As usual, click any photo to bring up a larger version.
Somewhere around five years ago my Father-in-law went to Africa to visit my Sister-in-law's family. They were doing development work in Tanzania, on the south-eastern coat of Africa.
As often happens, he eventually went looking for souvenirs to bring back for the kids and grandkids. When my name came up, Dad thought about how I am a woodworking hobbyist and concluded that I would probably just like some interesting wood. So they trotted off and found a furniture making outfit and the very puzzled artisans there agreed to sell him a board. (No, they didn't want a table or chair, just a board -- these crazy westerners...) It had to be cut to fit his suit case, so it was about 11" wide by 20" long.
This board has since then sat on a shelf in my shop for years, as I somehow could never figure out just the right project for it. I don't even know what kind of wood it is. Some kind of African mahogany perhaps?
This winter I started designing a small end table to go beside an easy chair in our Living room. It was to be pretty small and, inspired by a Greene and Greene design from a book, I designed a small table with an octagon shaped top, about 12" square. This original design proved to be too small, so I thought about stretching out the top to be more rectangular in shape.
This was when I remembered that Tanzanian board, sitting down in my shop.
The board was found to be just what I needed, the design was refined, and before long I was ready to start building.
The top was going to be made of that mystery board from Africa -- in the woodworking trade this goes by the highly scientific designation of "dunnowood", as in "I dunno what kind of wood it is". I did consult a wood identification book I happen to own, and I was fairly certain that this was some sort of African Mahogany, though African Walnut was also a minor possibility. (But, in hindsight, I have worked with wood enough that I should know by now that it is very hard to identify a type of wood from just ONE photo of it's grain. There are so many grain variations within Cherry, for instance.)
The rest of the table was made from some slightly wormy maple that I had on hand. One final touch I came up with was to run a dado down the center of each leg, and inlay a strip of the "dunnowood". I thought this would help unify the piece, pull the two species together, and liven up the pale maple.
It is a small table, at about 16x16x10, so it didn't take much material. I used my new Dowelmax jig to join the legs to the stretchers, which considerably simplified the construction process. The stretchers meet in the middle, where a lap joint connects them. The top is attached with pan head screws, set in slightly elongated holes in the top stretchers. (There is an upside-down photo below.)
Considering the personal nature of the story behind the board featured in this project, I really wanted to get the finish right. I experimented with a few different finishes on some scrap pieces. I'm quite fond of the Tried-and-True original wood finish -- which is basically a mixture of Boiled Linseed Oil (BLO) and Beeswax. It gives a lovely colour, and wipes on easily. However, as this was a table going to be in use in the Living Room, it is inevitable that something will sooner or later get spilled on it. As such I thought that the protection of a film finish such as polyurethane was called for.
Now, plain clear polyurethane -- I was planning to use Minwax wipe-on poly -- gives a pretty bland finish. To liven up the wood, I first applied two coats of straight BLO, and then after letting it cure for a minimum of 24 hrs, the poly was wiped on.
Here is where the ordeal began. This worked fine on the small test scraps, but on the big piece, the top remained slightly tacky. I tried to let it cure longer, I tried to put it in a small room with the heat turned up to make sure it was warm enough... nothing I tried would fix it.
Providentially, I happened to be reading Michael Dresdner's book "Wood Finishing Fixes" where I found a section where he is writing about how you can use just about any finish on just about any wood:
"The two notable wood exceptions that have special finish needs are certain species of aromatic cedar, and those exotics that belong to the genus dalbergia [Indian rosewood, Brazilian rosewood, Honduras rosewood, cocobolo, African blackwood, kingwood and tulipwood.] These woods inhibit oxygen polymerization and can prevent oil-based varnish and polyurethane from properly curing. ... avoid oil-based finishes for these particular woods, or, seal them first with dewaxed shellac or Zinsser Bulls Eye SealCoat."
I really didn't think (and still don't) that my board of mystery Tanzanian wood was a member of the rosewood family, let alone any of the others. But the truth is that I didn't know for sure what it actually was, and it sure seemed to exhibit that characteristic of inhibiting the curing of oil-based poly.
I've never sanded off the finish of one of my pieces before, but there seemed to be no choice here, and so the top came off the table, and the sander came out with the rough 80grit sandpaper. I did leave the poly on the legs, since they seemed fine, and I couldn't face trying to strip it off all of those tight small corners. I did have to sand it off of the inlay pieces though. What a pain!
Shellac seemed to provide the solution. Clear, dewaxed shellac, provides the barrier coat that I need. Shellac is reportedly great in other situations as well. For instance, if you want to use water-based Poly on top of BLO, you would first need a barrier coat of Shellac inbetween.
More finishing experiments followed, with the end result being (and to make a long story short) that I sprayed two coats of Zinsser shellac (from a spray can) on to the bare wood, it seemed to provide enough colour that I didn't think that the coat of BLO was necessary. Over that I applied three coats of Flecto water-based Varathane. I had the water-based poly on hand, and just didn't want to take any more chances with oil-based poly on this project.
The results were very nice, and this table is now ready to take a place of honour in our home. With all the stories around this table, I'm also confident that it will be an interesting conversation piece for years to come.