Epoxy and rust problem?

B

bridgeport13b

So I sprayed my quarter panel with epoxy primer about 6 months ago, car is completely rust free before original paint was stripped. Anyways I had rust bubbles coming up under spi epoxy. I know it is not a product issue but something I’m doing wrong. I had 3 wet coats of epoxy as well. Could it be accesive moisture in air lines? I recently bought a desiccant water separator and a condensor to remove water. Just curious if that is a possibility.
 
Sure it could be moisture or oil from compressor lines. Last week stopped by fellow who wanted me to weld his quarters in on 68 Mustang. He used paint remover on the hood and fenders then washed with water about 3 pm at 4 pm he already had primer on the parts...............wonder what that will look like down the road? Let us know Bridgeport what u come up with
 
Think back, of course, this could be water in the air line but it would really take a lot, so maybe but not likely.

My guess 6 months was December
And what will cause this is cold metal causing condensation on the metal that would not be visible at the time or cold metal temp say 55 degrees and shop 70.
The outside will skim and solvents at metal will not evaporate leaving solvents and air to do its thing.
 
Barry said:
Think back, of course, this could be water in the air line but it would really take a lot, so maybe but not likely.

My guess 6 months was December
And what will cause this is cold metal causing condensation on the metal that would not be visible at the time or cold metal temp say 55 degrees and shop 70.
The outside will skim and solvents at metal will not evaporate leaving solvents and air to do its thing.
Click to expand...

Seen this happen with body filler applied in cool/cold temps. Metal is like Barry says 55 or so and body filler applied to it. Catalyst type reaction heats the body filler causing condensation on the metal. One reason why epoxy is so important under body filler.

When you sprayed it did you come out to a cold garage and heat it up? Cold metal will condensate on a humid day when you turn your heat on, especially if it is fairly cold in the work area and you are raising the temp 40 or 50 degrees.

You mentioned rust bubbles. Are you talking about surface rust or actual penetrating rust? Rust that goes all the way through? If that is the case it has nothing to do with the epoxy or how you sprayed it.
 
Hi so the rust was surface rust, but I was using a blow gun the other day and it was dumping water. I literally held my hand in front of nozzle and my hand was pretty wet. I bought a condensor and water separator with auto drain valve so will be installing both of those between pump and tank so I don’t get a rusty tank. I’m sure that was the problem. I don’t use air compressor often and didn’t think I had a moisture problem. I only hand a water separator on tank, but after some research I need to cool air before running it through a water separator.
 
The only thing that is totally safe for painting is a refrigerant dryer or a desiccant system.
Vapors will go through 5 water seperators in a row and vapor results in a lot of problem calls on the tech line.
 
The only time I've experienced water in the paint, you saw it as soon as it came out. If you had to ask the question, I doubt this was water in the line, you would have seen it.
 
Last edited:
MP&C said:
The only time I've experienced water in the paint, you saw it as soon as it came out. If you had to ask the question, I doubt this was water in the line, you would have seen it.
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True, most of my calls are with vapors showing up next day or event a week later.
Also, base blushing is another call I get a lot of.
 
Appreciate the help, I attached condensor and water separator and it seems to really be working. My high temp rubber hose at pump to condensor is breaking down even though it is supposed to withstand that heat so I will do a copper bend up tomorrow. Is a motorguard toilet paper filter worth the extra cash?
 
bridgeport13b said:
Appreciate the help, I attached condensor and water separator and it seems to really be working. My high temp rubber hose at pump to condensor is breaking down even though it is supposed to withstand that heat so I will do a copper bend up tomorrow. Is a motorguard toilet paper filter worth the extra cash?
Click to expand...
I really like mine!
 
Barry said:
The only thing that is totally safe for painting is a refrigerant dryer or a desiccant system.
Vapors will go through 5 water seperators in a row and vapor results in a lot of problem calls on the tech line.
Click to expand...

Wow, learn something new everyday. Thank you Barry!
 
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