epoxy peeling

S

Steves69LS3

hey guys last week i sprayed two coats of epoxy followed by a 1:1:1 reduced coat .
my bodywork had 400 grit scratches i kept the heat on for at least 10 hours in the 80-90 degree range.
then i wetsanded with 600. today while i ran a gray scuff pad over the car i noticed on dome edges that i can scrape the epoxy with my fingernail. this only seemed to be in areas where there are edges. like trunk gutter edges and edges of holes where tailights are mounted. i took those areas down and feathered them back in but would like to get an idea of the cause.

thanks
 
That's a tough one as I know you would have prepped the panels, perfectly.
Only guess I have and maybe someone else will have a better idea??
Could you have dry-sprayed the edges? Staying away from them and getting an overspray build up? Only GUESS I have.
 
yea it is a tough one Barry. i'll try to get a pic later. it could be overspray but it also happened around the heater vents on top of the car where i covered with all 3 coats.but after scraping a little i start to hit fully adhered spots and then i just take 320 and feather it back in no problem. now i just have to go around the car and make sure i got it all
 
What was your cleaning procedure before applying the epoxy? and what reducer did you use? Does the epoxy seem soft?
 
Oh and using normal reducer. Didnt really turn heat up until last coat flashed off real good
 
Should i just play it safe and go over the carvwith 600 on a DA? Im seriously running out of time
 
That would really worry me. I'd feather those problem areas back and see if there is any more delamination.
 
Were the first coats not reduced and then the final coat reduced? I would bet the final coat reduced 1.1.1 while over none reduced coats then heated is the issue. I would give it the tape test. Get some good tape and put it on there rub it on hard and ripe it off fast and see if any material comes off with it. You might be able to use a blowgun with high pressure and see if you can get the edge to peal back.

I did something similar to that on a '57 Chevy door years ago and it was a warm day and when I came back to it the next day it had cracks all over it and I started the PITA sanding project. The surface dried faster then the base coats causing the extra work.
 
I'm always of the mind to put coats on from fastest to slowest, yet I've been told that reduced epoxy is faster than non-reduced. I can't imagine that the procedure used caused solvent trapping, but other than contamination it seems like a likely suspect.
 
Steves69LS3;n72734 said:
Here is a good pic of what the problem is like
Click to expand...

Being the problem is on an edge like that makes me wonder if the poor adhesion is from a cleanliness issue. This area- how long did it set between being sanded with 400 and applying the epoxy? The reason I ask...I've seen parts that were sanded and set aside or handled for a period of time have similar adhesion problems even when cleaned well with W&G remover before a reprime-anything that's been sanded and set aside for awhile I usually rub down with a scotchbrite before repriming, or sealer application. Sand back/feather those areas and do some tape tests on other areas to confirm the issue isn't anywhere else. After a one week cure it should have never chipped off like that.
 
Also what is under the epoxy in this area/edge? Is there any chance that this edge was not scuffed or sanded?
 
I seen a 32 chev coupe project start loosing all it's paint on edges and in various other hard to scuff nooks and crannies. Closer investigation found the old timer that did the work did not scuff and sand a lot of areas between priming sessions. He didn't realize the new to him urethane primer he was using required full sanding or scuffing for good adhesion and was using the primer like he did back in the old lacquer days. People back then didn't have to scuff everything between priming sessions-it all melted together.
 
Everything was scuffed with a red pad and cleaned very well. I'll do some tape tests after work today
 
Also the car did sit out in the sun for a few days body temps were mid 90's and there were no visual signs of any problems. It sat in the sun after i layed epoxy down and after i wetsanded with 600. Under neath was properly prepped slicksand dry sanded with 400 and red scuff pad day before my last coats of epoxy
 
Passed the tape test. So im thinking its just overspray like barry mentioned
 
That's good to hear, I'm releaved for ya that could have been troublesome. I would agree that it should be good to go, feather everything back and have some fun. Good call Barry.
 
Yes me too. I was using 3M yellow tape. Should i try another tape? Maybe duct tape?
 
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