What Chemicals are in Your Lacquer Thinner?
Not All Lacquer Thinners are Created Equal

Thinner #1 – 50* - 70* temperature range

25%    Light Alaphatic Hydrocarbon Solvent         64742-89-8                  3.9

33%    Toluene                                                            108-41-4                   1.5

0.9%   Ethylbenzene                                                   100-41-4                   0.7

5%      Xylene                                                           1330-20-7                  0.75

4%      Methanol                                                           67-56-1                    3.5

10%    2-Propanol                                                         67-63-0                   1.7

21%    Acetone                                                             67-64-1                    7.7

1%      2-Butoxyethyl Acetate                                    112-07-2                   0.03

Thinner #2 – 60* - 80* temperature range

66%    Toluene                                                           108-88-3                    1.5

7%      2Methyl-1-propanol                                         78-83-1                   0.63

2%      2-Butoxyethanol                                             111-76-2                     0.1

10%    Methyl Isobutyl Ketone                                 108-10-1                     1.6

15%    Isobutyl Acetate                                             110-19-0                   1.45

Thinner #3    90* – 110* temperature range

10%    2-Butoxyethanol                                            111-76-2                     0.1

20%    n-Butyl Acetate                                             123-86-4                     1.0

70%    1-Methoxy-2-Propanol Acetate                    108-65-6                    0.39

Thinner #4 – Extreme Duty Temperature range

100% 2-Butoxyethanol                                             111-76-2                     0.1

The reason for the CAS number is to clarify which chemical is which. These numbers are unique whereas the chemical names are not. It is not unusual for different manufacturers to have their own brand names. The names will change but the numbers will not. Sometimes that is a good thing. For example, p-Chlorobenzotrifluoride is commonly known as Oxsol 100 if for no other reason than that it is easier to pronounce.

Take a look at the last number in each line. This is the numerical evaporative rate of that chemical. This rating system always compares chemicals to n-Butyl Acetate, which is always regarded as 1. The lower the number, the slower it evaporates. The higher the number, the faster it evaporates. Thus, acetone has an evaporative rate of 7.7 and 2-Butoxyethanol is 0.1. Acetone evaporates much faster than 2-Butoxyethanol. You may know this chemical by the name Butyl Cellosolve.

The point of all this is to quantify how these chemicals will work together to affect the application of the coating. Acetone is a very fast evaporating solvent. It is not going to hang around very long on a warm day and help the coating to remain liquid. Butyl Cellosolve, by contrast, is going to hang around the longest. To that chemical, in this blend, we will give the designation of being the “tail solvent,” the last one to leave. This is the one that will affect how quickly to coating will tack up and dry. The higher it’s concentration in the blend, the slower that this event will come about. (Look for more information on chemical blends in finishing blog.)

Until next time, spray on!

Bernie Bottens writes and teaches on the subject of wood finishing in industrial woodworking. Based in Vancouver, WA, he teaches wood finishing to shop owners, shop foremen, spray technicians and finishers all over the Pacific Northwest. Bernie is the owner of Kapellmeister Enterprises Inc. He can be reached at [email protected].

Read the previous wood finishing blog by Bernie Bottens>>

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