Honored Advisor
Posts: 1,567
Registered: ‎10-21-2009

Well, the mail arrived …

[ Edited ]

Larry (and others);


… and I am most disappointed by what I have read.  The statements made to Ty with respect to the differences between Mineral Spirits, Odorless Mineral Spirits and Paint Thinner are simply inaccurate.  Paint thinner is not “reclaimed” mineral spirits.  This is the functional equivalent of saying that whisky is reclaimed beer.  In the case of both the issue is the level of refining (distilling).  A logical examination of the reclamation proposition should quickly reveal the flaws in that explanation; from where would a sufficient supply of impure mineral spirits be obtained to fill the shelves of all the Big Box, paint stores and corner hardware stores?  But, forget that; let’s look at the information found in the typical MSDS (Material Safety Data Sheet).


The chemical components covered by the MSDS are identified by their CAS number.  CAS stands for the Chemical Abstracts Service, a division of the American Chemical Society, the world's authority for chemical information.  When we examine the MSDS for a product we are able to determine the identity of the included chemicals by referencing the CAS Number.  If different products contain a chemical that is identified with the same CAS # then the chemical in those products is the same.  See the following answer to the question “What is a CAS Registry Number?” from the CAS website.


“CAS Registry Numbers (often referred to as CAS RNs or CAS Numbers) are unique identifiers for chemical substances. A CAS Registry Number itself has no inherent chemical significance but provides an unambiguous way to identify a chemical substance or molecular structure when there are many possible systematic, generic, proprietary, or trivial names.”  (Emphasis added to highlight the problem of imprecise names assigned to chemicals, usually by marketing departments.)


With this explanation established, what is the CAS# assigned to paint thinner and mineral spirits (including odorless mineral spirits)?  A quick examination of various manufacturers’ products will reveal that the CAS # is 8052-41-3.  This number identifies the chemical as “Stoddard Solvent”.  A list of typical common names follows; for example, mineral spirits; aliphatic petroleum distillates; white spirits.


Now, let’s specifically examine the MSDS of the two Klean Strip products pictured in the Ask WOOD reply.  The W.M. Barr Company provides an easily found MSDS for all of its products.  The following links take you to the Odorless Mineral Spirits and the Paint Thinner shown in the photo.  If you examine section 2, Composition/Information on Ingredients, you will find an identical CAS#.   You will also notice the addition of an ACGIH STEL number (250ppm) on the Paint Thinner MSDS.  This is the only section 2 difference between the two MSDS.   ACGIH stands for American Conference of Governmental Industrial Hygienists' (ACGIH).  STEL is short hand for Short Term Exposure Limits.  Its inclusion relates to the higher level of refining of Odorless Mineral Spirits relative to Paint Thinner to remove benzene, toluene and xylene (the “smelly” componants).  Other than that, Section 2 of both documents is identical; chemically they are the same thing.  Paint Thinner, Mineral Spirits and Odorless Mineral Spirits are all CAS #8052-41-3; all are Stoddard Solvent.  The only difference is the removal (further refining) of benzene, toluene and xylene from Odorless Mineral Spirits.  It is, therefore, clearly be a stretch of monumental proportions to refer to Paint Thinner as “reclaimed mineral spirits”.


As to the evaporation rate of turpentine compared to paint thinner/mineral spirits and odorless mineral spirits, put them to the test in your shop.  Carefully measure equal volumes of each, pour them on a glass pane and see how long each take to evaporate…



Finishing & Refinishing Forum Host
Honored Advisor
Posts: 2,698
Registered: ‎10-23-2009

Re: You have given me a reason to look forward to the mail …

ynoT wrote:

fredhargis wrote:

Page 70: "The least expensive of the three, paint thinner is ofen made from recycled minerals, Ty, so trace impurities prevent the manufacturer from labeling it purely as mineral spirits"

Wonder where they would get reclaimed MS?



Are we confusing the Mineral Spirits with Minerals?

It doesn't say from Mineral Spirits.

I don't think they would be one and the same, yes?



Tony, sorry...typo om my part. Should say mineral spitits.

"I long for the days when Coke was a cola, and a joint was a bad place to be" (Merle Haggard; 1939-2016)