Is anybody using the silica filler before staining these days? I haven't done that in over 40 years. The reason I ask is that I took on the sanding portion of a refinishing job. The surface looked and felt like the chalkboard paint used nowdays. The flaky stain scrapes off fairly easily but underneath the filler wasn't rubbed off and then sanded to give a good surface for the stain and the filler gums up my paper. That may be the reason I quit using it long ago. There was no top coat over the stain.
When you say "silica" I assume you mean Por-o-Pac? Do you rub the filler off across the grain with coarse burlap? If you are having trouble taking it off because it is drying too quickly, just apply a little more where it is stuck. If you are consistently having problems with it drying too quickly, increase the proportion of mineral spirits, or replace some of the mineral spirits with a solvent that drys more slowly, or use more elbow grease. If you are pigment staining, and the pores are intended to be the same color as the background wood, you can add the pigment stain to the filler (if they both use the same carrier) and skip a step.
Which type or brand do you use? I don't think it matters. I usually use the oil based fillers because I can pigment them with what ever I am going to use for stain (which is usually oil based) But I have used water based filler and they work fine too.
I think the product I used to use was called silex. The person who put it on the oak benches I'm working on didn't rub it down well and I think that is why the stain didn't penetrate and is chalky feeling. It has a greenish-grey color.
In Pore-o-Pac, Behlen has already graded the SiO2 and thoroughly mixed it with BLO. Optionally, it comes in several colors, with the pigment also already added.
Other than that, it's basically the same stuff and the same process. I have always thinned it with some mineral spirits, but I note that Behlon offers a reducer for it. In any case, if you don't get it thoroughly wiped off before the BLO polymerizes, the linseed oil will inhibit the absorption of subsequent coats of pigment stain. Getting the excess off can be a challenge, requiring rapid and vigorous exercise, especially if the pores you are trying to fill are large, because you can easily start too soon and pull the filler out of the pores. As I noted above, you can throw on more filler, or just some more reducer to remobilize it and remove it. Basically, what we are trying to do here is add back the VOCs that the State of California made us remove to help relieve their air pollution problems.
