Sealing a brass tube - an adventure of soldering, brazing and welding (+failed attempts).
The hardest part in making a heat pipe is sealing it off and keeping it sealed. Soldering the end shut is not hard and it keeps the tube sealed but such heat pipe cannot be soldered to anything after it's sealed because the solder would melt and the seal would fail. Commercially made heat pipes are welded shut. Such a seal is the best you can get but it requires a TIG welder to achieve and TIG welders can be pricey. The next best thing is brazing. It's basically soldering but at a much higher temperature. This way you can solder your finished product without the risk of breaking the seal. The biggest problem I've come into is the step between pulling a vacuum and permanently sealing the heat pipe. That step being the crimp, because before you permanently seal the end of your heat pipe you need a way to keep it sealed while the permanent seal is being applied. Crimp being the most popular method. The crimp has to be really good because any leakage in or out will disrupt th...