I am moving my seat belt receiver mount to my trans tunnel (from the seat rails) and using a 4x4 inch backing plate. Should I mig it in place with some short welds? Or can i use panelbond adhesive?
Pic of work in progress... I will radius the corners and bend it to fit tighter, but this is how it looks today
You're basically trying to spread the load and keep the nut from pulling through the plate and floor. The method of attaching the plate may not matter too much provided it is secure. Visable welds will make most people feel better about it though.
Thanks, that's what I figured - either adhesive or a weld will keep it stationary. And I wouldn't weld the entire perimeter, so I'd cover it up with seam sealer to close it up between the weld segments.
Only because it appears you are placing it exactly on a panel seam I would weld it. Anywhere else I just let the through bolt hold it on and seam seal it .
When welding I would drill some holes in the plate and then do plug welds which would be sort of like spot welds rather then weld along the edge of the plate to the body.
I would weld as there are shear loads that if there were an adhesive failure could basically try to use the bolt like a can opener. The plate being welded could better ensure resistance to that by not letting the plate slip, so there would be backing resistance to the bolt basically slicing through the floorpan metal.
Just a note for those who observe threads like this to learn. Panel bond and the structural adhesives are made with the intention that the metals are clean, prepped, and the pieces are screwed or clamped together tightly with virtually no "gap" for the panel bond to fill. There are 10 mil glass beads in 3M panel bond to insure the correct bond thickness when pieces are clamped or screwed tightly.
Want to learn more about panel bond or whether a structural adhesive would be a better product to use see this 3M pdf. https://multimedia.3m.com/mws/media/761729O/tds-08115-38315-58115-3m-panel-bonding-adhesive.pdf