁
I tell you what I have used but it’s a bloody expensive way of doing it is Liquid marine electrical tape! 😂 I’ll let ya know how well it does! 🙃
I need to get some of that for its more regular use!
For Port Light hatches Sashco Lexel is awesome, could be used widely above waterline
Other bedding 3M 4200
I haven't heard of Sashco Lexel. Are you US based? Thanks for the suggestion. :)
@@theincompetentcrew I"m trying to refit to escape the USA
@@EngineerSailing Seems we are all trying to refit to escape our respective countries. :)
Use CT1
I'll have a quick google for it. Thanks
You can get sikaflex 291 cheaper than that , and don,t they do a primer for glass ?
Ah really! I need to be buying it where you are 😁 how much does a tube cost for you?
Does Butyl seal hardware on teak decks?
Thats something I'd be interested to know myself. As the teak expands and contracts a little and with its oiliness, my worry would be it failing earlier. So far I have used stronger sealants (Sika 291 and deck caulk) to get a more adhesive grip under deck fittings.
@@theincompetentcrew Yes Butyl tape stays in a constant state of flex, think of it like tar, but fairly easy to work with and no mess.
@@timwhitrow7975 pretty much. I've got 50 year old butyl and it's still not crispy
butyl
Seems to be a popular opinion 😁