The Stovebolt Site Forums The Shop Area Paint and Body Shop Epoxy primer problems

I sprayed a RTS epoxy primer on my truck, and its been on the truck for a week or better. I sprayed some HB can primer on the epoxy to prepare for a guide coat and the primer cracked ( like wet lightening bolts) every where there was epoxy. I dont think the epoxy ever fully dried completely. If I was to run a DA over it, it gums up. What do I have to do now? Sand it all off? Or will it eventually dry completely? I had planned to spray poly primer next, is that a bad idea? I'm open to suggestions, I really hope I dont have to sand it all off because of the gumminess underneath because I epoxied the interior too, what a pain.

Sounds like it was laid down too thick.

http://autobodystore.com/forum/index.php

This site has good info.

I am not a painting expert but I will share my experiences and what I learned doing a lot of searching. The epoxy primer will never sand well but does get a lot easier over time, like a couple of months or more. I don't know if the primer you sprayed over the epoxy was compatible or not but in either case you were likely outside the overcoat window without sanding. You should at least scuff up the epoxy before the next layer if you are outside of the time for over coating. You need to determine if the two products you are using are compatible. If there are not the same product line you may have problems.

What I have resorted to is once the epoxy primer is dry I spray 2K sanding primer over that (72 hour window for my epoxy product). Then you are able to sand easily. Even when you get into the epoxy layer a little the dust or action of the 2k primer seems to keep the epoxy from balling up.

Chuck

A week should have been enough if you shot in the manufacturers temp and mixed correctly. I noticed you are in Michigan, what is the temp? What was the temp when you sprayed? And the following week? If you spray a topcoat outside the window you should sand. Though I don't think it would spider like you describe.

Just go back over the manufacturers mixing and temperature guides and be honest with yourself about whether or not you followed them to the "T".

I had it 70 degrees or more for probably 4 hours during and after spraying that day. Its been in the low 20's or less at night since then and no heat going in the garage. The primer was suppose to be already reduced and ready to spray according to the manufacturer. It was too thick Im sure, it was real hard to shoot. So my guess is that it was applied too thick because it shouldve had additional reduction/ with cold weather and that spray bomb primer must be a lacquer base and it ate the epoxy all the way to the metal. I wiped the primer and epoxy all off down to the metal where it cracked( mostly on the horizontal sufaces and places where the primer was probably the heaviest).
And left what didnt crack on. Do you think I can continue on with poly primer now that its fixed even though the remaining epoxy is slightly gummy underneath from being sprayed too thick.
Do you think it will eventually dry/cure? (The epoxy) and not cause problems down the road.?

If its still gummy, leave it for another week or so and see if it dries. If not, you'll need to remove it.

If you shoot over it you will just be trapping the wet epoxy under and you don't want that.

20 degrees at night is a huge swing in temp. Do you have a space heater for your garage?

Epoxy is great stuff, it's too bad you are having problems. I feel for you.

I remember spraying my axles with epoxy and it was terribly humid here in Florida and it took a solid two weeks before it dried to concrete.

Its going to warm up this weekend ...hopefully...lol
Maybe it will cure up soon. I do have a space heater but unfortunately it uses alot of propane and is expensive to run for long periods of time. It does seem to be curing a bit more everyday, but its still a little sticky down at the metal, especialy if I was to hit it with a DA. Does epoxy stay shiny on top for a long time because I noticed it is pretty shiny? Or is that another sign its not cured? I think this RTS epoxy is more for industrial projects, does that make much of a difference?

What brand of epoxy are you using?

Did you add a hardener?

I don't know of a single RTS or Ready To Spray epoxy primer, they ALL require a hardener.

Its made by martin seneour PIP 102 epoxy.I think its an industrial epoxy. There isnt any hardener to it, only thing is you can reduce it more with an additional reducer. I didnt know that at the time. I thought it sprayed hard because of the small tip old conventional gun I used. And I had never shot an epoxy before now so I didnt know how thick it was suppose to be.

Here is the tech sheet for the epoxy.

http://www.martinsenour-autopaint.com/media/pds/english/9492.pdf

Epoxy primers are meant to be force dried, by either a heat lamp or a spray booth with heat or a bake cycle.
Then wet sanded.
If not force dried it will stay gummy for a while.

I remember mine being shiny even when fully dry. Sanded nicely. I used Eastwoods Epoxy Primer and it came with a hardener.

How long did you let it set before shooting it? My epoxy primer needs to sit after mixing for a certain amount of time before spraying.

If there is no hardener, it's not epoxy. Epoxy cures by cross linking caused by the activator.

Good point Builder! I timed mine for 35 minutes as stated in the instructions.