Official Luthiers Forum!

It is my opinion that follow up threads are very important to keeping forums fresh and up to date, so in that spirit I would like to update my experiences with LMI glue and the bridge on my first kit guitar.

Bridge Moved

I think the 'first' part of the story should give a decent clue as to the reasons for the failure of my first bridge - it moved after about 3 weeks - slid 1/16 to 3/32 of an inch and was probably about to let go. This thread also began a bit of a discussion about the LMI product and I would like to report that after re-gluing the bridge is holding fine, and so is my faith in the LMI white glue.

The previous thread also began a disussion about the LMI product an I would like to report that in this case the failure was almost certainly user error (yeah I know, you already knew that). I rushed the clean-up and most likely left some finish residue, I might not have left it clamped long enough, though memory doesn't serve that well.

In my second attempt I roughened the surfaces, which I have since learned is not a good practice, but there was defintely no finish residue left, and I left it clamped for 48 hrs. and so far so good.

Just an FYI

LarryLarryH38746.4188888889

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Thank You and Best To All

Since that thread that spoke of some glue failures, I did some unscientific testing on some back and top center seam glue joints:

I had a pile of at least 20 cutouts of tops and backs leftovers. These were all glued with LMI within the last year or so. The pieces from the tops were cut-up into back reinforcement strips for backs. While I was making these, some little pieces of spruce (many types) were left over. The least amount of material (due to the guitar shape) was at the center glue line. With these scraps, I then flexed them till they broke being careful to try to keep the glue joint dead center. NONE of them broke along the glue line. I played around with simular tests with back material too. None of those failed along the glue seam. Cedar and redwood too. No breaks along the glue line I even did a pull test on a smaller section. That did not fail on the glue seam either.

Also in the past couple of weeks I processed a bunch of backs. I still use a chisel to cut out the channel for the braces to pass through the back reinforcement strip. None of back reinforcement strip glue joints failed, in fact when one of my chisels was a little dull (I know, I know) and I was lifting the spruce strip instead of slicing (more so lifting than cutting because of the dull chisel), some of the walnut back materila came off with the spruce.

Like I said, it was very unscientific testing so I only place this response here as information only. No conclusions.

Thanks a lot for the follow up.

Yeah, it's definetly unscientific but important IMHO, to report the successes as well as the rumored, and some documented, very real failures.

It's easy to wreck a reputation of a glue or even a company by posting just a thread about a bridge that came unglued due to user error.

Wanted to set the record straight.

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Thank You and Best To All

I always test cut offs from tops and backs - put a thumbnail on each side of the joint and try to break it - but I've never had a joint break with LMI glue.

              Paul Harrell