Master Pattern Foam
Dry floral foam for arranging artificial flowers is the cheapest and most readily available foam that’s suitable for making master patterns and it works fine.
You can purchase a higher density Polyurethane Foam specifically for making climbing hold master patterns which is typically twice the density of the floral foam.
Silicon
The silicon that you will make the moulds from needs to have suitable:
- Tear Strength – don’t want the mould to tear when you pull tight complex shapes out of it
- Hardness (Shore Durometer) flexibility for de-moulding and stiffness to hold shape of 20 or 30
- A low viscosity so that the liquid pours easily into small texture details without trapping air bubbles
- a suitable cure time – faster speeds up production, slower lets air bubbles rise and escape before the silicon sets
- a suitable cure type (depending on how long you want the mould to last in your library)
The product used in the photos is Smooth Ons Mould Star 20T Silicone Mould Making Rubber. This product is mixed from two parts, has a shore hardness of 20, a viscosity of 11,000 cps, a pot life of 6 minutes and a cure time of 30 mins and is a platinum cure
Model making shops and online stores typically have a wide range of mould making products available.
Urethane casting Resin
The semi rigid Urethane casting resin that you will cast your holds from needs to:
- Be strong enough to not break when used as a climbing hold
- Not be too rubbery / flexible so have a shore hardness greater than 60D
- Not be too stiff or brittle so have a shore harness less than 80D
- A low viscosity so that the liquid pours easily into small texture details in the mould.
The product used in the photos covering the process and example designs is Smooth On’s Smooth Cast 65D – Semi-Rigid Urethane Casting Resin. The product is mixed from two parts, has a sore hardness of 65, a viscosity of 120 cps, a pot life of 2.5 minutes and a cure time of 15 minutes.
Model making shops and online stores typically have a wide range of mould making products available. Most products indicate if they are suitable for making climbing holds
Urethane Dye
A suitable dye to colour your holds. The dye is typically mixed when the urethane casting resin is mixed.
Model making shops and online stores typically have a wide range of mould making products available.