Solvents are necessary for cleaning up after printing. Most solvents that were used 50 or 100 years ago would never be considered for shops today (think Kerosene and Gasoline). Unfortunately, the solvents which work best inevitably cause the greatest health concerns, and of course, the safest cleaning solvents do not always do as good or as quick a job.
Applications
Generally, all inks need to be cleaned up with some sort of oil-based solvent. This could be as mild as vegetable oil or vegetable shortening, or as harsh as an acetone or lacquer thinner.
Some solvents are water miscible. This means it can be mixed with water before use. Water miscible solvents are very effective at cleaning ink. Mixing your solvent (e.g. California Wash) will extend your supply of solvent and cut down on odor. Please note: water should never be used on composition rollers as it will ruin the roller material. The solvent itself is fine when not mixed with water and will still be effective for cleaning, though you will naturally use twice as much.
If your press has rubber form rollers, however, water-miscible solvents suitable for offset press washup will do the most effective job at cleaning and are necessary to maintain the integrity of the rubber.
Many shops use a variety of solvents, each to their strength. An example would be Vegetable Oil (very safe, no odor) as the primary cleaner, removing all color and ink, and then a final wipe-down with a California Wash/water mix (very effective, high odor) to clean off the oil. Whenever possible, keep it simple; too many solvents can cause confusion in the studio.
Safety Concerns
Health
Be wary of products labeled “all natural.” Solvents made from refined citrus oil can be just as flammable and dangerous as turpentine or gasoline. And after all, turpentine and gasoline are “all natural” too, though they are made from non-renewable resources.
Be cautious, too, with “odorless” solvents. While they are certainly more pleasant to be around than those bearing a heavy chemical smell, it’s easy to forget that you’ve been breathing fumes for an hour when you can’t smell them.
No matter what solvent you choose, always wear gloves. Nitrile gloves will protect you from solvents whereas latex will not. Nitrile gloves are available in both reusable and disposable styles. For every solvent, consult the (Material Safety Data Sheets) MSDS sheets available from the product manufacturer; this will tell you what safety precautions should be exercised and how dangerous or combustible it is. Keep a copy of it at hand in your shop for easy reference.
Storage
If possible, store solvents in a steel solvent cabinet. These cabinets contain fumes which may be flammable and prevent accidental spillage.
Disposal
Ventilation
Solvent Comparison Chart
| Solvent | Benefit | Issues | Type of Roller |
|---|---|---|---|
| Veg. Oil / Shortening | Very safe, no odor. | Slow to clean, leaves sticky residue with repeated use. | Rubber or Composition |
| Turpentine | Cheap, effective. | Heavy fumes and strong odor. Tends to stay greasy when re-inking the press immediately. | Composition |
| Odorless Mineral Spirit (incl. Gamblin brand Gamsol) |
Effective, safer than Turpentine. | More expensive than Turpentine, but otherwise the same. | Composition |
| Citrus- or Soy-based solvents | Effective, not petroleum-based. Can often be mixed with water to extend the solvent and aid in cleaning. | May smell strongly of citrus odor. Some schools and studios have banned soy-based cleaners due to concerns surrounding spontaneous combustion. | Rubber |
| Denatured Alcohol | Unsuitable as a primary cleaner but excellent as a finishing wash on rollers to clean off oily and inky residue, especially when changing colors. | Repeated use on rubber rollers may cause them to dry out and crack prematurely. Should never be used on wood type. | Composition |
| California Wash / Roller Wash |
Highly effective and designed specifically for cleaning ink from press rollers. Primarily Naptha based, and often intended to be mixed with water to aid in cleaning. | Heavy fumes and a strong odor. | Rubber or Composition |
| Lacquer Thinner | Unsuitable as a primary cleaner, but excellent for cleaning dried ink. | Highly volatile and very strong odor. Can strip the paint from your press if spilled. | Composition |
| Acetone | Unsuitable as a primary cleaner, but excellent for cleaning dried ink. | Highly volatile and very strong odor. Can strip the paint from your press if spilled. | Composition |
| Type Wash | For cleaning type only, not rollers | NA |
Contributors
Kyle Van Horn, Core contributor