Amalgamate Shellac

The old shellac on this table leg (left) was rejuvenated by wiping and brushing the surface with alcohol.

loose veneer, or you'll risk damaging the furniture. Then clean the surface with a dry rag and let the piece dry completely—usually overnight. Now wax the finish.

If your piece is grimy and wax has built up, use a solvent to do the cleaning instead of soap. I use a product from Mohawk Finishing Products called Wax Wash (see Sources, page 60) which removes wax and dirt without harming the finish. You can use naphtha or mineral spirits instead, since both will dissolve die wax and not affect the finish. Soak 0000 steel wool with solvent, and rub gently with the grain. When all the wax is dissolved, wipe the piece with a clean rag and allow the surface to dry. Then apply wax as above.

Determining the Finish

If the finish is badly cracked and very rough, waxing or cleaning won't be enough. However, you may be able to "re-knit" (bring the cracks together) and smooth the finish with a chcmical that will dissolve the finish. But before you use chcmicals, you need to find out whether you're dealing widi oil, shellac, varnish or lacquer.

Look at die finish. If it's oil, it won't have a surface thickncss to it because oil is a penetrating finish. You can test for shellac, varnish and lacquer in steps by applying one of two solvents in an inconspicuous area on the piccc to sec if it softens die finish. First, test for shellac by rubbing a rag dampened in denatured alcohol on the surface. The shcl-lac will soften instandy, but varnish or lacquer won't be affected. If the finish isn't shellac, test for varnish or lacquer by dampening an area in the same manner using lacquer thinner. Lacquer thinner will soften the lacquer, but won't soften die varnish.

Re-knitting the Finish

When you know what the finish is, you can re-am alga-mate—blend back together—the surface widi a solvent specific to that finish. Besides eliminating cracks and blemishes, this process will also rejuvenate an old finish that has darkened widi din and age. (See photos above.)

An oil finLsh doesn't break down with age as does shellac, varnish or lacquer. Instead, it will wear away over time. With an oil finish, the best restoration method is to smooth any rough surfaces with 0000 steel wool and apply a new coat of oil.

Here's how to re-knit shellac, varnish and lacqucr finishes:

To re-amalgamate shellac, apply denatured alcohol with a clean rag (an old T-shirt works well), making the surface as wet as possible without runs or puddles. Immediately wipe the surface lightly with a dry rag. The alcohol will soften the shellac almost instantly, so only work an area about 1 ft. square.

After one application, inspect the finish. If it isn't smooth, go back with die wet rag and soften some more of the finish, nibbing with enough pressure to force die shellac into the pores of the wood. Start with a circular motion to spread the shellac around, folding the rag often to keep the working surface of the rag clean. When the shellac is spread evenly over the surfacc, wipe lighdy widi die grain of die wood, using the same rag to smooth out the finish. For carved and liard-to-reach areas, use a small brush instead of a rag.

Let the piece dry for a few hours, then look at the finish. You may have some bare spots and areas of uneven sheen. If this is the case, sand lightly with 320-grit sandpaper, wipe off any dust, and brush or wipe on a few coats of 1 '6-pound-cut shcllac.

To re-knit varnish and lacquer, I use a product from Mohawk called Amalgamator (see Sources) that contains a blend of solvents designed to gently soften the finish. This lets you move the finish around to fill cracks and smooth die surface. (See photos below.) As the solvents in Amalgamator evaporate, the finish hardens back to its cured state. (Bchlen makes a similar product called Qualarcnu—sec Sources.) While lacqucr thinner will also dissolve lacquer, I don't recommend it for re-knitting a lacquer finish. Lacquer thinner Is likely to soften too much finish and leave bare spots of wood.

To use Amalgamator, moisten a clean rag with the liquid and rub the surface with a circular motion to remove cracks, staying within a 1-ft.-square area. After the cracks arc gone, keep wiping with die rag to soften the finish, and apply a little more pressure to spread the finish evenly over the surface. Finish by wiping with the grain to smooth the surfacc.

If you're not satisfied with the way the surfacc looks, you can sand lightly with 320grit paper after it's dried for a few hours, then rccoat with the original finish. However, I prefer to apply a mod-cm padding finish.

Using Podding Finishes

Padding finishes—also called padding lacquers—arc applied with a pad, as with French polishing, and produce a beautiful, fairly durable finish. (Sec sidc-

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Wood Working for Amateur Craftsman

Wood Working for Amateur Craftsman

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  • Dehab Haile
    How to amalgamate a shellac finish?
    3 years ago

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