Stirlingengineforum.com

If the copper pipe is being fitted to the side of the can, contour the end of it so that it fits snuggly against the curve of the tin, don't try and fill large gaps with solder, the close gap will give a stronger joint. A gap of between .001" (maximum strength), and .010" should be aimed at. The solder looses its strength (as do all metals) as the temperature rises . Don't expect to use temperatures too much above boiling water, ie., 100* C, maybe 120* C. When soldering, heat the metal and melt the solder against the metal, don't just blob it on by melting it with the torch, or soldering iron, with both parts tinned before assembly, the solder will flow into the joint, use as little solder as you can. Ian S C

i ones made displacer piston and the whole cylinder from brass sheet metal. soldered it together. it can be done and it's quite easy way to make any shape and size. the problem is the solders melt when I heated the engine. so the part that gets the frame cannot be soldered. Cold end parts can be soldered, but the bottom needs to be in ready shape so you don't have to make any solder seams near the hot end.

actually good solder joint is very strong.

If your going to make things out of brass that gets hot, you'll need to use silver solder. brass is not the best material to be using at the hot end of a stirling engine. Ian S C

Sweating copper pipe is not rocket science, although it operates under certain principles and techniques. Basically, it works on capillary action where the heat is applied to the flame of a heating tool or other pulls the solder to it, filling the space between the connector and tube. When it cools, it creates a solid seal.