Epoxy or Urethane High Build... what's next for me?

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JWRICH

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I've been working on my 71 Demon for a few years now and about ready for final prep before laying down the base/clear. The car has had lower quarter patches welded in and various small dings filled. Currently, the repaired areas have been primed with rattle can Rustoleum Auto Primer (I know, not the best stuff, but not the worst either IMO). There's a few place of bare metal exposed now after I've blocked it out.
Do I spray the entire car with Epoxy primer, or go straight to high build 2X Urethane? If epoxy, how much of the rattle can primer needs to be sanded off first?

Going for a show worthy finish, but will be driven regularly.
 
I would take all that rattle can primer off if want the paint to stick. Sand all bare metal areas really well, because there is probably surface rust starting already. Put a couple coats of epoxy over all bare metal and repaired areas. Than proceed from there.
 
I would take all that rattle can primer off if want the paint to stick. Sand all bare metal areas really well, because there is probably surface rust starting already. Put a couple coats of epoxy over all bare metal and repaired areas. Than proceed from there.

This... then go with the high-build.

I always buy the epoxy and high build in different colors so I can tell when I've sanded through.
 
I highly recommend spi epoxy, then 2k to block then base then spi clear. I haven't sprayed their clear yet but there epoxy is good stuff. They are responsibly priced and their tech guy is awesome he is always willing to help and will text with you and answer any questions you may have.
https://www.southernpolyurethanes.com
 
I completely agree with the other two guys. I have been painting for about 40 years. Rattle can primer may have its place, but that is not on a car. The problem with rattle can primer, and a lot of other primers for that matter, is that they absorb moisture and let air through. Hmm, let's see, what happens to metal when air and water can get to it? RUST. I only do one kind of paint job; down to bare metal and up from there. I always put epoxy primer on the bare metal. It will completely protect the metal. I like @flingdingo 's idea of different color primers. I use a dark grey epoxy and a lighter grey high build. You really need to get rid of all the rattle can primer and then spray a few coats of epoxy on the whole car. Then give it a few days to totally cure and then lightly block it with a 12-18" Durablock (or similar) sanding block and 220 or 320 paper. Do not go through the primer, this light blocking is just to show you if you have any low spots that need to be filled now. The more perfect you can get the body now, the better the blocking will go after the high build primer is sprayed on. I really like Evercoat G2 high build polyester. Some people like the 2K urethane. Whatever you use, you really do need to get rid of the rattle can primer. If you don't, there is a chance that the solvents from your paint can react with it and react in a bad way. Not worth the chance.
 
I completely agree with the other two guys. I have been painting for about 40 years. Rattle can primer may have its place, but that is not on a car. The problem with rattle can primer, and a lot of other primers for that matter, is that they absorb moisture and let air through. Hmm, let's see, what happens to metal when air and water can get to it? RUST. I only do one kind of paint job; down to bare metal and up from there. I always put epoxy primer on the bare metal. It will completely protect the metal. I like @flingdingo 's idea of different color primers. I use a dark grey epoxy and a lighter grey high build. You really need to get rid of all the rattle can primer and then spray a few coats of epoxy on the whole car. Then give it a few days to totally cure and then lightly block it with a 12-18" Durablock (or similar) sanding block and 220 or 320 paper. Do not go through the primer, this light blocking is just to show you if you have any low spots that need to be filled now. The more perfect you can get the body now, the better the blocking will go after the high build primer is sprayed on. I really like Evercoat G2 high build polyester. Some people like the 2K urethane. Whatever you use, you really do need to get rid of the rattle can primer. If you don't, there is a chance that the solvents from your paint can react with it and react in a bad way. Not worth the chance.
Thanks for the detailed response... when I get the rattle can Primer off, what grit sandpaper should I go with before spraying the epoxy?
 
Thanks for the detailed response... when I get the rattle can Primer off, what grit sandpaper should I go with before spraying the epoxy?
Barry from spi told me to sand to 180 then epoxy
 
If you think rattle can primer is "not the worst", then what is? Get that junk off. The way we're doing it at the shop is. Whole car gets chemical stripped or blasted. Then epoxy primer. Then metal repairs. Next polyester primer, then any filler needed and finally urethane primer then paint. With tons of blocking in between.
 
Like Dartfreak75, I have used SPI epoxy primer, and it is GREAT! You can apply filler or 2K primer over it without sanding as long as it is done within their specified window of time. I used SPI epoxy thinned with urethane thinner the other day as a sealer, before doing base/clear over it. Turned out slicker'n cat poop on linoleum! :D
 
I agree with all the above and yes I use epoxy reduced as a sealer before topcoat, maybe overkill but works for me. I like SPI epoxy, and good tech guy..
My routine is metal work, clean it, epoxy primer, filler, epoxy primer, high fill primer, epoxy primer sealer, topcoat. But I admit I no pro!! Just a hobbiest for 35 years, or is it 45???? I forget.
 
Thanks for the feedback everyone... So, here's my plan. Your additional comments are welcome.
  • Sand down as much of the rattle can primer as possible stopping at 180 grit. (I know for sure i won't get it all off b/c some panels are fully covered... it does sand incredible well though)
  • Spray entire car with SPI Epoxy Primer (white or grey)
  • Spray entire car with 2X Urethane high build primer (SPI... or is any brand fine?)
    • Block, block, and block again... stopping at 400 grit :)
  • Spray entire car with thinned SPI Epoxy Primer (as a sealer) (white or grey)
  • Then move on to the base/clear & buff
Car will be a bright red... looking at Viper Red or similar. Not sure if I'll use the SPI universal clear or something same brand as the base paint.

Anything I'm overlooking?
 
Thanks for the feedback everyone... So, here's my plan. Your additional comments are welcome.
  • Sand down as much of the rattle can primer as possible stopping at 180 grit. (I know for sure i won't get it all off b/c some panels are fully covered... it does sand incredible well though)
  • Spray entire car with SPI Epoxy Primer (white or grey)
  • Spray entire car with 2X Urethane high build primer (SPI... or is any brand fine?)
    • Block, block, and block again... stopping at 400 grit :)
  • Spray entire car with thinned SPI Epoxy Primer (as a sealer) (white or grey)
  • Then move on to the base/clear & buff
Car will be a bright red... looking at Viper Red or similar. Not sure if I'll use the SPI universal clear or something same brand as the base paint.

Anything I'm overlooking?
I would keep the brands the same. If you go with spi epoxy go with spi 2k also. And follow all the directions and clean clean clean clean. Prep and CLEAN! Haha I'm not a professional either this is my first "real" paint job I painted my dart with tractor implement paint 16 years ago does that count? Lol sounds like you a have a plan. If you have any questions text Barry at spi his number is on their website he has helped be tremendously day or night mon-sun no joke. You dont have to start with 180 to remove the old primer you can go courser to get it off just finish at 180 before you spray your epoxy!
 
Just remember any flaw at all will show up in the top coat. I bet you will need to do plenty of blocking the high fill where you applied filler. Correct techniques with long boards maybe. One thing IF you make a mistake, you an go back andmake it right or at least better.
Be carefull these materials can kill you. Really!
 
Yes... lots of health hazards with these materials. Especially when doing it in my home shop with a DIY paint booth. (might spray the primer outdoors). I do have quite a bit of experience with body work... just been a long time sense my last project, for which I did not use epoxy and had a pro-shop do the final prep & paint. I've done every other task on this car... I'm confident that I can get a good finish. Just have to take my time and listen to the advice from more experienced people on this site and others.
 
Thanks for the feedback everyone... So, here's my plan. Your additional comments are welcome.
  • Sand down as much of the rattle can primer as possible stopping at 180 grit. (I know for sure i won't get it all off b/c some panels are fully covered... it does sand incredible well though)
  • Spray entire car with SPI Epoxy Primer (white or grey)
  • Spray entire car with 2X Urethane high build primer (SPI... or is any brand fine?)
    • Block, block, and block again... stopping at 400 grit :)
  • Spray entire car with thinned SPI Epoxy Primer (as a sealer) (white or grey)
  • Then move on to the base/clear & buff
Car will be a bright red... looking at Viper Red or similar. Not sure if I'll use the SPI universal clear or something same brand as the base paint.

Anything I'm overlooking?
Sounds like a good plan. I love viper red. Just remember one important thing. A paint job can be no better than the prep work. A really nice paint job has a zillion hours of prep behind it. Good luck. Looking forward to pictures. Some white stripes would look good with the Viper Red.
 
What saves my old ***, I that I will drive my car and it will never be or stay perfect. So when the wife points out a flaw in my body/paint work, I just tell her I left it there so she realizes beyond a doubt, that I am not perfect!!
 
SPI Epoxy Primer (white) and 2X High Build Primer arrived today! :) If the forecast holds, I should be all set to get a bunch of panels sprayed mid-next week. Still working on stripping all the Rustoleum primer off main body... just have to finish up the door jams, engine bay, and inside the front wheel wells.

FYI, I've found that the CitriStrip isn't too bad for paint removal. Nothing like the Aircraft Remover of yester-years, but still works. Just have to be patient. I've found that 2 good thick coating, soaking overnight, will strip to bare metal on 90% of the panel. Some area need another treatment or more effort with the wire wheel / sandpaper afterwards. Let it soak, then I hit it with the pressure washer and finish prepping it after it has dried good.

I'll try to post some pictures after I get some panels primed up.
 
FYI, I've found that the CitriStrip isn't too bad for paint removal. Nothing like the Aircraft Remover of yester-years, but still works. Just have to be patient. I've found that 2 good thick coating, soaking overnight, will strip to bare metal on 90% of the panel. Some area need another treatment or more effort with the wire wheel / sandpaper afterwards.

It also helps a lot if you scuff the paint with 80 grit before you put the stripper on.
 
Well, it's been A LOT of work getting all the spray bomb primer off and car ready for primer, but today was the day to start the Epoxy primer. The SPI Epoxy primer is awesome stuff. 2K High Build goes on tomorrow, then will be getting the Epoxy onto the main body after that.

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