Speeding Up Set Time of Plaster

As a casting artist, I feel that plaster is about the most versatile and efficient material for making both molds and casts. I use it regularly in my art studio and have even tried my hand at making life casts with the multipurpose plaster.

The only downside I face is the curing time. Indeed, art plaster takes a long time to set and cure completely – a few hours or even days at times. I often try to speed up the process with direct sun exposure, hand dryers and even baking in the microwave oven. This requires additional care as plaster can crack or spall at high temperatures. Therefore, it often gets quite frustrating to wait out the drying time, especially during humid weather.

Recently I chanced upon QwicKast Plaster and Gypsum Accelerator on the EnvironMolds website, www.artmolds.com. This accelerator claims to decrease set time to almost 8 minutes! And just a tiny amount will suffice.

I decided to give a try. All I had to do is add 1% accelerator to the plaster powder by weight and voila! The plaster cast had actually set in just 8 minutes. Adding 0.5% will bring down the set time to about 12 minutes while 0.2% require set time of around 18 minutes.

A word of caution - Use a gram scale to get the proportions right and never add the accelerator to the water first.

Apart from the useful accelerator, EnvironMolds also stocks plasters, gypsums and plaster of Paris bandages.


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