Epoxy didn't stick

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Prplpny68

Hi everyone. I am new here and need some help. I worked at a resto shop for several years that used SPI stuff and I loved it. I changed jobs about six years ago and just recently got my garage set up to do some painting. A couple of weeks ago I tore into my 68 mustang. It was my first car and I want to do it right. It has 3 paintjobs on it so I am stripping it to bare metal. Since I have been out of it for a while I have spent the last month reading a lot of the posts on here and taking copious amounts of notes. Here are my details.

So far I stripped the quarters and trunk jamb with a razor and stripping disc on my angle grinder; no chemicals. I used a kerosene space heater to get my shop around 90 degrees and made sure my metal was plenty warm. I drained my compressor and air lines. I let my epoxy induce for 30 minutes, went over everything with 80 grit, used waterborne w/g remover, waited 30 minutes, and put on 2 coats of un-reduced epoxy with 30-45 minutes flash time in-between. After the air was clear I turned my heater back on for a few minutes. I checked again that evening and it was still nice and warm in there. That was Sunday. I went in Tuesday morning and spread a layer of tiger hair on the patch seams. Wednesday morning I hit the tiger hair with 36 grit on my DA and then 80 grit with a block and noticed that the epoxy was not feathering at all. I used my blower to blow off the dust and the epoxy started to blow off in chips. I tried a razor and peeled up more of the epoxy effortlessly. The ambient temp here has been from the 50s � 70s the past few days.

I did my other mustang the same way several years ago and had no issues. Can anyone think of something that I missed or offer any advice?
 
So, you are using black epoxy? From the pictures, it doesnt look like bare metal under the epoxy. Was the epoxy itself room temperature when sprayed? If it was stored in a cold garage, I bet it was not warm enough.
 
My guess is the waterborne W&G remover wasn't flashed off completely.
Personally I prefer the solvent based as a final wipe. Did you wipe on and wipe off with a clean and dry towel?
 
Definitely looks like a contamination issue between the metal and the epoxy, I use waterborne cleaner all the time and it works the best IMO. Maybe the kerosene heater put a film on there? Did you have any fisheyes?
 
I don't have an answer for you but look at the size of the fish eyes in picture three under the glass, these are extremely bad, may or may not be related.

Any chance you used a low grade reducer with the epoxy? Or have an oil problem with the compressor?

Rarely will contamination cause a major problem like you have, usually only spots, so only thing I can think of to cause the epoxy to do it uniformly would be a low grade reducer or an acid film or not activated properly.
 
strum456;17599 said:
So, you are using black epoxy? From the pictures, it doesnt look like bare metal under the epoxy. Was the epoxy itself room temperature when sprayed? If it was stored in a cold garage, I bet it was not warm enough.
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Ok, I can see it is bare metal now. I mess all kids of stuff up when I try to use my wifes "smart phone".
 
Thanks guys. The car still had the original paint under the two other paint jobs and it was stuck really well so whatever happened was caused by me. I got the same fish eye problem on the other quarter at the same spot and nowhere else so I assumed maybe it was some of that thick grease from the quarter windows since I had to take them out.
I guess it could be the heater since it was fairly close to the car. Never had a problem with kerosene before, just diesel! I didn't use any kind of reducer for the epoxy, just 1:1 with the activator. I did however have to add some oil to my compressor, but I made sure I didn't overfill. Is there any way I can test to see if I have oil mixing with my air? And is there any kind of fix for my mess or will I have to strip it and start over?
 
Should not have happened with the prep you described but I would bet the metal suface was contaminated.
Has silicone ever been used on those windows?
 
I only have a small desiccant dryer right off of the compressor. From there in runs through pvc into the booth. I have ball valves in 3 different locations to drain what water collects in the pipe past the dryer.

As for the windows, I have never used any silicone on them. They are a pain in the butt to take out so that was only the second time I have messed with them. I knew I got some of that grease around the opening but I was afraid to use lacquer thinner or anything like that. I guess I should have used multiple applications of the waterbourne stuff.

I will do some more checking on my compressor and lines and maybe try it again this weekend.

Thanks.
 
There has to be some reason for adding oil to the air compressor, so it sounds to me like your compressor is putting oil in the air system. Might be time for rebuild, and definitely a better air dryer system. Your desiccant dryer should only have to remove whats left after the air is cooled and gone through all the water traps.
 
i have run toilet paper filters in my booths for years. if anything makes it to the booth they will catch it . if oil were to make it that far the paper turns yellow.
but something else is going on here. too much coming off to be contaminate and not enough fisheyes.
 
shine;17631 said:
i have run toilet paper filters in my booths for years. if anything makes it to the booth they will catch it . if oil were to make it that far the paper turns yellow.
but something else is going on here. too much coming off to be contaminate and not enough fisheyes.
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I agree. My vote is that this is a temperature issue. I am not sure if it is a good idea to use a kero heater near your anything you are going to paint. I don't even own one, but I doubt they burn all that clean?
 
If it is a temperature problem is there any way to fix what I have? I mean if I get my booth hotter than hell could the epoxy finish doing its thing or is it "done" and I need to take it all off and start over?
 
Probably the best thing you could do is call Barry and tell him everything that could be a factor. I just about avoid painting anything in the winter altogether because temperature is everything with epoxy.

I am completely guessing, but if your epoxy was stored in the garage, then you heated the garage, the epoxy itself would still be whatever temperature your garage was before you heated it. This combined with questionable temperatures to begin with are the basis for my GUESS.
 
by now it should be done so to speak. if it is bonded now it was temp if not then it needs to come off. rule of thumb for me is everything needs to be 70. paint - metal - booth . i use a diesel heater outside of the booth and can keep it 70+ even in winter.
 
Soo many variables that can cause problems like this.. Im with shine here.. It should be either locked up and stuck or if it still peels, it needs to come off
 
Ok. Thanks again everyone. I will take it off and start again this weekend...

Shine, do you have a specific filter system for you heated air? In the first shop I worked at we had a mechanic side and a paint/body side. After about 3 jobs with terrible fish eye problems it dawned on us that we did some work on a diesel truck and the exhaust was close to the filters for the booth. We replaced the filters and it cured our problems with fish eyes. I use my little kerosene bullet heater to get the temp up and then use an oil filled electric heater to maintain the temp. But if the kerosene might be my problem I need to figure out a way to use it but isolate any fumes from it.

Also, can anyone recommend the proper amount of time to maintain 70+ temps to cure the epoxy?
 
just regular sticky filters and they are old as dirt. i use farm diesel . if i heat the booth with my small one i clean right before i shoot. in winter if i have to shoot i heat it all up at once. i try to be in the build room during summer and winter.
 
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