LOSTCIRCUITS

Thus far, we have eight radial fins, that is eight air channels that we want to utilize as efficiently as possible. Therefor, we need eight vent holes. The easiest way to determine and even spacing is to start out with a cross through the center of the bottom and then divide it further in to 1/8. If you have problems with that, the frienly guy from the Pizza parlor next door can certainly help you out. Afterwards, all you need to do is to mark the center of the drill holes with a felt pen, or better, with a nail to provide initial guidance for the drill bit.

Copper is very soft and the drillbits have a tendency to wander off. The best thing, if you don't have a drill press (me neither) is to use "pilot" drill bits that self-center and then follow up with a larger calibre bit.

The bottom of the cap is divided into eights and the rest is easy. Just extend the lines down the flanks of the cap and center them with another horizontal line around the circumference.

The Rawling

Ater drilling the holes, the cap should look somewhat like this:

Make sure that you don't tighen the vise too much during drilling, copper is soft and will bend easily destroying everything you have worked for in the last 15 minutes. Best is to use two pieces of wood between the vise and the copper.

Time for the Blowtorch

In order to to actually use the fins for more than cosmetic purposes, they need to be soldered into the bottom of the cap. The easiest way is to use some of the solder flow to provide a somewhat sticky base into which the individual crescents can be stuck. Warning, don't use too much, it makes a terrible mess if the stuff starts burning.

After soldering the fins in, the entire piece looks pretty ugly with residue of burnt solder flow forming a black coating over most of the inside surface. Luckily, it is relatively easy to scrub it off using some wire brush. We had something better though.

next page:    => The Finishing Touch =>