SIG Basswood
Easy to cut and easy to sand, basswood is ideal for many hobby and craft projects. Ideal for wing spars, longerons, and numerous other model airplane parts where additional strength is needed. Basswood is the wood of choice for wood carvers.
Spruce vs. Basswood

For decades, model airplane builders have used spruce for many structural parts where high strength with moderate weight is required. No doubt the use of spruce in model airplanes dates back to its use in full-scale airplane construction all the way back to World War I. Over the years many modelers have discovered that basswood has almost identical strength and weight characteristics to spruce, and thus makes a perfectly adequate substitute at a lower price. Here are the facts.

. lbs/cu.ft. bend/elastic limit max. crush shear strength
Spruce 27 6200 5000 750
Basswood 26 5600 4500 720

As outlined in the chart above, there is not a dramatic difference in strength between spruce and basswood. Pound for pound, the difference is minimal. Also, basswood is more uniform in grain than spruce. It remains perfectly straight and true when cut and provides light, strong structures. Consequently, we recommend basswood over spruce for almost all model airplane applications.

Another important point is that basswood contains less pitch (sap) than spruce. This makes it much more favorable for CA type glues as well as slower curing epoxies and aliphatic resin glues like Sig Bond. Spruce is not "CA friendly". While it is true spruce is a tiny bit stronger, basswood is lighter and much easier to work with. It will permit you to build faster and because it contains less pitch than spruce, glue joints will be stronger.