Fixing a cracked guitar tailblock with the Scissor Jack

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Issue 277 January 12, 2017

A hard knock on a strap button will crack an acoustic guitar’s tailblock. Alex Whitman at TR Crandall Guitars in New York City shows a clever way to close that crack for gluing! Dan Erlewine collected this Trade Secret at their repair shop.

In this Trade Secrets video:
  • Dan Erlewine visits a great guitar shop in NYC
  • New use for a Scissor Jack: horizontal pressure instead of vertical
  • Alex Whitman’s idea uses dowels and repair magnets

Video Transcription

[on-screen text reads: Fixing a cracked guitar tailblock - StewMac]

Dan Erlewine: Hey. Hi, I'm here at T.R. Crandall Guitars in New York City, which is a wild, beautiful vintage guitar shop with a killer shop in the basement. Tom Crandall is a repairman here, along with his partner Alex Whitman. Coming up the stairs I run into these two killer guitar players here, one of which I saw at an Asia convention 20 years ago when he was nine years old, and that's Julian Lage, and his friend Armand Hirsch.

[Julian and Armand start playing acoustic guitar music in the background]

Alex Whitman: Hi, I'm Alex from T.R. Crandall Guitars in New York City. Here we have a guitar with a tough problem that could be tricky to repair, a cracked tailblock. It can be very difficult to reach your hand in and apply pressure to line the crack up properly.

Creating horizontal pressure with the Scissor Jack

Sometimes we got to make a little more room to work [Alex rips the top of the guitar off with his hands]. In most cases it's inappropriate to rip the top off a guitar in order to work better inside of it. This happened to be a donor guitar that makes a perfect demonstration. So what we've done is come up with a way to use the StewMac Scissor Jack and extend its reach by using a dowel on each end to apply pressure to the tailblock and head block.

So first we take a dowel and just put a finish nail on the end to help line it up through the hole for the end pin, and then we take a magnet and a fix it to one end of the dowel. This just helps line it up when we're working through the soundhole. Then we take a second dowel to line up with the head block, and using the Scissor Jack we can apply just the right amount of pressure in order to line up the crack in the tailblock, then get it perfectly in register to glue it nicely and make for a very clean and near invisible repair. So using the Scissor Jack has made a tricky repair much simpler and leaves us with clean results that keep us and our customers very happy.



Alex Whitman

Guitar Builder and Repairman

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