I'm working on a hood but not that experienced with body work/ paint. I used an Omni 2K high build primer and blocked it out. There are were a few (high) spots that went through the primer. I reprimered again tonight with the 2k and overall not looking too bad. There are just a couple spots where emblems have been shaved and holes welded that are still pretty visible. Now I don't think primer will fill it completely.

Can I use filler over the 2K primer?
Instead of bondo, I do have some finishing putty. (USC Icing Lite Gold Finishing Glaze) Would this work?

Other issue - I used up the entire quart of primer. Can I use a rattle can filler primer (like duplicolor or rustoleum) over just the couple spots that I need? Or would it be better to re-coat the entire hood?
The autobody supply place is not open until Monday and I was looking to paint this weekend.

Thanks!

No do not use spray can primer its garbage compared to the real stuff.

Yes you can use filler or putty over the 2k.

Recaot entire hood and block sand w/ guide coat.

my 2 cents worth.

Thanks for the input HemiRick.
Good news about using the finish putty. Was hoping that I could get away with some spray can in the 2 small areas and block the whole hood again. I'm guessing I shouldn't paint directly over the finish putty?

any putty or filler will prob show thru if not primed correctly.itried the rat can spot prime and the bondo showed thru the paint at certain angles,had to redo the whole qutr panel to make it right.

Yes the putty is what ya use. I try and stick with a poly based primer as fillers are polly based
I like the Evercoat brand products. Fillers and primers If relly needed blocked slick sand or equatorial
If plenty work was done after blocked i use a sealer PPG DP40Lf or what ever color ya need. one part hardener, one primer and one laqure thinner {paint grade slow}
Seals the deal before paint
And yes as stated no on the spray bomb

Keep in mind a poly based catalysis type putty, is "Super Bondo" so it is thin and has less chance of air holes.
A heavy filler type primer like slick sand is also a poly based product and can fill plenty like a liquid bondo

Solvents used to reduce two part primers and paints can lift the non-hardened stuff that comes out of aerosol cans.

Thanks all. I'll recoat with 2k.
No major filler, just a couple spots needed a skim coat. Was deep enough where filler primer wasn't cutting it.

Another issue - I have one small spot (.5 inch line) on the front of the hood where the primer isn't covering over. Ie. Coat with primer and it kinda lifts only along that line. How do I fix this? Hopefully the solution isn't stripping the hood to bare metal!

What is under that line that is causing it to raise up?

looks like self etching primer. It may have been a small spot I sanded and broke through to bare metal. I put the 2k over it. (The paint place said that it's not a problem if the 2k goes over small spots of bare metal.) There was other similar spots that covered no problem.

grease/oil?

I attached a picture of the problem after the last coat of primer. Doesn't look like much - but it kept coming back.

I did the finishing putty and re-coated. Everything looked good so I started the final block sanding. When sanding near this spot it suddenly broke through the primer and a chunk of primer came off. Under it was a red oxide looking primer. Then disaster. Was able to peel off all the new primer. The only spots that were really stuck was where I had the finishing putty. Now over $100 of material of the garage floor and have a big mess to fix. What went wrong?

The hood was painted with Hot Rod Flatz (1 stage Urethane) by the prior owner. I'm not sure what kind of primer he used. I was just going to repair and repaint it with the same paint. I sanded the hood with 220 grit. Then did a few coats of the Omni 2k high build primer. Let dry overnight and then block sanded. Another couple coats of primer, let dry overnight and then block sanded. Used the finishing putty today and sanded it. Sprayed a couple final coats of primer. I let it dry for 4 hours and then started sanding. That's when the problem arose. It was pulling the original primer off (under the original paint). What a frustrating day.

Unfortunately you have now been bit in the ass by the previous owner's improper paint job. That's why many shops insist on starting with bare metal. Sorry that happened to you.

Edit: Or did you mean the original factory primer/paint?

No, I meant the prior owner. It appears he started with bare metal. It was already painted so I thought I could just smooth it out and repaint. Unfortunately the entire truck is done like this. It makes me cautious to do any more repainting.

For future repairs - would applying an epoxy or sealer help? The primer I applied did not separate from the paint. It went a layer below the paint.

That's really odd, since the primer he applied did not adhere properly to the bare metal.

Wonder if he used a chemical stripper and didn't get all the residue off? Or some bizarre incompatibility between his paint system and yours?

I'd be nervous about painting over any existing finish on that vehicle. Sometimes you just gotta start all over again...

It was painted 3-4 years ago. The original builder seems more like a fabricator than a body man. The only reason I touched it was to clean up some welded holes.

I can't see why it would be incompatible. We are both using the same paint topcoat, just different primers. It also waited 3 days before I had a problem. Would the solvent in the 2k primer seep down through the paint and impact the existing primer? I'm not that familiar with the chemistry of these paints/ primers.

I'm not stripping the entire vehicle at this point. That might be a project for a future owner!

"Would the solvent in the 2k primer seep down through the paint and impact the existing primer? I'm not that familiar with the chemistry of these paints/ primers."

Yes, it can seep through and cause lifting. Best remedy is to sand the whole area to bare metal , then spray with the 2K primer.
Look at the way the whole panel is lifting. Either the primer that the PO put on was inferior or there was poor prep done before topcoating. Could be both. Sand that whole panel down to metal, prime with 2K.

Should I use the 2k primer or an epoxy primer over bare metal? Need to make a run to the autobody supply store tomorrow.

If I do any more panels in the future, is there anything that can be applied to prevent the lifting? It's not like the paint is falling off currently.

Epoxy first over the bare metal. Then the filler, then the high build 2k. Reason for doing this is the filler will absorb moisture and if put over bare metal. putting it between the two encapsulates it. I know most to not do it this way and will put the bondo to bare metal. I have done it myself. But if you are doing it on a car to last forever the above method is the proper way.

BTW that red primer underneath looks like the old red oxide lacquer primer. If so make sure you strip that hood before repainting. Based on the problems you are having I would strip it to bare metal at any rate.