will it rust even if I use a weld thru primer?

Anything you can do to stop or prevent rust in these cars is a good idea.

Get the spray wands as suggested above - or elsewhere.. shop the net.

Get a gallon of OSPHO.. and spray it inside that upper fender support (for that matter spray it inside all areas of the body that you can't easily reach to stop rust). Spray it first to WASH as much dirt/grim out as you can.. you can flush the area with water, as the OSPHO will protect the bare metal from flash rust... Once you feel that the area is flushed out clean - blow it dry - and spray it again with OSPHO and let its chemistry do its work until dry.

OSPHO is sold at most automotive paint and supply stores. It is a mild phosphoric acid solution. It will chemically convert iron oxide into iron phosphate, effectively stopping the oxidation process (ie killing the rust). Once the rust is stopped, you can simply spray any good rust proofing paint in there. That area isn't exposed to the elements, so you simply have to keep the moisture in the air at bay with a good layer of paint.

Washing metal with phosphoric acid to stop rust is a proven method - mil spec standard stuff.. been around for a hundred years and so far nothing has proven to be more effective at stopping rust. I'd flush and spray it one day.. give it a day to work completely, then spray it again and give it another day to work.. then spray the paint.

I like POR-15 - and I use it all the time where durability is important and where the metal can be properly prepared... but it isn't needed inside those panels IMHO.

FWIW,

Carl B.

Carl Beck

Clearwater, FL USA

http://ZHome.com

Thanks guys, I think I have a decent idea on how to handle this now...