How to Make a Brush-On Mold with Mold Shell [Part II of II]

Part I of this video tutorial demonstrates how to make a brush-on mold using tin-cured silicone rubber (TinSil® 80-30).
In Part II, we complete the project with the following:
• mold shell construction (using Poly 1512X polyurethane plastic)
• cutting the mold
• how to make a plastic casting using a rotational casting machine (using EasyFlo 120 polyurethane plastic)
The Steps in Part I of this tutorial:
1. Establish Pour Hole
2. Weigh & Mix Rubber for First Layer of Mold
3. Brush-On First Layer of Mold
4. Weigh, Mix & Brush-On Second Layer of Mold
5. In the Meantime, Cast Rubber Pieces for Parting Line & Keys
6. Weigh, Mix & Brush-On Third Layer of Rubber
7. Weigh, Mix & Brush-on Final Layer of Rubber
8. Create Thick Parting Line
The Steps in Part II of this tutorial:
9. Construct Mold Shell
10. Remove Mold Shell
11. Cut Parting Line in Mold
The Final Step: Rotational Casting with EasyFlo 120 Polyurethane Plastic
Music Credit:
“Bust That Rap Like Nobody’s Listenin’ (Dare 2 B Great remix)” (freemusicarchiv...) by Eric Steuer (freemusicarchiv...)
“B-3” (freemusicarchiv...) by BoxCat Games (freemusicarchiv...)
“Our Ego [Feat. Different Visitor]” (freemusicarchiv...) by Broke for Free (freemusicarchiv...)
“Telluric Undercurrent” (freemusicarchiv...) by Revolution Void (freemusicarchiv...)

[@aliv1908]

What is the benefit of using this as a mother mold over plaster? All I can guess is strength?

[@PolytekDevelopmentCorp]

Hello April - yes, these polyurethane plastics are strong and can save time.

[@nixland]

The 1512 pu plastic is used only for mother mold or can it be used as casting resin too? Please advice, thanks.

[@PolytekDevelopmentCorp]

Hello - Yes, Poly 1512 Liquid Plastic can also be used as a casting resin; however, it's not the best option for slush or rotational casting.

[@nixland]

Polytek Development Corp. Thank you for the info. Is it because 1512 takes longer time to cure? (pour time)

[@PolytekDevelopmentCorp]

That is part of the reason, yes. We typically recommend EasyFlo 120 for rotational or slush-casting because of the shorter working time (2 - 2.5 minutes) and because it has more of a gradual set (versus snap-set), which caters to this type of casting.