I have some African mahogany sapwood I bought because of its beautiful grain. I had never worked with sapwood before, I just loved the figure of the wood.
I made a small “treasure box” from that and padauk. In trying to decide how I’d finish it, I ran across an article in FWW #217 titled “Foolproof French Polishing”. It described a method using diluted shellac and 4F pumice to fill in the pores. On a sample piece of the AM I rubbed in the pumice with the shellac at least 5-6 times, before the shellac began to gum up.
I then dyed the piece and sprayed 3 coats of lacquer on it after which I applied paste wax. When it was done I could still see unfilled pores. It looked pretty much the same as the padauk which had not been filled.
I followed the pore filling part of the article exactly as described. The only difference might possibly be the number of layers of pumice that the wood needed. I don’t think not finishing the piece with shellac was the problem as the article clearly states shellac should not be used as a filler as it shrinks over time.
What am I doing wrong?
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Treasure Box
I know I'm going to upset the french polishers here but here's what I'd do.
Raw wood - seal with shellac - fill grain with oil based grain filler - top coat with lacquer-
SA
Several problems arise frpm your approach. One can fill pores with pumice and shellac but it's more than just a rub in process, it's really the first step of a full fledged French polish process, where the pumice is also acting as abrasive so you are filling pores with a mix of pumice, wood dust, with shellac as a binder holding it all in. Shrinkage does occur (though some will actually argue otherwise) the solution is really just a matter of patience, doing the substantial filling process one day and then waiting for a week or so to conclude. It also works best on the wood the process was best with the very dense Cuban or Dominican Mahogany used in the early 19th century. Larger pores of Honduran and even larger pores of the Aftrican "mahogany" are harder to fill and shrinkage a bigger problem.
The French polish only works well on wood that has not been dyed or stain since the abrasive pumice can damage the color. But also note that once you have applied shellac, dye is not approriate except in special situations. In general, and certainly if enough shellac has been used to fill pores, the shellac prevents dye from penetrating into the surface of the wood. Even with just a thin wash coat of shellac, the penetration won't be even.
Oil based pore filler, especially brands with high percentages of Silex (silica) as the filler, works much better, and with woods that need coloration offers methods that really help give a . attractive results. For example, I have started with a medium yellow dye on mahogany, given a light (1 lb. cut) wash coat of shellac followed by brown mahogany dye. The second dye coat is not very even, creating golden high lights on denser part of the wood, and darker red brown color on the more porous parts. (In some woods this could look awful, blotchy or stripped. You must run tests of your entire finish schedule.)
After the dye steps, I then seal again with shellac. Then I use pore filler tinted to a shade a tad darker than the base color created by the dye,. This helps give "depth". The pore filler will act as a pigmented stain as well, toning down possible blotchy look of the dye alone stain. Then you can use whatever top coat you want, including shellac.
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