Primer/paint prior to welding? More noob questions.

[Mudhen]

Another noob question for you guys...regarding primer and paint prior to welding - what do you use?

I've removed the rusted outer sill...about to sandblast the inner area.  Then what?  I bought a product from Eastwood for enclosed areas that don't need paint only to discover, 'flammable, use after welding is complete'.  Crap, so that won't work for the inside of the sills since I have to weld the outer piece on after.  Seems like the closing panels for the rear valence will be the same way?

Looks like they have a metal etching, weldable primer...then regular old paint?  This months Mini World has an article on rust prevention and they mention a product by Bilt-Hamber called 'Electrox' which is a zinc rich primer that doesn't need to be painted over...probably no worries about breathing the welding fumes off that stuff.   22.gif

I assume after whatever I put on it, then clean up just the areas where the welds will be - and after all is done maybe some waxoyl or something up inside?  I'd assume there must be areas of bare metal up in there after welding is complete...

Another silly question while I'm at it - what about new panels?  They obviously come painted - do you clean all that paint off prior to putting on your primer?  Both sides of the panel?

Thanks a lot.

Pat

[94touring]

I was using some high temp paint along some of the seams I was welding and it didn't burst into flames.  The kinda stuff you use on engine blocks.  Otherwise I just paint it like I normally would.  Small spot welds keep the heat pretty confined to one spot so isn't a huge problem overall. 

Once you get any bare metal  exposed and you're ready to prime you can throw on an etch primer and primer over after it flashes with a primer of your choice, or just epoxy sealer primer the bare metal.  What I've come to doing is epoxy seal the shell/body panel, let flash as recommended on the can, then prime over with a filler primer to sand down later.  After I'm done doing the sanding on the filler primer and getting any additional areas filled in during the prep phase, the final coat before paint is once again sealer primer.  Which is then sanded more with 320-600 grit prior to paint.  You can however seal primer again, let flash, and then paint right over that.  The idea there is the chemical bond between the two while they're within flash times is the greatest. 

New panels..I've noticed a couple differences.  The ones that come with grey primer have pretty lousy adhesive quality.  I can tell this when I sandblast, that stuff just flies off.  The panels with the black primer is pretty decent and I scuff and prime/paint most of that.  I had a couple of these older panels that sat around with the black stuff on there begin to show surface rust however, so I ended up stripping some of it anyways.  I would be more inclined to stripped the outside of the panels and not the backside, since the backside won't be getting hit with rocks, or bugs, or a high pressure washer...anything that would strip it from the body.  The backside scuff and paint for sure and don't waste your time.

Waxoyl the insides, yes, good idea.  Paint what you can before you enclose it obviously.  I've gotten into the habit of shooting grease inside the enclosed panels.  Pretty easy to shoot it in there too on a regular basis.