Here’s a great DIY method to copy a vinyl record, making a copy that you can actually play on a turntable. The German website Zeit.de had this article up in German, however it’s now unavailable, and only available via archive.org.
Here it is in it’s full form, translated into English:
Nail together four 36.5cm-pieces of wood to create a frame and put it on a glass plate. Seal off the edges using caulking, and make sure everything is completely airtight.
Take the record that you want to copy and put it into the box, making sure that the side that you want to copy is facing upwards. Squeeze in some caulking or insert a dowel to mark where the hole in the record is.
Mix silicone rubber (Smooth On OOMOO 30 or OOMOO 25) for about 3 minutes..
Pour the silicone rubber mixture into the mold. start from one corner, and fill the mold until it is about 5mm deep. Make sure the that surface is even, and let it dry overnight.
Peel off the silicone from the cast and cut off the excess.
Pour on some casting resin (eg Smooth On Task #4) on top of the silicone cast.
Make sure that you don’t have anything spill over the round form. You can also brush off any air bubbles that might occur.
Carefully loosen the plate from the silicone form. Using a drill press, bore a hole through the center of the plate (this doesn’t need to be done if you used the appropriate sized dowel).
You can keep using the silicone form and make multiple copies. Definitely a darn fun DIY project.