Giant craters

50Shep

Promoted Users
I cleaned body filler with w&g waterborne and let it sit 24 hours before spraying epoxy. I got this weird issue (giant craters). I’ve gotten the smaller craters before if air pressure is too low but these are bigger than normal, like an adhesion issue. Any ideas? Should I strip it back down to the filler? Thank you
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yep thats the epoxy and what i does when sprayed too heavy with too much airflow over it. is from the alcohol in it flashing off too fast. when air from the gun blows on the surface then it flashes off the alcohol too fast and leaves you with the massive cratering. alcohol based wood stains and dyes do the same thing. it doesnt harm anything though. sand smooth and continue on.
 
Out of all the epoxies I have used(transtar,ppg) SPI is the only epoxy I have had this happen with it and honesty its been happening more and more. So according to jim, I need to tighten up my fluid and possibly lower my air pressure alittle?
 
Good news. Thank you. I hadn’t had this issue in awhile so I think I got over confident and put it on too thick. orangejuiced86, I’ve been all through this forum: you will find that some people say to turn the air down, some say to turn it up…. I take it to mean there is an elusive happy medium….. thank you all for the replies.
 
Out of all the epoxies I have used(transtar,ppg) SPI is the only epoxy I have had this happen with it and honesty its been happening more and more. So according to jim, I need to tighten up my fluid and possibly lower my air pressure alittle?
tighten the fluid a little. dont back off the psi because that will just make it go on heavier. back your gun away from the panel a couple more inches instead. add 10-20% fast reducer as well. i have been spraying the epoxy almost daily for 20 years and i still have this happen. the thinnest full coat you can get the better. your right, its the only epoxy that does it. i dont know why they put the alcohol in it. just stick with regular solvents, im not the chemist though lol. functionally its a great epoxy but it can be really frustrating to spray at times.
 
I never ran into that issue for years and I think maybe I just got lazy in the spraying technique.
 
I don't think the epoxy has changed. Depending on a person's spray style a "1.5" coat technique can be helpful, a light coat followed immediately by a medium coat. I'm not sure why it works but it seems to help.
 
At least I know I’m not alone! I wish it was consistent, just seems to be no rhyme or reason to it. Actually, it happens more when I use my 3M performance gun. My harbor freight purple gun shoots the epoxy better…. Go figure.
 
I have the same issue. I’m a noob but I’ve had some nice looking coats of epoxy but I’m clearly still finding the sweet spot on my gun settings. This was supposed to be the last one before 2k and blocking. Should I sand out and respray epoxy or better to move on to 2k and blocking? Will it come out or will I regret not addressing it now? I have just enough epoxy to do my final seal coat and prefer not to buy another full gallon. On that note, is it odd that I’m about to finish my 2nd gallon on the same car?? I’m clearly not efficient with any of this.
 

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I was consistantly getting this when I was using my LPH-440. I switched to my LPH-400 for epoxy and it mostly cleared up unless I get too greedy on the first coat or overlap too much.
 
It's just piling on too much material at once, just that simple. Moving faster or adjusting the material screw inward will help. Same goes for the LPH440 which can spray epoxy just fine if adjusted right. My 1.6 LPH440 does not have an issue, but larger tip sizes will need more restrictive fluid nozzle adjustment because the viscosity of the epoxy is lower than most other kinds of primer.

LPH440 is more efficient with material, operates well at lower pressures, and produces much less overspray. In applications that will be blocked and not used as sealer, it is much better than the LPH400 if it can be tamed.
 
I have the same issue. I’m a noob but I’ve had some nice looking coats of epoxy but I’m clearly still finding the sweet spot on my gun settings. This was supposed to be the last one before 2k and blocking. Should I sand out and respray epoxy or better to move on to 2k and blocking? Will it come out or will I regret not addressing it now? I have just enough epoxy to do my final seal coat and prefer not to buy another full gallon. On that note, is it odd that I’m about to finish my 2nd gallon on the same car?? I’m clearly not efficient with any of this.
I would level it out before shooting 2k. No need to apply more epoxy in the recoat window imho.

Don
 
I would level it out before shooting 2k. No need to apply more epoxy in the recoat window imho.

Don
Thanks Don, that was another instinct I had… to just flatten them out b4 2k. I just really don’t want to hit metal again… but I’ve already started to flatten out those spots. I also found some low spots on one side when I pulled it out in the sun so I had some more filler work to do anyway. …Never ending process with a 50 year old car. I have about the same number of “dents” in my 51 years.
 
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