Projects such as my VFH FM Wireless Microphone (BUG) and other VHF projects, use small value capacitors, under 15pf. Wouldn't it be nice if you could make small value capacitors to order for the job at hand? But suppose for tuning (the BUG?) you needed a capacitor between, say, 12pf and 15pf to put the transmitter between those two strong stations! No problem. Take a bit of single-strand plastic covered hook-up wire about 15cm long (15pf) and fold it in half, crossing the ends. Hold the loop so formed with a pair of plyers and begin twisting:
Continue twisting tightly until the twisted section begins to curl. Now cut off the loop so that the top is no-longer short circuited. Strip the ends and you have a perfect vow-value, high-voltage capacitor of about 15pf - 20pf.
Too many pico-farads? Cut it down to size. I have cut this one down to about 5pf for my latest project; a VHF FM crystal/controlled transmitter for packet radio using four of these capacitors. I'll bet you that Tandy would pot them and charge you the earth - if ony they knew how.
Cut off too much and the capacitance is a bit too small? Twist it tighter or roll it up into a ball - Dead easy! In this way you can also make yourself a preset tuneable capacitor. Let Tandy try to pot that!
Have fun and "lets twist again" in the 90's, de HARRY, Upplands Vasby, Sweden.