Discovery

Understanding Compressed Wood

Compressed wood planks arrive surfaced on two sides (S2S) with a coarse sanded finish. While this innovative material can be resawn like any other hardwood, it often has a natural bow that requires special handling techniques. The key difference from traditional hardwood is that compressed wood performs much better on band saws than table saws due to this tendency to bow.

 

Straightening Bent Planks

When you encounter a bowed plank, resist the urge to use a jointer, which will cause tear-out and waste valuable material. Instead, straighten the plank manually by bending it and clamping it to a bench top or straight plank overnight before resawing. If the plank isn't staying straight enough, you can use shims to create a slight reverse curve that will help maintain straightness during the resawing process.

 

Resawing with Band Saws

 

Band saws are strongly recommended over table saws for compressed wood work. Use a blade with 3 to 4 teeth per inch in the widest width that your saw will accommodate. A half-inch blade works very well and is often the only option available on most saws. Many woodworkers use half-inch blades frequently when it's inconvenient to change to something wider.

 

An underpowered band saw with a dull blade will struggle with 6-inch planks of hardwood, but most saws with new blades can manage the task effectively. If you find your saw cutting too slowly with the standard 3 to 4 teeth per inch blade, you might try switching to a 1 tooth per inch blade to speed up the cut, though this will require more sanding work afterward to clean up the rougher cut surface.

 

Storage and Timing Considerations

 

Keep your compressed wood in as large a plank as practical and wrapped in plastic until needed for bending. The ideal approach is to resaw just before bending, or at most within a day or two of when you plan to bend it. This timing is crucial because the wood's moisture content directly affects its flexibility.

Fine strips that have been resawn will begin drying fairly quickly, typically within a day or two. If you're not bending them the same day, wrap these strips with kitchen stretch wrap and return them to their original tube bag for storage. Thicker boards that are resawn to half an inch or more will keep for months when wrapped properly, but quarter-inch strips and thinner pieces dry much more rapidly, sometimes losing their maximum flexibility within just a few weeks even when well-wrapped.

 

Rehydration Techniques

 

For wood that hasn't been kiln dried, many users successfully rehydrate partially dried compressed wood by soaking it in warm water, which works particularly well for thin strips. You can also warm older compressed wood in a microwave to aid flexibility, but this requires careful attention. Use short intervals of 20 to 30 seconds at a time until you develop a feel for the process, as too much microwaving will dry and stiffen the wood, and excessive heat can even cause it to burn.

 

Planing Methods and Limitations

 

Traditional thickness planers and jointers are not successful with moist compressed wood and are not recommended for safety reasons. The wood will tear out badly and may create dangerous situations. Instead, rely on resawing techniques or abrasive planing methods. A coarse paper in a drum sander or wide-belt sander can effectively remove resaw marks from the surface.

 

Keep in mind that you typically wouldn't joint or straight-line a plank of compressed wood anyway, since it's destined to be bent rather than straightened. Even spiral planer heads don't perform acceptably on wet compressed wood. However, the wood does plane successfully if you work across the grain rather than with it. Hand planes used across the grain or at an angle to the grain can work quite well. The wood is remarkably soft in its moist state, making it as easy to carve as softwood.

 

Working with Routers

 

Compressed wood typically comes in S2S blanks in square and rectangular forms, but it cannot be routed while wet. Most standard routing techniques work effectively on the dry material, but by that point the wood has already been curved and becomes difficult to route anyway. The wood performs exceptionally well in dowel makers and on lathes because these machines cut around the circumference or across the grain rather than along the length with the grain, which provides insight into how the material responds to different shaping approaches.

 

If you plan to create molded profiles in the wood, the recommended sequence is to first resaw it, then sand it, bend it into shape, and finally do the detailed shaping work after it has dried in its new curved form.

 

Turning Compressed Wood

 

Cold bendable hardwood offers fascinating and rewarding possibilities for woodturners. Some innovative turners have developed techniques that involve partially drying the wood first so it can be glued, then gluing up assemblies, turning them on the lathe, and finally rehydrating the turned pieces by soaking them overnight before bending. This approach opens up unique possibilities since compressed hardwoods don't require backing straps during bending.

 

You can bend turned spindles, bowl sides, plate sides, and decorative elements like handles, spouts, vines, and leaves. When bending a turned spindle, remember that it will bend more readily at the thinner sections, so plan your design accordingly to take advantage of this characteristic.

 

Maintenance and Mold Considerations

Since the wood remains wrapped while wet, the moisture environment next to the wood surface may occasionally promote mold growth over time, particularly if oxygen is also present. Tight wrapping can help exclude oxygen and reduce this risk. Mold appears most commonly with maple and beech species.

It's important to understand that mold growth will not affect the wood's flexibility or working properties. If mold does appear, it can be easily removed through light surface sanding. This is simply a cosmetic issue that doesn't compromise the wood's performance characteristics or structural integrity.