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Dan Does It!

Brief answers to readers' questions on techniques

The way I would do this job is:

Get 3 buckets of very cold water, 50 to 55 degrees.Sift the plaster into the first bucket.Have a friend mix the first bucket, while you start sifting plaster into the second bucket.After 2 1/2 minutes of mixing, have your friend pour the plaster from the first bucket into the mold.You should have the second 2 buckets ready to mix by this time.You mix the second bucket, have your friend dump it in the mold, while you start mixing the 3rd bucket.  Dump the 3rd bucket in the mold and you're done.

I have done this process by myself, without a helper, but you end up racing around, knocking things over and spilling things on the floor.  The colder the water you use, the slower the set of the plaster.

  #2)   Hi Dan,
I have a problem with tiny pinhole air bubbles when I cast plaster into my plastic molds. What can I do about this problem?

If you are getting air bubbles when you cast plaster into plastic molds, here are some suggestions:

Make up your own mold wetting agent with 2 gallons of water and about 1/3 of a cup of Palmolive Dish Detergent, or dilute a bottle of Windex with an equal amount of water.   Either of these can be sprayed into your mold just before you pour. 

Do not mix air into your plaster prior to pouring.

Let the plaster slake or settle a couple of minutes before mixing.  Pour the plaster in a thin stream and blow on the plaster as you pour it out to break up the air bubbles.

After the mold is poured, vibrate it to make the air bubbles rise to the top.  You can blow on them to break them up also.

  #3  Dear Plaster Master,
I have a plaster statue that has been kept outdoors. The paint has peeled off and it is starting to pit. Since it's already damaged, I thought I might do some experimenting on it. I would like to create the look of old cracked paint on this statue. How can I achieve that type of finish?

Outdoor statues should be made of concrete or cast stone.  If you want to experiment, you can try this.

First, you must let the statue dry out thoroughly. If you bring it indoors for the winter and set it in a warm place for a month or so, it'll be thoroughly dry. Paint will always peel off of a plaster statue that has been painted when it is damp.

To produce an antique, cracked plaint type fininsh, purchase some crackle varnish. You can purchase crackle varnish at craft stores (also know as Craquelure). It is sold in a package including 2 varnishes - one oil-based and the other fast-drying water-based.

Apply the oil-based varnish first.  Allow to dry until slightly tacky.

For the second coat, apply the water-based varnish evenly over the surface.

The difference in the drying times between the 2 varnishes causes the cracks.  The oil-based varnish is slow drying and the water-based varnish is fast drying.  The longer you wait before you apply the second coat the smaller the cracks will be.

Allow the second coat to thoroughly dry.  Get a tube of artists' oil paint. It can be some dark color such as reddish brown.  This color will be rubbed into the cracks.   Wipe off the excess to the desired finish.  When the oil paint is dry, get some polyurethane varnish and coat the entire piece.

A good polyurethane sealer might preserve the statue for a little while.

As I said, this is just an experiment.  You may wish to practice first.

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