Review on Harris 500K Al-Solder 500 Aluminum Solder Kit: Premium Solution for Efficient Aluminum Soldering by Scoony Taker

This might work if you have 100% access to both surfaces to be soldered. However, do not expect this material to leak or capillary into the joint the way solder flows into the joint of copper tubing. It just builds up in its own molten bubble until you rub the solder through the thick, sticky flux and hit the aluminum surface. The aluminum alloy tried on was 6061 and was heated from below to bring the aluminum up to temperature without burning the flux. The flux also forms a thick deposit that the solder will not remove without human intervention. I know soldering, soft soldering and welding well - one of the three almost every day since the 80s.