Stephen,
This response is a little long...and over-simplified! However, without the use of pictures or diagrams...simple is good!
I have made "homemade" gaskets for a number of different projects...however, never for distilling. I"ve used both plain silicone and aquarium grade silicone ,no chemicals that will kill the little fishies!, both with equal success. Since I don"t know exactly what component you are needing a new gasket for...I"ll just lay out the basics. The last gasket I made needed to be 6" in diameter about 3/8" wide and the thickness was not relevant...as long as it would seal.
You will start with a piece of flat wood ,plywood or old countertop, etc, or other nailable surface that is larger than the diameter of the needed gasket. I used a 6" stainless steel mixing bowl ,it had a nice flat lip around the top, for my template. Wrap wax paper over the wood and attach it so that it is tight. Lay the bowl on the wax paper and nail in 4 or 5 6-penny finishing nails equally spaced around the bowl. They should be "almost" vertical and leaning away from the bowl only slightly. Your bowl is now trapped and can"t move. ,If you took the bowl out, it would easily drop back in...still centered between the nails,. Trace around the bowl with a marker onto the wax paper. Use tape on the bottom and sides of the bowl ,NOT around the lip,to make a handle or tabs so that you can lift the bowl up without having to get your fingers under the lip.
The last gasket I made needed to be around 1/8" thick. I have some 1/8" washers that I used for spacers ,coins will work just as easily,...I"ve used dimes for really thin washers,. Slide the spacers under the lip of the bowl until evenly spaced around the bowl. Now slide them out so that they are just barely under the lip and tape them into this position ,taped to the waxed paper,. Remove the bowl and apply a lubricant ,non-stick, to the top lip of the bowl. ,I"ve used everything from WD-40 to 3n1 to Pam cooking spray,. Also apply a little to the ends of the spacers that will be under the lip of the bowl. Don"t apply it to the wax paper as a release agent! ...a little on the wax paper where the spacers are won"t hurt...just try to be neat.
Open your fresh tube of silicone and put a heavy bead on the wax paper following the circle that was made and ensuring you don"t have any thin or broken spots. Now, using your handles or tabs on the bowl, lift the bowl and slowly slide it down between your nails ,remember the nails keep everything lined up and the spacers keep the bowl from bottoming out, until it is resting on it"s own. Sit a weight on top of the upside down bowl ,it needs to compress the silicone and should be resting on the spacers...so NOT twist/turn the bowl!, and let it sit overnight. Don"t rush it...just let it sit.
Now pull out the nails, cut the wax paper and lift the bowl and what ever comes up with it ,wax paper, spacers, etc,. Slowly peal the gasket away from the bowl. Use caution around the spacers ,remember they should have only been slightly under the outside lip of the bowl,. The wax paper ,depending on the type of silicone, will usually peal off. If not, use hot water to help melt the wax and it will easily slide off the silicone. Now trim the inside and outside edges of the gasket as needed. Gently wash with warm soap and water and now your gasket is ready for use.
This has always worked for me and I hope you find it helpful. Good Luck!
Travis
