Most of the UNA rigs use a wire bent to a Z shape to avoid that kind of weakness at the joint of the spars. There’s lots of good info here on building them. Try searching for UNA and McRig.
Your build has been a learning process, but don’t give up…you’re almost there!
Bill
here is a diagram of how i plan to fix it.
i would repeat this on the other side.
Don’t bother fixing it, build another correctly to begin with. You’ll be much happier with the results. Its not like the materials will break the bank.
I been working on fixing it the pas couple days using a lot of JB Weld I never realized the strength of this stuff. now that its done hardening its over twice as strong as before it broke.