Why not just use turpentine? It's a serious health hazard. Additionally, some people are, or become allergic or sensitized. See this OSHA document for details.
Solvents are used for thinning oil paint, cleaning brushes and as an ingredient of mediums. OMS can handle thinning and cleaning but may not be strong enough for some mediums.
I pulled up the Material Safety Data Sheets (MSDS) for these brands of artists's OMS:
- Weber Turpenoid - Aliphatic Hydrocarbon 100%
- Gamblin Gamsol - Naptha(Petroleum), Hydrotreated heavy
- Winsor & Newton Sansador - Distillates (Petroleum), Hydrotreated light
There are significant differences that make true, highly-refined odorless mineral spirits safer alternatives to turpentine. True odorless mineral spirit has the aromatic component refined out of it – less than .005% remains. Most significantly, OMS has an evaporation rate approximately 3 – 5 times slower than turpentine – this means that during a painting session you will work around less evaporated solvent. In addition, OMS has a high flash point, and is not absorbed into healthy skin.
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The other factor we will want to consider is the health issue of solvent exposure. You'll find some art store brands to be less toxic than a typical hardware store variety... The following are Threshold Limit Values (TLV) for an 8 hour work day (according to ACGIH). Higher values are LESS toxic.
Turpentine 100ppm (including W&N distilled)
Aliphatic Hydrocarbons 100ppm (Turpenoid, Utrecht Odorless)
Iso-paraffinic Hydrocarbons 171ppm (Maimeri Odorless)
Common hardware store OMS 100-200ppm
Hydro-treated Heavy Naptha 300ppm (includes Gamsol)
Hydro-treated Heavy Naptha at 300ppm will have the minimum of aromatic solvent content and be less toxic, as the AMIEN staff suggested. The art store OMS at 200ppm may have less of the really nasty "impurities" of the common hardware store OMS like 1,2,4-tri methyl benzene at 10ppm.
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