Liquids and Chemicals in the Workshop

Liquids and Chemicals in the Workshop

Graham Hicks

It seems that hangar talk frequently produces new and better ways of doing things. During a particularly productive recent discussion, it occurred to me that during my 45 years of model building, I have found uses for half-a-dozen or more liquids and chemicals, and often my modeling friends are unaware of the availability or uses of such chemicals.

I will discuss a handful of such substances. Although I will address most of their uses, this article is certainly not inclusive. Rather, I hope to remind you of other materials or other uses for the chemicals listed, generating a lively discussion that will benefit more modelers.

Several of these chemicals are extremely toxic, caustic, flammable, and even explosive. I will reemphasize these characteristics as I discuss each chemical, but I cannot stress too strongly that it is of the utmost importance that you understand what you are working with and that you take the proper precautions. Be sure that your shop has proper ventilation, or work outside. I'll start on the "low" end of the danger zone and work up to the more powerful chemicals.

Water

The world's universal solvent. Given time (and in some cases that may be eons), water will dissolve almost everything.

I keep a plastic jug of tap water and a jug of distilled water in my shop. The tap water comes in handy for working with decals, sprinkling on the shop floor to keep down dust, and for general cleanup. I often use it to dilute carpenter's glue for applying tissue or building ultralight models.

The distilled water is saved for uses that require a more purified water. Since almost all tap water contains certain minerals that make it unsuitable for many chemical applications, distilled water is used for topping off lead-acid batteries and certain NiCd cells that use a potassium hydroxide solution as their electrolyte.

Perhaps the best reason for having a gallon of water at hand is safety. If you splash paint, thinner, or something more hazardous in your eyes, grabbing that water jug within a few seconds and flushing your eyes may reduce or even avoid permanent damage. Don't worry about wetting the shop floor or a model—nothing in your shop is as valuable as your eyes.

Bicarbonate of Soda (Baking Soda)

Plain old baking soda is great to have in the shop. There are few ways you can get into trouble with this gentle powder.

• Useful for putting out small grease fires if your shop fire extinguisher has lost its pressure. (You do have a good fire extinguisher mounted on your shop wall, don't you?)
• Mixed into a thick paste with tap water, it soothes minor skin burns.
• Makes a great filler-bonder for cyanoacrylate (CyA) glues.

Mineral Spirits

Also known as petroleum spirits, this liquid is refined from crude oil. It is available in several "types"; type 3 is usually used for thinning oil-based paints. It is highly flammable and should be kept in the original container.

I have found its main advantages as a paint thinner are:

1. It is much less expensive than turpentine.
2. It has almost no odor.

Mineral spirits are excellent for dissolving the adhesive used on servo or wing mounting tape, sticky-back tape, and the adhesive used to hold lead weights in place. You can purchase it in small bottles at an art store or in gallons at a paint or hardware store.

Glycerin and Green Soap

Glycerin is a thick, syrupy liquid that is nonflammable by itself. It attracts water strongly, so keep the container closed when not in use. It is used industrially to manufacture a wide range of items, including cosmetics and antifreeze.

Green soap is a liquid soap with some antibacterial properties and does an excellent job of cleaning hands—particularly if you have small cuts or scrapes.

• Mixed 50/50, glycerin and green soap form an excellent lubricant for rubber motors used in indoor/outdoor free-flight models. Some modelers add a small amount of K-Y jelly (a surgical lubricant) to the mixture for an even slicker lube. The easiest way I have found to apply it is to squirt a few drops into a plastic food bag, add the rubber motor, and simply massage the two together from the outside. All three products are available at drug stores.
• Glycerin can also remove sticky-back tape from many surfaces. Soaking dried paintbrush bristles in glycerin for a day or two will often revive a brush.

Keep the glycerin container closed; it attracts moisture.

Vaseline (Petroleum Jelly)

Vaseline is a trade name for petroleum jelly, another product refined from crude oil. It is nonflammable and used commercially for many purposes, such as hand and body liniments and lubricants for firearms and machinery.

• Occasionally useful to lubricate brass tubing fittings that must slide easily.
• Handy to coat abraded skin temporarily.
• Will temporarily lubricate O-rings and other rubbery fittings, but test on a waste sample first—many petroleum products cause some rubbers to swell and lose dimensional stability. Auto parts stores sell silicone-based lubricants that are safer for rubber parts.

Trisodium Phosphate (TSP)

Trisodium phosphate (TSP) is a nonflammable, strongly alkaline powder that forms a powerful detergent when mixed with water in various proportions.

• Useful to clean caked grease and dirt surfaces before painting.
• A fairly strong solution will usually restore a paint brush that you forgot to clean—either hang the brush or let it lie flat in the solution for a day or two to avoid setting the bristles.
• Follow directions on the box and always wear rubber gloves and eye protection when mixing or using TSP.

Isopropyl Alcohol (Rubbing Alcohol)

Isopropyl alcohol is a useful, moderately strong solvent with a sweet, liniment-like smell. A 70% solution is sufficient for most modeling purposes.

• An excellent general solvent; start with rubbing alcohol and a cotton swab when water won't do the job.
• A shop towel doused with rubbing alcohol and stored in a coffee can is handy to wipe stickiness from hands while fiberglassing.
• A finger dipped in rubbing alcohol smooths a moist microballoon/resin fillet without affecting setting time or hardness.

Caution: isopropyl alcohol is flammable. Use it away from open flame or sparks. If rubbing alcohol doesn't clean a surface after several minutes of work, move to denatured alcohol.

Denatured Alcohol

Denatured alcohol is ethyl alcohol with additives that make it unfit for consumption. It is poisonous and flammable.

• A potent solvent that will attack certain plastics—test on a scrap before use.
• Wear eye protection and rubber gloves when using it.
• Never use near open flame unless intended; one neat use is as fuel for a small alcohol burner.

Alcohol burner instructions (exercise caution and common-sense safety):

• Use a baby food jar. Solder a one-inch piece of brass tubing (about 5/16-inch diameter) into a hole in the jar's top.
• Feed a four- or five-inch piece of soft cotton rope through the tubing, leaving about 1/4 inch sticking out the top, and coil the rest in the jar.
• Pour a small amount of denatured alcohol into the jar, screw the top on, and wait a few minutes for the alcohol to wick up the rope. When the tip feels wet, you can light it.
• This provides a low-heat, low-carbon flame for shaping plastics and heat-soldering small joints. Keep a crimped piece of slightly larger brass tubing as a cap for the exposed wick to reduce evaporation.
• If not used again soon, pour remaining alcohol back into the original container to avoid evaporation.

Naval Jelly

Naval Jelly is a rust dissolver containing phosphoric acid. It is extremely corrosive.

• Apply with a stiff brush, leave for five to ten minutes, then rinse with cold water.
• Excellent for removing rust from metal surfaces.
• Will attack chrome, aluminum, and many painted surfaces—mask these areas and wash off immediately if contact occurs.
• Use rubber gloves and eye protection when applying.

Handwarmer (Cigarette Lighter) Fluid

This lighter fluid (sold as fuel for catalytic handwarmers) is a useful solvent in the shop. It is flammable—handle with care and keep away from open flame.

• Excellent general cleaner for many plastics and painted surfaces.
• One of the best cleaners for contact cement residues (sticky goo left by price tags) and adhesive spots left by masking tape; a cotton swab dipped in lighter fluid makes quick work of these.
• Caution: lighter fluid can dissolve some enamels. For example, Modelmaster spray enamel on a T-28B washed with a cloth soaked in lighter fluid began dissolving after only a couple of days. Be careful using it on painted surfaces; it generally cleans cured two-part epoxy paints well.
• After-run oil tip: a 50/50 mix of lighter fluid and regular transmission fluid makes an inexpensive after-run oil. When finished flying, run the engine briefly on this mix (or add a few drops into the venturi) to coat moving parts and drive out methanol, which attracts moisture and causes rust.

Prolonged skin exposure can cause irritation—use rubber gloves if desired.

Acetone

Acetone is a volatile, highly flammable liquid with a pungent odor. It will attack and dissolve most modeling plastics—this makes it useful but dangerous.

• Wear rubber gloves, eye protection, and a good respirator when using open containers.
• Applied sparingly with a tiny brush, it is an excellent cement for many plastics and can dissolve acetate-based cements.
• An impromptu glue: dissolve pieces of an old toothbrush handle in acetone to make a strong plastic glue (color depends on toothbrush color).
• An excellent debonder for cyanoacrylate (CyA) glues—keeping clogged CyA tips submerged in acetone will clear them in a day or so.

Methyl Ethyl Ketone (MEK)

Methyl ethyl ketone is the most dangerous material discussed here. It is highly flammable, readily absorbed through the skin, and inhalation of fumes can cause severe effects.

• Always wear eye protection, a respirator mask, and rubber gloves if using more than a cotton-swab amount.
• Avoid skin contact—MEK will sting and enter cuts quickly. A splash in the eye can cause permanent corneal damage if not washed out immediately.
• Breathing the fumes can cause headaches, nausea, drowsiness, and physical deterioration. Use only with good ventilation and proper respiratory protection.

Uses:

• Dissolves almost any paint except cured two-part epoxies (and may damage those if exposure is prolonged).
• An excellent plastic model cement when used sparingly.
• Useful for cleaning airbrushes and paint guns after spraying epoxy paints, Railroad Colors, lacquers, etc.
• A dried-up dope brush can often be restored by soaking overnight in MEK.
• Clean a soot-covered engine by removing O-rings and soaking the engine in MEK—oil and grease come off completely.
• Oil-soaked wood can be restored to a gluelike condition by soaking overnight in MEK.

MEK is sold in paint stores; a gallon lasts a heavy user about a year. I strongly recommend wearing a good-quality charcoal respirator mask for protection during use. A properly fitted mask improves safety and comfort and helps with sanding dust and chemical fumes.

If you've learned something from this article, great. If it has triggered an idea, write to the editor of Model Aviation and give the rest of us the benefit of your experience. Above all, be careful with these materials. Although they serve you well, they deserve the greatest respect.

Transcribed from original scans by AI. Minor OCR errors may remain.