When doing body work on bare metal ,what is better primer first or body filler first. I'm thinking of the long term so rust won't develops later

Many schools of thought on this but I always put filler over a good etching primer like DP-90. I know its somewhat old school but filler is porous and will absorb moisture from the air. If you leave it long enough the primer will trap moisture in the filler and it will eventually rust from the inside out. That's just the way I learned to do it.

Some people swear its better to put the filler over bare metal and they have good reasons that make sense to them. I just prefer to put it over a good etching primer so the metal is sealed from the environment first.

Probably your best bet is to prime the bare metal with a good epoxy primer, scratch it up good after it's hard, and do your filler work on top of that. I was always told to never put filler on top of primer, except for epoxy. My 2 cents!

Another vote for epoxy primer first. Strip the car to the best of your ability, I then treated the bare metal, then shot epoxy, then started filler. Any dent work or metal work is done first, then epoxy then filler. Just the way I have done 3 cars. Mainly tutored by people here and autobody101 webpage and forums plus a great paint salesman who goes to PPG schools and shares their method applying their products.

any [good ?] epoxy primer available in spray bombs for small jobs ? i realize once mixed or shaken, it may set up in the can, rendering the rest unuseable for future use. if not, who makes the best spray bomb primer ?

I am not aware of any true 2 part epoxy spray cans, be interesting to hear about though.

I would lean towards a DTM epoxy under filler, instead of a self etch, and I really like self etch in rattle cans for ease of us. I wonder if OP has a limitation on spraying epoxy primer, why couldn't he just brush it on, if its going under filler?

I'm not a big user of spray bombs, but Tower paint in Wisconsin has supplied me with some unique paint products/opions in spray bombs over the years, any paint product/mfg can be supplied thru them in spray can


Mike

Thank you, learn something every day.

I use a Preval sprayer for small primering jobs. I have applied single stage urethane paint to engine blocks and heads with them as well. Very cheap and you can find them at pretty much any hardware store.

Once you use one a couple times you get a feel for how much material you'll need in the jar to cover whatever it is your painting and you can get to where there is very little waste. Run some reducer thru the sprayer when your done and you can reuse them until the propellant is used up. If you don't clean them the paint dries inside and it's game over.

http://preval.com/

I can understand the ease of use for the 2k aerosol, but if there is a decently large ares ( Footbal size or bigger ) I believe a true 2k epoxy would be best , if for no other fact than mill ( thickness) build.

I prefer Southern polyurethanes epoxy, and just mix what I need at that moment in time.

As far as restoration work-
1. Sandblast
2. Clean.
3. Clean again
4. Epoxy
5. Filler work after 24hrs of epoxy drying.

Eastwood sells lots of different kinds of the Spraymax and AeroSpray 2K Aerosol spray cans, including epoxy primer.

http://www.eastwood.com/eastwood-s-2k-aerospray-epoxy-primer-gray.html