What kind of filler over oil based primer?

[les45]

I plan to use Valspar tractor paint with oil based primer and topcoats on my weekender. I have sealed the plywood skins with four coats of CPES, filled all screw holes, staple holes, dents, dings, etc. with Smiths Fill-it epoxy filler, and glassed all the joints with Aeromarine 300/21 epoxy over 4" glass tape. My question is what kind of filler do I use over the oil based primer for those small places that I might have missed while final sanding? Will the Fill-it work over oil based primer or is there something else I need to consider?
Thanks,
Larry S.

[doug hodder]

If you haven't put the oil based primer on it yet....hit it with some rattle can primer or a dark paint, just enough to give it some color coat, then block sand with a long board. Any high and low spots will show. I wouldn't be planning on any type of filler over an oil based primer however. Doug

[les45]

If you haven't put the oil based primer on it yet....hit it with some rattle can primer or a dark paint, just enough to give it some color coat, then block sand with a long board. Any high and low spots will show. I wouldn't be planning on any type of filler over an oil based primer however. Doug

Any compatibility problems with the rattle can primer over the epoxies? That bond becomes part of the critical path for the topcoats.
Will the Fill-it bond with the rattle can primers if I use it for final touch up filler?

[doug hodder]

Automotive type paints can be shot directly over the epoxy. Any fillers need to be put directly on the epoxy coated substrate, whether it be bondo or thickened epoxy. Once you find the low spot...I take a pencil and circle the area....scuff the epoxy really well, and apply the filler/fairing material. On a cured epoxy substrate, it's all mechanical binding on the paint at that point so it needs to be scuffed. You use a spot putty to take care of any blemishes once you prime it. However, the spot putties are lacquer or solvent based so they probably won't work on your oil based primer. I don't know of a spot putty made for your material.

I use acrylic urethanes on my paint work, so am no expert on the oil based products. I'd drop the manufacturer an e-mail with your specific questions. An oil based primer and top coat will hide a lot of issues I'd imagine though. Doug