I still remember
the very first piece of chalkware I poured. I had obtained a couple of molds, some plaster of Paris and a little spare time. I clamped the molds, mixed the plaster according to instructions and poured. How easy is this! It's like pouring Jell-O in a mold! 15 minutes later I open the molds--my chalkware Santas look like Swiss cheese--full of holes. I was so discouraged I put the molds away for a year or so.
the very first piece of chalkware I poured. I had obtained a couple of molds, some plaster of Paris and a little spare time. I clamped the molds, mixed the plaster according to instructions and poured. How easy is this! It's like pouring Jell-O in a mold! 15 minutes later I open the molds--my chalkware Santas look like Swiss cheese--full of holes. I was so discouraged I put the molds away for a year or so.Now 100's if not 1000's of chalkware pieces later I have a little confidence.
What you'll need:
Metal or plastic mold with open bottom, Plaster of Paris or art plaster, Cheap plastic or rubber mixing bowl, Cold water, Spring clamps, Sanding pad and knife
Don't count on the little clips that may come with your mold to hold up to plaster. Get some spring type clamps from the hardware store. Use more that you think you'll need. You can use 2 oversize ones to stand your mold upside down or place it in florist foam or packing peanuts, anything to keep it standing straight when full of plaster.
Fill a large flexible plastic or rubber bowl with some cold water , (keeps the plaster from setting too quickly). Just estimate the amount of water based on the molds you have ready. Just start with one or two until you get experience.
Gently shake some plaster into the water, as it keeps absorbing keep adding plaster. At some point you'll see the plaster (roughly a 2 parts plaster 1 part water ratio though I never measure) peeking up from the surface.
Gently shake some plaster into the water, as it keeps absorbing keep adding plaster. At some point you'll see the plaster (roughly a 2 parts plaster 1 part water ratio though I never measure) peeking up from the surface.
I wear a disposable lightweight rubber glove to mix. Just start squishing the plaster around, squeezing out lumps and making it uniform. Do this carefully to not create air bubbles It should be the consistency of a thick milkshake. If not add a little more cold water or a little more plaster. You only have about 20 minutes total before your plaster sets so work quickly. With practice this will become easy. If your plaster is too thin your casting will be weak, if too thick it will be difficult to pour. You're shooting for as thick as you can mix it and still pour.
Slowly pour the plaster (I dip a plastic measuring cup in the mix) into the mold, not in the center, just carefully to one side. Keep tapping the mold while pouring if you can. This will release any air bubbles. Make sure your mold is perfectly upright and bring any sort of straight-edge across the bottom to level it. Now just sit back for about 15 minutes.
The plaster will heat up and expand a bit. When it starts cooling down it's ready to unmold. Take off all the clamps and carefully pull the mold off. There will be seams along the edge. It's best to take a little knife (a woodworker's curved carving knife works well) and shave off all the seams. If there are tiny air bubbles here and there you can fill them with ready mixed spackle. Large voids are almost impossible and that's why careful mixing and pouring are so important. It keeps you from tearing your hair out when you're unmolding.
For clean-up let the plaster dry in the bowl and flex it out when dry. Have a five gallong bucket ready full of water and clean the molds and clips in it. Don't put any of this water down your drain. Just let the clean-up bucket sit and the plaster will eventually sink to the bottom and dry. You'll be able to pour off the clean water and the find the hardened plaster at the bottom.
Let your casting dry. Take a sanding sponge and smooth all the seams until they're no longer visible. Level off the bottom by firmly drawing it across a sheet of sanding paper on a work surface. Now you're ready to paint. But that's a story for another day.
In the photos are some molds and finished and partially finished chalkware. Last photo is a St. Nicholas with lots of hand painting and embellishments.
Slowly pour the plaster (I dip a plastic measuring cup in the mix) into the mold, not in the center, just carefully to one side. Keep tapping the mold while pouring if you can. This will release any air bubbles. Make sure your mold is perfectly upright and bring any sort of straight-edge across the bottom to level it. Now just sit back for about 15 minutes.
The plaster will heat up and expand a bit. When it starts cooling down it's ready to unmold. Take off all the clamps and carefully pull the mold off. There will be seams along the edge. It's best to take a little knife (a woodworker's curved carving knife works well) and shave off all the seams. If there are tiny air bubbles here and there you can fill them with ready mixed spackle. Large voids are almost impossible and that's why careful mixing and pouring are so important. It keeps you from tearing your hair out when you're unmolding.
For clean-up let the plaster dry in the bowl and flex it out when dry. Have a five gallong bucket ready full of water and clean the molds and clips in it. Don't put any of this water down your drain. Just let the clean-up bucket sit and the plaster will eventually sink to the bottom and dry. You'll be able to pour off the clean water and the find the hardened plaster at the bottom.
Let your casting dry. Take a sanding sponge and smooth all the seams until they're no longer visible. Level off the bottom by firmly drawing it across a sheet of sanding paper on a work surface. Now you're ready to paint. But that's a story for another day.
In the photos are some molds and finished and partially finished chalkware. Last photo is a St. Nicholas with lots of hand painting and embellishments.
