Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Great jig there Daniel, well done !

As far as aluminum welding and soldering goes, my experience is nil, but i have purchased a few "Alumaloy" rods, to test them out (one day)..donīt know if that product will cover your needs?
Plenty of movies on youtube demonstrating Alumaloy, and it seems very easy to use

https://www.youtube.com/results?search_query=Alumaloy

Thanks for that link Jan. I also have a bundle of alumaloy rods that I picked up some years ago, but still haven't used. I saw a live demonstration from the guy I bought them from, and have seen some YouTube videos as well ... but do appreciate the link. My impression is that the alumaloy requires a rather high heat, and the rods I have actually possess a cross section that is greater than the aluminum rails I wish to join, thus the danger of actually melting the thin edges of the rails webs and flanges seems acute!

I have now also acquired some aluminum specific soldering flux paste that is supposed to work well on aluminum when used with the Stay-Brite line of silver bearing soft solders (5% Ag) to form a strong joint at much lower temperatures. That is how I'm going to start out anyway, and see if/how that works.

But of course first, there must be a fixture for holding the various parts in proper position for soldering, and before that there must be a clamping and angulating fixture for milling the the tapers and joining surfaces. I'm well along on an attempt at this second fixture, and hope it will be as easy as my current plan seems to indicate. Basically just a pair of oversized (for my vise anyway) parallels, with some clamping screws, spacer strips, and sine bar like riser blocks cut at specific lengths to create the needed angles using my 4" vise ways as the bottom plate. Looks promising so far, but much needed to do to complete and verify the concept.