Terminology: Glueglo

A 1971 4001 with severe Glueglo

Glueglo. What is it, what caused it, and when did it happen? Let’s see if we can answer those questions quickly, but with a little more depth than you usually get. Here we go.

So what is Glueglo? It’s a term collectors use for guitars where the black colorant from the checkered binding has bled into the surrounding wood, creating inconsistent dark ring around the edges of the body—most commonly seen on Mapleglo guitars.

So “glue”, because it was caused by an interaction between the binding and adhesive process, and “-glo” because that dark ring is similar to the sunburst effect found in “Fireglo” and “Autumnglo”.

All guitars made during the Glueglo era are potentially susceptible to it, but it’s obviously most visible on Mapleglo guitars since there is no dark finish to hide it. If you look closely, though, you can sometimes spot it on Fireglo guitars—and occasionally even Burgundy.

So when was the Glueglo era? Online you’ll read that it was a “fairly brief period”, but examples on the Rickenbacker Register appear from at least January 1971 through November 1972—and there may be examples on either end of that range as well. So “fairly brief” is relative.

So what actually caused it? A change in the binding process.

Here’s the important thing to understand: acetone is commonly used when applying binding because it softens—and effectively melts—the binding material. In fact, if you drop a small piece of binding into acetone it will eventually completely dissolve. Applying acetone to one side of the binding allows it to “melt” and fuse with the wood as it dries.

Many builders use acetone alone to durably attach binding to a guitar. Others use a paste made from acetone with dissolved binding material. Rickenbacker used the paste method before and after the Glueglo era. During the Glueglo period, however, they changed to using straight acetone alone. Given the other cost reduction efforts going on at the time, cost was likely the driver for the change.

Unfortunately, it appears that straight acetone proved to be too aggressive for the black colorant in the inner checkered binding. Over time, the colorant leached into the surrounding maple—and voilà: Glueglo.

The effect didn’t appear overnight. It took time for the discoloration to show up on finished instrument and for the process to be changed back. But eventually it was.

At this point, the discoloration is as bad as it’s ever going to get, and the issue is cosmetic only. Structurally there is nothing wrong with either the binding or the body wood. The severity can vary quite a bit—from barely noticeable to extremely dramatic—and not every Mapleglo guitar from this era is afflicted.

If your guitar from this period isn’t Mapleglo, this is probably a non-issue. But don’t assume you can strip and refinish one as a Mapleglo. Sand it down and you may get a very unwelcome surprise.

And that’s Glueglo.

A 360 with Glueglo on the back

Look closely and you’ll see the Glueglo on this Fireglo 1972 4001