I need to join a .250" Al solid round perpendicularly to a plate of aluminum ~.125"
I have no access to TIG, nor access to tap or die. It won't be under a load, but it needs to be bonded well enough.
Can I solder or braze on the cheap?
By far the best way to do your task with an adhesive is to use original JB weld (not the quick dry stuff) and follow these rules strictly.
First sand the two surfaces to be mated.
Clean both surfaces with rubbing alcohol.
Mix the JB Weld correctly and cover each surface with it.
VERY IMPORTANT > Use a wire brush and scrub the JB Weld into both surfaces then attach them and let dry for 24hrs.
Aluminum will oxidize the instant it is exposed to air. Covering it with glue and THEN scrubbing the glue in will cut through the oxidized layer and the glue will prevent air from touching it to again oxidize it. These bonds can be very similar to welding in strength and we depend on them all the time.