Pumice and BLO as a grain filler

[Michael O'Sullivan]

I have heard folks talking about using this as a grain filler -- has anyone here tried it? If so does it work? And if it works, how exactly do you do it?

[Bryan Berguson]

I've never tried Pumice and BLO but I'm sure someone here has the answer. For grain filler, I like Waterlox applied with 220 wet/dry sandpaper to start. Work it in good and then wipe it off before it dries. (trust me, you do want to wipe it off, lots of work sanding if you don't) :o

On a hickory project I did this up through 1000 grit SP. It was unnecessary to go that far IMO. I do a coat or 2 with 220 and maybe one with 400 and then finish as normal. Ultra smooth finish that you have to feel to believe.

Bryan

[John Keeton]

Michael, Jeff Jewitt has a section in his book Hand Applied Finishes on this technique, and I am going to try it - just haven't yet. I bought some pumice just for this purpose.

I posted a similar query in a prior thread and there were a couple of responses with pics. It can produce a very slick and flat finish. But, what I am wanting to do is to fill some walnut and end up with more of a satin sheen that would give the appearance of an old hand rubbed patina.

It will be interesting to see the responses you get. Would like to see some pics of finishes less glossy than the "piano" finishes, and the techniques used.

[John Keeton]

Bryan, by the time I had posted you had already responded. Interestingly, Jewitt also has a technique similar to what you have done. He begins with a mixture of one part pure tung oil, one part mineral spirits, and one part Waterlox Transparent Varnish. After sanding the wood to 320, apply a wet coat of the mixture to the wood. Wait 20 minutes, and then wet-sand with 320 wet/dry, wipe off the excess. After 24 hours repeat process with 600, and repeat again until the finish builds to your liking.

[Larry Fox]

I do it all the time when applying a french polish and sometimes when doing other schedules where shellac is the first step in the schedule of topcoats. I don't think that shellac being the first step is a requirement though.

The way I do it is exactly the way that Jeff describes in his various articles. I actually learned it from Jeff in a class he taught at the Philadelphia Furniture Workshop a few years ago. It is really easy to do. The key is to not over-do the pumice.

As a side note, if you are doing a French Polish you can also do it without BLO but the initial wash / spit coat has to be on and it is very important to use as little pumice as possible. Another important point with this particular method is to never apply the pumice directly to the piece but instead apply it to the muneca and clear it first. If you use too much you get piles under the finish which are really, really tough to get out (DAMHIKT). Below is a link to the doc that I view as the last and mightiest word on French Polishing and they talk about the method.

http://www.milburnguitars.com/fpbannerframes.html

[Prashun Patel]

If you are a member of FWW online, you can download an article on how to do it. You can do it with Rottenstone too if you want to accent the grain.

Warning, though - it's not very efficient. I had to do it several times.

The technique is simple: Sprinkle pumice on the surface, then pour a little BLO and then rub it in. Don't soak the sfc with BLO. Yr goal is to make a slurry. The pumice will actually mildly SAND the surface, so in theory it's possible to eat through yr dye layer if go bananas with the rubbing. I did not experience burn through though on my dyed mahogany. Rub at 45 deg to the grain to work it in. Then gently blot the excess oil off.

When it dries, come back and buff off any excess pumice. Check yr work in raking light and with a raking fingernail.

After you're satisfied, let the pc dry for a day or two, and then topcoat.

The 1st time I did this (I've done it twice), I THOUGHT I'd filled the grain but my 1st few coats of varnish revealed that I hadn't. I ended up filling that grain with the varnish; sanding back and topping several times. It was slow going.

After doing it right on a 2nd project, I've concluded that next time I'll use commercial grain filler. It's just not worth the effort to do it the old fashioned way.

I can't speak to French polishing with pumice. I imagine it's a tad more bearable because of the quick dry time. But if it were me, I'd spring for a can of real paste filler. One and done.

[Frank Hagan]

This is my favorite finishing technique for red oak. I spread some BLO on the surface, sprinkle on a teaspoon or so of pumice, and then rub in a circular motion with a terry cloth rag. The slurry cuts into the red oak and creates a thicker slurry with wood dust, pumice and BLO.

The pumice has the added benefit of keeping the BLO from oozing out of the pores in the wood multiple times. Check it again in an hour or so, and that's about all the oozing you'll get. Coating with shellac allows you to then finish it with any topcoat you like (if needed).

I used it on the baby cradle I made ... it looks like most of the pics are gone now ... but this page (http://www.sawmillcreek.org/showthread.php?t=27469&highlight=boat+cradle&page=3) still has a couple of pics. The finish is a nice smooth, satin finish using this technique.

I haven't tried it on mahogany yet.

[Montgomery Scott]

I recently completed a set of Queen Anne chairs and made a wet sanding finish with BLO, mineral spirits and spar urethane at about a 1:1:1 ratio. With 320 wet/dry sandpaper it filled the walnut grain nicely.

After drying and finish sanding with 600 grit paper I sprayed several coats of spar urethane and let it dry for a month. I then used a cotton rag with ~1 oz of pumice as you would when French polishing and used mineral spirits liberally. It gives a smooth satin finish, though it's rather time consuming.

[glenn bradley]

http://www.taunton.com/finewoodworking/fwnpdf/011177121.pdf Jeff Jewitt discusses pumice and P of P.

"If you have trouble finding pumice, plaster of Paris is an easy-to-use alternative. Mix the plaster with water until the filler has a fairly stiff consistency similar to drywall compound. The wetter the mixture, the more it will shrink after it has been applied to the wood. Using a cloth, work the filler into the wood in a circular motion. Unlike the linseed oil/pumice filler, this water-based filler dries very quickly, so you will have to work in one small area at a time. After you’re done, let the wood sit until the surface feels dry. Wipe off some of the excess with a damp cloth. Let the board dry overnight, and then sand it with P220-grit paper. To turn the filler translucent, apply
a coat of boiled linseed oil."

[Michael O'Sullivan]

Thanks for the responses -- I have had a mixed bag of experiences with grain filling, and this is one I had not tried.