As promised, a posting about how I make my oil pastels from scratch. I based my experiments on the information provided by Kenneth Leslie in his book
Oil Pastel: Materials and Techniques for Today’s Artist (Watson-Guptill, 1990), but I have modified some of his method and his recipe. Please note that I cannot ensure the longevity of the OPs, since we do not have definitive specific information about the contents of artist-quality oil pastels.
To begin with, here are a few warnings. There are at least three areas of concern. If you decide to try to make your own OPs, please research these issues thoroughly.
First: the flammability of the oils, mineral spirits, and wax. Do not use near an open flame, or smoke while using them. This implies you should NOT use a gas stove for making OPs. When melting the wax, keep the temperature as low as possible. Wax melts at 140-150F; don’t let it get any hotter. Keep an appropriate type fire-extinguisher or at least some baking soda at hand to extinguish a potential fire. Do NOT attempt to put out such a fire with water.
Second: potentially noxious fumes can develop if you over-heat the wax. When melting the wax, make sure you have adequate ventilation.
Third: the toxicity of some of the pigments. You need to avoid breathing in, inadvertently consuming, or skin contact with, pigment powder. Avoid using the most toxic, and wear a government-approved dust mask and gloves when dealing with the pigments. Wear long sleeves and pants to avoid skin contact. Keep some water and paper towels at hand to clean up any stray pigment dust. Do not mix the pigment with a fan blowing or the window open. It is best to work in your studio, not in the kitchen where pigment might contaminate your food. Keep pets and children out of the area.
(This being said, encaustic painters have worked with pigments in heated wax for hundreds of years.)
I have included photos of my equipment and materials. I was able to purchase everything locally.
Materials:
Bleached beeswax – this can be purchased at an art store or at Michaels. Bleaching makes it white, which you need for lighter colours. An even purer grade is Pharmaceutical grade, which can be purchased on the Internet. See
www.fineartstore.com for a discussion of the pros and cons of different waxes for encaustics, some of which is relevant to the making of OPs.
Pigments – I was able to buy small containers of pure pigment (Demco brand, a Canadian company) at my local art store. All were in the $7-$8 range, except for the one Schminke brand I bought (pthalo blue) which was $30.00.
Odourless Mineral Spirits – Leslie uses turpentine to mix with the powdered pigment to make a paste. I don’t like the smell of turpentine and have substituted OMS. It seems to work fine for this purpose.
Oils – I am currently using half mineral oil (bought at the drugstore) and half Winsor and Newton Stand Oil for my oil. Leslie only uses stand oil, a slow-drying form of linseed oil. Mineral oil is a non-drying oil, which appears to be used in today’s artist-grade OPs. So I have combined the two, but this combination is experimental and subject to change.
Equipment:
Griddle – Some people, including Leslie, recommend melting the wax over hot water, using a double-boiler on an electric hotplate, as the safest method. I have chosen to use an inexpensive griddle with a temperature control (bought at Walmart), based on reading about encaustic equipment. I determined the correct temperature-control setting by heating water in my wax-melting container and measuring the temperature with a cooking thermometer. I do avoid splashing or dripping wax on the griddle surface.
Container for melting the wax – As I make only one OP at a time, I’m using a stainless-steel measuring cup (1/2 or 2/3 cup size) in which to melt the wax. Since the wax cools very rapidly when removed from the heat, you will waste a lot of material if you use too large a container. But you need one which is tall enough to prevent spillage when you are mixing in the oils and pigment paste.
Glass plate for making pigment paste – I bought a glass cutting board at my local Home Hardware store. One side was textured, but the other side was smooth, which is what you want.
Measuring spoons – For dipping out appropriate amounts of the pigments you are going to combine for a given colour. It’s best to have several in different sizes, so you don’t have to stop and clean them during the pigment-mixing stage.
Large flat palette knife, narrower-bladed palette knife – The large knife is used to mix and grind the pigment paste to a smooth consistency on your glass plate.( A glass muller is not necessary.) The narrower-bladed knife is used to stir the melted wax, medium and pigment paste to blend them.
Eye-dropper, syringe – To draw up the right amount of mineral and stand oil from their bottles. Stand oil is very thick, much like honey, so you need a dropper or syringe with a wide opening.
Mask and vinyl gloves – Needed particularly for the pigment-paste mixing stage.
Pastel mould – See below for one type of mould you can use
Oven mitts, and fire-extinguisher or baking-soda – I find that my measuring-cup handle doesn’t actually get hot (I keep the cup at the edge of the griddle), but the gloves will protect your hands if the wax splashes for any reason.
Making the OP:
Step one: Make the pastel mould
Leslie recommends rolling a double layer of heavy-duty aluminum foil around a cylindrical object of the required diameter to create a tube. I use my pastel holders for this. I happen to have two, one smaller diameter and one larger, so I can make either size. Then you fold over a seam (I double fold the foil to make a secure seam) and fold up the bottom. Remove the cylindrical object at this point. To hold the tube upright, use Play Dough, or you can make a permanent support out of self-hardening clay. (See illustration). Place the mould on newspaper or paper towels so you can catch any drips when you pour the liquid into the mould.
Step two: Make the pigment paste
Wearing a mask and vinyl gloves, place the pigments you are using for the particular colour you want in the centre of your glass plate in a mound. Hollow out the centre and, using an eyedropper, add some Odourless Mineral Spirits a bit at a time. Using the large palette knife, mix and scrape the pigments and OMS together until no lumps remain and the colours are well integrated with each other. Use only as much OMS as is necessary to make a paste. (see illustration)
Step three: Create the medium (Beeswax, Stand oil and Mineral oil combination)
Open the window or ensure other adequate ventilation. Extinguish any open flames. Using a griddle or a double boiler, melt the wax at 140-150F. Do not overheat. Remove the container from the heat and add the stand oil and the mineral oil. The proportion of wax to oil should be approximately 3 or 4 parts beeswax to 1 part oil. I am currently using a mixture of 50% stand oil and 50% mineral oil for the one part oil. If the wax starts to solidify, return the container to the heat briefly.
Step four: Mix the pigment paste and wax medium
The desired proportion of pigment paste to wax medium is approximately 50/50, depending on the pigments used, since pigments have different oil absorption rates. Add the pigment paste to the wax medium mixture and stir well to combine. Return the container to the heat if necessary to keep the wax medium melted, but don’t leave it on the heat for a prolonged time.
Step five: Pour into the prepared mould
Carefully pour the liquid into the mould. Leave the pastel to harden for at least two hours, preferably more. I leave the tinfoil on the OP as a wrapper, peeling it back as necessary.
I hope you find this interesting and informative. But, as the saleslady at my art store said as I was going out the door with my beeswax, don’t burn the house down. Jane
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