Tips for gluing hard to reach Brace

[Matt Haugen]

I just picked up an old Regal parlor that is missing the furthest back back brace. I made a brace and it is ready to go in, but I am having trouble figuring a good way to put pressure on the brace once it is in place. I know about the stew mac scissor clamp, (I have a story about this below) but that sure is a lot of money. I then thought I would try coiling up some thin metal, holding it tight in a coil and then letting it unravel inside of the body over the brace. I figure the pressure of the metal unraveling would push the brace tight against the back of the guitar. Anyways, I just wanted to post this to see how others go about gluing braces back down on a guitar repair.

The side note I wanted to post is that a while back I was gluing a brace and I came up with a drawing of a small jack, like a scaled down car jack. I told my wife that this would be a great tool for gluing braces inside of guitars. One of the ideas that she actually liked. Anyways, I did nothing about it and about a month after I showed her this drawing I received a catalog from Stew Mac with their scissor jack on the cover. Funny how things like that happen.

Anyways, any thoughts or processes are welcome. Thank you all.

[Mark Pollock]

I've clipped the ends off of small turnbuckles, and then made cauls that fit on the ends. These fit inside the guitar and can put plenty of pressure on any brace - enough to bust the guitar wide open. Thus, I also clamp some semi-flexible scrap around BOTH front and back of the guitar to provide plenty of solid support. I'll also put a piece of strong scrap on the other side of the inside of the guitar to make a sturdy base for the turnbuckles to press against.

No matter what you do, this is going to take plenty of prep time to get it right. All this repair work would be so much more fun if we didn't spend 90% of our time cleaning, sharpening, finding, prepping, making jigs, or cussin'.

[Matt Haugen]

Thank you Mark, that sounds like a great idea, I am going to give those turnbuckles a try.

[Mark Pollock]

Found a picture of a glue-up I did for some tough braces on a Goya G-10. Pretty dang crude, but it worked.

[Russell Vance]

I recall from my reading years ago and I cannot attribute it due to CRAFT (can't remember a freaking thing) syndrome -  a tennis ball squashed up and allowed to release between the brace and the adjacent top or brace also provides a simple fix for those skinny semi-hollows and electro-acoustics where space ain't. Don't laugh, I've used it - Maria Sharapova (sigh) would be proud of me.  Rusty.

[Matt Haugen]

Thank you Russell. I weighed my options and ended up going with the tennis ball. The back was a bit wavy and the ball, along with a shim gave the necessary pressure to force a nice tight glue joint.  Best to you.

[Bart van Weperen]

Hi Marc!

 

I'd give it a try using magnet-clamping power. Just make sure you get the brace where you want it and do take care not to damage the finish. You could make magnet fixtures like Frank did ( http://www.frets.com/FretsPages/Luthier/HighTechDept/Magnets/MagPlu... ).

Use 3 to 4 magnet-pairs, depending on the length of that brace.

[Paul Breen]

I have been using magnets for this, mounted to very thin plywood with a fulcrum point.

If more than one of these fixtures is to be used side by side, the magnets must be configured so that they repel the stack next door. Figure this out before hand and have them laid out, ready to go in the correct order, so there is no confusion or mistakes when you start applying them.

They are placed one at a time and anchored with a magnet stack on the outside of the instrument protected with a scrap of leather.

My hands and arms can get inside to place and hols the fixture while I place the outside magnet stack and I can usually reach the furthest in braces.

These are powerful magnets and can do a lot of damage if they get away from you! Practice applying the magnet fixtures on a thin scrap of wood before trying this on an instrument (strongly recommended). Clear your bench of anything that can be attracted by the magnets. Work slow, deliberately and keep a firm grip on the outside magnet stack when you apply it.

I mostly use original Tightbond for brace repairs with the magnets. I have more open time with it and don't feel compelled to rush getting the magnets in place. I use a glue injector that I bought from Stewart MacDonald's modified with some flexible and rigid tubing, the needle wedge fits on the tubing. I have palette knives ready to go as well.

Here you can see the squeeze out, a good indicator that you have it glued well.

Clean up is done with a bit of cloth on palette tools and hot water.

This has worked well for me but there is some risk with this process. It is easy for me to understand why Frank Ford went through the trouble and effort to create a fixture to reduce the risk of a flying magnet!

[Ned Knepp]

That's Brilliant, Paul!

[Eric Steven Johansen]

I am impressed. Instructive, informative and well written, this is a great post. I've used these magnets for glueing cleats for years but the pivot fixture is brilliant. Question, did you glue the stacks of magnets together and with what? 

[Paul Breen]

Thanks Ned and Eric!

Eric, the magnets are stuck to the plywood with double stick carpet tape. They stick to themselves with their own magnetic power, no glue needed between them. Each magnet that is added increases the magnetic pull of the stack. These are 1" X 1/8" discs and a stack of four of these seemed to adequate for the task but more could be added if necessary to increase pull.

Keep in mind though, increased magnetic pull also increases risk of accidental damage if something goes wrong and magnets start flying. I spent some time practicing with these before using them on an instrument. A stack of four magnets can double itself in the blink of an eye. Please take the time to become familiar with them and keep all attractable objects well away when using them.

[Kerry Krishna]

Brilliant is exactly the right word!  Paul, I am totally blown away by that ingenuity of yours!

[Eric Steven Johansen]

Paul, I was thinking about flying magnets thats why I thought you had glued them together. The first set of these I bought slid across my bench at each other and exploded on contact. Amazingly strong in a pair and I presume incredibly so in a stack of four.