I did some more work to see if I could create a higher sheen with Rubio. As background, Rubio recommends sanding to 120 grit, and not to exceed 150 grit, before applying a single coat of finish. I sanded to 120 grit on a recent project that used walnut and Baltic birch plywood. The sheen on the walnut was decidedly matte. To see if I could increase the sheen I prepared another walnut specimen. I sanded one side of it with 120 grit and 600 grit on the other. I applied a single coat of Rubio 2C. After 3 or 4 days buffed half the side sanded to 120 grit with 2000 grit Abralon. To the left of the dotted line is 120 grit buffed with 2000 Abralon after curing, 120 grit in the middle, and 600 grit on the right side.
The side sanded to 600 grit had the highest sheen and felt baby butt smooth but the color appears lighter and inconsistent. This could be due to flexing of the veneer as I sanded it; I'm not sure. The portion buffed with 2000 grit Abralon feels very smooth, too. The sheen looks a little higher from some angles, but sort of cloudy from others. I came away without any specific direction on what to do improve the sheen w/o introducing potential issues. I do know from my prior testing that if I sand to 120 grit, apply a coat of Rubio, let it cure for several days, and then sand it with 325 and apply a second coat it feels very smooth, the clarity is still good, but the sheen is still matte.
While I was at it I did a similar test on a piece of Birdseye maple. The results are quite startling. 120 grit on the left, 600 on the right.
The side sanded to 600 grit has a beautiful semi gloss luster and chatoyance and is silky smooth. The side sanded to 120 feels smoother and the sheen is higher than the comparable walnut sample. Clearly, the species of wood has great influence over the results. That's probably to be expected with a finish where you only apply one coat of finish and is consistant with what happens when you use an oil/varnish finish.
Where to go from here? I have not tested the durability of the portions sanded to 600 grit and that could be a showstopper if the results are poor. My feeling at this point is that 220 to 325 grit is likely a happy medium to get a smooth feel w/o compromising finish absorption and durability. No proof yet though. To increase sheen, if that's desirable, the better way than trying to sand to high grits before application or buffing afterwards, is to apply a coat of Maintenance Oil or to pursue Osmo PolyOx or another hardwax oil that comes in more than one sheen. Osmo is available in matte, satin, and gloss.
John
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