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Making A Plaster Mold – a How To (3 of 3)

Previously, GIDP was called to the Frick Museum to repair a hole in their ceiling (see previous related posts: Part 1: Ceiling Repair at the Frick Collection and Part 2: Ceiling Repair at the Frick Collection While GIDP doesn’t make a habit of fixing plaster or making molds, small spot repairs are possible and can be done. It’s also good to have skills that expand beyond painting. Pierre Finkelstein of Grand Illusion Decorative Painting shows you how to make a plaster mold when in this case, it was destroyed from falling from the ceiling.

The missing section of the cieling

HOW TO CREATE THIS FINISH

Use our step-by-step instruction below

MATERIALS NEEDED:

Here is a list of the tools & supplies you will need to achieve this technique.  Supplies available at fauxbrushes.com are linked below and listed at the bottom of the page.

1

CREATE A MOLD

STEP 1 – CREATE A MOLD: Following the directions on the box for a fast drying silicone putty, a mold was made. As instructed, two ingredients were mixed together to make a pliable, elastic mold that dries fast.

After mixing the putty, it was placed on the model piece and thoroughly pressed.

The putty dried to a perfect print of the missing section.

2

FILL THE MOLD

STEP 2 – FILL THE MOLD: A liquid slurry from the mold box was mixed and poured into the cast.

To fill the mold completely, blue tape was used to erect a wall around the mold to hold it in. Using a Palette Knife, the mixture was then pressed down and compacted. This is very important.

Then the plaster was left to dry (however not completely dry).

3

REMOVE THE MOLD

STEP 3 – REMOVE THE MOLD: Gently break away excess or cut the silicone away to avoid breaking the mold.

Here is the plaster freshly pulled out of the mold.

4

CURE THE MOLD

STEP 4 – CURE THE MOLD: Next, let the mold dry completely. At the museum, the GIDP crew had the convenience of this kiln to assist with drying (at low temperature). Otherwise, be sure to dry to cure (6-12 hours).

5

REFINE PLASTER

STEP 5 – REFINE PLASTER: Using specialized chasing tools, scrape away excess plaster.

Etch the backside so the wet plaster can adhere well.

Cleaned and ready to go.

6

REMOVE EXCESS

STEP 6 – REMOVE EXCESS: Using a marker to mark what sections need to be removed before attaching. Then cut off excess plaster that is not needed.

7

ATTACH TO THE CEILING

STEP 7 – ATTACH TO THE CEILING: Mix the plaster of Paris and Wellbond to “glue” the ornament on the backside.

Additional carving and shaping was needed during installation. Use extra plaster to fill the gaps on the surface after it is in place.

8

PROTECT AND FINISH

STEP 8 – PROTECT AND FINISH: Shellac was used on the surface to seal the plaster.

9

BLEND WITH FINISH

STEP 9 – BLEND WITH FINISH: Finish the ornament with base paint. The plaster was decoratively finished.

See also:  Part 1: Museum Plaster Ceiling Repair, Part 2: Plaster Molding Ceiling Repair

COMPLETED FINISH

FEATURED

PRODUCTS

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