I did some digging and here are the results, and the hopeful message :
- AK odorless thinner = turpentine as per their website
- AK white spirit is self explanatory.
Now comes the interesting part: I did some research on the safety levels for both of them, and it seems that white spirits are “safer” than turpentine (even though turpentine is considered a “natural” product):
I am going geeky now but bare with me:
The exposure limit (PEL) for turpentine is <100ppm (525-590 mg/m3). For example in US(OSHA) the limit is below 525mg/m3, while in UK is <590mg/m3). The exposure limit for white spirits is 500 ppm (2900 mg/m³).
Ppm stands for parts per million and that is just a unit of concentration and one ppm is basically one millionth of the total vapor volume.
The PEL or permissible exposure limit is the amount of exposure a worker is allowed to be subject to in (commonly) 8 hours . Any more exposure than that over an 8 hour period must be mitigated or reduced in some form.
Talking the Turpentine solvent which is the worst of the too as an example, this means that in case one is working in a normal room of 4x3x2.2=26,4m3 the PEL is 525*26,4=13.860mg/26,4m3. This translates to 16,116ml of Turpentine, that we should be using to be in the danger zone.
For white spirits the limit is way higher (76.560mg/26,4m3, or 96,1ml)
Now in my case, which is the case for most of you, I do not use more than 4ml when I do my weathering, so it seems we are safe… I still wear my respirator though
White Spirits, White Spirits 2
White spirits Hazard labels: Interesting about this document is the Hazard labels of white spirit products (note, the AK white spirit has only the H304, which means it is one of the softer WS solvents).
I hope this is helpful and will bring some ease of mind to restless spirits like me
Note: One aspect I could not scientifically confirm, is that odorless Mineral Spirits are heavily refined to remove as many harmful pollutants as possible so the formulation doesn’t negatively affect respiratory health. This could mean that the AK odorless thinner (turpentine) has potentially higher PEL than standard turpentine.