Engine bat painting

[HemiPar]

Let me start by saying, I KNOW, I KNOW. thiis tread is worthless without pics. I will try to post some later. Until then.....
I am sanding the engine bay down to metal. I have had to patch a few spots, weld a few screw holes and smooth it down. My question is, After I sand down to metal;
1 should I epoxy prime then filler or
2 do filler then epoxy prime.
Thanks to all those who have a sugestion..

 

[OldVart]

Once you're down to bare metal, clean it well with a good wax and grease remover, then wait long enough to ensure there's none of the remover residue left on the metal. Give it 2 good coats of a quality epoxy primer, then you can do your filler on top of the epoxy primer. Just lightly scuff the primer where you're going to put filler.

 

[HemiPar]

Thanks OldVart. What grit paper should I use. I was thinking something in to 80-100 range. Now after I do filler, should I epoxy prime again or use epoxy primer as sealer?

 

[RedFish]

I will spray bomb a light coat of some primer on bare metal, if only to prevent rust starting before filler work is finished. Todays bondo will stick to glass but a rough surface is best. With the sanding , welding, grinding you've done already , it should hold well. Two good coats of exopy primer before filler is overkill in my opinion. It's all getting primer before paint anyway, right ?

 

[bobs340dartsport]

You should always seal the bare metal with epoxy (or some other type of self etching primer) prior to body filler application. Body filler can soak in moisture at a later date and the epoxy primer will prevent this from causing rust issues farther down the road.

I remember in the 80's when we used to grind to bare metal , apply bondo and then cover with primer as SOP. That is when many folks had a lot of bad experiences with polyester body fillers. I have used both methods and have found the paint manufacturer's recommendation to prime then fill to work the best.

Bob

 

[Rob]

Stay away from etchimg primer, epoxy over bare metal, like Old Vart said, sand it a bit for tooth and do your filler work, seal it with epoxy to prevent blead through, then high build primer if you want to block it and really get it straight. You can seal that with epoxy if you want but you don't have to as long as you have consistant coverage, so you're spraying your paint over a uniform color which is especially important with a base/clear system (base does not cover well).

You can rough sand your filler with 80 grit and work up to 220, high build primer will fill 220 scratches without a problem, final sand your high build with 400 - 600 and paint away.

Anytime you spray anything make sure you have either sanded the surface or you are within the top coat window, usually 24 hours.

 

[HemiPar]

Thanks guys for the info. I am hoping to finish the sanding this weekend but i think my compressor died on me. it has been cold here and I left it on. I went out to the garage last night and it is locked up. I am hoping I can work on it saturday and finish the bay area. Then prime, filler, prime again and paint. For the bay i plan on just useing singel stage. it does not have to be glass smooth but i dont want lot of waves. Again thanks guys