Plastic bottle spud gun

Step 4 Bottle it

Fire up your skanky old soldering iron, covered with rust from before the days when you appreciated the true necessity of tinning an iron tip. If you don't have one, fire up your clean new soldering iron and hope you can clean the plastic off it afterwards. Mark a circle the size of your barrel on the bottom of the bottle.

Using a judicious combination of patience and the soldering iron, open out a circular hole just smaller than the barrel. Test fit the barrel, slightly enlarge the hole and repeat. Patience at this stage will pay off as a bad gas fit around the barrel seal will decrease the ultimate performance of your gun. Once the hole is a snug fit around the barrel, let it cool (without the barrel in it!) until hard. Try to make the hole "straight" through the plastic, it will make your life easier later on.

Heat up the end of a needle or a piece of your solid core wire in a lighter flame and push two holes about 1cm apart near the neck of the bottle. These are the holes for your electrode wires - they should be within a finger's reach from the neck of the bottle to later facilitate adjustment.