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  • Wax additive issuesApproveRejectUn-ApproveSubscribeUn-Unsubscribe
    Question asked 2016-12-09 09:16:08 ... Most recent comment 2016-12-09 10:34:00
    Oil Paint Paint Mediums Varnishes
    Question
    When using Oleogel as a medium, does the wax in Oleogel pose an issue to safely cleaning the painting in the future? Or create issues with the longevity of the painting by making it more susceptible to heat or other issues?
Answers and Comments
  • EditDeleteModerator AnswerReading through the description of Oleogel on Natural Pigments' website I see no mention of wax. It appears that it is composed of drying oil thickened by fumed silica. We have asked George O'Hanlon to comment here to clear up any confusion.
    Baade, Brian
    2016-12-09 10:40:29
  • EditDeleteModerator AnswerEven though Oleogel does not have any wax additions that we are aware of, it is a good to wonder about how additions of wax may adversely affect your paint layer if you are adding it to oils. Small additions are likely alright but more research is needed to clarify just how much is “ok.” Certainly adding as much as 1/3 wax medium to your oil medium (as has been suggested in other recipes) will create a paint film that will remain sensitive to solvents and possibly some of the issues I have listed below which can be found under the “Encaustic” section in the Mediums and Additives document in the Resources section:

    It is generally considered best practice to apply wax paints on rigid supports as the paints can potential crack on flexible supports, especially at lower temperatures.

    Store and exhibit alkyd paintings in dust free environments with relatively stable levels of temperature (60-70 F) and humidity (45-60%). Paintings should not be subjected to light levels over 200 lux or exposed to direct sunlight.

    When wax mediums are exposed to extremely low temperatures they become increasingly more brittle and therefore more susceptible to cracking. Conversely, high temperatures can lead to softening of the medium and in some cases can cause the medium to permanently deform. Environments with higher levels of temperature and humidity can also lead to the accumulation of dust and grime on the surface; if the wax becomes soft, dirt and grime can become permanently imbibed in the surface. High humidity alone has also been found to cause wax coatings/layers to bloom, as water molecules can become trapped in voids or interfaces between layers creating an overall hazy appearance.

    It is not advised to apply paints containing large amounts of wax over other mediums; however, some artists prefer the aesthetic effects created by applying wax mediums over oils, alkyds, acrylics, etc. Such layering is still considered to be an experimental technique.

    It is best to not apply a varnish over paints that are rich in wax. Varnishes that are dissolved in common solvents (e.g. mineral spirits) will likely dissolve the wax medium in the underlying paint layers, causing smearing and/or becoming permanently incorporated into the wax paint.

    As an alternative to varnishing, it is far preferable to buff the surface to create an appropriate level of sheen using a piece of silk fabric.

    Certain pigments have been known to react adversely and/or degrade over time when present in high pH environments (saponified wax). Artists should select pigments that are known to withstand high pH mediums (e.g. lime/fresco) when working with saponified wax mediums.

    Unlike oils, tempera, acrylics, and other mediums, encaustic paintings can be re-worked years after they have been completed, although this may trap any accumulated surface grime between/within layers of encaustic paint.

    Kristin deGhetaldi (CAS)
    2016-12-09 10:45:58
  • ApproveRejectUn-ApproveUser CommentOleogel contains a small amount of castor wax, less than 1%, which is a non-hygroscopic derivative of castor oil that imparts a high degree of thixotropic thickening to the medium. The other ingredients are fumed silica and linseed oil. Castor wax has a higher melting point (85 °C [185 °F]) than beeswax and does not dissolve in polar and nonpolar solvents at room temperature. Castor wax dissolves in hot nonpolar solvents at 45 °C (113 °F) or higher, so we do not believe it is as susceptible to solvents as are most other waxes used in paint today.
    2016-12-09 13:05:50
  • EditDeleteModerator AnswerThanks for the clarification George. Given the very low concentration and the physical properties of this stabilizer, it does not appear that its presence in Oleogel would contribute to the concerns mentioned by the original poster.
    Baade, Brian
    2016-12-09 13:42:40
  • ApproveRejectUn-ApproveUser CommentIn looking at Oleogel and Walnut Oil Gel for glazing effects- on a small test panel, found that the Walnut Oil Gel dries more transparently although much slower in drying than Oleogel and that with the Walnut Oil Gel the glazes are more workable. The addition of the fumed silica probably increases the drying time of both mediums and the transparency and a bit opacity of the glaze . It also has recently been published in the last few years that ground glass may have been a more common additive to old master painting practices than previously believed. For example- a number of artists have told me that ground glass added to blacks tend to make the blacks more transparent and vibrant. Katlan, Alexander W. 2016-12-20
    2016-12-20 12:15:43
  • ApproveRejectUn-ApproveUser CommentCorrection - meant to say "increases the drying" not "time for drying." Alexander Katlan
    2016-12-20 14:54:43
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