The Stovebolt Site Forums The Shop Area Paint and Body Shop Body panel adhesive.

I know this is non traditional, but before you get out the flaming torches and pitch forks, I'm interested in feedback.
I've used the 3M stuff a few times recently on other projects and find it has some advantages to welding. The biggest is no warping, so no weld, hammer and dolly, weld, etc.
Many new cars are assembled this way (doesn't make it right).
Flange the replacement panel and, as directed, spread the epoxy on both joint surfaces, than lay a bead 1/4" from the edge of one surface. Clamp in place and smooth the extra adhesive over the joint.
After it dries sand and it may not be necessary to use any body filler.
In areas where the back of the seam is not visible or is impossible to clamp, I fit the panel in place, drill some holes for pop rivets and remove the panel. Use dimpling pliers on the holes on both pieces to take countersunk rivets and then apply the adhesive. The rivets add strength to the joint and make assembly and alignment easy. It's also easier to smooth the joint with out the clamps in the way.
The epoxy also fills and seals the entire flange joint so there is no there is no way for moisture to get into the flange.
I used it on the recent 5 window conversion on the '51 COE, for the joint at the belt line. It was originally going to be spot welded as per factory specs, but the process of cleaning both sides of both surfaces (rusty original bottom and well primed new upper roof panel) perfectly bare for spot welding was daunting to say the least. Since the 2 panels were through bolted in 4 places to the rear cross brace, I didn't worry about strength So I only had to clean the joint surfaces. Also the idea of filling and sealing the whole joint instead of trying to squeeze a bead of sealer into the joint after welding was a plus.
I have some pics if I get around to moving everything to some place other than Photobucket.

Brian (MartinSr) has a thread he posted that stress tested welds and panel adhesive in a pull test using a frame machine.


http://www.67-72chevytrucks.com/vboard/showthread.php?t=241030


Welds and adhesive were used on the same test parts to see which would fail first. In all cases, the welds pulled apart before the adhesive. Does it have it's uses? sure does! But these seams will require an offset flange, and yes, ghost lines don't care how you put the panel together. So you need to PLAN where you can make a seam using this product that body features will help to hide it. As I said in the other thread, put a seam where it doesn't belong using a flanged/offset seam, and it will show, via welding or panel adhesive. Look at the OEM's now using adhesives. They are used at the edges of a panel where a seam does not overlap, or is covered by seam sealer (think roof edge seam) or hidden by plastic bumpers. They DON'T use the stuff to seam down through the middle of a large panel because chances are pretty good that it will show.. Food for thought....

We have done testing with the 3M product, for applications in our fab shop. As already stated, the joints should be designed to accommodate this type product, not just use the epoxy to replace welds. At this time the only area we are comfortable to use it is joining dis-similar metals that can't be welded such as steel brackets on an aluminum substrate panel.

In shear, the epoxy will yield 18 gage and even sometimes 16 gage steel. In tension, depending on joint design, epoxy is not nearly as strong as welds. If your joint will have any tendency to peel apart, the epoxy is not likely to hold.

I've never been fond of cutting through the middle of panels for a patch. Cutting on the edge, trim line or style line (pre 1957 Chevy trucks don't have any of these) is a much better choice.
The adhesive is not for structural joints (as the instructions point out) , But I think it has it's uses, The beltline joint is an excellent example.
Now the inner panel for the 5 window could have been another example. However, the Chinese replacement panel fit so poorly requiring a lot of clamping force at the window openings, that 270 spot welds were a much better choice.