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Subject: Re: [motm] Another WOO-WOO! -Building Tip

From: kheck73@...
Date: 2006-09-23

Just finished a 440 late last night. Sweet.
 
Thought I'd pass along a simple tip possibly already discussed. I noted this in a nice module built by Don Ojeman. I obtained a heat gun with a low power setting ($9 at the local Harbor Freight), and 1/4" and 1/8" heat shrinkable tubing. For the triple twisted stranded going to outer pots, be sure the strand is twisted tight, then shrink 1/4" long collars of 1/4" diameter tubing near the ends. Leave enough individual wire length at the ends with longer stripping (for the pot connections) to slip a 1/2" length of 1/8" tubing over each, and still have the bare wire end exposed for soldering. If you need more separate wire length to push the 1/8" tubing farther away from the joint when soldering, I suppose you could put the unshrunk segment of 1/4" tubing on the cable just before finishing the pot connections, then shrink it last. 
 
I also put shorter 1/8" long collars of 1/4" tubing on the twisted pairs to the switch and jacks, leaving the twists tight all the way up to the connections. Use a low heat setting, and wave the gun around starting far away, then moving closer while rotating the wires. The gun gets really hot (even on low) and can melt things or burn your fingers if you get too aggressive.
 
The use of 1/8" tubing is mentioned in the module directions. Just before soldering the pots, put a 3/8"-1/2" length of 1/8" diameter tubing over the end of each wire. If you didn't already collar the pot end of the wire twist, put a segment of 1/4" tubing on the bundle before you solder the pots. When soldering the connections, be careful not to let your soldering iron get too close parallel to the tubing, or let heat rise from underneath, as the tubing may start shrinking prematurely (I hate it when that happens ;). Before mounting the pots to the panel, be sure you have good joints (you'll never see them again), push the tubing over the joint and up against the pots, then shrink it. Don't get carried away with the heat gun, it doesn't take much heat for very long. Stop when you see the contours of the joint appear from beneath the tubing. Keep the heat away from the PCB. I didn't put tubing over the switch connections because I wanted the twisted pair to remain tightly twisted all the way up to the switch (no room for tubing).
 
Just a little added extra touch worth an extra 15 minutes. You're going to build the thing only once.
 
-Karl.