Two Year Old SPI Epoxy Prep

Machspeed

Machspeed

Member
Hey friends, media blasted the car a couple of years ago and put two coats of SPI epoxy on it. I'm finishing up all the metal work and hope to paint it this year. I wish to paint the undercarriage and engine bay soon, both to receive a single stage paint.....slop gray undercarriage and satin black engine bay. I think I know the answer to this question but gonna put it out there anyway. How would you prep these two areas before application of single stage paint?
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I would sand the existing epoxy with 180 and use a red scotchbrite pad in hard to sand areas. Then spray another coat, or two, of epoxy. This will open your window for a chemical bond to proceed with 2k, or final paint if you decide to sand out the epoxy with 400/600 depending on your type of final paint used.
 
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Machspeed said:
Hey friends, media blasted the car a couple of years ago and put two coats of SPI epoxy on it. I'm finishing up all the metal work and hope to paint it this year. I wish to paint the undercarriage and engine bay soon, both to receive a single stage paint.....slop gray undercarriage and satin black engine bay. I think I know the answer to this question but gonna put it out there anyway. How would you prep these two areas before application of single stage paint?View attachment 25292
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In lieu of sanding the underside, you could use Scotchbrite in the appropriate grit to scuff sand it. Would be a world easier than trying to sand it with paper. That would be a nightmare and take forever. With the Scotchbrite you could do it on a few hours.

3M 7446 is roughly equivalent to 150 grit which would work well. It will not be as aggressive as using 150 grit paper. The next closest is the 6444 which I think is roughly 240 grit. Personally I have used the 7446 for underside work and like it. 2-3 coats of epoxy will more than cover the scratch pattern.
 
If you do decide to do that, you will have to order it online as I have never been able to find it (3m 7446) anywhere in person.

Good to see you posting again as well my friend. :)
 
I thought 3M's 7747 was the go to pad for scuff sanding, but doing a search here on the forums I see no reference to it. Does anyone use it or have an opinion on it?
 
DanMcG said:
I thought 3M's 7747 was the go to pad for scuff sanding, but doing a search here on the forums I see no reference to it. Does anyone use it or have an opinion on it?
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Maroon is my go to scuff pad. I use these that Jim C recommended but the ones you are using are fine too.
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Why I recommended what I did is because of the fact Barry says it needs 180. Maroon SB pads are like 360 grit or a touch finer. I thought maroon was OK for small areas but for larger areas not ideal. IDK. Maybe that's coarse enough IDK. Perhaps @Barry can clarify.

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DanMcG said:
I thought 3M's 7747 was the go to pad for scuff sanding, but doing a search here on the forums I see no reference to it. Does anyone use it or have an opinion on it?
Click to expand...
I use the 7747 Maroon pads for scuffing prior to painting. So far I have not had any issues using it. Hoping Barry gives his thoughts on the subject soon.

I use the 7448 Light Gray for scuffing clear prior to recoating.
 
Hey fellas, thanks a ton!

Chris, thanks for the welcome back! I've been lurking, just don't post much. Really hoping to get paint on the car this year. I've been addressing all the metal work which was a little more than I expected. Cutting out rust and making patch panels when I can't get the appropriate panel. I was going to paint the car myself, but a guy in my Church who used to be a painter and who now owns an auto paint supply store will be painting it. He does incredible work and is mentoring me through the body work. Moreover, he has access to a really nice paint booth. I really think I could have painted it but I really don't want to experiment on my baby.....LOL!
 
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