Saturday, September 19, 2009

Staining the Back & Pre-Staining the Soundboard

Saturday, September 19, 2009

Since my last post I have finished staining the back and am really happy with the results and have spent a considerable amount of energy testing and researching how to stain the soundboard without ruining it - and I think I have figured it out.

First, lets take a look at the back.

As you will recall, I left you last time with the back and sides stained once with my Tobacco Brown stain and then sanded it off in order to bring out the shimmer of the maple. From there, I applied my finish stain.

I started by applying the Tobacco Brown around the outside edge and then feathered it up toward the center where no stain is yet applied.

Then, starting from the center, I applied Amber stain and worked my way out. When done (a pretty easy process, really), the hardest part was making the transition from dark to light smooth and not to dramatic.

Then it was time to start working on the test wood again to figure out how to stain the soundboard. As you may recall, I tried this once on my first junk soundboard and was not at all happy with the results. When I tried again this time, instead of preparing the wood with a hide-glue solution, I tried it without any preparation other than sanding. Sadly, as with the previous attempt, I hated the results. Here is what some of those looked like:

In this composite shot, the lower left area is actually a bit of a success since it shows where I made an attempt after applying a pre-stain (I will get to that in a minute). The other three areas show where the stain has been absorbed by the wood in way-too-random of fashion. My goal is to get a much more even distribution.

This shot shows my second sunburst staining attempt (disappointing) as well as where I am testing of my top coat.

Time to go back to the Mandolin Cafe again and do some research.

After reading many threads in the Cafe’s “Builder’s” forum, it became apparent that hand-rubbing a sunburst stain on a spruce soundboard is difficult, at best. Many of the pros have a hard time with it and some don’t even bother with doing it by hand but use an airbrush instead.

I don’t have an airbrush. And even if I did, I don’t have a place (or the knowledge) to use it.

In addition to this, however, I did learn a couple of ways to improve my chances of success.

First way is sanding. The level of sanding, the thoroughness of it and the attention to this bit of detail is CRITICAL to the success of hand-rubbing a sunburst stain. I already knew it was important to get rid of all the scratches left from rougher grit papers and scraping marks, but what I did not know was that sanding to too-fine of a grit is not good, either. By stopping at 220 grit, the surface of the spruce is left a bit “fuzzy” (I see this under my magnifying glass) allowing the less porous areas of the wood to absorb more of the stain, more like the way the end-grains do. On my two full-soundboard test attempts I had sanded down to 600 grit so for my smaller test areas I sanded again to a 220 grit.

The other way is to find and apply a store-bought Pre-Stain. Using a pre-stain apparently seals the end-grains enough to prevent the stain from soaking in too much, but not enough to prevent it from soaking in at all. The result should be to allow for a more even distribution of stain across both end-grains and straight-grains.

I attempted to make my own pre-stain on my first test using the hide-glue, but not having a good idea how to handle it and a fear that the glue itself would prevent the stain from “taking”, I might have sanded too much of it off again before applying my stain. In any case, that attempt did not work, so I went out and bought a can of Min-Wax Pre-Stain that is especially made for water-based stains.

Here is how one area of one of my soundboards looked after using the Min-Wax Pre-Stain:

As you can see, not only is the light-colored ring no longer there (this I attribute mostly to rougher sanding), but the end-grain has taken a lot less stain than it did the first time. It took a whole lot less effort to get this result, too.

So, now that I have a technique that looks like it will work, I will be staining my soundboard for real this weekend. This is how I am doing it.

Here is the soundboard before applying anything to it. I have sanded it down to 220 grit, wetted it twice to raise the grain and then re-sanded.

Using old T-shirt material, both inside and out, I have created a “swab” as an applicator. This is the same kind of swab I am using for applying my stain and finish later.

I find that the wood appears to soak this stuff right up, so I will be applying two coats of it. These photos are of my first coat and I have let it dry over-night. This morning I applied my second coat (that appears to have soaked in every bit as quickly as the first one) and will wait at least until this afternoon before attempting to apply the stain.

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