Wednesday – Stain Prep

We’re on hold for a little white again as I check the color with Blake & Marilyn. Problem? No, not really: the color is just not quite what I had expected it to be. But, it is probably what it is supposed to be at this stage.

To clarify all this let me explain the principle of a pigment stain. Pigment stains consist of teeny globs of a coloring agent (think of paint) suspended in liquid carrier. Applying the stain to a wood surface, the teeny globs of color get lodged in the miniscule pockets and furrows that are the woods’ surface. When the liquid carrier either evaporates or catalyzes into a film, the color is locked into the wood.

Two things affect the quality of a stain job: One; the size of the teeny globs, two; how the surface was sanded prior to staining.

Varathane claims to provide much smaller globs of color than most pigmented stains, thus provide more even coloring. My own experience with this brand would bear this out. That is why we are switching to Varathane as our primary brand – because I’m quite impressed with the richness of the color we get.

Sanding a wood surface with successively finer grits of sand paper removes minor surface damage and large, open grain in the wood by making successively finer sets of scratches in the woods’ surface as a little bit of the wood is removed. Sanding some woods too much (too fine a grit) removes nearly all the places for the stains’ color globs to lodge and the resulting color is too light.

Some woods with uneven graining will present the stain with greatly varying degrees of hiding places, resulting in splotching. In most cases, a wood conditioner, also referred to as a stain blocker, can be applied to seal up the “wild” grain some and even out the degree of coloring.

In the past I’ve used two methods to prepare a surface for staining. One is to flood the wood with clean mineral spirits (if using an oil base stain), allow the wood to absorb as much as it will take, then wipe the surface dry and stain immediately. The mineral spirits that remain in the grainy parts helps to repel the stain so it doesn’t get so dark. This is especially useful in preventing end grain from getting so much darker than face grain.

The other is to apply a seal coat – I like blonde shellac – allow it to dry then sand the surface again with your finest previous grit to remove most of the seal coat. Only in the grainy parts will the sealer remain undisturbed and so it will prevent the stain from collecting there and becoming so much darker than the rest of the surface.

Today is our first experience with the Varathane Wood Conditioner, and I believe they left off a key element in their instructions for use. They say to apply, let set for 30 minutes and stain. This led me to believe that it worked on the principle of the first method mentioned above. The results however say something different. The board on the left in the photo was prepared with the Wood Conditioner according to instructions. It looks like that really should have been sanded again before being stained.

The color we achieved on the unsealed board is more even, but much too light. This may be because the surface was sanded to too fine a grit or it may require 2 or possibly 3 coats to achieve the right color. I sanded to 220 grit per the instructions on the can, so it may be that we will have to apply multiple coats. But, each coat must dry for eight hours before recoating or the previous coat can be dissolved and cause it to creep. If it does that on the curio, we sand it all off and start over. And I don’t want to do that!

Also, the color sample chip in the Varathane color chart is represented on Red Oak lumber, we are using maple lumber for this curio. The difference in color between the woods will have an effect on the stain color as well, especially with just one coat applied.

The last time we used Varathane was in making the Mission Oak version of our Deluxe Sewing Cabinet for Paula. On that piece, one coat of stain was all we needed for a wonderful rich color, but that was oak and I did not sand to such a fine grit -- I didn't read the can first, just prepared the wood like we always did for the Sherwin Williams stains.

So I’ll make up another sample board and try it with 2 coats. I’ll let you know how it went tomorrow.

Doug