Welding Nuts - OK Fab guys, chime in.

[hotrod1]

I frequently weld nuts behind a bracket, braces, or to conceal it (perhaps in the frame). I usually weld all sides of the hex to the part, but perhaps I seem to over do it. I am concerned about the heat and temper of the nut from welding but also the strength restricting of the nut when you crank on the bolt that goes with it (stops it from spinning). Here is a commercial seatbelt blind tab. They only weld a few of the corners. It looks too light in the weld department to me but I am not sure.

What are your guys thoughts? Any articles?

[Donaldo]

Test one - bend and stretch the heck out of it and see when and where and if it fails.

[joedoh]

one time I was setting up a back half (cut a frame off at the cab and was welding on a new rear frame section. I put 8 tacks, 2 on each vertical joint, between the old frame and the new section which were butted together. A buddy saw it and said "man I wouldnt want that falling on me when those tacks break" and I just stepped up and stood on the very end of the frame. the 8 tacks held the frame section and my hefty self, even with the torque of standing at the end.

in my case and in the case of those nuts, the direction of force is perpendicular to the direction of weld, so they should be good. if for example, the bolt was left loose and a sledge hammer hit the bolt head, that would be force in the direction the weld and it would be weaker. Since all you are doing with the tacks is resisting the turn, the eventual clamping force of the bolt will be stronger. said another way, you dont need to put 8k lbs of twist into a bolt and nut with a pair of wrenches for it to have 8k lbs of holding force.

welding all the way around I would worry about warping the nut and unintentionally making it a locking fastener. Just my two cents as an engineer and a hobby welder.

[mr48chev]

You just need to weld them enough so they are secure when you screw the bolt in and torque it down or break it loose and unscrew it.

I'd suggest putting a dab of antiseize on the bolts going into blind holes though.

[_Ogre]

i use 2 tacks. that is all.
though i do use a bolt to tighten it to the base metal before i weld the nut
fyi... my seatbelt blind nuts are 10 gauge minimum

[Lowlyfe]

I've always had good luck with using anti seize and snug the bolt down good with the nut, then tack both sides and fully weld all around quickly. If it's in sheet metal just a few quick tacks is good enough for me. I always let the assembly cool before removing the bolt as well.

[HUSSEY]

I'm doing an S10 conversion on my truck. The motor mount use bolts and nuts. I just tacked the nuts down. I agree with what was already said, all you need is enough weld to hold it in place while tightening it down or breaking it loose.