Tailpiece repair

[snakehips]

The lab had never worked on guitars before, unsurpisingly, nor nickel-plated brass, so although in theory their laser-welder should work, they didn’t want to promise how much cosmetic damage there might be.

I had a broken NRP tailpiece - so I let them try it on that on first, ha ha !!!

Something slipped or something, so they lost a bit nickel-plating further away from the 90 degree edge, on the NRP tailpiece, but even that isn’t too bad - see photo.
Photos of the silicone putty index/impression/jig formers with an unbroken vintage tailpiece, and the tailpiece on the putty.
Photo of just the putty shows the tiny scorch marks - really not much collateral heat/damage.

[snakehips]

Sorry, I was struggling to post the photos for some reason.

Attachments:

[davey]

Thanks for the replies, folks. There's a chance that I won't be acquiring the Mandolin after all, I spotted a number of other problems including a nasty area of burn under the pick guard where the Cellulose has damaged the plating.

I'd like to have it as I like a restoration job but the plating is not fixable as it's a style O with patterns on.

The other problem with resonator Mandolins old and new is the lack of space between the coverplate and strings. The neck has to be set perfectly otherwise your pick is hitting the coverplate all the time. I keep buying them though.

Cheers, Davey

[charliechitlins]

Silver solder can be surprisingly strong, and the heat is much lower that brazing and MUCH lower than conventional welding.
I would give silver solder a try...underneath where the plating could be removed...not much sticks well to chromium.
Braze (bronze) would work.
Some heat sink putty would reduce collateral damage.
As stated...both of these act like glue.
Welding actually melts the metal into a puddle that runs together. The rod is called "filler rod". It builds up the area where the metals run together.
Some welds are done without it.
I'm not sure about lazer, but electron beam is done without filler.

[snakehips]

Hi again,

Laser welding heats the actual metal you want to join, in VERY small hot spots (one at a time, in an instant).
There is no solder or filler metal, unless you need it BUT it all forms one continuous piece of metal again, rather than having a glue/silder material between the broken ends. While soldering might be perfectly strong enough for joining metal guitar bodies together, I doubt a solder joint, on 2” long is gonna hold under full string tension for long

[pete1951]

Soft solder would, as snakehips suggests , not be strong enough on a but joint, if an angled plate could be soldered underneath you might get away with it. Silver solder is much stronger and might well bridge the gap, as would brazing, but the area around the repair would discolour with the heat. Looks like the laser is the way to go.
Pete

The mandolin tailpiece has a raised area that could have an angled plate hidden under in,
As Davey is no longer getting the mandolin we may never know.