[thingstodo]

There has been progress on preparing for the next test of a bolted joint:

1 - I cut out 3 plates measuring 1.75 inches x 1.75 inches from 1/8 inch aluminum stock as well as 1 plate 1.75 inches x 1.75 inches from 1/8 steel stock. These will work as 'large washers' to (hopefully) prevent the bolt heads from pulling through the wall of the aluminum tube. This is the failure mode that I have seen in testing so far.

2 - I picked up some epoxy.

The aluminum needs to be prepared similar for both:
- cleaned with alcohol
- sand off aluminum oxide
- clean off the grit

Loctite 330, from one of our local vendors that handles the Loctite product line. This is intended for metal, quite simple to apply - activator on one side, adhesive to the other, assemble within 5 minutes, clamp. 24 - 72 hours cure time. 2000+ psi shear or tension.

Permatex Cold Weld metal epoxy. A 2-part epoxy that claims 4500 psi strength ... not sure whether that is tension or shear. Mix equal parts thoroughly. Coat both sides and clamp. Sets up in 8 minutes.

3 - I dropped off 5 pieces of tube and they have been butt-welded at 90 degrees to form 3 joints. I will be picking these up on Monday and testing them. Perhaps to failure, perhaps to the extent that my equipment will go.
I messed up a bit - I don't have any 2 inch tubes left that are long enough to allow testing with 1 (bolted) or 2 (epoxy) methods.

So .. the plan is to test the welded joints from part 3 on Monday. If the joints fail, I'll cut the welds off. If not, I'll rotate the tube 90 degrees.

Epoxy the joints on one end with part 2 and drill the other end with the plates in part 1.

Testing on the bolted joint can be done on Monday if time permits, but not on the epoxy joints as they take time to set. It will likely be Saturday before I can test them.

But these are just plans - we'll see what I get done