Sunday, November 28, 2010

Why Hide?

So what's the big deal about hide glue?  Why is it so important in instrument repair?  It's an old glue.  Isn't super glue or gorilla glue or epoxy stronger and/or better?  These are really important questions, and they deserve a good answer.

First of all, what is hide glue?  Hide glue is an animal glue.  It is actually made from the hide of an animal.  There are two different forms that one can buy it in.  It comes in a liquid form in a bottle, and it comes in granules that can be mixed in a pot with water and heated.  Is there a difference?  Yes!  A BIG difference! 

The bottled hide glue seems so convenient and is easier to find.  The problem with it is that the ingredient that keeps it in a liquid form also weakens the bond, so this type of glue is not good for most instrument repairs.  It simply isn't strong enough. 

When it comes to the granulized hide glue, there are also several different types you can get.  International Violin sells to the general public at very good prices, and they have several different types available with descriptions of them.  For instance, you can get fast tack, slow tack, and even rabbit hide glue, which is actually the strongest of the hide glues they offer.  It is excellent for violin neck repairs because of its high strength.

What about epoxy, super glue, gorilla glue, wood carpenter's glue, or any other of the super strong glues out there?  What's wrong with using them?  When it comes to instrument repair, especially violins, these instruments are made to come apart so that repairs can be made to the inside of the instrument.  Usually, hide glue is actually stronger and holds better than these other glues.  The main reason why is that it does not shrink or expand as it dries.  Even better than that is if you heat it, you can break the bond.  That is really important because it allows the luthier to take the instrument apart to make repairs to it without harming the instrument itself.  So if you do get that epoxy or other strong glue to hold tight, and a repair is needed that requires the instrument or part of the instrument to be disassembled, it's really a problem!  Damage to the instrument is possible because the instrument ends up being weaker than the glue bond.  With hide glue, the opposite is true when it is heated. 

This is also why you don't want to leave your instrument in a hot car.  Imagine what could happen to a violin when it is stored in the trunk or back seat of a hot car, or in a hot attic for years!  The good news?  It CAN be put back together again.  So don't throw away that old violin that's been in your attic for years and is now in pieces.   And if you decide to put it back together again yourself, imagine how everyone will look up to you when you tell them why you used hide glue!

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