Building a Mould

We have made many many moulds, and these are the step by step instructions that has worked for us. 

Make sure your timber is lower than 14% moisture content. Anything higher than that and the timber is too green to use for epoxy work. It can twist, cup and bow whilst it continues to dry. Kiln dried slabs are usually better than just seasoned slabs, as the kiln not only removes the moisture, but also kills woodworm. 

  1. To create your mould you will need a sheet of MDF or Form ply to be the base. 3mm or 6mm thick is fine, but totally your choice. You then use Pine batons for the sides. Ensure that the mdf and pine you purchase are larger than your piece. For example: If your piece will be 1100 x 400, get mdf that is 1200 x 600.
  2. Trim your timber to the desired size. Always trim it bigger than your final measurements, as the piece will need to be trimmed after de-moulding.
  3. Once you have measured and trimmed your timber, then measure and trim your mdf sheet and pine batons (remember to make them bigger).
  4. Cover both the mdf base and side pine batons with Scotch Brand clear packing tape (its in the storage and moving section at Bunnings). Epoxy will pull straight out of a mould covered in this tape, so no need for mould release.
  5. Once covered in tape, you then need to attach the base to the sides. Screw together your side batons, and then once the frame is ready, place the mdf base on top. Use screws to secure it to the sides.
  6. Once all screwed together, you now need to use Selleys clear wet area silicone on your inside and outside seams. This helps to prevent leaks (because epoxy will find even the smallest hole). Do not use caulk as it can affect some epoxies. Run a gloved finger over your silicone to get a smooth finish, and make it water tight.
  7. Leave your mould for 24 hours, for the silicone to dry completely. Your mould is now ready to use.
  8. Place your timber is the mould. You will need to weigh it down, because even though its' heavy.. timber can float. Either use chucks (covered in packing tape) and then bars across the top and then clamped to the bench top. Or fill some old large epoxy bottles with water, and rest them on top of your timber. Epoxy wont stick to them.
  9. Remember to pour your epoxy in a low humidity environment, ideally within 18-22 degrees Celsius. Any warmer than that, we recommend to reduce the max pour to prevent a flash cure. Pour in 2 layers if you have a very deep piece, if its in a warm/hot room.