Block Sanding Epoxy Primer

Interested in the above post.
I have my car finished in 180. Very few sand throughs and the body is very straight....the light patterns on the wax and grease remover would be perfect for base.....except for the 180 scratches.
I'm bad at using high build and either go too slow or fast.....too close or too far. I ran it and sprayed dry in some spots and created a lot of orange peel and runs in others. And others it was perfect.
The first time ran it dry and had to take it back off. So I'm in about 40 hours of just the first round of blocking. Hence my apprehension to spraying more on there

2 coats spi and 3 coats of high build on there

Gun is finishline 4
30psi at regulator
Fan was wide open
Fluid was all the way out then 2 turns in

When I spray this again with high build to fill the 180.... Then sand that with 400. If I run it and get either runs or uneven wave 400 will flatten it but it won't cut out the imperfections.
Then I was going to seal it and maybe run into more trouble. What should I do here if I do get the mess I had before. I won't over it with a da to take down the orange peel and still had enough on there for block sanding
http://flic.kr/p/mSExS6

http://flic.kr/p/mSGj49

can I spray maybe 1 or 2 coats of epoxy.....sand with 400-600 and then base clear. The epoxy will fill the 180 scratches? I've sprayed epoxy a lot and get better results with it.

This would save me a weekend. It took me 15 solid hours to block the car.

Another question
Using a red scotch Brite pad to get into tight spaces,......like the roof rack or tail light housing.....or the window seal bases spot welds. The pad gets in there much better. Will it provide the scratches I need to either put on more high build or epoxy? I can always go back over it with 180 for the main surfaces but the pad gets into places like the crevices in the seam sealer and the rugged mounting mechanism of the roof rack sub base. None of it will be seen.

The primer is marhyde.....switching to everything spi
The epoxy is spi
 
I sprayed the regular SPI 2K through a 2.2 tip, rest of my gun settings the same as when I sprayed SPI epoxy out of a 1.8 tip, sprayed beautifully. No dry spray at all.
 
If you block it out with 180 and still have enough material left there to block it again with 400 then there's no reason to reprime, just apply guidecoat between grit change. 2 coats of epoxy will take care of 180 grit scratches but I'd let it cure up a week before final sanding-JMO, either way you should apply a sealer coat of epoxy before your paint. A maroon scotchbrite is plenty coarse enough for primer adhesion.
 
Why are you "sandwiching epoxy"?

Bob Hollinshead;35757 said:
If you block it out with 180 and still have enough material left there to block it again with 400 then there's no reason to reprime, just apply guidecoat between grit change. 2 coats of epoxy will take care of 180 grit scratches but I'd let it cure up a week before final sanding-JMO, either way you should apply a sealer coat of epoxy before your paint. A maroon scotchbrite is plenty coarse enough for primer adhesion.
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I take my cars to bare metal and apply SPI epoxy(black) 3 coats.thats it .then apply 3 coats SPI reg 2k.NO MORE EPOXY! I block 2k with 150 grit dry on a 11 inch dura block.I like to sand poly primers with 120 grit dry.
 
mikhett;35972 said:
I take my cars to bare metal and apply SPI epoxy(black) 3 coats.thats it .then apply 3 coats SPI reg 2k.NO MORE EPOXY! I block 2k with 150 grit dry on a 11 inch dura block.I like to sand poly primers with 120 grit dry.
Click to expand...

Why not??? The epoxy is a better product than any urethane or polyester, and asking it to fill 180 grit scratches is no sweat. There's no issues with using SPI epoxy as your final primer-only benefits.

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mikhett;35972 said:
I take my cars to bare metal and apply SPI epoxy(black) 3 coats.thats it .then apply 3 coats SPI reg 2k.NO MORE EPOXY! I block 2k with 150 grit dry on a 11 inch dura block.I like to sand poly primers with 120 grit dry.
Click to expand...

Why not??? The epoxy is a better product than any urethane or polyester, and asking it to fill 180 grit scratches is no sweat. There's no issues with using SPI epoxy as your final primer-only benefits.
 
Putting epoxy over urethane primer, even a sealer coat, adds to adhesion.
Since I started adding a sealer coat of epoxy right before base coating my bumpers
I've noticed a tremendous drop in future road rash. It really helps.
It's also got an advantage of coming in different colors, like black,white & red..
I mix them to get the shade I want to use under any given color.
 
Hi guys, I realize this is a super old thread, but it's relevant to my question. I'm in the process of doing a respray on my car. I'm scuffing the OEM paint, which is still in very good condition with the exception of dents/dings/couple rock chips. My plan is to do all of the body work, then spray the whole car (some bare metal spots, some filler spots, and some OEM paint/clear spots) with SPI epoxy....

Is it too ambitious to think that I'll be able to block the whole car down using only epoxy primer? 3 coats of epoxy, block, repeat until no sand throughs. Or am I better off going with a high build 2k or something similar after spraying epoxy? The bodywork will be very close to perfect, but I know I'll need to take advantage of doing some block sanding before base...just trying to figure out the best way to go about it.
 
urethane is for speed , epoxy requires more cure time but well worth it . time your epoxy so you know when to block .
 
Thanks! Speed is of no concern. So I should be able to spray a few coats of epoxy, let it cure for 48-72hrs, block it, repeat till I'm happy. How well does epoxy "build" compared to a regular 2k primer? I've heard SPI epoxy sands pretty well, so I'm hoping this plan should work without having to spend additional money on another primer/high build.
 
I did both my cars over paint it came with from GM & bodyshops.
I never scuffed- i blocked what was on there all over till i hit primer in some areas.
Use existing paint as if it's a few coats of primer.
I'm a diy guy so my technique isn't pro but it looks good.
If i had the means, i certainly would do as Shine suggests.
 
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