This video tutorial features the making of a brush-on rubber site mold. Some of the columns in this commercial building are damaged -- a brush-on rubber mold with plaster mold shell is made of an intact column in order to cast plaster replacements for the damaged columns.
Mold Materials: Poly PT Flex 20 (a soft, polyurethane rubber) and a Plaster/Burlap Two-Part Mold Shell. A full list of materials used are listed at the end of the video.
Part I: Prepare Column & Make Brush-On Rubber Mold
Step 1: Establish Mold Area
Step 2: Apply Sealer [Pol-Ease® 2350 Release Agent] & Let Dry
Step 3: Make Flange Supports for the Top & Bottom of the Mold Area
Step 4: Apply Release Agent [Pol-Ease® 2300 Release Agent]
Step 5: Mix Rubber
Step 6: Brush On Rubber Allow Rubber to Fully Cure
Part II: construct Two-Part Plaster Mold Shell
Step 7: Spray & Brush Out Release Agent [Pol-Ease® 2300 Release Agent]
Step 8: Mix Plaster & Construct Two-Part Mold Shell Allow Plaster to Fully Cure Part III: Remove Mold Shell & Rubber Mold
Step 9: Carefully Remove Mold Shell
Step 10: Carefully Remove Mold Part IV: Cast Plaster in Mold
Step 11: Pour Plaster into Mold