Huh? I don't get it...I'm guessing scuffing with 400 is a bad idea? I thought I would just use 180-220 since I have a lot of that and it sounds about right.

Another question...I've got areas where the previous owner sprayed rattle can paint and I need to remove it. It's the difficult to sand areas that are a problem...I have tried using a lacquer primer soaked scuff pad and it works great. But, if I get to aggresive (and maybe the old, original paint is weak/thin in that area), it will start to take off the original paint/primer. If I let it dry out really well, is there any concern with primering directly over this?

Thanks, Scot

If your epoxy primer is cured past it's recoat window then simply scuff it up with 180 grit before applying any polyester fillers-no problem. If you have original paint that is soluable with lacquer thinner then I would recomend you remove it all-no sense in putting expensive quality epoxy and 2K products over old 1K paints and primers IMO. The finished job is only as good as what is below the paint's surface and lifespan will be shortened with any 1K products in the mix.

Thanks for the info, baddbod. I hear what you're saying...never thought about it that way, about the paint melting from the lacquer thinner and that being an indication that it is weak. I was amazed at how hard it was to sand off so never really thought it was a bad substrate. Curious to know about what time period that 2k products became commonplace?

Please don't think your advice is falling on deaf ears. I do have a strong desire to know all the details, reasons, etc. and like to do things the right way. This project, however, doesn't have to be perfect, i.e. it's not that great of a subject and that's why I wanted it...less pressure to make it perfect. If it lasts a couple of years, I'd be totally happy. I've learned a huge amount already (thanks to this forum...I love it!) but have barely learned a thing when you look at the big picture. I plan to practice on this one and move on to something better. I guess you could say I want $50,000 paint job advice but have to settle for $5000 paint. This one, I gotta do what a shop would do if you gave them $2-4000 to paint your car. I'm okay with cutting corners IF I know what those corners are and what the consequences are. I file away all the good info I learn here because it will come in handy some day.

Thanks again, Scot

Test your epoxy by wiping it down with a lacquer thinner soaked rag. If it comes off onto the rag you might consider redoing it with a different brand. I have never used the DuPont epoxy primer, so it may hold up. A while ago there was a thread about PPG DPLF epoxy primer not being very durable. The contention was that once it was cured it could be wiped off with a lacquer thinner soaked rag. I was in the process of building my 34 at the time and had used PPG DPLF to prime some metal pieces. They had been primed for months, but I was able to wipe off the epoxy. I eventually removed all the expensive PPG DPLF and applied SPI epoxy. After a suitable cure time I tried the same experiment. I could not remove the SPI with lacquer thinner and a rag.

FWIW
Vince

__________________
Here's to you DoC, you will always be here.
My project 34
http://www.hotrodders.com/forum/34-...ght=34+progress

This is a sealer/primer. I would follow the directions for spraying over OEM or painted surfaces.

Then do what you want to finish it.
I agree that removing ALL the old paint down to bare IS best but your not wanting to go that far with this deal so,
ROCK ON.

BTW for those interested.
DTM Dupont product

I'm relieved to be able to say that the Dupont epoxy does not wipe off with a lacquer thinner soaked rag. I was worried about that.

I have a possible problem, though. I sanded off some of the epoxy and scuffed the bumpy pitted areas (previously sandblasted) and then applied filler. Sanded the filler with 40 grit to rough shape, then 80 grit to get it level with the metal. Then quickly ran a DA over it with 180 grit. I blew off the dust with air, but then thought I needed to wipe down with cleaner (I'm using a Nason aerosol...forget the product number). I then re-primed over the filler.

I'm using Evercoat Fibertech and Rage fillers, total drying time before primer was probably about two hours.

I'm not sure if it's a problem, but the areas with filler look dry...more so than the areas where it's just metal underneath. I noticed this on the first coat of primer. At first I thought it was some kind of reaction between the primer and filler, but after looking at it a bit, it looks more like painting over a porous surface, i.e. like painting over wood vs. metal.

I waited 30 minutes and applied another coat of the epoxy. At first, it looked like the primer covered the filler areas and there was some uniformity/smoothness to the appearance. As time went on and the primer started to dry, those dry filler areas are easily noticable again. Is this going to be a problem later on?

I'm thinking my possible mistakes were sanding the filler with too coarse paper, possibly the Nason cleaner was absorbed by the filler, possibly the filler needs to dry longer...and who knows what other newbie mistakes I've made today.

Anyway, I thought I had read a lot, done my research, etc. and had a plan of action. Now I'm wondering how badly I messed up. Can someone please offer up some advice?

Oh, also, can someone tell me what sand scratch swelling (I think that's what it's called) is and what causes it? Is it like the paint, or whatever is underneath like filler, is shrinking as it cures?

Thanks, Scot

ScotY, you ARE priming over a porous surface. Theres probably pinholes in the filler...but after 2 coats it usually looks uniform. Pictures?

Sandscratches come mainly from pounding on the surfacer toooo wet and thick, not allowing enough flash times. Follow that with a quickly sanding and painting the producting...the surfacer hasnt fully settled, yet its been sanded smooth. As a result, once it DOES settle, the previously smooth finish has now sunk into all the bodywork scratches.

And, simply too coarse of finishing scratches look like hell. Lighter colours metallics can show very well. The metallics track into the scratches, creating a finish that looks like hell. Some people reccommend always finishing with a DA , creating swirls rather than lines, so any marks are harder to track. Ive also heard on here a lot of people double-up gray scotchpads and run over the surfacer in circles...never done that one before.

Thanks for the reply and thanks for the info re. sandscratching.

Maybe I didn't screw up too badly? I went and looked at it again today and it sure looks like what you're saying...it's a porous surface so it absorbed the primer. Being it's maybe kind of thin, the second coat didn't fill in the pores? I tried to take a picture of the spot, but it didn't come out...you can't see the details well enough.

I also am learning technique...rather, screwing up and now I have to do it again. I'm using a black hard foam block (Durablock, I think it is?) and it looks like I sanded too hard...the filler areas are lower than the surrounding surface. I'm assuming something is flexing enough so the softer filler gets removed below the surface of the metal.

LOL.. Now your learning another "art form",Blocking.
Ther are a LOT of posts here about this so I won't bore everyone with what most of us already know but,
Those blocks DO flex,Use just enough pressure to cut with and use a guide coat and reguide often.Change your paper often.Dull paper is the WORST for dips as you end up pushing too hard to cut.
If you have pinholes in your filler,you will learn about another product.
Glazing filler.
THis is a very thin catylized polyester filler designed for use over your "main" filler like Rage for filling these holes or deep scratching, feathering it out into your existing primer.Guide coat it and reblock.This is usually done before applying more epoxy or primer. You will always get "ghosting" of the filler area and after your first coat of epoxy or primer has flashed well,usually overnight applying a second coat usually covers it up.One other tip is when mixing your filler is to fold it back over itself instead of stiring it up which can trap air and folding then chopping thru it will help. Lot's of posts on this as well.