Architectural Restoration: Making a Rubber Mold of a Plaster Column

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.

The Steps:

–Part I: Prepare Column & Make Brush-On Rubber Mold– 0:39

Step 1: Establish Mold Area 0:47
Step 2: Apply Sealer [Pol-Ease® 2350 Release Agent] & Let Dry 0:56
Step 3: Make Flange Supports for the Top & Bottom of the Mold Area 1:07
Step 4: Apply Release Agent [Pol-Ease® 2300 Release Agent] 2:01
Step 5: Mix Rubber 2:20
Step 6: Brush On Rubber 3:26

–Allow Rubber to Fully Cure– 5:23
–Part II: construct Two-Part Plaster Mold Shell– 5:28

Step 7: Spray & Brush Out Release Agent [Pol-Ease® 2300 Release Agent] 5:35
Step 8: Mix Plaster & Construct Two-Part Mold Shell 5:46

–Allow Plaster to Fully Cure– 9:12
–Part III: Remove Mold Shell & Rubber Mold– 9:16

Step 9: Carefully Remove Mold Shell 10:27
Step 10: Carefully Remove Mold 11:07

–Part IV: Cast Plaster in Mold– 12:46

Step 11: Pour Plaster into Mold 12:51

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Music Credits:

“Our Ego [Feat. Different Visitor]” ( by Broke for Free (

“The Great” by Broke For Free (

Post time: 02-01-2017