The Ultimate Glue Revisited (Again)
The right wood glue for your wood aircraft
Michael C. “Mick” Myal, EAA 7978, firstname.lastname@example.org
Michael C. “Mick” Myal
The 1960s were good times for homebuilders. A wide variety of wood and tube airplane plans were available with most needing wood wings. Weldwood plastic resin glue, Weldwood Resorcinol, and Aerolite (urea-formaldehyde) were the principal glue choices for wood structures. At the time, I was strongly considering building either a Minicab design or an Emeraude, with the Minicab ultimately winning out because of its record-setting performance. I was using Resorcinol but quickly learned of its weak points. My search for a replacement brought me to 3M’s 2216 B/A, a two-part epoxy paste that was designed for metal, but ultimately led me to work done by Forest Products Laboratory. My simple modification of its FPL 16A formula was the solution to penetration.
FPL 16A, sold under the name of Hughes Glue, is available exclusively from Aircraft Spruce and Specialty Co. It’s sourced from a small formulator at about 12 gallons per year. The once-specified toxic curing agent diethylenetriamine (DETA) has been replaced with a benign substitute. Many builders vouch for its gap-filling and penetration characteristics. Two cautions are in order: 1) Stir epoxy well before using, and 2) take care when mixing small batches. (10:1 ratio or 11 drops to a teaspoon of resin is about the smallest batch I could mix successfully.) Although it’s promoted as being suitable for many other materials, I can’t recommend it for anything but wood-to-wood bonding, without specific testing.
To read Mick’s original October 1967 article, click the link below: