MIMF

So in construction of a few large-body acoustic bass guitars, I have run into the normal hide glue problem: lack of working time when gluing the top and back to the sides.

A fellow builder asked me, "Well, how do they do it on upright basses and cellos?"

And I have no idea. Would someone mind enlightening me? Thanks in advance.

The most usual method is to dry clamp everything, so that you get the alignment, and then remove them a section at a time to put in the glue. Jim Ham uses a neat variation on this. He sizes everything on both sides with plenty of hot hide glue, and allows it to dry. Then, after dry clamping, he uses steam to reactive the glue in sections. This allows him to clean up the excess glue before clamping things together, avoiding the runs and drips one often sees inside old instruments.

There was an article in AL a year or so ago that documented Mr. Ham's procedure.

See http://www.luth.org/back_issue/al109-112/al109.html

(Fish glue!)

When I glue up my archtops I use alignment pins on the top and back. With two pins ( small dia. wood dowels ) you can quickly locate the plate. Then use a clamping caul to speed the clamping process. The whole thing takes less than a minute. The pins are useful during construction also. I put one under the neck and one under the tailpiece. For a flattop the detent to accept the pin would have to be shallow at the tail block. Be sure not to drill to deep.

Having read the Ham article, I tried the steam method on my last build, and found a few issues.
The first time, the steam didn't penetrate fully enough, and the glue only reactivated along the very edge. The top quickly separated, so I removed it, cleaned off the glue, and tried again.
The second time, I steamed it longer to get better penetration, and this produced some very ugly markings on the spruce top. I was using distilled water, so I don't think that was the problem.

So if anyone's tried this and figured out the best way to do it, I'd love some feedback.