Series editors' preface - Wood Tools

USA solvents (also known as) TLV (AICGH)
Mineral Spirits odorless mineral spirits (Shellsol OMS) Shell 174–204 346–400 100 29 9 5100 100
mineral spirits 200 HT (Shellsol D43) Shell 162–206 324–402 100 (52) 32 13 3400 100
Sol 340 HT (Shellsol D38) Shell 159–176 319–349 100 (54) 32 27 1700 100
mineral spirits 150 EC (Shellsol 3 EC) Shell 163–199 326–390 97 (50) 3 33 13 3400 100
mineral spirits 145 EC (Shellsol 7 EC) Shell 162–199 323–390 93 (48) 7 35 14 3250 100
VM&P Naptha HT Shell 119–139 247–282 100 (46) 35 150 305 300
Sol 320 (obsolete) Shell 157–179 314–355 93 (50) 7 38 28 1700 100
mineral spirits 135 (Shellsol 15) Shell 160–181 320–357 85 (43) 15 45 10 4700 100
Napthenics Cypar 9 Shell 138–164 280–328 100 (100) 41 67 700 None
assigned
Cypar 7 Shell 98–114 209–237 100 (100) 46 380 120 400
Aromatics Cyclo Sol 100 (Shellsol A100) Shell 160–176 320–348 100 56 21 2200 25
Cyclo Sol 150 (Shellsol A150) Shell 182–215 359–419 100 58 9 5000 50
TS28 Shell 161–198 322–388 25 75 73 14 3200 25
xylene (mixed isomers) Shell 139–142 282–288 100 90 76 600 100
toluene Shell 110–111 230–232 100 105 200 226 100
A wide range of hydrocarbon solvents is available through commercial distributors. Some important properties of hydrocarbon solvents are listed here. Most of the solvents have been
mentioned in conservation literature, although some have been included for comparative purposes. Within each class, solvents are listed in increasing order of ‘polarity’ on the basis of
their K-B value. Related information can be found under sections 11.3.1 (Hydrocarbon solvents), 11.3.2 (Evaporation rates, vapour pressure and density; Toxicity), and in Chapter 12.
Note that both exposure limits and product descriptions are subject to regular review. Conservators should consult current literature to ensure their information is up to date.
In cases where individual solvents become obsolete (e.g. Sol 320), this chart can be used to select a replacement solvent with similar properties (e.g. Shellsol D38). The evaporation
rate can be used in combination with the exposure limit to compare the relative risk to the conservator of different solvents, or to select a solvent suitable for a given application. For
example, the evaporation rate or aromatic content of a solvent can significantly affect the process of cleaning, consolidation, retouching or varnishing.
The Boiling range describes the temperatures between which the solvent was distilled. Pure solvents have a narrow boiling range (e.g. xylene, toluene). A wide boiling range
indicates the presence of a mixture of substances (e.g. turpentine).
Aliphatic/aromatic content can be useful for selecting a solvent with the required Teas solubility parameters for cleaning, retouching, consolidation or varnishing.
The Kauri-butanol (K-B) value is a shorthand measure of aromatic content and can be used to find the least aromatic hydrocarbon solvent that will dissolve a given substance. The
K-B value is not particularly useful in judging comparative solubility properties of non-aromatic hydrocarbon solvents, which usually have a K-B value below 35.
The nBuAc number is a common measure of evaporation rate. Seconds to 90% evaporation is also a useful tool for comparison of evaporation rates. Not all manufacturers supply a
figure for ‘seconds to 90% evaporation’. This figure can be estimated by dividing the nBuAc number (e.g. 14, where nBuAc = 100) by 100 (14/100), inverting this fraction (100/14) and
multiplying it by 458 (seconds to 90% evaporation of nBuAc). For example, for a solvent with an nBuAc (=100) number of 14:
100
458 = 3271 seconds to 90% evaporation
14
The OEL/TLV (ppm), in combination with the evaporation rate, is essential for choosing the least potentially harmful solvent for a given purpose. For example, Shellsol D40 and low
aromatic white spirit have very similar K-B numbers and evaporation rates. The aromatic content in low aromatic white spirit, however, results in a lower OEL, indicting it is a
potentially more harmful solvent than Shellsol D40. In contrast, xylene and Shellsol A100 have different OELs and evaporation rates but present a comparable risk to the conservator
(see Toxicity under section 11.3.2). It is important to note that in the absence of an assigned OEL or TLV, conservators should identify the OEL/TLV of similar materials and use them
as a guideline, always erring on the side of caution.