Economics of wood bowls

Making bowls using traditional wood turning technique on a lathe results in wasting most of the wood.  I wondered about the economic aspects and tried an alternative method to wood bowl-making to determine if it could really be advantageous. 

My conclusion is that, although savings can be significant depending on wood species and size of bowl, giving up on the "good old fashioned way" of turning wood bowls is not justified, at least not for financial reasons alone because there are many other factors, e.g., labor/ time spent and creative limitations that need to be factored into  the decision.  It becomes a complementary technique, not a replacement.

In simple terms, in order to make a wood bowl, you procure a  large, solid piece of wood and hollow it out by removing wood and replacing it with air.  Because of the tools and process of cutting wood out on a lathe, the wood that you remove (as "shavings") is, for all intents and purposes, wasted.  And although I "recycle" it in my compost, I find this to be a poor use of wood from both economic  and ecological points of view.  For the purposes of this discussion, let's consider the shavings as wasted wood.

I currently know of two techniques that can be used to reduce this waste:

• For pieces of wood that are large enough, e.g., tree trunks or sections of trunks, specialized tools exist that allow you to "core" concentric bowl-shaped pieces of wood (so called "blanks") on a lathe.
• Bowl blanks can be constructed from planks/ boards glued together from which concentric circles are cut. These concentric cone-shaped pieces are then stacked back together so as to minimize the waste.

Both techniques have pros and cons.  As I have experimented with the second technique recently and wanted to determine the impact it could have on the cost of making a bowl, I'll focus on this below.

Imagine that you'd like to make a 20 cm diameter bowl that is approximately 9 cm tall.  If you take a wood board that is 20cm square and 3cm thick, you can probably see that, by cutting out three concentric circles, each 3 cm wide, you could construct, if these could be stacked upon one another, a 9cm tall cylinder with three different diameters: one 20cm, one 17cm, and one 14cm.  Stacking them together becomes possible if you now imagine that you have cut each concentric circle at an angle, say 45 degrees, from outside edge towards the center, and from top to bottom.  In this case, the diameter at the bottom of each larger circle will be smaller than the diameter at the top of each successively smaller circle, which allows the bottom of the larger circle to rest upon the top of the successively smaller circle.

You will also have noticed that the shape is hollow for the top two circles.  This hollow is the wood that has been saved.

Financially here's how it works out:

• Wood cost at lumber yards (in the USA) is calculated per species by volume (board foot= (LxWxH inches)/144 = Board Feet).  Calculating the cost in this way makes the shape of each piece of wood irrelevant since it is the "amount" of wood that is used.  (It is actually a bit more complicated since thicker wood is harder to find but let's keep things simple here.)  Here are approximate board-foot costs of species I regularly use: 
  • Ash $4.85
  • Maple $6.85
  • Cherry $8.50
  • Walnut $14.00
  • Morado $25.50
• To make a bowl from a solid piece of wood that is 8 in. x 8 in. x 3.5 in (approx 20cmx20cmx9cm) the wood cost comes to approximately the following:
  • Ash: $7.50 =>  ((8x8x3.5)/144)x$4.85
  • Maple: $10.65
  • Cherry: $13.25
  • Walnut: $ 21.75
  • Morado: $39.70
• Whereas making it from a 8x8x1.25 (20cmx20cmx3cm) board would cost the following
  • Ash: $2.70 (saving $4.80)
  • Maple: $3.80 (saving $6.85)
  • Cherry $4.75 (saving $8.50)
  • Walnut $7.80 (saving $13.95)
  • Morado: $14.20 (saving $25.5)

Note that this is the price saved per bowl.  People who make a living making bowls will have over 50 in inventory at any one time, which represents significant savings in cost of raw materials (wood).   Of course, if bowl making from either one piece of wood or from several boards used the same amount of labor, it would be simple.  However, as we saw above, making a bowl from boards requires some additional work: cutting the boards into angled concentric circles and gluing these together in order to create the general bowl shape.  Assuming the cost of glue is negligible, let's look at the time aspect.

Let's assume that the wood turner is capable of making a good bowl from a solid piece of wood in 1.5hours and let's assume that a wood turner earns an average of $16.25/ hour (recent statistics for wood workers in New Jersey.)  This means that the bowl cost should run from $31.90 (Ash) to $46.15 (Walnut).

My experience shows that the measuring, cutting and gluing operations add an extra hour to the work.  This means that the bowl's cost should run from $45.50 (Ash) to $54.63 (Walnut).  If, however, the bowl were made from Morado, it's cost would be almost the same $64.10 (traditional) compared to $66.15. 

As we can see, only if wood costs were much higher would it make economic sense to avoid the wasted wood.  But there are, in fact other considerations - both for and against.  The main ones that come to mind are as follows:

• "Environmental" cost due to waste of a precious (renewable) resource for local woods but what of woods that are transported great distances?
• Using a solid piece of wood to create a bowl leaves the artisan the greatest flexibility regarding the bowl's shape.  As wood is removed the options for the final shape of the object become reduced.  Stacking pyramid-like concentric circles on each other reduces shape options significantly.
• Using boards to create bowls allows additional creative techniques to be applied by gluing different wood varieties and colors together - creating a bowl with multiple layers - whereas making a bowl from a single, solid piece of wood can only be as beautiful as the natural characteristics of that piece of wood (grain, chatoyancy, color, etc.)

This exercise has demonstrated to me that the different techniques for creating and turning bowls each have a place in the artisan's craft and although economics is an important concern, in this case it does not justify abandoning the traditional methods.