Here are some top tips for keeping your moulds perfect. With proper care your silicone mould can make 1000s of castings. It's important to note that epoxy resin and soap/wax fragrance oils can degrade silicone more rapidly, shortening the lifespan of your mould.
Storage: store your silicone moulds in a single, flat layer. Storing them in a pile may lead to warping. Once this happens it cannot be fixed.
- store them in a cool dry area, out of direct sunlight. excessive heat can lead to warping.
- if out of use for a while think about storing the mould with a casting in it to help it maintain its shape! If its a tricky mould to demould and your worried about this candle wax can be used.
Castings: mould release spray can be really helpful getting your castings out and will help prolong the life of your mould!
Dont make any holes in your mould. This can lead to it losing its shape.
- Soap and Water - Dish soap and warm water can be used to keep your mould clean. Before every pour it is sensible to clean to remove any dust. Silicone can withstand high temperatures (up to about 250'C) so don't worry about warping the mould with warm water. Never use steel wool, scrubbing sponges, or anything abrasive. This might scratch the surface of the silicone. Damaged spots on the silicone mould can create sticky spots in your mould. Do not use solvents and do not put the mould in the dishwasher. Ensure they are completely dry before you store them.
- No Over Stretching - This can lead to tearing of your mould.
- No Torching - DO NOT EVER torch the epoxy resin in the silicone mould to pop any air bubbles that have formed! Even a quick torch will lead to breakdown of your mould over time. There are a few ways to prevent air bubbles:
- Torch the epoxy resin in a separate container and then pour it into the silicone mould.
- Vacuum the resin before pouring.
- Heat the mixed resin a few minutes to a maximum of 40'c (use a ban marie)
- use a pressure pot while curing, it will make the air bubbles so tiny that you won’t see them anymore,
- spray a fine mist of isopropyl alcohol (best is 99.9%) into the mould just before pouring and on the epoxy resin surface after pouring. This can be repeated a few times at short intervals, but don’t overdo it to avoid traces and other unwanted surface irregularities.
- Stuck finished pieces - If a finished piece seems stuck and won’t unmould, then don’t panic and tear up the mould!
- Check your cure time and the temperature for your resin are correct. Increases in temperature can shorten cure time.
- If very stubborn try putting the mould in the freezer for 30minutes or so - this wont work if your silicone is fused due to torching...
- Read the Instructions for your epoxy resin - This is critical.
- Pouring in layers - If you pour too thick, you run the risk that the epoxy in the mould will become extremely hot. This can damage the piece and your mould! Thinner layers also means fewer bubbles.