Projects When to apply body filler?

Ask ten automotive body guys, refinishers, painters or hobbyists ONE question and you'll get twenty different answers. Filler over metal or epoxy either way is fine.

What I absolutely refuse to use are any types of one part, lacquer based spot putties or primers.

 

Thanks for all the responses everyone! I went ahead and put the body filler over top of epoxy primer. I have now run into another issue. I have MANY air bubbles in the dry primer. I had some before, so I sanded it and tried again; and I just made it worse. What can I do to get rid of these air bubbles in the primer? Would a glazing putty take care of it, or is there something else I need to do?

 

can you take a photo of the "bubbles"?

 

Need pics.
What epoxy and how old is it?

 

Epoxy with air bubbles sorta negates all the reasons anyone would apply epoxy

 

The first image is a portion of the bubbles without flash, the second is with flash on. I'm pretty upset about this...I've been spending months just trying to get this right, and I mess up right close to the end...

I have epoxy primer underneath, and the bubbles seem to have appeared after I used high build primer.

 

That panel isn’t ready for high build primer yet.whats under the high build?
Filler, yes but what type, brand.
Sorta looks like the air bubbles are in a bad batch of filler.

 

Wait I'm a little confused...I put down epoxy primer, then filler, then put down more epoxy primer. The bubbles started appearing after I put down the high build. The filler was Evercoat Z-Grip, and the epoxy primer was a 2K i bought in an aerosol can and the high build SEM aerosol. I can't afford anything better than that.

 

The only place I'd use an aerosol can on body panels is hidden underneath or inside. Never on the outside.

 

Hmmmmmm
2k aerosol cans ain’t cheap.
There are quality, lower cost professional products out there designed for this process.
Every aerosol product I have used is designed for spot repair.
Not all overs.

 

This just keeps getting better....

 

Just watch John Kosmoski. This is a great video and I've watched it several times. Lots of great info to glean here.

 

That panel is far from flat and straight enough for high build primer.
Are you trying to fill those low spots with high build primer?

 

I agree that panel needs more than hi build. But, the pits are either fish eyes from contamination under the primer or solvent pop from trying to build too much with that thin aerosol. The pic isn’t clear enough to tell. In any case it has to be sanded to a flat surface. I’d block it with 120 and take a look after the pits are gone

 

My first guess is way to much aerosol product And too fast Let alone before it’d ready. But I’m just guessing. And somebody left out the little fact they were using spray can epoxy under the filler. Most of the opinions came from guys using real stuff, high solids professional epoxy with quality solvents and resins. Spray can ??? Who knows what’s in there.

Never enough time or money to do it right the first but somehow there’s enough time and money to do it 2,3 or 4 times.

 

Looks like the high build reacted to the epoxy. Did you read the data sheets for both products before using? SEM TDS does not list epoxy as a suitable substrate for their aerosol high build primer.

 

1950= when you get the metal within 1/4”
2020= when you get the metal within .005”

 

I'm not too concerned about the imperfections; I know its not going to be perfect, I'm not a professional, I'm a guy in a suburban neighborhood garage. As long as it looks better than rust, and obviously new metal lasts longer than rust, then I'm good. I'm concerned about the bubbling because I don't want moisture being trapped in there.

 

Looks like unhappy chemicals

 

The sanding block and bondo spreader won’t know the difference where they are.
The chemistry don’t give a shit either,,, it’s got to be right no matter who’s doing it or where it’s being done. Everyone is on an even playing field on that one thing and everyone dances to the chemistry’s tune.

 

First mistake was using a spray bomb epoxy primmer. Did it sit long enough to fully dry?
Then you added the filler, probably OK, if the epoxy was fully dry.
After the filler, you sprayed another coat of epoxy, then a coat of high build primmer. There is a good possibility the two primmers don't like each other.
My next thought was that maybe you sprayed the primer coats on too fast on top of each other and they couldn't fully dry and what you are seeing is the gasses trying to come out.

At any rate, the fix is to sand until you get past the bubbles and get everything back to smooth. Sand until the bubbles are gone, even if you have to go all the way back to the bare steel. Then you need to use just the filler and then the high build as you sand it smooth. Be sure you let the primmer set long enough to fully dry, the spray bomb can will tell you how much time you must have between priming and a top coat or between priming and sanding. You can not short cut the drying time.
Do not spray any more epoxy on your repair. Its OK for the bare metal, but after that, use just primmer and filler, not epoxy.

I've painted a whole car with spray bomb cans of primmer, covered with spray bomb cans of a top coat color and some of those paint jobs have lasted 4-5 years. The drying time between coats of paint and primmer is important, being too quick, or taking too long between coats always ends with bad results. Gene

 

Let me preface what I'm about to say with this: I'm not trying to pick on you.

That being said, I absolutely despise this attitude. In cars. In life, generally. It's an excuse. A cop-out. An acceptance of mediocrity. Ask the right questions on how to do something the right way, then ask the next questions about how to accomplish it within your constraints. People on here are taking the time to give sound advice. If you don't care about how it's going to come out, why bother asking and wasting their time? And while you may not be an expert or professional today, the knowledge you glean from doing your best is just another step closer to getting there eventually. Or you could just say, screw it, I'm just a guy in a neighborhood garage.

BTW, this car had paint and bodywork done in a suburban neighborhood garage. There are plenty more examples of the same on the HAMB.

37561_784832801724_3724913_n by 57JoeFoMoPar posted Aug 1, 2014 at 1:26 PM

 

How long did you let the epoxy dry before you sprayed the high build? If a specified recoat time is not listed for the type of product you are putting over the epoxy you should generally wait at least 24 hrs to avoid reactions.

Sent from my SM-G950W using The H.A.M.B. mobile app

 

This

Go back to my post on the 2nd page. There are guys on here giving you info that is way above what you're trying to achieve. Follow the steps in my post. Do the body work as best you can, straighten the metal first the best you can get it. When you've done the best you can, then apply filler, get that step as best as you possibly can. Take your time, several thin coats is better than 1 thick one. Feel it with your fingers as you work it, your fingers can feel things your eyes won't see. When you've got it as best as you can get it, cover it and any bare steel that is left in self etching primer. When all of that is done, when all you have left now is to level out the surface, THEN go to the high build primer. Spray it and block sand it down; repeat, again, and again. And again. Use a guide coat to help you identify low spots. A guide coat is a VERY light coat of a darker color, flat black works fine. As you sand the guide coat you will see the low spots. Lay down more high build primer and do it again, until all the low spots are gone. Take your time with this and you can end up with a better paint job than a professional job where the guy skips this because it takes too much time. After a final blocking seal it a with a sealer primer and you're ready for the color. If you don't have spray equipment you can do all of that with spray bombs. Guys have been doing that for decades, going back to whenever it was that spray bombs were first invented; it is traditional. Search out the threads here on the HAMB of driveway paint jobs, and rattle can paint jobs, and brush or roll on paint jobs, there are threads for all of those. That's where you need to be on this project. As Gene Koning posted, pay attention to the time between coats, there are time windows that you have to follow. Failing to follow those time frames can result in the failure you have now, not letting the previous layer gas out before applying a coat over it, or waiting too long.