Hi everyone Here is the next step of making your silicone inner and fiberglass moulds
So, once you had prepared the silicone inner for the mould you are now ready to start the process of creating the fibre glass outer section of the mould. The reason you need to add a fiberglass outer is to support the silicone as it will not hold its shape through the next step..
Product needed and equipment needed :
- Gel coat
- Fiberglass matting
- Plastic sheeting
- laminating fibreglass resin
- paint brush
- You need to start by removed the mod-roc and clay wall from around the edge of the cast. Then use paper towel to remove any moisture that may be onto of the silicone the reason you must do this is If the silicone is damp or wet, the fibreglass would not cure.
- Next trim away any excess silicone around the edges of the silicone to create a clean edge. Depending on the surface you apply fibreglass to, a release agent may be needed as fibreglass adheres to pretty much anything however silicone is flexible and can easily peel away.
- When the silicone is ready you can move onto mixing the first stage of the fiberglass. So you need to begin by measuring out half a cup of the gel coat.(this will be enough for two face casts .)
- Next added a catalyst which will allow the gel coat to vulcanise. Measurer on the bottle up to the 2 marker. Adding any more that this to the gel coat will make the gel coat cure quicker that we need it and it will be a waste of product .
- Next thoroughly mixed it together and applied a thick coating over the top of the silicone with a medium paint brush.
IMPORTANT INFORMATION : Never place the cups and brushes directly into the bin after use –as it heats up when it cures, meaning it is a fire hazard. It is best to let it cure in sight completely before disposing in a safe manner.
- Once the gel coat is applied leave it to cure for around an hour. This will allow the gel coat to cure but not become completely dry – leaving the surface slightly tacky ready for the next step.
- Next cut 15-20 3inch square pieces of fibreglass matting to prepare for the next step (any squares left over can be used for the next step ).
- You need to prepare a work space as fiberglass can become quite messy and it does not come off any surface when dry . So laid out another piece of plastic sheeting onto the table to protect the surface. then laid out 4 pieces of the matting onto the plastic to preparation for the next step.
- measure out half a cup of laminating fibreglass resin using a new cup – to prevent cross contamination of products . Also added the catalyst to the resin using the same measurement of 2 again then mixed it thoroughly.
- Then used a brush to paint a layer over the tacky surface of the gel coat this will help the next layer adhere.
- Next used a brush to soak the 4 piece of matting you have laid out with resin. Once all four have been coated they will have absorbed the resin making it easier to mould to the shape of the silicone inner. Repeat this process till you have covered all the surface but make sure to overlap each piece. make sure there are no air bubbles .
- Leave the layer to dry for around 20 minutes until it goes a green colour. To prevent using a grinder power tool you can use a pair of scissors to cut the edges of the fiberglass whilst it is still setting . Once it is set and solid this is not possible and you need to use a power tool.
- repeated the process adding a second layer. Then leave it to dry completely overnight
So that this part of the process completed , I will blog about the next step next week
Thank you for reading