Article: How to Lacquer Furniture Using Aerosol Finishes
For small to medium size jobs, lacquer can be applied with aerosol spray cans. In this article we'll discuss application techniques and other points of interest.
Aerosol lacquers are a vital part of every finishing shop. While the amateur can use them for refinishing, pro's will use them more for spot finishing & touch-up. Toners come in so many shades it's sometimes hard to decide which shade to purchase.
Aerosol lacquer can be a very effective way to achieve a professional looking finish
Many amateurs also use aerosols as an inexpensive substitute to buying a spray gun – inexpensive, at least, as long as the amount of finishing being done is not too great. Aerosols are ideal for smaller projects.
Most popular finishes are packaged in aerosols in sheens ranging from gloss to flat. These include polyurethane, shellac, waterbased finish, lacquer and pre-catalyzed lacquer. (Pre-catalyzed lacquer is a fast-drying finish like lacquer, but it’s considerably more durable so it’s often used to finish kitchen cabinets and office furniture.) Other useful products, such as sanding sealers, toners and blush removers, also are packaged in aerosols.
For small to medium size jobs, finish can be applied with aerosol spray cans. Dust-free drying is not as much of a problem with aerosol lacquers because it dries quickly, and because lacquer dries so fast it is not difficult to work with.
Lacquer fumes can be both toxic and explosive, so great care must be taken. Don't use near an open flame or heat source. Wear a protective respirator to protect yourself from breathing in the fumes. If working indoors, only use lacquer in a ventilated area, where the fumes can be removed by a fan.
Lacquer can be used on most woods, but it should not be used on teak or rosewood; the oils in these woods will bleed through the finish. Lacquer can be used over lacquer-base, non-grain-raising (NGR) and water-base stains and over lacquer-base fillers. It can be used over other oil-base stains and many fillers, assuming they are fully dried.. Thinned lacquer or shellac or a compatible lacquer-base sanding sealer should be used as a sealer under a lacquer finish.
I happen to be partial to Mohawk brand for my aerosols. Aerosol lacquers are a vital part of every finishing shop. While the amateur can use them for refinishing, pro's will use them more for spot finishing & touch-up. I tend to use the Pre-catalyzed clears and the Toner aerosols, and for the most part those are the only aerosols I need. Mohawk makes great Aerosol lacquer in multiple sheen's and the toners come in so many shades it's hard to decide which to buy.
Lacquer Application Techniques:
Wood to be finished with lacquer must be properly prepared, sanded, and sealed. Immediately before applying lacquer, clean the piece of furniture thoroughly with a tack cloth. Use only aerosol spray lacquer, and protect your working area with drop cloths or newspaper.
Make sure ventilation is adequate. Before applying lacquer, test the spray can on a piece of newspaper or cardboard. Spray cans have different patterns of spray; practicing and watching the test spray pattern will give you enough control to properly cover the surface you're finishing.
First spray the top edge of the surface; then cover the entire surface in horizontal strips, from side to side, top to bottom. As you work, overlap the lacquer spray patterns slightly. The edges of each sprayed area are thin; the centers are thick. Overlapping equalizes the thickness of the lacquer film, keeping the surface even. Never try to equalize the film by brushing the lacquer. Apply only a thin coat of lacquer; this finish must be applied in many thin layers.
Drying and Recoating:
Lacquer dries in no more than half an hour, but it should cure completely between coats. Let the newly sprayed wood dry for a few hours, or as directed by the manufacturer. Then lightly smooth the surface with 320 grit silicone carbide sandpaper or a scotch brite pad, and clean it thoroughly with a tack cloth.
Apply a second coat of lacquer as above. For a smoother finish, let the second coat dry for a couple hours, smooth the surface with 320 sandpaper or a scotch brite pad, and apply a third coat of lacquer as above.
Runs and sags are usually caused by too much lacquer. If you get runs, don't touch them until the finish has cured for an hour or more. Then lightly scrape the run with the flat edge of a razor blade and then very lightly sand with 320 sandpaper before re-coating.
For a very rich, deep finish, use many very thin coats of lacquer. Let the lacquer dry completely between coats, and rub the surface between coats with a scotch brite pad. After applying the final coat of lacquer, let the piece of furniture dry for 24 hours before rubbing out.
Toning with Aerosols
Toning is under-appreciated, especially among those who have never sprayed. It involves applying color to a surface by adding a pigment or dye colorant to the finish itself and spraying it. (Brushing a toner can create uneven coloring or very noticeable brush marking). Too much pigment will muddy the wood like a thin coat of paint, but dye will add coloring and be almost totally transparent.
Toning can be used to adjust the coloring of an entire object after a sealer or finish has been applied, or it can be used to adjust the coloring of just part of an object. Examples include blending sapwood with heartwood or a light wood species with a darker species. Another example is creating highlighting in some areas, such as the centers of panels, by spraying toner on the area around them. Most higher quality factory furniture has been toned.
Removing Water Rings
One of the most useful functions of an aerosol is as a “blush” remover. A blush is the milky white coloring that sometimes occurs when spraying in high humidity. It’s also the milky whiteness of a water ring, and it’s much easier to use an aerosol with the right solvent to remove the ring on-site than it is to take a table to your shop and use a spray gun.
Water rings are caused by moisture getting into a finish and creating voids that refract light and prevent it from passing through. The voids usually are near the surface, so abrading the finish with fine steel wool or rottenstone and a lubricant usually removes them. But this disrupts the sheen, causing the rubbed area to appear different.
A less disrupting method is to mist the damaged area with the very slow evaporating lacquer solvent, “butyl Cellosolve,” which is contained in aerosol blush removers (available from woodfinishingsupplies.com).
Remember that you’re dissolving the finish, so don’t spray too much or touch the sprayed area before it’s thoroughly dry.
Whatever liquid an aerosol might contain, the cans themselves are pretty much the same – a nozzle (made up of a valve and an actuator), a diptube and a gas to propel the liquid through the hole in the nozzle.
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