Stitch Welding
 

Just stitched welded my stiffners but now the questions is, what can i do to cover the areas that werent welded to prevent rust?

Good coat of rustolium or bed liner.

Are you suppose to stitch weld that. Seams like you might want to full weld something like that. I mean the point is to stiffen it right. I just think a real weld would do a much better job and you wouldn't have to worry about rust.

I stitched mine because I didn't want to heat the sheet metal too much and I prefer a stitch because if it pulls it stops with the weld whereas a full weld pulls completely off.

That's why you do short alternating welds to keep the heat down. About 1"-4" long depending on what your welding and how thick it is. And if you have good tack welds it really shouldn't move all that much i "if you full weld it in one pass"

A better question to the question might be, who's stiffener did you weld and maybe a picture of your concerns......

I would think that a stitch weld would cause more stress at the ends of the welds, which would actually help it crack. Then I guess it also depends on how long the welds are and how much space there is in between them.

stitch welding is the proper way to do any for of stiffening because it allows for flex, welds are very hard so if you full weld and then go wheel the piss out of it theres a good chance your gonna tear your unibody a new one.

i dont agree with this, many many people have done this before and no problems with it, everyone says it helps

Why would a stiffener want to allow flex. Might just be me but that sounds like it is defeating the purpose. Call me crazy.

To me it just seems like flex would cause stress on the ends of the stitch welds. Having it completely welded would spread the stress out.

I guess the real question from here would be, has anyone experienced cracking at the welds of their unibody reinforcements?

just sheet metal screw it on

To answer the orig. question, use automotive seam sealer, it's availabe in a tube or you can get it in brush form as well, use acid brush to apply.

I would'nt think the item be fully welded, not required and you stand a better chance of undercutting the material/unibody in the process.

x2 on the seam sealer or even a silicone caulk (flexible). I prefer the seam sealer but it can be a bit pricey.

isnt there weld through primer? Thus you can remove all the undercoating/paint on the unibody, primer up the rails, then weld through the primer, thus the metal you preped behind the stiffeners wont rust.