Epoxy primer issue suggestions please!

[my5thmopar]

ops:This was the first time I have sprayed epoxy primer. The can had the VOC mix at 4:1:.5 so, that's 1/2 on the reducer. Well the data sheet (which I didn't have before all this) says 4:1:3 conventional primer or 4:1:4 for sealer using a 1.5 to 1.8 tip at 35-45 psi at gun. I shot it using a 1.4 tip and 30 psi at the gun. I did bump up the pressure and lowered the fluid and several other things but, no help. I can fix the spraying issue and I should have realized it was just too thick.

Here is the problem.....it came out thick, rough and stringy. I'm not too concerned with the underside of the d100 but the inside of the cab will be eventually painted.

I'm wondering should I sand the epoxy smooth and shoot the paint?
Use 2k over the epoxy and sand and paint as usual?
Correctly apply more epoxy then What???
BTW..I only have 1.4 and 1.8 tips.

Just not sure what to do. What say you bodymen?

 

[sireland67]

4 is the primer
1 is the reducer
.5 is the hardner

You can add more reducer to thin it out, what temp did you spary at, does it match the reducer temp.

Use the 1.8 tip, make sure the gun is clean, sounds like your gun is clogged or you have the air pressure way to high.

Just sand what you have and shoot over it.

 

[CudaChris67]

4 is the primer
1 is the reducer
.5 is the hardner

You can add more reducer to thin it out, what temp did you spray at, does it match the reducer temp.

Use the 1.8 tip, make sure the gun is clean, sounds like your gun is clogged or you have the air pressure way to high.

Just sand what you have and shoot over it.

yup, just need more reducer, and less hardner. I have had success with the 1.4 and the 1.8. With the 1.8 it probably goes on a little heavier (and faster) than it should, but it works.

if you stick duct tape on it and pull does the epoxy stay on? If so , it's good enough. just knock it down a little and do your high fill, should level out ok.

 

[B-onefan]

4 is the primer
1 is the reducer
.5 is the hardner

You can add more reducer to thin it out, what temp did you spary at, does it match the reducer temp.

Use the 1.8 tip, make sure the gun is clean, sounds like your gun is clogged or you have the air pressure way to high.

Just sand what you have and shoot over it.

I believe you are wrong, 4:1:.5 is
4 parts primer
1 part hardener
.5 reducer.

I would ask what brand epoxy primer?
What hardener?
How old is the hardener?
What temp was everything sprayed at and what was the temp of the primer/hardener? Make sure it is at least 65-70 degrees primer temp(not stored in a shed or cold garage.
Also, is the pressure 35psi at the gun or regulator on wall/compressor?
Even 35psi at the gun is low for a hvlp and would cause rough paint because of lack of atomization.


Hope this helps.

 

[sireland67]

I believe you are wrong, 4:1:.5 is
4 parts primer
1 part hardener
.5 reducer.

I would ask what brand epoxy primer?
What hardener?
How old is the hardener?
What temp was everything sprayed at and what was the temp of the primer/hardener? Make sure it is at least 65-70 degrees primer temp(not stored in a shed or cold garage.
Also, is the pressure 35psi at the gun or regulator on wall/compressor?
Even 35psi at the gun is low for a hvlp and would cause rough paint because of lack of atomization.

******************************************

Most paints I have seen are reduced as follows.
First number base (in this case primer)
Second reducer
Third hardner (some systems use it, some dont)

Anyways, we dont know which paint system he was using, either it was mixed way wrong, or possibly he did not stir the cans enough before mixing.

Or his gun settings are way off, how does the gun shoot when you clean it out? Does the gun shoot straight laquer thinner out the tip in a nice even pattern?

 

[my5thmopar]

Thanks for the suggestions. The primer is autobody masters 8411,8121,8870. I've used their stuff before and never had an issue. Quote... from data sheet, It was mixed as VOC Compliant Primer 4 parts Epoxy Primer 1 part Epoxy Catalyst Up to 1/2 Part Urethane Reducer. 5 Min. Mechanical Induction. Primer was kept in the house and garage was heated to 70 degrees. I'm sure the issue was thick paint, small nozzle, and low pressure.

I tried the duct tape trick in several places this morning and it wont pull off. The primer is hard and it is sands producing dust and not gum.

The inside of cab was sanded with 80 grit. I'm sure the epoxy had something to bite to. I took the surface back mostly to metal where the paint came off easily. The cab had one bad repaint which the paint and red oxide primer was removed completely. Some original paint on firewall and behind seat was sanded and didn't want to come off.

How should I finish the inside of the cab?

Any need for more epoxy or just scuff and 2k. The rest of the truck is going to get epoxy and 2k. It seems that maybe a coat of 2k would be easier to sand before paint. Again this is my first time with epoxy.

Thanks Craig

 

[B-onefan]

I would check the gun and pressure out first. If it didn't spray the epoxy very well, then the 2k will probably be worst and that's too many $ to waste. Was the hardener brand new, never opened? Once you bust the seal on any kind of hardener, it's days are numbered, depending on type, humidity and such. Also, check that the epoxy has no zinc in it. Most of the epoxies I have used are designed to NOT be sanded because of zinc content and the possibility of zinc poisoning thru your skin and breathing the dust. Also, most 2k primers are not designed to go over large metal areas and may not stick as well as it should.

Good Luck and let us know what you found solved the problems.

Mike

 

[CudaChris67]

Sounds like you got it to stick. If you are doing body work now is the time. But if you are ready for the 2k, decide f you are going to shoot in the recoat window, or if it looks like stucco, maybe knock it down first.
X2 on checking the gun before shooting more, waste can be costly.

 

[Idaho]

Not a body man but I'm wondering what your test spray pattern looked like when setting the gun?

 

[Ramdude]

Let me see if I can help clarify things a bit. There are two things that could have happened with the epoxy when it was mixed. Either not enough reducer was used, or the wrong reducer was used. Certain solvents like xylene don't melt into the epoxy very well (you'll know when stirring it. If it doesn't mix in easily its the wrong solvent). Always mix epoxy and catalyst first, then reducer. When properly mixed it should be slightly thicker than water in consistency.

The only application I would use epoxy primer for is bare metal. Epoxy sticks really well and is very corrosion resistant. Urethane (2k) primers are used for priming over other coatings and body fillers. Urethane primers are easy to use and sand really well. You can also use a very thinned down epoxy as a sealer before applying finish.

For your project I would prime all bare metal with epoxy. Apply urethane primer over epoxy and sand with 320 grit paper until smooth, then apply finish. For areas such as under the cab you could just apply finish over the epoxy.