Problem Solved
If you've got to have problems, then the best ones to have are the kind that solve themselves. Not long ago, I thought I'd created a mini-disaster when I started using some so-called "Perfect Glue" from Liquid Nails. I wasn't aware that it's a polyurethane glue, which as a rule I never use because it swells. The result was that the stone abutment for the wooden truss bridge separated from the retaining wall:
My good fortune was to simply leave it alone and go about working on other things, with the intent of coming back to it at some future point armed perhaps with a good idea on how to correct it—I needed a really good idea, because in spite of its fatal flaw, polyurethane glue is really tough stuff. But I didn't need any good ideas; evidently the glue had some sort of chemical reaction with the plastic casting, and it slowly turned to useless rubbery gunk. I was able to pull the abutment away with ease, and I had only to strip the remaining mess from the retaining wall to get back to Point A.
Once things were cleaned up, I re-installed the abutment with Loctite PowerGrab, which is a caulk-like adhesive I've used extensively for layout construction. And so the mystery remains why I didn't use it in the first place! No matter; what counts is that the abutment is back where it belongs, fitting snugly against the retaining wall. And all is right with the world... tonight.
