Note from Caleb: this is a guest article by Benjamin Greenberg of Greenberg Woods, a wood supplier who deals in a huge range of wood for knives, from maple to cocobolo, from burls to spalts. I asked him to write a primer on the most common handle material for knives: wood. This article will take us through a few common types of wood, the stabilizing process, pricing, and finishing techniques, giving a few whats, whys, and hows in the wood world.
Some quick wood info
Maple: Acer spp
Figured maple is a longtime favorite of many knife makers, because it is incredibly easy to stabilize, work and dye. Its figure is described in a few ways. Curly means the grain has "fold" that reflect light differently, creating perhaps the most common and well known figure. This is most often seen in quarter sawn pieces “those cut radially to the grain,” often just called figured. Birds eye shows small circles in the grain resembling the eyes of a burl, though often they do not have the surrounding rings of grain normally found in burls. This almost only occurs in hard maple, while all other types of figure are most prominent in soft maples. Tiger/ flame and fiddle back maple all refer to a very tight pattern of curls. Quilted maple is another type of figure at resembles water with a breeze. The folds seem to lap into each other and become quite complex, giving a very 3d figure. This one is most often found in the big leaf maple of the pacific west coast and shows up best when flat sawn. Maple also forms huge and sometimes extremely well figured burls.
Mexican Kingwood: Dalbergia congestiflora
Also called Camatillo. The wood is a beautiful royal purple, swirling with scarlet, black, gold, violet and pinks. The wood is incredibly beautiful, with amazing grain patterns and unmatched color. The wood is also mechanically superb, with amazing hardness and density ratings that in many cases beat even those of Desert Ironwood. Able to take an amazing polish with almost mirror like finish, it is also water proof and wears well. This is my personal favorite wood, though it has recently been CITIES listed and supplies are dwindling. The two main ways are to finish with wax or oil. An oil finish will greatly darken the wood down to a deep purple black, while a wax finish will leave the wood with its right purple and all the contrast, my personal favorite way to finish.
Perhaps the most unique “wood” on this list. Black Palm is technically a member of the grass family and there for a monocot. The wood is also incredibly unique, lacking any growth rings or other features commonly associated with wood. Instead, the wood contains varying densities of incredibly hard, tough dark fibers embedded in a softer deep brown matrix. These darker fibers give palm is strength and pieces with a high density of these fibers can be incredibly strong and denser than water. Most of the Palm you will find on my site is Bias cut and stabilized.Bias cut means that it is cut and an angle relative to the direction of the denser fibers, which grow parallel to the height of the tree. This results in a stunning effect of what appears to be fish scales or a grouping of leopard spots. The wood is stabilized not for added density or strength, to properties Palm is not lacking for, but rather to prevent tear out. In unstabilized pieces, the darker fibers often tear out of the matrix leaving unsightly gaps. By professionally stabilizing the wood this can be mostly if not completely eliminated.
Stabilizing is a process that is not well understood by many people. To put it simply, it is the process of forcing a plastic polymer into wood at incredibly high pressure before curing the resin, thus leaving a wood that is impregnated with plastic to make it heavier, stronger, resistant to water and able to be easily polished to a high finish. The thing to know about stabilizing is that it does not fill voids. You cant take a voided wood and stabilize it solid. It makes wood denser and more stable, it will resist warping and cracking due to heat and moisture changes.
Many people will try home stabilization using all manner of vacuum pumps and off the shelf chemicals. This simply does not yield the same results as professional stabilization.
What woods need stabilization? There is some debate about that. My list of exotic woods shows my personal suggestions for stabilization, but again. These are suggestions. In general, stabilizing is generally recommended for woods of about the density and hardness of walnut or lower. Thick maple, koa, redwood, mango and oak.
Finishing Stabilized woods: Stabilized wood finishes differently than even the same wood untreated. The injected resin means that the filled pores can be finished to a much higher degree. While something like natural maple, walnut, buckeye or koa would normally be sanded to in the range of 220 grit as a finishing grit, 1000-2500 is not uncommon with stabilized woods. Stabilized woods are also much easier to finish with a buffing wheel, as the filled texture does not stain and hold onto compound like raw wood.
When buying stabilized wood, it is a good idea to ask where the wood was stabilized. Most sellers on ebay sell a lower quality home stabilized product. In general, a stabilized block will be about 10 dollars more than an unstabilized block
A question I often get is “Why are knife handle blocks so expensive?”
The answer is; are they? It's important to think about the labor and competition involved in delivering a clean, knife handle sized block of wood. The most important thing to remember is that knife making is a back water industry as far as wood sellers are concerned. The real money is is Guitar making, veneer making and turning, all of which use a far greater volume of wood than knife makers and drive up the price of fine woods.
The next is labor and yield. It stuns most people to hear that the loss rate from cutting up a burl can be as high as 90%. With some large domestic burls such as maple, buckeye and walnut, a 50 pound burl may yield 10-20 pounds of high quality blocks, and given that burl is normally sold by the pound, thats a lot of lost product. With high end exotic burls like rosewood, ironwood or bloodwood burl, the losses can be incredibly. A recent batch of 65 pounds of high quality bloodwood burl yielded a mere 8 pounds of useable burl blocks, with an even smaller percentage being top quality. The labor and tooling required is also surprising. Breaking down a large burl can easily take the better part of the day, and combined with sanding, finishing and buffing its not uncommon for each block to have 5-10 minutes of work put into it.
All these factors combined with the cost of shipping, stabilizing and website hosting contribute to the cost of blocks. There are exceptions of course. I carry 3 species of wood, African blackwood, Kingwood and Cocobolo that i do minimal work to. The surfaces are not sanded past the bandsaw finish, the blocks are not individually photographed and they are cut from large logs rather than small burls, and these blocks sell for 10-20 dollars, a real bargain when you consider the cost of wood and time.
Finishing your wood handle
A good finish starts with good sanding. After shaping, jump up grits in increments of roughly 50, making sure to remove ALL scratches before continuing on to the last grit. This is often done using the slack of a belt sander, and j-flex belts like those sold by Tru-Grit are perfect for this. Use scalloped belts for best results, as these help to blend in edges and don't leave sharp dug in lines. I tend to stop belt sanding at 600 grit. Now, its time for hand sanding. Jumping back down to 400 grit, using either plain paper backed by your hand or with a heavy piece of felt or cork, go over the handle until a uniform scratch pattern is achieved. From here, continue up the grits until 1000-2500. After you are completely finished sanding, jump back down to 1000 and do one final pass before finishing again with your final grit. Why all this jumping up and down? Scratches have a way of hiding and not appearing until you are getting ready to send off the knife. The extra time with paper will save you a lot of time and heart ache later.
After sanding, I love to use the buffer. Using a large, soft wheel using a small amount of finishing wax, go over the handle several times. Some people like to use brown Tripoli, but i find this has a tendency to get trapped in pores, and if the sanding was done properly its not needed. The heat of the buffer will allow the wax finish to melt in and give a very flat, even coating.
After machine buffing, finish the wood with a very vigorous hand buffing using a soft cotton cloth.
Beware the call of oil! Flooded oil finishes are something of a siren song. When first applied, NOTHING looks better than a heavily oiled handle, however the oil will darken the wood, muddle figure and blend colors. Resist the urge, and use a high quality finishing wax or light coats of tru-oil following the advice of makers like Nick Wheeler.
I've actually been aware of Greenberg Woods for quite a while now, but until lately have not needed a more constant and larger supply of handle material; I didn't (and don't) exactly have the fastest tools and skills ever. That said, having looked over and read his site and seen his stuff, I'm very excited about the possibilities: Benjamin has some of the best prices for some of the best material available. I just ordered a bulk set of kingwood blocks from him and can't wait to put them to use. There is a ton more on his site, both wood selection and valuable information on wood, stabilizing, finishing, etc. He is definitely work checking out!