Mineral Spirits
 

I should know this but I must admit my lack of knowledge on this subject.

I have been working under the idea that Turpenoid is an odorless mineral spirit. I have used this in the past for clean up and for thinning a final varnish.

Is this a good idea?

It's not the same stuff and I've heard bad things about it.

Thanks, Michelle,

What brand do you use?

Anyone else have any opinions on Turpenoid?

I use Gamsol mineral spirits because I understand it 's less flammable than other brands.

Thanks, again, Michele,

One question regarding Gamsol. I read that it is not compatable when reducing Damvar varnish. I don't use Damvar but I wonder if you have heard the same.

Pick your poison.

Turpentine is a distilled organic fluid obtained by the complex distillation of resin obtained from trees, mainly various species of pine. It is flammable and volatile.

Turpenoid is a distilled mineral spirit usually made from a petroleum base. It is reasonably nonflammable and has low volatility.

Ingesting either is bad. On the inhalant side turpentine is the bad actor.

Being a tree resin like damar, turpentine works well when mixed with damar. Turpenoid does not.

Thank you, Richard,

You've expained the difference and the cause very effectively. I appreciate your help.

A few other points of interest:

Turpentine, strictly speaking is the gum exudations of pine trees. Pure spirits of gum turpentine is the distillate. Rosin is the solid resin which that distillation leaves behind.

Currently, most "hardware store" turpentine is derived from the steam extraction of forest waste products (stumps and limbs) and smells nastily of creosote. This is to be avoided for purposes of oil painting. Good turpentine smells like a fresh pine forest, and in fact most of the "good stuff" goes into the making of all those pine-scented air-fresheners and other similar household products.

Cutting natural resins such as mastic or dammar with petroleum distillates results in a cloudy varnish.

Used as a solvent to control the viscosity of paint or mediums, turpentine has chemical advantages over mineral spirits; combined with linseed oil, turpentine forms hydroxides by absorbing free acids in the linseed oil. Hydroxides draw atmospheric oxygen, causing paint to dry throughout the film rather than only from the "top down" , which one notes when fresh paint "skins over".

In my opinion, mineral spirits is a convenient solvent for cleaning brushes and tools, but is best omitted from paints and mediums. Odorless or not, MS releases volatile hydrocarbons as it evaporates, same as turpentine. Adequate ventilation in the studio and sensible, sparing use of all solvents are necessary for safety. Turpentine is neither more volatile than MS, nor particularly flammable; a lighted match can be extinguished in it.

Be careful, though, in this discussion. Inhalants are not the only problem. Turpentine is more toxic and is absorbed through the skin, and mineral spirits are much less of a problem in this regard.

The best discussion of the various solvents is, I think, at the Gamblin site.

--Tom

Absolutely. Painting at the easel, a competent adult will "be careful" enough by dint of reasonable workmanship. Poor ventilation is less obvious, and more insidious. However, it's no more adviseable to drench painting surfaces, tools, brushes and hands with MS than with turps.

Gouache is a better material choice for those terrorized by possibilities of toxicity.

Tom, could you be so kind as to point us to a qualified source of factual information on the toxicity of turpentine? The Gamblin site appears to be a "sales pitch" in the main, and states nothing more substantive than turpentine is "a known respiratory irritant". It goes on to speculate on the misuse of turps by "painters of 50 years ago . . . [who] created huge canvases of oil colors diluted with turpentine".

Further, "Rembrandt used no painting mediums." A statement knowledgeable painters should find at least controversial if not ridiculous. The intent is to convince readers of the adviseability of using Gamblin's proprietary mediums.

Gamblin's market strategy has been to emphasize that their products are non-toxic and ecologically friendly. Certainly laudable aims in themselves, no doubt reflecting a realistic assessment of the sensibilities and anxieties of their customer base. However, they seem insecure enough with that stance that information on the site for the most part evades hard facts, and tends toward hyperbole and unsubstantiated opinions.

I had an hour and a half conversation with Micheal Harding ( the paint maker) about this and other subjects, (his nickel, thank heavens).

He recommends using ONLY the purest turpentine. He only uses mineral spirits to clean his paint making machines as it is a powerful solvent and breaks down paint very efficiently. This is not the sort of thing you want in your paint . He had a more detailed description of how mineral spirits can weaken your paint surface but I cannot at this time find my notes. He DOES not sell turpentine as far as I know.

I use mineral spirits only for brush cleaning now.

I have info somewhere on the toxicity of turps, but I can't lay hands on it. I'll post it when I can find it.

For me, it's an academic discussion anyway. I have to use mineral spirit exclusively in the studio as I'm allergic to pine trees and pine products.

Part of the problem of determining the safety of thesesolvents for our purposes, is in defining the products. "Pure spirits of gum turpentine" is supposed to be definitive, but lately is applied to the "stumps and limbs" brew that reeks of creosote. It is NOT the same as the turps distilled only from the gum exudations of suitable pine species. Some grades are refined to the extreme and are used in . . . cosmetics! (as are highly refined petroleum distillates as well)

Information on the toxicity of turps and MS is "generically" available if you access the OSHA pages on each, but include a wide range of materials and grades which are not applicable to studio painting. Specific materials are not clearly identified. I really don't know what benefit information from that quarter is to us, since exposure levels stated are ridiculously high, and the bottom line is, if you drink or bathe in either one for a long enough time, you're gonna die .

Mineral spirits is a catch-all term, many grades of MS derive from that fraction of petroleum distillation that entails everything from #2 diesel fuel and kerosene through highly refined grades with specific uses. The most refined being white spirit and the "press wash solvent" printers use to clean their presses. The range includes solvents which are more or less flammable, such as solvents used to clean mechanical parts in repair shops.

K-1 kerosene is probably the best solvent for cleaning oil paint from brushes and tools because it is the most penetrating solvent in that "genus". It is not particularly odorous. It would also be the worst possible additive in oil paint!

Mr. Harding's comments reiterate what I was taught a long many years ago, i.e. the "cutting" or solvent action of petroleum distillates is deleterious to the strength of paint films bound by natural oils and resins in ways turpentine is not.

Certainly Tom has very good reason to avoid turpentine, but this discussion is more than academic, as he can adjust his painting materials and methods to accommodate the omission of turpentine, and the discussion of the merits and disadvantages of materials should be useful for arriving at the best alternatives.

It's possible mediums and varnishes containing turpentine may not distress individuals with a turpentine sensitivity, even when the "straight stuff" does, since resins and oils dissolved in turps change its vapor pressure and volatility.

In all cases, whether one has materials sensitivities or not, avoiding contact with the skin, and ample ventilation in the studio are inviolate rules for the use of all materials associated with oil painting.

Richard--

Let me clarify....the discussion of mineral spirits vs. turps is academic for me, as I can't use turps anyway. This is not to imply it's academic or irrelevant for anyone else. Quite the contrary--studio safety is vital.

Best-T

Tom, thanks for that. This subject strikes a chord with me, because I am interested in the mechanics of craft, and also because I'm one of those "nut-cases" who revels in the aroma of the studio and painting materials in general - the acetic-acrid smell of flake white, linseed oil, the various resins, turps, spike . . . all of it!

By the same token, I'm aware of the hazards of inadequate ventilation and careless exposure, and take every precaution against them. I know first-hand how serious problems allergic reactions and sensitivities pose to those affected.

A serious painter from his 'teens, in his 60's my father precipitately developed a sensitivity to turps which caused painful lesions to erupt on his hands upon contact. As his preferences for painting materials and methods were well established at that point in his life, it caused a lot of stress and inconvenience in his work, to say nothing of the physical discomfort and questions of health. Without rhyme or reason, after nearly a year the reaction to turps ceased abruptly as the onset had been, and he was able once again to work around it with no problems.

After spending lots of money on Gamsol I have switched to Sunnyside Odorless Paint Thinner. It smells less than Gamsol, which is already pretty odorless, and costs about $6 less than Gamsol per gallon. Both products have less odor than Turpanoid. BTW: Turpanoid Natural is not even in the running. A horrible gooey citrus oil that never dries and is only good for stripping dried paint off tools.

Sunnyside Odorless Paint Thinner is available at Truevalue and Servicestar hardware stores but you will have to special order it. More and more art stores also carry it. I order mine from a local lumber store that deals in Sunnyside products.

http://www.sunnysidecorp.com/gold.htm

Hardware store supplies are not a good substitute for artist-quality materials. There are many considerations other than what a solvent smells like.

Michele, I agree with you, hardware store solvent is bad stuff. However, Sunnyside Odorless Paint Thinner is not typical hardware store quality. It is not stocked by hardware stores like the cheaper stuff but must be special ordered. Both Gamsol and Sunnyside have the same low toxicity rating on their MSDS: health-1 and flammiblity-2. Both also have the same recommended exposure limits of 300 ppm. The flash points are different: Gamsol is at 145 and Sunnyside is 120. But it is used at Shanks

Hmmm... sounds interesting, especially if they use it at Incamminati. I'll have to take a look at it.

Bah! These days, neither are art supply store supplies . . . all too often.

Sunnyside materials are sold at Home Depot here in Iowa, but I haven't looked for "odorless paint thinner" there, I admit. Regular Sunnyside is among the cheapest of the paint thinnners they carry. I have tried Sunnyside turpentine (it's awful) and I routinely buy Sunnyside's traditional paint thinner but I only use it to clean brushes.