Popular Woodworking 2002-08 № 129, страница 86
You can, of course, place oily rags in airtight or water-filled containers, but you should keep in mind that this prevents spontaneous combustion only while the rags remain shielded from oxygen. When they're removed, they are still a fire hazard. To allow the oil to cure so the rags are safe to throw in the garbage, hang them separately or spread them out on a table or the floor and let them harden. Unless I have a lot of rags, I usuallyjust drape them over the edge of a trash can, making sure to avoid overlaps. Throwing rags with cured oil in the trash is no different, environmentally speaking, than throwing a piece of wood with a cured-oil finish in the trash. Materials with a Shelf Life All finishing materials will eventually go bad, but the time it takes varies considerably depending on the product. The most obvious problem in most shops is water-based products that can freeze. Though they may survive a couple of mild freezes, it's unquestionably best if you store these products in a location that never freezes, even in your house if necessary. Varnishes (including polyurethane varnishes) and oils exposed to oxygen go bad by developing a skin on the surface, or by turning into a gel, and then eventually hardening all the way through. Varnishes are much more susceptible to this than oils. (If varnish is still liquid under a skin, you can remove the skin and strain the varnish, and it should be fine to use.) There are a number of methods to extend the shelf life of varnish, including: • Close containers securely. • Transfer varnish to smaller containers to minimize air spaces. • Displace oxygen in a container with an inert gas (by using Bloxygen, for example). • Turn the can upside down and let the skin form. Then when you open the can, the varnish will be at the top and fully liquid. • Fill the can with marbles or clean rocks rocks (silly in my opinion, but I needed to mention it because others suggest doing this). Shellac begins losing its water resistance and ability to cure hard from the moment it's dissolved in alcohol. The deterioration rate of this finish is slow, so you can use shellac on furniture or cabinets with good results Drying oils create heat as a byproduct. Wadded up The final step in cleaning any stain or finish out of a oily rags can cause a disastrous fire.When drying out brush is to wash it in soap and water until suds form your rags, drape them over the edge of your garbage easily. That's when you know your brush is clean. can or a bucket and don't overlap them. for up to a year or so from when the finish was mixed, but you risk poor performance after that. Shelf life is extended if you store the shellac in a refrigerator or other cool place because this slows the deterioration. Shellac in flake form also goes bad, especially the bleached or blonde varieties. You'll know that the shellac is bad if it doesn't dissolve properly. Again, the process is slowed if the shellac is stored in cool conditions and it is accelerated in hot conditions. Lacquers and catalyzed finishes have a very long shelf life without any special care. Dyes fade in bright light, so you should store these colorants in a dark cabinet if you keep them in glass jars. Finishing Equipment Finishing equipment includes brushes and spray guns. Here's how I recommend you clean and store your brushes: If you intend to use the brush again in a day or so, you can wrap it in plastic wrap or hang it in its cleaning solvent: water for water-based products; mineral spirits (paint thinner) for varnish and oil; alcohol for shellac; and lacquer thinner for lacquer. If you want to store the brush for several days or longer, use the following cleaning steps for each finishing material: • For water-based products, wash the brush in soap and water. • For varnish and oil, rinse several times in mineral spirits, then rinse in lacquer thinner or brush cleaner (a similar product) to remove the oiliness of the mineral spirits, then wash with soap and water. • For shellac, wash in half-and-half household ammonia and water or rinse several times in denatured alcohol and then wash with soap and water. • For brushing lacquer, first rinse the brush several times in lacquer thinner and then wash it with soap and water. Shake the excess water out of the brush and return it to its holder or wrap it in paper to hold the bristles straight while they dry. Secure the paper with a rubber band or masking tape, and store the brush in a drawer or cabinet, or hang it on a wall. To clean a spray gun, replace the finishing material in the cup with the cleaning solvent for the product, and spray the solvent through the gun. Do this right after you finish spraying so there's not time for the finish to harden in the gun. Including soap with your water will be more effective for water-based finishes, and lacquer thinner is the most effective solvent for all finishes. Remove the air cap, fluid nozzle and fluid needle from the spray gun and soak them in the proper cleaning solvent or in lacquer thinner. If necessary, scrub them with a brush, such as a toothbrush. When everything is clean, replace the parts and hang or store the gun in a place where it won't get dirty. PW Bob Flexner is the author of "Understanding Wood Finishing" and a contributing editor to Popular Woodworking. |
