Hot Rods Need help with primer PLEASE

Actually this time I did not search. I would imagine there are a billion posts about primer. Flame away if you want to, but if you do, please have an answer to my question. If I am going to take a beating, leave something behind. But my situation may be different. I have a 32 5 window body that was sand blasted and the blaster did not take all the bondo off. I am going to leave a lot of it on. So I have a body that is raw metal with bondo on it. Which primer would work BEST? I am not going to take it down to bare metal.

 

You always want to do most of your body work on bare metal. If you're confident there's no rust or adhesion issues that may haunt you, then you're exactly where you want to be before primer. You'll either want to use an etching primer or an epoxy primer. Lots of opinions for each - I've traditionally used etch but now moved on to epoxy.
If you're at the stage for a high build, get that on per the spec sheet for the first primer you are using to eliminate the need to re-sand.

 

I should have mentioned that I need to add more bondo in certain places. So should I do that before primer? Or primer and more bondo before that?

 

Bondo before primer. Make certain the area has good tooth - you don't want to apply to a smooth surface. You should be 99% before shooting primer - then high build and glazing putty to fix minor imperfections.

 

Buzz it down with either 80 or 180 to get rid of the sandblasted texture,
prime the whole thing with an epoxy primer.
Do the filler work over that, when that is done, spot prime the bare metal with EP again,
then put a urethane high build primer over the whole thing.

I normally use polyester based high build, but it is considered an open primer,
and will absorb moisture such as rain.
You can do that if you cover it with a urethane based primer before it gets exposed
to the elements.

 

Every paint manufacturer has a tech help/information phone or website connection. You can get these contact numbers online or just ask the autobody paint supply store where you buy your materials. The manufacturer's reps are only too willing to give advice about their products and the proper use of them. Saves EVERYBODY time, money and hassle. Go to the source for best information, not to an opinion forum.

 

Use epoxy primer first before you spray any poly fill/sprayable body filler or urethane primer

 

I would get rid of all the old filler, replace that with new, then when you are 99% close to being done, spray self etch primer, then primer surfacer, and block sand the entire car. Fill any imperfections with glaze reprime and you should be done

 

With the cost of PPG, I've been using SPI. GO TO WWW.SOUTHERNPOLYURETHANES.COM.
Great stuff and amazing prices, tons of info on the website.

 

I do epoxy over bare metal or filler. If the existing filler is in good shape with good adhesion and no signs of rust under it I would leave it. Normally I put Urethane 2k primer over my epoxy in the recoat window for a wet-on-wet application. I normally sand any areas needing filler work with 80 grit or coarser. Then apply filler. Normally that will remove all the primer, but I don't get too worried about filler over primer if theres good bite.
- Jeremy

 

This doesn't seem to be a problem in Arizona. At all. It's really, really dry here.