Epoxy cratering, need help.

S

ssinnovations

So I know I am doing something wrong here and at this point I just need to salvage the job. I am painting the under body of my vehicle, it was media blasted and meticulously clean before I started. I followed the recommendations, prep with the SPI waterborn W&G remover, waited an hour before painting. Garage is heated, temp about 70-75 degrees. Air is clean, 30 feet of pipe, Sharpe 606a + Motor Guard M100, new hose. Devilbiss FLG4 1.5 tip

I shot Thursday night and when the work was done I had tons of spots all over it, they look like little craters everywhere. When shooting the first two coats I was having trouble with the regulator at the gun, pressure kept falling off, I read through a bunch of posts, talked to Barry, concluded my pressure was too low. Today I spent hours sanding all bad areas and prepped for a final coat. Bought a new regulator, set pressure at 24lbs, fluid tip out two turns, fan 90%. Still cratering.

Not sure what to do now, any help would be much appreciated, I am really frustrated with this stuff. I tested it out on my fuel tank last week and got great results, now when it matters I am botching the job. 100_2967.jpg
 
According to what I am seeing in your picture, if these are not indentations from pit rust, then I would say it looks like fish eye to me. Your fuel tank may have come out ok, but that is a smaller area to spray. It appears that although you cleaned the surface and used grease and wax remover, that you still have a fish eye issue. I would have to assume it is coming from your air line (compressor). Have you tried to take a wipe all and hold it against an air blower and blew into it for a time period, watching for anything that might be oil? I used to check myself like this and look at the wipe all afterwards to see if I could see a coloring in the wipe all that would represent oil. I would bet as long as no one was spraying anything around silicone based in your working area, that your issue is with your air compressor and contaminated air lines. I would think if it had been an issue with the product it would have done it on your tank also. Hopefully someone else will chime in. Maybe Barry will have some answers for you. Good luck getting this straightened out. Keep your head up. :)
 
i have had this problem before. its very apparent with the white epoxy. i have sprayed full cars with the black epoxy with perfect results. when spraying the epoxy the first coat is extremely critical. i have read that guys on here would spray their first coat very light to kind of act as an initiator for the second more heavier coats. i have even tried that technique with the gray epoxy shooting the shell on my camaro. i sprayed the first coat with my fluid adjustment on my gun only 1-1/2 turns out. let it sit for around an hour and sprayed my next 2 coats with the fluid out 2-1/2 turns with about an hour in between. not one blemish.

just be patient you will have great results
 
here is a quote from Barry when I had cratering issues

use this as a reference

If they show up in the first coat it is always one of the three.
To low air pressure.
Wax and grease remover still in pores of metal.
Water vapors in air line.

The above is under the assumption that there is not a contamination issue.

If in second coat:
Water vapors in air line.
Two low air pressure.
Not enough flash time.

Testing of this has showen, that the epoxy will cure out and bond well AS LONG as it is not a contamination issue, cure just may be slowed down a few days.
 
Great info here.

No rust pits, metal was in extremely good shape.10.jpg

I just tested the air on a clean white piece of paper towel, held it there for 5 min and it's perfectly clean and dry. Filters seem to be doing their job well.

I waited an hour after W&G remover, I am confident it was gone.

I guess I am back to an air pressure problem?
The only other thought I had was this is somehow related to a gun angle issue. I am using a Devilbiss FLG4 HVLP with a siphon feed set-up. It has Dekups and works at any angle but maybe the fact that it's parallel to the ground is messing up the atomization? FLG4-CNS-115_HVS-315.jpg

I purchased this one because I knew I would be on my back painting this, the car is about 2 feet of the ground. The cup on the bottom made things a lot easier.

Anyways, what's my next step? Yesterday's coat (#3) went on last night. Should I sand again and try to re-shoot? I have more paint already mixed so if it's fixable in the near term I would like to use it.
 
I get those when I get to heavy on my application of primer.
 
I spray epoxy with a 1.4 tip and only have trouble if I lay the first coat on too heavy. The black seems to be more forgiving in this regard but even it will produce craters if applied too wet.
 
Okay, less fluid more air. 28 lbs too much with 1 .5 ?

Also, looks like the humidity here extremely high today (88%) Should I wait?
 
Thanks for all the help guys, I sanded and shot a final coat with raised pressure and reduced fluid, worked great. I only wish I had this figured out in the beginning, there are still several areas with issues that I am going to leave alone, it could have been perfect but glad to learn.
 
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