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Castor Wax vs Damar Resin

Comparing Castor Wax & Damar Resin in Encaustic Medium

Damar resin has long been the hardener of choice to combine with beeswax in encaustic medium recipes.  Because of its high melting point, it aids in making a more robust painting than pure beeswax and allows for vigorous buffing over a curing period to bring the work to a shine.  A downside can be that due to its organic nature, damar has been known to yellow over time.  This may happen in varying degrees over months, years or decades, though artists who combine pigments with their medium will typically never notice this.  For those who rely on many clear layers, it could become an issue. Most pieces seem to remain as the day they are painted, but if you do experience yellowing, or simply want a whiter medium, there is a solution. I recently took a deep dive into the use of an alternative to damar, castor wax.

Australians pioneered the use of castor wax as a replacement in their encaustic medium years ago in response to the exorbitant price of importing damar.  The wax is derived in a roundabout way from castor beans, available domestically and much less expensive.

After many conversations and e-mails with artists using this combination for years, I embarked upon testing.  I can’t yet speak to its longevity in my own experience, but those I spoke with assured me that time has had no effect on their pieces.  Some had art on hand created years ago using each recipe (castor and damar) and there were no noticeable differences. They all confirmed that no yellowing had occurred.

Using Castor Wax in Encaustic Medium

My major impression of using castor wax is that it is a joy to work with. 

4 layers of each painted onto bare birch.

Following are my findings.  In all cases, I am comparing caster to damar as combined with beeswax to make encaustic medium.

  • It makes a whiter medium, not clearer, just whiter. See photo of 4 layers of each painted onto bare birch.
  • It seems to flow smoother and thinner off the brush.  Damar medium has more body and viscosity.
  • It is more slick and less sticky when cooled. If you get it on your hands it’s not as gooey as damar, nor does it roll into a ball as easily.  When doing transfers the paper tends to slide around the wax more upon initial placement.
  • Castor has a lower melting temperature than damar, but still higher than pure beeswax. This should be of no concern to the final artwork as Australians have used it with great success for years in their warm climate.
  • Anecdotal reports indicate it hardens up well over time.
  • You can use the same ratios for each.  Most I spoke with use 8:1, but Langridge Artist Colours in Australia uses 6:1 in their commercial formula.  I preferred 7:1.
  • Castor makes a more brittle medium when comparing similar ratios, but nothing that would affect my work on a rigid support.
  • It appears to buff to a shinier finish than damar.
  • No straining is required as there are no organic bits embedded in it.
  • Castor performed well in my freezer tests, adhering to bare birch panel, encaustic gesso (R&F) and chalk paint (Cottage Paint brand).

All of that said, I have come up with a formula that works well for my process that actually includes a combination of both damar and castor. I expect this will change with each batch as I hone in further, but I can’t really see myself ever going back to full on damar in my medium.  Don’t be afraid to experiment with small batches to discover the specific formulation that allows you to bring your vision to life.  A digital scale is your friend.

Castor wax flakes are widely available in stores carrying botanical ingredients for those making home balms and creams.

If you’re looking to purchase encaustic supplies, please support local small businesses when possible. You can purchase encaustic medium made with Castor wax from Karen Brown.

Have you tried Castor wax? Please add a comment below and let me know what you think.

About Sue McNenly

Sue McNenly is a Canadian contemporary encaustic painter creating minimalist artworks out of her home studio near Guelph, Ontario. A metalsmith as well, Sue combines gold and silver fabricated components into her pieces, contrasting hard edged details with ethereal wax planes.

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21 thoughts on “Comparing Castor Wax & Damar Resin in Encaustic Medium”

  1. I find the use of castor wax for encaustic painting interesting. Is this available already mixed with beeswax or would you have to make your own?

  2. I was so pleased to see this post as I have been using castor wax in lieu of damar for many years now; although I always felt slightly “naughty” not using the “standard.” I too have seen no yellowing and or other side effects of the substitution. I really like the whiteness of it as well as the ease in making medium. I have found that if I want a more yellow and creamy looking medium I just use unbleached beeswax instead of the filtered white pellets and I am able to get that warm tone. When mixing medium with white, the castor wax/beeswax medium is definitely my first choice to achieve sparkling whites!

  3. Does the addition of castor wax make the medium more translucent and cloudy? Is it as transparent as damar or more opaque?

    Thanks!!

    1. It seems that with very thick layers the castor is not quite as clear, but on thinner layers I didn’t see a difference. Do some experiments using different amounts for your own work style to check if it would affect you.

    1. I don’t feel qualified to speak to any medium re what happens chemically when heating, but I have noticed no smell or obvious fumes. I don’t really notice fumes when I melt my damar either as I melt it at the lowest temp I can and don’t let it smoke.

  4. Fantastic article! I’ve been struggling with the yellow hue of traditional medium. I will definitely give this a try! Thank you!!

    1. Yes, the beans/seeds are poisonous. The process of extracting the wax/oil seems to change that chemically, but I’m not a chemist so please do your own research in order to feel comfortable. It is used in creams and balms so seems to have a history of safety.

  5. Great info here. I am new to encaustic, and have been making my own medium with castor for the above mentioned reasons. When I assess the hardest of the encaustic medium block before using I would say it was on par with the Langridge medium I used the first time I applied encaustic. My ratio has been 7:3, as I found that when researching before I made my first batch. I might try less castor and see how it compares. I am Australian, so climate is an issue:)

  6. Wow, almost 2:1 ratio! There are no official rules and whatever works for you is wonderful. That’s why I’m also adding some damar still….it just works best for my process. Keep us informed re your experiments:)

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