When to stop?

Todd Gatman

New Member
This is a coat of SPI epoxy sealer. I am working towards shooting basecoat, so I am wetsanding. I intend to wetsand to 600 grit and then lightly scuff everything just before spraying the color. You can see some previous sanding scratches in this part. After I wetsand everything WAY smoother than this, will basecoat and UV clear make these appear to be flat. This is my first paint job, so I am not sure how good is good enough. My base has a very fine metallic in it. Appreciate your advice.
 

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texasking

Active Member
Two coats of UNreduced epoxy over whatever scratches those are would have given you plenty of material to sand them out. One coat of reduced epoxy as a sealer is only there for adhesion and very light sand scratches, not for filling. Don't reduce epoxy if you are going to sand it, as a general rule. Reduce only right before base. The base and clear will only amplify what is under it, not make it appear flat, if it isn't.
 
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Todd Gatman

New Member
This part is an old one and likely one of the first I did, the scratches are probably from 320. I just wet sanded a little in the same area of the previous photo. You can see a very faint line running vertically in the center from my thumbnail barely dragging across the surface. I was kind of hoping this would give a sense of scale. Thanks for the comments
 

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crashtech

Combo Man
320 should be a fine enough grit, it's just that the scratches look coarser than that. If I'm going to sand the sealer, I will put two coats on because one will knock through very quickly
 
It would be helpful to know what your entire process has been up to this point. What materials were used, how many coats, sanding process, etc. before you shot the sealer.
 

Todd Gatman

New Member
This project has been going on for about 5 years now. I thought it made sense to try to get all of my parts and panels finished and sealed prior to paint, and then do a final wetsand with say 600 grit just before I applied the basecoat. I am about at that stage.

My process; generally, I took everything to bare metal, replaced panels,etc. I shot unreduced epoxy on the bare metal and then applied filler and blocked everything. Sometimes I had to spray more epoxy because I sanded through. Before I applied anything, I cleaned with solvent based wax and grease remover (SPI). I sanded the epoxy with 220 and applied at least two coats of regular build primer. I finished this using 320 grit. Sometimes I had to skim with filler and reapply 2k. There are many thin layers of everything on this car, but nowhere is there more than about 1/8" of filler. Once in a while, I got carried away and feathered my filler with 400 dry. I would always scuff with a red Scotch brite before spraying. After the regular build primer was blocked to a point where I thought I was happy, I would shoot epoxy that had about 10 to 15% reducer in it. I would move on to the next panel.

I hope this makes sense. I tried to not write a book that no-one wanted to read.
 

crashtech

Combo Man
Your procedure seems mostly sound, I could pick on it a little but many have done worse. One thing stands out though: Sealer has to be applied just prior to painting, otherwise it's just a thin coat of primer. Aged epoxy can't be painted directly, it must be recoated with epoxy again within 48 hours of painting.
 
Guide coat is your friend at this stage. It's like fingerprint powder and will hide in the smallest of scratches and imperfections. Once you try it, you will be convinced.
 

Todd Gatman

New Member
Just to be clear, after wetsanding the old sealer and cleaning it, I can spray new sealer on it just prior to t basecoat with no adhesion concerns? This is my understanding, just dont want to go backwards anymore. Thx again
 

crashtech

Combo Man
Just to be clear, after wetsanding the old sealer and cleaning it, I can spray new sealer on it just prior to t basecoat with no adhesion concerns? This is my understanding, just dont want to go backwards anymore. Thx again
That's exactly right.
 
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