What have you guys been using over polyester spray filler as a sealer before paint? I use Car Systems spray poly and then an acrylic urethane primer typically. Is epoxy good to use? if so water based or solvent based? any advise is good. Thanks

With the urethane primer on top of the polyester, there should be no reason for a sealer. The only time I use sealers is when I am worried about the interaction between the existing paint and whatever I am top coating it with. I see no reason to use a sealer in this instance.


Regards, John McGraw

I always use epoxy (solvent based) as a sealer before base coat. I usually thin down 15%. Because epoxy is practically non-porous, I feel better about moisture being permanently blocked from reaching the metal.

I also converted to always using epoxy over the bare metal and then using any filler over the top of the epoxy.

Are there any issues to be had when spraying epoxy primer over a polyester filler, or is the problem only when spraying a polyester product over epoxy?

I used SPI epoxy primer reduced 25% with slow urethane reducer as a sealer one hour before spraying base coat.

Sealer prevents dieback, promotes adhesion, acts as a holdout agent by preventing topcoats from sinking into primer which reduces gloss. Also decreases amount of basecoat needed if using a tintable sealer or valueshade system.

Thanks for the input. I think Ill be safe and spray the epoxy over the urethane, reason being I have some breaks through to bare metal and spray filler here and there.

Brian, from my reading epoxy under poly spray filler is a no no, but epoxy on top is ok. This thread confirms it for me.

Brian, from my reading epoxy under poly spray filler is a no no, but epoxy on top is ok. This thread confirms it for me.

Whaaaat?? I think you're misinterpreting. Epoxy over bare metal, then filler,skim coat, sprayable poly, 2k high build, epoxy sealer.

Jerry

Yes you are correct but the Car Systems Spray poly does not recommend epoxy filler or sealer under their spray poly.

Probably the same disclaimer made by most polyesther fillers. I wouldn't apply anything polyesther based without epoxy first, at least on any high end job.

Jerry

I will be making the transition to epoxy under my filler on the next job we do, the 67 Dynacrap Camaro we are finishing.

I have never heard of issues using polyester primer over epoxy or epoxy over polyester. I use Evercoats Slicksand and usually PPG epoxy.

Is that what the technical sheet says for your particular polyester primer?

I laid down the Epoxy and it looks good, just got a few dust nibs to sand out and Ill be basing in the morning. Ill post some pics.

Thanks for the advise guys, here's how it came out

http://www.bsmexhaustworks.net/images/480_IMG_7481.JPG

http://www.bsmexhaustworks.net/images/480_IMG_7493.JPG

Its not a Chevelle or even a GM for that matter but we work on Fords too..