Welding tip of the day

Y'all probably know the trick of holding a chunk of copper against the back of a piece of sheetmetal when patching holes. Well, where to get a chunk? If you got some dead computer stuff laying around, you might be in luck. Some processor fans have a chunk of copper, about 1" around and 1-1/4" long. Square fans tend to be all aluminum, some of the round ones have the copper center. Like the one in this pic:

http://img252.imageshack.us/img252/1497/cimg1713lc2.jpg

First one I used the band saw to slice the aluminum part on each side. Then I tried just hammering it out, and couldn't do it...so I hit it (the aluminum part) with a propane torch, and a couple of hammer taps dropped the copper core right out.

I was scrapping out a couple of computers the other day...most of the steel makes it into my recycle pile, and I try and grab the easy to get pieces of aluminum for the alum. scrap pile. I just had a 'lightbulb' moment and figured out that the heatsink I just pulled out weighed more than if it was solid aluminum.