Two at once? I’m crazy… 1975 build

[jimtweet]

With Ruby build on hold for winter months taking this opportunity to get started on the next build.

1975 911, originally yellow,… but not for long. Picked this car up about ten years ago and been stored in my inventory. Had an awful widebody kit on it upon arrival.

I’m extremely pleased at how solid this car is turning out to be so far!

[SiracHaile]

Looks like a ton of work to strip it down. Any reason why you didn’t sand blast it?

Looking forward to see the progress

[jimtweet]

Originally Posted by SiracHaile

Looks like a ton of work to strip it down. Any reason why you didn’t sand blast it?

Looking forward to see the progress

Prefer to do by hand, sandblasting doesn’t do well on undercoating. Another reason is epoxy doesn’t like blasted metal, so car has to be sanded anyway.

[MattTHEpainter]

Originally Posted by jimtweet

Prefer to do by hand, sandblasting doesn’t do well on undercoating. Another reason is epoxy doesn’t like blasted metal, so car has to be sanded anyway.

What did you use to get it to bare metal?

[jimtweet]

Originally Posted by MattTHEpainter

What did you use to get it to bare metal?

Wire wheels. Can strip a whole tub in 2/3 days

[ChrisHamilton]

Originally Posted by jimtweet

Prefer to do by hand, sandblasting doesn’t do well on undercoating. Another reason is epoxy doesn’t like blasted metal, so car has to be sanded anyway.

Not true at all. Epoxy loves properly media blasted metal. Probably the best tooth there is for epoxy. It's done all the time. Soda blasting would need to be neutralized before applying epoxy.

[jimtweet]

Originally Posted by ChrisHamilton

Not true at all. Epoxy loves properly media blasted metal. Probably the best tooth there is for epoxy. It's done all the time. Soda blasting would need to be neutralized before applying epoxy.

Been using SPi epoxy now for last 7/8 years, numerous conversions with Barry (owner) regarding this topic. He says all blasted metal should be da”ed with 80 cause the blasting does not leave the proper tooth for the epoxy. Maybe that’s just his epoxy, not sure, but that’s all I use. I think there is something about this on his TDS.

[dg567]

can't wait to see the final result!

[ChrisHamilton]

Originally Posted by jimtweet

Been using SPi epoxy now for last 7/8 years, numerous conversions with Barry (owner) regarding this topic. He says all blasted metal should be da”ed with 80 cause the blasting does not leave the proper tooth for the epoxy. Maybe that’s just his epoxy, not sure, but that’s all I use. I think there is something about this on his TDS.

I'm familar with the passage in the SPI Tech Manual that you are referring to. I've reached out to Barry to get a little clarification as it doesn't make sense to me. Media blasted steel with something like crushed glass or coal slag has a far better "tooth" than simply sanding with 80 grit. The media is usually coarser (40-60 grit) than 80 grit so it's illogical to me. Many of us have done it (epoxy over blasted metal) for years and never seen the first issue. Many of us are on the SPI forum that have done it that way.

Like I said I reached out to Barry and will report back what he says.

[ChrisHamilton]

The only reason I can think that Barry says what he says is to cover if someone is using walnut shells, plastic, glass beads, etc that would not leave the correct tooth in the metal. Like I said above when using 40-60 grit media, then sanding with a finer media to get "tooth" should not be required.

[ChrisHamilton]

Barry just got back to me, here is his reply.

Epoxy loves blasted metal and yes for 20 years said day with 80 but in the last few years my stand has been using coal slag or sand just clean with 700 and epoxy as sand leaves a nice anchor.
All other media must be da'ed with 80.

I then asked him if crushed glass was acceptable as well and he said yes.


Barry is a really good guy BTW. I owe him a lot.

[Shaun @ Tru6]

Originally Posted by ChrisHamilton

Barry just got back to me, here is his reply.

Epoxy loves blasted metal and yes for 20 years said day with 80 but in the last few years my stand has been using coal slag or sand just clean with 700 and epoxy as sand leaves a nice anchor.
All other media must be da'ed with 80.

I then asked him if crushed glass was acceptable as well and he said yes.


Barry is a really good guy BTW. I owe him a lot.

I'm surprised he said crushed glass, that doesn't create a tooth, it creates dimples. Cerakote requires aluminum oxide to create a tooth and they say precisely not to use glass because it leaves a dimpled surface.

And I like a blasted surface because it gets everywhere, especially in little nooks and crannies that nothing else can, and in seams, an important place for adhesion.

[ChrisHamilton]

Originally Posted by Shaun @ Tru6

I'm surprised he said crushed glass, that doesn't create a tooth, it creates dimples. Cerakote requires aluminum oxide to create a tooth and they say precisely not to use glass because it leaves a dimpled surface.

And I like a blasted surface because it gets everywhere, especially in little nooks and crannies that nothing else can, and in seams, an important place for adhesion.

Glass Beads leave a surface you are referring too, crushed glass leaves a surface nearly identical to coal slag or sand. It is essentially the same as coal slag or sand when blasting. Leaves a really good tooth and gets steel "white". Been using 40/60 crushed glass for years. I think it's actually more aggressive than coal slag, it cuts quicker, removes rust faster, probably not as aggressive as sand but I never use sand because of the free silica in it.

All of what I'm referring too is in the context of blasting a body. Al OX would be prohibitively expensive to use completely on a body. At least for me. I will go through 15 or more 50lb bags of media when doing a body.

[Shaun @ Tru6]

Thanks for the clarification. Agreed on the sand. I only use Al oxide for Cerakote work and send a body to NH for blasting. They use black beauty I think. The owner operator is a real life Flashdance character, wears a heavy respirated outfit, peels off her hood and is quite beautiful.

[ChrisHamilton]

Originally Posted by Shaun @ Tru6

Thanks for the clarification. Agreed on the sand. I only use Al oxide for Cerakote work and send a body to NH for blasting. They use black beauty I think. The owner operator is a real life Flashdance character, wears a heavy respirated outfit, peels off her hood and it quite beautiful.

I got started using crushed glass because it was available locally and cheap. Black Beauty/Black Diamond is priced similar but for whatever reason I have never liked it as much. Lots of folks do though and get good results. Some of it may come down to the equipment that is being used. I have a decent but nowhere near top of the line pressure blaster. Maybe one day but the really good machines are $5K and up and hard to justify when only blasting 2 or 3 per year.

You do great work BTW. Have enjoyed reading your posts and seeing the results you get on stuff.

[Shaun @ Tru6]

Everyone has their preferences, I'm the same way with all kinds of products. Agree on the justification on equipment purchases. That said I bit the bullet and paid handily for a new screw compressor earlier this year that I want to grow into its capacity over several years.

Thank you, I definitely love what I do, working on some new exciting projects now.

[Matt at Pelican Parts]

Interesting! What color are you thinking about for this one?

Originally Posted by jimtweet

originally yellow,… but not for long.

[Shaun @ Tru6]

Originally Posted by ChrisHamilton

I got started using crushed glass...

Chris, what is your opinion on 3M's clean n strip discs for surface prep for epoxy?

[jimtweet]

Originally Posted by Matt at Pelican Parts

Interesting! What color are you thinking about for this one?

Continental Orange!

[ChrisHamilton]

Originally Posted by Shaun @ Tru6

Chris, what is your opinion on 3M's clean n strip discs for surface prep for epoxy?

They are very good for stripping. I do go over them with 80 grit afterward as they seem to have a tendency to "polish" the surface some. The 3M ones are nice but like everything 3M they are expensive. Here is an alternative that I have been using, work just as well as the 3M ones at a fraction of the cost. They last just as long too. I have been very happy with them. Especially when you consider a bag of the ones you posted a pic of cost well over a $100 bucks.Certain areas though the 3M ones that you use a mandrel with work really good. The Rolocs do pretty much the same though.

These are for a 5/8" arbor
https://www.empireabrasives.com/4-x-5-8-easy-strip-and-clean-disc/

Same company also makes a roloc version as well.

https://www.empireabrasives.com/3-quick-change-easy-strip-clean-disc-clean-rust-paint-removal/

Just to reiterate, these aren't cheap HF crap. They work and they last.