soldering aluminium

soldering _ aluminium H.M. Wolber Constructors use aluminium a great deal because it is relatively inexpensive and very easy to work with. However, soldering it causes problems, for using an ordinary soldering iron and solder just does not work. The solder does not seem to feel particularly attracted to aluminium. Nonetheless, Mr. Wolber has come up with a solution which allows "normal" (60/40) solder to be soldered on aluminium. The problem with aluminium is that it oxidises quickly. In other words, aluminium is always covered in a layer of oxide. As you know, this is a very.. good insulator and prevents solder from even touching the aluminium. However hard you try to scrape the oxide layer off, oxidation occurs so rapidly that a new layer will appear as soon as the "old one" is scraped off. To prevent oxidation, apply grease or oil to the solder point. Then scrape off the layer of oxide with a sharp object underneath the oil. The oil prevents oxygen from reaching the clean alu- ...