Off Roading Forums banner
1 - 7 of 7 Posts
G

·
Discussion Starter · #1 ·
I'm welding in new steel into my tub where the red cancer has got her. I'm a little worried about the places where the metal has to overlap a little 'cause this seems to be where the old tub rusted out first. I remember hearing about this primer that you could weld through, made of zinc or somthing. Does anyone know what I'm talking about? If so, how well does it work? Where can I get? I figure if I put that stuff in there, seal up the seams good and It might last even longer than the original tub. What do you recomend for sealing the seams by the way?

Thanks

 
G

·
Discussion Starter · #2 ·
3m makes a weld through primer that works very well. I work in a body shop and use it quite often on high dollar cars. You con get it a paint or a welding store. If you can not find 3m's brand dont settle for the SEM brand cause it contaminates the weld too much

 

·
Registered
Joined
·
1,838 Posts
If your welding the new metal to any rusted spots it will pop like hell . Keep cutting away until you get good metal and then use the ZINC primer ( be careful not to breath that gas when welding).
I`ve used all brands of seam sealer and found 3M brand to be really "stringy" , you leave off the seam and it`s like a thousand little hairs follow off the job , really annoying . I found PRO-FORM to be the best by far . Hope this helps .



O|||O /wwwthreads_images/icons/cool.gif
 
G

·
Discussion Starter · #4 ·
There is a little snafu with the ZINC primer. Zinc melts at about 700 degrees, and the steel is going to melt above 2500 degrees. This is a problem, because the zinc is still liquid long after the metal has solidified. Now you have this liquid zinc in your weld, with no place to go, so it finds the most convenient place it can. This place is usually the grain boundaries of the steel you just welded and the grain boundaris in the weld puddle. This would be fine, except that zinc has poor physical properties. So in essence, you have just created a bunch of little zinc filled cracks in the metal. If the joint you just welded is stressed at all, it will fail. Not to mention the toxic fumes that come from welding zinc. The zinc primer is good, if you put it on after the weld has cooled. I would use the weld through primer by 3M, and then seal the joints with Silkaflex. The silkaflex is a caulk we used on semi-truck trailers. The stuff is durable. I would apply it after the paint. I would think you could find it at almost any paint supply store. They might even have some that is paintable.

Cage Up, Wheels Down
Jeepfiend
All my Jeeps are in pieces!
 
G

·
Discussion Starter · #5 ·
Jeepzilla, I am cutting back to good metal. I've seen what happens when you just pop rivet or poorly weld in thin steel to an already rusty tub. You get way worse rust than if you left it alone. Right now I have the front floor completley removed and the back is coming out soon. I've also cut out part of the side. I got a big piece of 16 gauge steel I'm going to cut the new pieces out of.

That 3M weld through primer sounds pretty good, unlike the zinc stuff.

Thanks for the help

 

·
Registered
Joined
·
1,838 Posts
Here`s what mine looked like along the way , rear floor removed etc... I ended up rebuilding everything in that tub /wwwthreads_images/icons/tongue.gif . But she will last a long time .

Jeff



O|||O /wwwthreads_images/icons/cool.gif
 

Attachments

1 - 7 of 7 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top