@@AutoExpertJC I reckon you’re all right John. You’re a bit like the Carborundum disc. You slice through all the shit but you never end up full of it. 😉👍
Im a pretty competent backyarder. I like your vids, so I started out thinking this is going to be a bunch of crap I already know and dont need. You certainly changed my POV very quickly. Nice, clear, concise (and entertaining as usual), well done John
No worries Phil. I started on the tools at 15 years old mate - I haven't talked about it much, but I'm going to. There's a ton of stuff like that, which most people don't know.
Yep, it is great knowledge, even a reminder as we all get a tad lazy sometimes, and get the first disk you see rather than looking that little bit longer.
Few cents worth from a metalworker and knife maker Mostly it comes down to velocity of your sanding, if you're running an angle or belt grinder, doing it by hand or a slow speed linisher or disc sander Scale and welding shmoo- wire bush will save you a lot of pain, wear gloves, apron and face mask as they will also cause you a lot of pain! Aluminium Oxide- slow speed machines and hand sanding, mostly for wood but at the higher grits the Al-Ox is quite good on non hardened metals as it breaks down into finer particles which in turn give you a nicer finish. It wears out quicker than a politicians promise so buy a lot of it, it is also very cheap Zirconium is a machine abrasive, usually between 40-120grit and will work well on either metal, hardened metals and wood- just adjust your speed to suit the material. Its in the between for Al-Ox and Ceramic for a price point and also has much better wear resistance than Al-Ox Silicon Carbide- a hand sanding or very slow machine speed, comes in the very high grits and is used for finishing metals. Typically between 80 and 8000grit for the very high polished look. It does wear and cut comparatively quickly and shop around for the most reasonable price point. That may lead you back to Al-Ox for the 40-600grit in some cases being better value Ceramic is a specialist machine abrasive, you must run this fast and use light to moderate pressure when grinding metals- typically hardened metals and annoying things like stainless and titanium. Its expensive, its worthless at slow speeds and will fracture during use which is self-sharpening and gives it a very long cutting cycle A couple not discussed- Unstructured Abrasives, usually used in round discs, hand pads and belts, its often Al-Ox or Sil-Carbide mixed in with a loose, strong, wooly material that looks and feels like a dish scrubber. Goes by the name Scotchbrite or some others. It comes in Brown (heavy cut-around 80-120g), Red (medium- 150-180g) Blue (fine- 240-320g) and Grey (super fine 500-600g) and gives a wonderful scratch finish when used in conjunction with one another. Run them slower end of the spectrum and they are expensive Structured Abrasives Mostly found on belts but sometimes discs, these are a specially made compound of of Al-Ox made for machine use that is specifically for hardened steels and difficult stainless finishes. They look like lots of blunt rectangles on the surface and run them in the low-middling speeds for best results. Come in their own micron codes which roughly translates to 80-800grit, they do last nearly forever and if they get a bit glazed you can clean them with slow-speed and just run a steel brush over them to perk them up again. Edit- they are also horrendously expensive so make sure you know what you're getting into before laying out the cash
@@ScottMurrayBestFamilyCars Yeah we got anglo'd in the early 1900's immigration moving here from Prussia so no one wanted to spell Stahl. In a funny sort of way, I'm probably better qualified on telecommunications systems but that's a whole other story.
Very informative. Useful for nerds like me who stand in Bunnings on Saturday morning staring blankly at the wall of sandpaper wondering what to choose for my weekend project. Also can I just take a moment to appreciate that shirt? Very clever.
@@AutoExpertJC I also noticed that - and I know that views are the name of the game but I think this has a great deal of value and I'd hope that if it became a series it would gain a bit more of a viewership. It certainly deserves more views than its had to date.
This was a really informative segment. It was fun to learn about the physics and chemistry of the various materials and that is something missing on other channels. I hope your regular viewers encourage you to do more segments like this because they do fill a niche that has not yet been addressed. Good stuff Dude...
I work in metal fabrication, my place of employment uses a sand blaster with metal granules to remove mill scale and a finishing mechine with media pebbles as more gental to remove mill scale and wont leave any scratchs on the metal surface, Its more cost effective in the long run then using buff pads, except for starter up costs in buying the equipment, usually I grind off excess material with the regular grinding discs then finish of with the sanding pads.
Thanks for this one mate. I was already aware that the brown ones were emery, blue zirc, red ceramic and the wet and dry was silicone carbide. I hadn't put 2 and 2 together to notice that that was always the case though. I just recognised that in the brands that I buy that's the colours they used for those products. Not colour = material. I'd also already worked out the hard way that zirc discs are no good on mill scale, I haven't found a good use case for ceramic discs yet, but am a fan of them in belt form. Usually for mill scale I just go at it with the emery hard grinding disc and then clean up the gouges after with the soft emery or zirc. Getting that nugget of wisdom re the concrete discs though, that's brilliant. I mean, it's obvious now you point it out but 20 mins ago I had no idea. As I said before, thanks mate. Much appreciated.
Grinding wheel colours in the machine shop: Carborundum - grey, Silicon carbide - green , Aluminium oxide - white, blue, grey, Diamond - charcoal. Most grinding wheel types are made in different degrees of hardnesses which is governed by the bonding material. Generally soft wheels are used for hard material and hard bonded wheel are used for soft material regardless of grit type or size. The easiest way to get rid of mill scale is to purchase bright steel in the first place, the scale is removed at the steel plant by pickling in acid. Bright steel is coated with a light grease to prevent rusting and in turn makes for messy handling. Cheers
Love your work John, was briefly trying to explain this subject to a friend the other day, admittedly not in as much detail and while taking the ultimate lazy approach to mill scale banishment good old acid & suitable safety equipment. (on a side note kiddies if it eats the scale & will happily devour the metal your removing it from given enough time, then your little fingers certainly ain't going to be any form of notable challenge for said product to dissolve. Do it safely I Can not stress that enough there is no need to take silly risks using an easy shortcut & always wear a suitable breathing apparatus. ) Besides that grinding stuff just looks like hard work, a little bath for the material a quick coldie for me. Some minutes later after a little rinsing & the added benefit of being less parched for it. Certainly works well for me when the opportunity affords such laziness.
Really helpful John. I'm a blacksmith/farrier and we end up with a ton of scale on a horseshoe. At farrier competitions we I forced to be luddites and use a hot rasp to safe of edges and whatnot, but in the field will use either a linisher or an angle grinder to do that. We generally use Zirc, but going to have a bit of a play with some of the others. Thanks, great content 👍👍
Hi John, you forgot to mention that angle grinders were invented so orthopedic surgeons could pay for their daughter's annual swiss ski trips. We've got quite a collection of the DIY disaster pictures when angle grinders attack human flesh in my ED, quite sobering when you see a 60 year old who has managed to cleave his face in two through his nose and skull from one.
Great vid John. For big stuff that'd take forever or small intricate stuff with tight corners that a grinder won't get into, sandblast it. Buy a cabinet if you can justify the expense or for big stuff, take the job to a sandblaster.
Great tips John👍 I’ve worked as metal fabricator most of my working life and never considered using a masonry grinding disc for mill scale, I’ll certainly be giving it a go in future. As an engineer I’d imagine you’d know that there’s no such grade as “mild steel”. A cert 4 teacher I once had advised our class never to use that term in an exam because it’s not listed in any standards and you’ll loose marks if you do. I’m guessing you use the term to describe low carbon steel ?
Fantastic informative explanation, I guess we glossed over this in Electronic engineering, I often wondered what the color disks were. Time to buy a couple of new ones, green I think. Thanks John.
Walter Flexcut Mill Scale, best grinding disc I’ve used for mill scale, Suhner magic disc is unbelievable on stainless steel. Flexovit on everything else! I’m going to try those concrete grinding ones I’ve never heard this tidbit!!
Hi John, I am a little confused with your "blue" colour designation. To my $4,000 OLED monitor everything you said was blue was actually green, and the contrast was very clear when looking at the belt sanding media in the bottom right of the screen. The one on the extreme right is definitely Blue, and just to the left of it is a belt that is definitely green - but the same colour as you described as "blue" for the Silica Ceramic Alumina discs in the presentation? So which is it "Greeny-blue" that you call green or "Green." Also, what is the material very blue belt sanding media?
I've tested quite a few abrasives with industrial sanders - thought I'd mention ceramics don't do well with softer materials (hardwoods, composite) either. The grains don't break off, just round and glaze over.
Thanks for this vid. As someone who is starting out trying to learn how to weld (for home hobby stuff), I have been floundering in which abrasive was best for cleaning up the job prior to welding, and which is best for cleaning up my shitty welds once I am done. This has helped me get a better understanding of some of the differences. Now to learn to weld better so I don't need as much grinding at the end :)
Great video, we need more of this. BTW, I am sure you are working on some projects in the Fat Cave. How about some videos on the Projects you may have on the go.
Good video, and informative. What type of disk works best for grinding out porosity in a hot weld? At my work, we have access to the ceramic disks, but they don't last long when you put them to a red hot weld that is full of porosity.
my last gig in a panel shop as a TA, pretty much consisted of taking the scale off new truck bodys for paint prep. i never really took much note of the colours, i find it interisting learning about the diffrent meterals. the layered flat disk i called slappers, no ming moles in the panels shop just good old slappers. hahaha I mainly used the disks that look like there made from a bath loofah, if i remeamber right both disks where black. so i would remove all the scale then sand with 80 grit , mask up and prep wash. riveting times. so what are the white sand papers and sanding disks made off ?
@@AutoExpertJC yeah they did , i disk per body / trey , back in them days it was still 9 inch grinders, sanders , buffs etc. all meterals would of been worked out on cost.
@@AutoExpertJC just cuts bruises burns , guess i got lucky. some pretty sketchy stuff back in the day. well i have to run a combustion motor at max rpm and chop stuff with blades, yeah i better mow the lawn.
If you have time, a trick for loosening up mill scale is to leave the part in a damp place for a while (a few weeks). The moisture will cause the steel to rust under the mill scale, making it flake off. It's then easy to clean up with a sanding disc/flap wheel. Obviously this is more appropriate if you purchase your stock in advance of actually needing it.
As a future prime mincer, you sure know how to grind the opposition down and without help from Rupee. While we are at it, I have a lot of work with aluminium...what do you reckon I should use? I guess aluminium oxide is a bad choice so perhaps Zirc or should it be silicon carbide?
I have learnt a heap. Quite a bit I sadly didn’t know even though I have been working with metal for 30 years. However if paint is part of the future for a piece of metal I still much prefer to get things sand blasted and powder coated.
Is there a safe way to lift my vehicle up so I can fix my front bumper's bottom lip that has scrapped against high kerb? I would like to sand and repaint the bottom lip.
Blimy those Zirconium flap discs are expensive in Australia, I pay the equivalent of of 2.87 Australian Dollars including VAT here in the UK I can get the cheap Chinese ones for 1.66 Australian dollars. Sold for finishing Stainless steel. But I use them for everything, never had clogging problems except with painted materials, the way the flaps wear means that there is always fresh cutting surface .
Citric acid removes mill scale really well, you just need to immerse it for a few hours. One tub from the supermarket to 2 litres of water seems to work well.
Super informative, thanks JC!! Btw isn’t your mitre/compound mitre saw heavy for wall mounting? I’ve got a Bosch 10in sliding compound and that sucker is crazy heavy. Great tool mind you.
as a retired furniture maker who has done a fair bit of sanding, the big rookie mistakes i see with people using a sander, is pressure and speed. basically the weight of the sander is all the pressure you need. movement along a piece is about i inch a second. doing this you will cut your sanding time down and result in a better finish.
Where did you get your "stay at home, wear a mask" nerd shirt? I need one of those to go with my "there are only 10 types of people, those who understand binary and those who don't" nerd shirt.
259km/hr (72m/s) but who's counting. Great preso - I never knew that about SiC and mill scale - very happy to now know. Have you tried pickling your mill scale first to remove it?
Mill scale? - Muriatic acid - Put a gallon of water in a plastic tub, (with a lid so yo can leave it out in the rain) Dump in a gallon of Muriatic acid . Put the parts in the solution and go do something else for a couple hours, Come back and fish the parts out with a pair of plastic tongs and hose them off and squirt them with WD,,,,, Pickled and oiled steel right in the yard behind the shop.
No. Cubitron is a man made pyramid shaped abrasive. Standard sand/aluminium/carbide is a mineral/rock shaped abrasive. Hundreds of jagged points instead of 1.
@@janeblogs324 Yeap, hence my saying that from memory it was similar to ceramics…, there was a brand of ceramic from memory that was synthetic like Cubitron.. Certainly Cubitron was in a completely different class…, if I ran a fab shop etc I would just use 3M… I sold it& used it…. My customers always reduced they effort, time & costs… i didn’t actually sell it.., I really only demo it…
Great video. Things here I never learned in "Engineers" school. I think I must be colour blind as your BLUE discs really look GREEN to me. Is this just a blue variant? or am I missing something?
Many thanks for the abrasive info. I knew they were different but not why. In amongst you usual content please include such general engineering practices from time to time. Start educating us a bit a a time
Bloody good John…..!!! Interesting though wouldn’t you think that in the event all the different meanings of these colour codes are news to so many of us wouldn’t you think that’s a huge marketing fail on the companies who are trying to sell them…???? All of that was news to me other than there were obvious differences in grit and robustness but not down to that detail Surely they should be explaining this much better in their marketing…? Comparatively I feel as though I know more about tampons based on the TV ads alone…..
And cause grinding is a 💩 bag of a job, it’s hot , dust n noisey , the quicker n easier you get it do the better.., one of the most rewarding places in a w/ shop to spend your $ is on abrasives…
@@AutoExpertJC Cool, sorry I haven’t had a chance to watch yet.., Have you heard of it.., they’re synthetically grow crystal/ abrasive grains that are exactly the shape 3M want.. rather than crushed random shapes….cuts like it made with thousands of milling cutters on the surface.. truely amazing …
Sweet, I’m sure others do it now.. it was 10 + years ago I was selling it.. Nucon we’re grinding back their w316 weld repaired rotors.., 1 off 5” P40 cubitron fibre disc replace 8 off 5” dressed centre wheels.., 3 M do a ventilated backing disc to go with them…., they were $3 a disc , twice cost of a dressed centre…, but man.. The grain were applied electrostatic-ally to the backing… so all the tip/ points were sticking out n cutting…, no sore forearms….
Some would argue that you're one of Australia's great abrasives, John.
On a serious note, I enjoy this style of video.
A bit rough 😂
That's true, Tone. I'm certainly not in the appeasement business.
@@AutoExpertJC But worth the price of admission.
@@AutoExpertJC
I reckon you’re all right John. You’re a bit like the Carborundum disc. You slice through all the shit but you never end up full of it. 😉👍
Im a pretty competent backyarder. I like your vids, so I started out thinking this is going to be a bunch of crap I already know and dont need. You certainly changed my POV very quickly.
Nice, clear, concise (and entertaining as usual), well done John
No worries Phil. I started on the tools at 15 years old mate - I haven't talked about it much, but I'm going to. There's a ton of stuff like that, which most people don't know.
Yep, it is great knowledge, even a reminder as we all get a tad lazy sometimes, and get the first disk you see rather than looking that little bit longer.
This is great. I would love to see a video on drills and drilling and sharpening drill bits
Sure - will do.
Me too
Love the shirt, John. Took me a minute to get what it meant, but I got a good chuckle once the penny dropped. :-)
I had to have it the moment I saw it.
Ditto, dude.
Richard Kaz, your ‘ip v6’ translation was the best👍
I never thought it could be explained so simply. Funny how I know what I know but it takes someone else to explain it to me. Cheers.
Explaining techo things is hard - you have to make it relatable.
@@AutoExpertJC I think that's a point some of my uni lecturers miss. I've gotta dumb it down for myself to understand it.
Few cents worth from a metalworker and knife maker
Mostly it comes down to velocity of your sanding, if you're running an angle or belt grinder, doing it by hand or a slow speed linisher or disc sander
Scale and welding shmoo- wire bush will save you a lot of pain, wear gloves, apron and face mask as they will also cause you a lot of pain!
Aluminium Oxide- slow speed machines and hand sanding, mostly for wood but at the higher grits the Al-Ox is quite good on non hardened metals as it breaks down into finer particles which in turn give you a nicer finish. It wears out quicker than a politicians promise so buy a lot of it, it is also very cheap
Zirconium is a machine abrasive, usually between 40-120grit and will work well on either metal, hardened metals and wood- just adjust your speed to suit the material. Its in the between for Al-Ox and Ceramic for a price point and also has much better wear resistance than Al-Ox
Silicon Carbide- a hand sanding or very slow machine speed, comes in the very high grits and is used for finishing metals. Typically between 80 and 8000grit for the very high polished look. It does wear and cut comparatively quickly and shop around for the most reasonable price point. That may lead you back to Al-Ox for the 40-600grit in some cases being better value
Ceramic is a specialist machine abrasive, you must run this fast and use light to moderate pressure when grinding metals- typically hardened metals and annoying things like stainless and titanium.
Its expensive, its worthless at slow speeds and will fracture during use which is self-sharpening and gives it a very long cutting cycle
A couple not discussed-
Unstructured Abrasives, usually used in round discs, hand pads and belts, its often Al-Ox or Sil-Carbide mixed in with a loose, strong, wooly material that looks and feels like a dish scrubber. Goes by the name Scotchbrite or some others. It comes in Brown (heavy cut-around 80-120g), Red (medium- 150-180g) Blue (fine- 240-320g) and Grey (super fine 500-600g) and gives a wonderful scratch finish when used in conjunction with one another. Run them slower end of the spectrum and they are expensive
Structured Abrasives
Mostly found on belts but sometimes discs, these are a specially made compound of of Al-Ox made for machine use that is specifically for hardened steels and difficult stainless finishes. They look like lots of blunt rectangles on the surface and run them in the low-middling speeds for best results. Come in their own micron codes which roughly translates to 80-800grit, they do last nearly forever and if they get a bit glazed you can clean them with slow-speed and just run a steel brush over them to perk them up again.
Edit- they are also horrendously expensive so make sure you know what you're getting into before laying out the cash
Yes - I think that's generally true. I covered most of that. Pressure is of course the other operational variable (to go with speed).
Please tell me that's your real surname.
@@ScottMurrayBestFamilyCars Yeah we got anglo'd in the early 1900's immigration moving here from Prussia so no one wanted to spell Stahl.
In a funny sort of way, I'm probably better qualified on telecommunications systems but that's a whole other story.
Hi John, I'm very much looking forward to watching your future presentations on tools and fabrication, very interesting stuff.
Thanks very much Steve.
Hi John, I've been using angle grinders for 40 years and never been taught so much information about grit. Keep up the good work.
Thanks for the lesson on abrasives, good information to know.
No worries Shane.
I learned many new things about abrasives today. Thank you John.
This is by far my favorite video you've posted. Great explanation, I know much more now. Going to buy some sil carbide now!
Very interesting JC. Thought I knew a lot on the matter but still found myself learning one new thing from you 😉👍👩🔧
Very informative. Useful for nerds like me who stand in Bunnings on Saturday morning staring blankly at the wall of sandpaper wondering what to choose for my weekend project. Also can I just take a moment to appreciate that shirt? Very clever.
Love the direction that the new wing of the fat cave is going in John.
I've been a boilermaker/engineer for 40 years, but still learned some stuff. 👍
That's a big compliment, Anthony - thanks very much mate.
Thanks John, looking forward to future episodes from this wing of the Cave
Will do, Mahcoo - thanks for watching. (This was far from one of my more popular videos...)
@@AutoExpertJC I also noticed that - and I know that views are the name of the game but I think this has a great deal of value and I'd hope that if it became a series it would gain a bit more of a viewership. It certainly deserves more views than its had to date.
20+ year metal builder.
On the spot with this one John.
Thanks, 'loose'.
This was a really informative segment. It was fun to learn about the physics and chemistry of the various materials and that is something missing on other channels. I hope your regular viewers encourage you to do more segments like this because they do fill a niche that has not yet been addressed. Good stuff Dude...
Ah, quite a handy vid this. Thanks John. Also, love the shirt...makes my inner geek happy!
Perfect timing. I'm getting stuck into my Bedford this weekend.
I work in metal fabrication, my place of employment uses a sand blaster with metal granules to remove mill scale and a finishing mechine with media pebbles as more gental to remove mill scale and wont leave any scratchs on the metal surface, Its more cost effective in the long run then using buff pads, except for starter up costs in buying the equipment, usually I grind off excess material with the regular grinding discs then finish of with the sanding pads.
Thanks for this one mate.
I was already aware that the brown ones were emery, blue zirc, red ceramic and the wet and dry was silicone carbide. I hadn't put 2 and 2 together to notice that that was always the case though. I just recognised that in the brands that I buy that's the colours they used for those products. Not colour = material.
I'd also already worked out the hard way that zirc discs are no good on mill scale, I haven't found a good use case for ceramic discs yet, but am a fan of them in belt form.
Usually for mill scale I just go at it with the emery hard grinding disc and then clean up the gouges after with the soft emery or zirc.
Getting that nugget of wisdom re the concrete discs though, that's brilliant. I mean, it's obvious now you point it out but 20 mins ago I had no idea.
As I said before, thanks mate. Much appreciated.
Love these videos John! Very informative mate. Can’t wait for the next one!
Great tip re: masonry disc for mill scale.
Looking forward to the new fabrication videos!
The best way to get mill scale off, get someone else to do it. Great information John.
Grinding wheel colours in the machine shop: Carborundum - grey, Silicon carbide - green , Aluminium oxide - white, blue, grey, Diamond - charcoal. Most grinding wheel types are made in different degrees of hardnesses which is governed by the bonding material. Generally soft wheels are used for hard material and hard bonded wheel are used for soft material regardless of grit type or size.
The easiest way to get rid of mill scale is to purchase bright steel in the first place, the scale is removed at the steel plant by pickling in acid. Bright steel is coated with a light grease to prevent rusting and in turn makes for messy handling. Cheers
Pickled and oiled rocks.
I agree with you on all fronts. Cold rolled is another option for some sections and grades.
Love your work John, was briefly trying to explain this subject to a friend the other day, admittedly not in as much detail and while taking the ultimate lazy approach to mill scale banishment good old acid & suitable safety equipment. (on a side note kiddies if it eats the scale & will happily devour the metal your removing it from given enough time, then your little fingers certainly ain't going to be any form of notable challenge for said product to dissolve. Do it safely I Can not stress that enough there is no need to take silly risks using an easy shortcut & always wear a suitable breathing apparatus. ) Besides that grinding stuff just looks like hard work, a little bath for the material a quick coldie for me. Some minutes later after a little rinsing & the added benefit of being less parched for it. Certainly works well for me when the opportunity affords such laziness.
I’m liking your new spin off videos (not about cars)
You even managed to go a whole video without telling us you have an Engineering degree :)
Thanks; I definitely learnt some useful things from this.
Thanks very much, Ross. Glad it was helpful mate.
"This bit of steel is *10" x 10" by about 8mm* .... friend of mine measures shit like that as well ... something will be 6 foot and 25 mil.
I'm bilingual like that. I was trained by an old toolmaker and we had a running competition of metric/imperial conversion one-upmanship...
@@AutoExpertJC I thought most Aussies did that. Then I went to Canada.
More technical videos like this please
Good stuff, John. Thank you for producing this. I enjoyed the first Ghetto Engineering, and look forward to more.
I learnt a few things, thanks John.
Really helpful John. I'm a blacksmith/farrier and we end up with a ton of scale on a horseshoe. At farrier competitions we I forced to be luddites and use a hot rasp to safe of edges and whatnot, but in the field will use either a linisher or an angle grinder to do that.
We generally use Zirc, but going to have a bit of a play with some of the others.
Thanks, great content 👍👍
Try a masonry grinding disc on the mill scale mate, and please let me know your thoughts.
@@AutoExpertJC Yep going to give that a go, especially.
Will definitely report back 👍
Hi John, you forgot to mention that angle grinders were invented so orthopedic surgeons could pay for their daughter's annual swiss ski trips. We've got quite a collection of the DIY disaster pictures when angle grinders attack human flesh in my ED, quite sobering when you see a 60 year old who has managed to cleave his face in two through his nose and skull from one.
Great vid John. For big stuff that'd take forever or small intricate stuff with tight corners that a grinder won't get into, sandblast it. Buy a cabinet if you can justify the expense or for big stuff, take the job to a sandblaster.
Great tips John👍 I’ve worked as metal fabricator most of my working life and never considered using a masonry grinding disc for mill scale, I’ll certainly be giving it a go in future.
As an engineer I’d imagine you’d know that there’s no such grade as “mild steel”.
A cert 4 teacher I once had advised our class never to use that term in an exam because it’s not listed in any standards and you’ll loose marks if you do.
I’m guessing you use the term to describe low carbon steel ?
Thankyou for the workshop tip. I look forward to the next one.
Thanks for watching, Bill - more to come.
Fantastic informative explanation, I guess we glossed over this in Electronic engineering, I often wondered what the color disks were.
Time to buy a couple of new ones, green I think.
Thanks John.
No worries, Lindsey.
Walter Flexcut Mill Scale, best grinding disc I’ve used for mill scale,
Suhner magic disc is unbelievable on stainless steel.
Flexovit on everything else!
I’m going to try those concrete grinding ones I’ve never heard this tidbit!!
Thank you John, very handy video. Could you consider a video on sealants and bonding. Silicon, Sika automotive 227, 221 etc. thank you.
Potentially, yeah, sure. Thanks for watching.
Hi John, I am a little confused with your "blue" colour designation. To my $4,000 OLED monitor everything you said was blue was actually green, and the contrast was very clear when looking at the belt sanding media in the bottom right of the screen. The one on the extreme right is definitely Blue, and just to the left of it is a belt that is definitely green - but the same colour as you described as "blue" for the Silica Ceramic Alumina discs in the presentation? So which is it "Greeny-blue" that you call green or "Green." Also, what is the material very blue belt sanding media?
Well explained. Please more information on workshop tools and procedures.
Will do, RB.
Cheers for that John
I've tested quite a few abrasives with industrial sanders - thought I'd mention ceramics don't do well with softer materials (hardwoods, composite) either. The grains don't break off, just round and glaze over.
Interesting - I haven't tested that.
Thanks for this vid. As someone who is starting out trying to learn how to weld (for home hobby stuff), I have been floundering in which abrasive was best for cleaning up the job prior to welding, and which is best for cleaning up my shitty welds once I am done. This has helped me get a better understanding of some of the differences. Now to learn to weld better so I don't need as much grinding at the end :)
Bevel the ends before welding. Then there will be more weld below surface level...
Great video, John. Slightly different than your norm, but nonetheless, very informative and interesting. Keep up the good work.
Will do, thanks Stephen.
Great info thanks John
Any time
Looks like you’ve made you’re own Honda workshop with that paint choice.
Not what I was aiming for.
Cheers mate, I had no idea about the differences and I thought I knew a bit.
No worries Adrian. One of those things that's hidden in plain sight mate.
Hands down, that is the best shirt to date, John.
Thank you, Christopher. I saw it and my inner nerd couldn't pass it up.
Wow Thanks John.
I do like your new segment.
And I found it interesting 👍#respect
Thanks for watching Dawayne.
Thanks, didn't know any of that!
Love the T. Retired IT guy here 😄
Great video, we need more of this. BTW, I am sure you are working on some projects in the Fat Cave. How about some videos on the Projects you may have on the go.
Will do. I'm presently making a fixturing surface.
Good video, and informative. What type of disk works best for grinding out porosity in a hot weld? At my work, we have access to the ceramic disks, but they don't last long when you put them to a red hot weld that is full of porosity.
Great content! Love that shirt too!
Thanks very much, Eddy.
my last gig in a panel shop as a TA, pretty much consisted of taking the scale off new truck bodys for paint prep. i never really took much note of the colours, i find it interisting learning about the diffrent meterals. the layered flat disk i called slappers, no ming moles in the panels shop just good old slappers. hahaha
I mainly used the disks that look like there made from a bath loofah, if i remeamber right both disks where black. so i would remove all the scale then sand with 80 grit , mask up and prep wash.
riveting times.
so what are the white sand papers and sanding disks made off ?
The black ones would have worked OK - silicon carbide is pretty good at removing mill scale.
@@AutoExpertJC yeah they did , i disk per body / trey , back in them days it was still 9 inch grinders, sanders , buffs etc. all meterals would of been worked out on cost.
9" grinders ... still got all your fingers?
@@AutoExpertJC just cuts bruises burns , guess i got lucky. some pretty sketchy stuff back in the day.
well i have to run a combustion motor at max rpm and chop stuff with blades, yeah i better mow the lawn.
If you have time, a trick for loosening up mill scale is to leave the part in a damp place for a while (a few weeks). The moisture will cause the steel to rust under the mill scale, making it flake off. It's then easy to clean up with a sanding disc/flap wheel. Obviously this is more appropriate if you purchase your stock in advance of actually needing it.
Immersing in vinegar for 24hrs is also effective.
As a future prime mincer, you sure know how to grind the opposition down and without help from Rupee.
While we are at it, I have a lot of work with aluminium...what do you reckon I should use? I guess aluminium oxide is a bad choice so perhaps Zirc or should it be silicon carbide?
i like your choice of shirt for this video.
Thank you David - I try to make them fit.
I have learnt a heap. Quite a bit I sadly didn’t know even though I have been working with metal for 30 years.
However if paint is part of the future for a piece of metal I still much prefer to get things sand blasted and powder coated.
Agreed on the sand-blasting and powder-coating. Perfect prep and durable finish.
Is there a safe way to lift my vehicle up so I can fix my front bumper's bottom lip that has scrapped against high kerb? I would like to sand and repaint the bottom lip.
Blimy those Zirconium flap discs are expensive in Australia, I pay the equivalent of of 2.87 Australian Dollars including VAT here in the UK I can get the cheap Chinese ones for 1.66 Australian dollars. Sold for finishing Stainless steel. But I use them for everything, never had clogging problems except with painted materials, the way the flaps wear means that there is always fresh cutting surface .
Citric acid removes mill scale really well, you just need to immerse it for a few hours. One tub from the supermarket to 2 litres of water seems to work well.
Vinegar works also - 24 hours of immersion usually does it. If pickling in acid you typically need to de-grease first.
What would be the better option for woodsanding
Alumin-oxide is fine.
I needed that t-shirt one year ago.
Hopefully it's just a museum exhibit now...
Grinding disks made for stainless steel are pretty handy as well on carbon steel.
Yep - agreed.
Super informative, thanks JC!!
Btw isn’t your mitre/compound mitre saw heavy for wall mounting? I’ve got a Bosch 10in sliding compound and that sucker is crazy heavy. Great tool mind you.
How the hell do you reach the blue sorting boxes? Bugged me the entire video :)
The red paint strip is a really classy touch!
Of course, simple household white vinegar with your parts in a tub overnight can remove the need for all that elbow grease all together?
Difficult to do this when the beam is 1.8m long and weighs 65kg...
Very interesting
Avesome lockdown themed t-shirt :)
I had to have it when I saw it... (My inner nerd.)
as a retired furniture maker who has done a fair bit of sanding, the big rookie mistakes i see with people using a sander, is pressure and speed. basically the weight of the sander is all the pressure you need. movement along a piece is about i inch a second. doing this you will cut your sanding time down and result in a better finish.
Even more so with metal. Let the abrasive do the work.
Loving the shirt
great video, what works best for wood
Aluminium oxide for wood, generally.
👍how do you get to those blue storage bins on the wall?
I hover.
@@AutoExpertJC I knew you had superpowers! The hat is like Clark Kents glasses!
Tiffany is my Kryptonite...
Episode 1 of John the tool man John, the next reality-based TV series since Tim the toolman, 😆😆.
Can't wait for Tiffany the tool chick.
Where did you get your "stay at home, wear a mask" nerd shirt? I need one of those to go with my "there are only 10 types of people, those who understand binary and those who don't" nerd shirt.
I can't remember, but your nerd shirt is better IMHO
@@AutoExpertJC as a network guy I prefer your's as it further sorts the wheat from the chaff :)
259km/hr (72m/s) but who's counting.
Great preso - I never knew that about SiC and mill scale - very happy to now know.
Have you tried pickling your mill scale first to remove it?
Yes I mostly use vinegar for 24hrs but never on hardened or high strength steels because of hydrogen embrittlement.
Best abrasive product - a politician at a policy launch, especially Scotty from marketing.
Yeah - he never goes blunt and would wear anything down.
So what would you recommend for aluminium, other than "good luck with that"?
Just look at it the wrong way.
@@AutoExpertJC I'll just live with brass then. 😏
Ok I actually learned something here. 👍🏻
That was the point.
Mill scale? - Muriatic acid - Put a gallon of water in a plastic tub, (with a lid so yo can leave it out in the rain) Dump in a gallon of Muriatic acid . Put the parts in the solution and go do something else for a couple hours, Come back and fish the parts out with a pair of plastic tongs and hose them off and squirt them with WD,,,,, Pickled and oiled steel right in the yard behind the shop.
Interesting. Cheers
No worries mate.
I think the Cubitron 2 is similar to/ a form of ceramic??? Possibly
No. Cubitron is a man made pyramid shaped abrasive.
Standard sand/aluminium/carbide is a mineral/rock shaped abrasive. Hundreds of jagged points instead of 1.
@@janeblogs324
Yeap, hence my saying that from memory it was similar to ceramics…, there was a brand of ceramic from memory that was synthetic like Cubitron..
Certainly Cubitron was in a completely different class…, if I ran a fab shop etc I would just use 3M… I sold it& used it…. My customers always reduced they effort, time & costs… i didn’t actually sell it.., I really only demo it…
@@janeblogs324
I certainly stand to be correct on that brand of ceramic.., might have been saint gobain..?
Great video. Things here I never learned in "Engineers" school.
I think I must be colour blind as your BLUE discs really look GREEN to me. Is this just a blue variant? or am I missing something?
If I had to call it blue I would choose aqua - blue-green; I would have called that colour green too
Love your 10 x 10 inches them mm in thickness being a Canuck being metric from the British imp system 👍
Many thanks for the abrasive info. I knew they were different but not why.
In amongst you usual content please include such general engineering practices
from time to time. Start educating us a bit a a time
Will do, David - thanks for watching mate.
Bloody good John…..!!!
Interesting though wouldn’t you think that in the event all the different meanings of these colour codes are news to so many of us wouldn’t you think that’s a huge marketing fail on the companies who are trying to sell them…????
All of that was news to me
other than there were obvious differences in grit and robustness but not down to that detail
Surely they should be explaining this much better in their marketing…?
Comparatively I feel as though I know more about tampons based on the TV ads alone…..
And cause grinding is a 💩 bag of a job, it’s hot , dust n noisey , the quicker n easier you get it do the better.., one of the most rewarding places in a w/ shop to spend your $ is on abrasives…
How do I get my Abrasives 101 certificate from the Cadogan trade school ?
Just imagine it really hard, and it will pop into existence.
Again: *WHERE CAN I BUY THIS T-SHIRT* John⁉️
Alumi num. al u min ium??
Americans don't speak English. Still.
@@AutoExpertJC I'm not American eh !
@@AutoExpertJC just checking my abrasiveness. 40 or80 grit?
I have been using voice recordings of Gladys to strip paint and remove rust.
Ecologically sensitive but my cat hates it.
Very coarse abrasive there. And impervious to wear. Univerally effective.
I think its time for you to do "ToolTime" talking about tools. cheers
I intend to do a lot more DIY stuff. There's a lot of misinformation out there on that also...
@@AutoExpertJC Yes do it call it Tool Time Australia if that helps stop the copy right stuff!
This will be interesting… I wonder if 3M Cubitron is mentioned 🤔
It's not.
@@AutoExpertJC
Cool, sorry I haven’t had a chance to watch yet..,
Have you heard of it.., they’re synthetically grow crystal/ abrasive grains that are exactly the shape 3M want.. rather than crushed random shapes….cuts like it made with thousands of milling cutters on the surface.. truely amazing …
@@AutoExpertJC
Really enjoyed your last vid on AU government EV BS
I'll check it out - thanks for the tip.
Sweet, I’m sure others do it now.. it was 10 + years ago I was selling it.. Nucon we’re grinding back their w316 weld repaired rotors.., 1 off 5” P40 cubitron fibre disc replace 8 off 5” dressed centre wheels.., 3 M do a ventilated backing disc to go with them…., they were $3 a disc , twice cost of a dressed centre…, but man..
The grain were applied electrostatic-ally to the backing… so all the tip/ points were sticking out n cutting…, no sore forearms….
John you have forgotten the most abrasive. The ex wife surly she must be counted?
Thanks for the enlightenment.
Regards Tony
Which one?
Stay at loopback
Wear a /24
Home/mask...
T.A: me, looking up @ the wall, "these consumables l need these for my personal gas plant construction"