Tuesday, February 11, 2014

Good info on paint thinners. OMS = Turpenoid

Sansodor, turpenoid, gamsol, Daler rowney low odor thinners, and several others are virtually and functionally the same thing though the specific mix of organic solvents will vary. Petroleum based solvents are a mixture of many volatile organic solvents. Mineral spirts or white spirits if you are in England has the strongest solvent dissolving power, then common odorless paint thinner or odorless mineral spirits from a hardware store has less power, and finally low odor thinners or sansodor, turpenoid, gamsol have the least power.It is the same lineup for evaporation rate. Mineral spirits contain more volaltile organic solvents, OMS less, artists low odor solvents have the least. They are all distilled from crude petroleum oil, artists low odor solvents are distilled to a greater degree, this costs more so these artists quality low odor solvents cost more. They really do evolve less vapor, you can look at the permissible exposure limits: low odor artists solvents= 300 ppmodorless mineral spirits=200 ppmmineral spirits=100-200 ppm (turp is also 100 ppm ) these are the concentrations of vapors that you may be exposed to in an 8 hour time period and not expect it to be considered hazardous.that means you can sniff three times as much sansador as you can turpentine before you would expect to have the same hazardous exposure.This is why turp is more powerful as a solvent and used to dissovle natural resins.I would expect any application in which you would use gamsol, that you could substitute sansodor or turpenoid and use them also. You can use any ofthem for painting mediums including alkyds and any drying oil with the caveat that if you are using a natural resin like damar or copal then you need to use turpentine instead.
Found here

Ran across this because David Grey recommends cutting walnut oil with something called OMS for doing an initial oil wash-in. Turns out OMS means odorless mineral spirits, and via the above thread I discovered that's the English name for Turpenoid. Cool - I already have some!!

(To be clear, yes, there's a hardware store OMS which is stronger then the art store type, but what David was using I'm sure is the art store variety)

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