Reinforcing kickups and joints

[donsrods]

Another thing we do when welding the joint in a kickup is to insert a backing plate inside the joint before we slide the two pieces together for final welding. It allows us to really crank up the heat on the welder and get much deeper penentration and a stronger joint.

What we do is cut some pieces of flat stock about 3/16 thick x 1.25 wide into shapes that look like arrowheads. We cut them to a size that will allow them to slip into the inside wall of the tubing and permit the other piece to dovetail over them. To hold them in place until we do the final weld, we drill a couple of holes in the frame rails right at the edge of the joint and rosette weld (plug weld) through the holes and into the backing plates. They now become part of the first piece of tubing.

Now you can slip the two pieces of tubing together after beveling the cut edges, and weld the two together. We first do our clamping and welding on our welding table so that both rails turn out the same shape exactly, then we move to our frame jig to put the crossmembers in.

Here are some pictures of that process.

Don

 

[joes23t]

Don: just a quick question would drilling the oppisite piece the same as the first so that when the pieces are butted together(plug weld the drilleded holes)weld up the seam spreading the load away from the joint tyeing the plate across the joint to both pieces?

 

[donsrods]

If I understand your question correctly, are you asking if there would be any benefit in also plug welding the backer to the other piece of tubing, not just one piece? If so, probably not. All it does is sit there until you fully weld up the seam between the two pieces. It serves no structural function at all, simply gives you a backing so that a very hot weld can be put in there. If it were hollow you would possibly burn through with the hotter weld, but the backer acts like..........well, a backing plate. You will be clamping all of it down to a solid base so the heat from the weld can't pull it out of shape anyway.

It does become part of the joint because the weld also joins the backer to the two seperate pieces. Have I explained that well enough, and answered what you were asking?

Don

 

[joes23t]

Don Thanks for the explanation I think that the joint the you have discribed so clearly looks better then one's that I have seen with a visable coupon welded over top of the joint. Keep up the excilent info and photo's. And thanks agin
Joe (Hope to do a proper intro.this weekend when i get home.)