Any advice would be appreciated. I made a fireplace mantel for a friend from solid 3/4″ walnut and finished it with four coats of Watco Natural. Each coat was applied with wet/dry sandpaper beginning with 220, then 320, then 400, and finally 600 grit. It was super smooth.
But both my friend and I thought it looked a bit dull. She didn’t want it glossy, so I decided to finish it like I do most of my boxes – padding on shellac and buffing out with 0000 steel wool.
So, after letting the Watco cure for three or four days, I added several coats (at least five) of thinned shellac (Zinnser waxed shellac diluted with alcohol 4:1). I padded on the coats the same way as I’ve done on other pieces and sanded after each coat beginning with the third coat. I used either 320 or 400 grit using mineral spirits to prevent clogging the paper. After letting the last coat of shellac sit for 2-3 days, I buffed on wax with 0000 steel wool.
When all done, I’m not happy. I see blotchiness in the walnut…I’ve never seen that before in this wood and didn’t notice until I added shellac. Maybe it’s just this piece of wood. But worse, there appear to be dull spots throughout…almost as if I didn’t sand/buff all shellac. It’s difficult to see in this photo, but with a glancing light, I can see it. Any thoughts are appreciated.
Replies
Did it do the same thing on the other side?
This is just a guess, but one of the main ingredients in WATCO is raw linseed oil which can take weeks to cure 100%. I'm wondering if applying shellac over partially cured linseed oil is the problem.
Mike
My background - I only work with oil finishes. Have been for 10 years.
Only my opinion, but you started by adding oil to a naturally-oily wood and didn't allow sufficient time for curing.
Still, if you'd have gone to 800 grit then 1000 grit for the finish, I believe you would've gotten the results you were aiming for. Then, spray on a shellac finish (2 coats) to seal it.
I recommend spraying because sanding shellac heats and blends the natural oil with the Watco causing the blotching and allowing the oil to stay viscous. I found out the hard way, cost me a bundle on a rosewood project.
Mikaol
Hard to tell without being there but, to my eye, it looks like the shellac did not level well and the "blotches" are actually low areas in the shellac that were only minimally touched when you rubbed with the steel wool.
I think the best thing you can do is strip off everything and start over. Once all of the finish is off, sand by hand to bare wood with a flat block making sure the wood surface is level and smooth to at least 180 grit. Then add a coat of Watco if that is what you like. Let it cure for a couple of days and then apply 2-3 coats of oil based polyurethane; semi-gloss or satin. You don't need or want the shellac. The poly will adhere just fine without it. Once the poly is dry 2-3 days, polish with 1000-2000 wet/dry and apply a coat of paste wax. Done.
Having said all that, with walnut, I don't think that the Watco adds any benefit if you use polyurethane. The poly alone will darken and enhance the grain and color. If you want to darken it further or add some warmth to the existing color, just use a good stain of your preference.
Thanks to everyone here for helpful advice. I think I've probably got a problem generally defined by several of you. I suspect that the Watco didn't properly cure before the shellac coat and that I didn't lay on enough shellac to completely cover the more opened pore sections of the wood.
I plan to sand down through the shellac and starting from scratch. Thanks for advice from all.
You have been using almost all finishing products on top of each other and using different abrasives to apply them. If I was to troubleshoot the problem I would be at a loss as there are so many variables. My advice, keep it simple and for a desired end result, aim first at the product(s) and methods that are proven, I do not think that the recipie you ended with exists.
I'd second what Gulfstar said.
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