67 F-100

I tried this in the Body Repair forum but didn't get any bites. Anyhow, the seam that runs the length of my bed was all rusty. I pulled out the stuff that was in there, cleaned it up as well as I could and sprayed in some laquer based primer. My question is: What do I put in there now before painting? This link shows several photos that will illustrate the problem. Thanks.
jor

http://home.comcast.net/~jor/side_molding.htm

 

Auto body stores sell an "autobody sealant" that comes in a tube like caulk. Also known as "body seam sealer". You get what you pay for though, some of the cheap brands will later dry and crack.

 

When you are ready to paint your truck, get them to use some sort of sand or media blasting system that will not hurt the metal on the truck body itself. You are looking to remove all signs of rust and the factory caulking substance they used.

Then get you a good body man and get them to use a type of body filler called "all metal". I had my 68 dont this way and it worked great, and will not bubble out like regular body dope will do after a period of time.

 

be real careful on the sandblasting clean up. it didn't take much to blow thru the metal on my 1970 swb i am still working on fixing that mess up

 

All metal consists of aluminum powder and is waterproof so it's a good repair, I use it on all lower body repairs and it seems to hold up very well.

 

You could weld it. Yes that's one heck of a long seam down both sides. Mine looks exactly like yours. The aging factory putty is cracked and coming out in some spots. When I paint the truck soon I intend to fill that all. I am considering welding it all and grinding it smooth, and while I'm at it filling the post holes and a few other odd spots. I figure the weld won't be a worry ever again, where as filler could be in the future.

Hawkeye

 

Unless it's already been done, I think we all have this problem... all metal is available at most major parts houses?

 

You should have used phosphoric acid, POR 15, or Zero Rust on the seam before putting the laquer primer on . Even a little bit of rust will continue to grow and will have to be redone. When you have it painted I would have them bead blast it and then put one of the above to get rid of the rust.

 

Yeah like I said, you want to have some one blast your truck that really knows what they are doing.

All Metal is available at all paint stores for automotive painting, that I know of.

As for welding, you also better know what your doing. The only real way to weld that whole seam is to spot weld every so many inches apart, going from one end to the other, then go back and repeat the above until you have filled it all in. Otherwise there is too much potential for it to weaken the metal and look as wavey as the ocean when its painted!

 

Thanks to everyone for the excellent feedback. I'll post after I decide how to go.
jor

 

I redid my 72 several years ago and there wasn't much sign of rust there but the putty was aged and seperating. I cleaned it all out, sandblsted the seams, used an acid bare metal prep, urethane primer, the correct seam putty and finally the regular primer and paint. Within three years it was rotted out with holes you could stick your fingers through inside and out. If you look at the width of that seam you can see there is no way to really get all the rust out, short of cutting the spot welds and removing the panel. If the seam never had a chance for the rust to get started you may have a good chance for success or with some of the products mentioned here that I didn't try.

 

I actually plan to clean all of my putty out and just leave it open. If there is nothing in there to trap moisture, it is less likely to rust again. I did this about 20 years ago on a Datsun truck and it worked just fine, if you don't mind the gap.

 

Well, that's an idea that I hadn't considered. I live in Arizona and rust isn't really a problem. I don't know though - kinda makes me uneasy.
jor

 

I have racked my brain trying to figure out a better way than I failed at. POR 15 wasn't popular then so maybe that is an option but I was thinking of welding it shut.

 

I have used "Ospho", which is a phosporic acid based product for years with great success. It's water thin so it gets into virtually all cracks and holes, and also works on new metal. I have put bondo and epoxy over it with no problems. It must be painted (or covered with bondo or epoxy) as it is not designed to be a topcoat. For that I use "Wax-oyl", a great product which works very well on areas that you aren't going to paint, or can't paint, like the inside of body pillar. I don't think it's made to be painted over. I have seen the results of Por-15, and it looks like great stuff. Anyone painted over it? When I run out of "Wax-oyl" I'll probably try it. All these products, WHEN USED PROPERLY (key, as with everything), will stop rust. Period.

One thing I know for sure is that unless you are an expert welder with the proper equipment don't even think about welding on your bodywork. Even then proceed with great trepidation. Odds are you will have a bigger mess when you are through than what you started with, for a number of different reasons. These new problems will be harder to fix than the original problems too. Heat and nice smooth sheetmetal just don't mix. Besides there will almost certainly be rust behind that weld that will be right back anyway.