Using glycerin to cure loose screw holes

[JimmyM]

A guy on alt.guitar.bass recommended using glycerin to cause stripped out screw holes to swell and tighten up. I've been playing for 30 years and never heard of this before. Has anyone else? I would like to hear mostly from luthiers and manufacturers, but anyone who knows anything about glycerin, please chime in.

[lemur821]

I can't see how it would be better than sticking a toothpick in the hole.

[Nick Ioannucci]

youre better off putting the tip of a toothpick and some wood glue in the hole.

[Anesthesia]

glue some more wood like a toothpick in thats a tried and true method

[Hambone]

Originally Posted by JimmyM

A guy on alt.guitar.bass recommended using glycerin to cause stripped out screw holes to swell and tighten up. I've been playing for 30 years and never heard of this before. Has anyone else? I would like to hear mostly from luthiers and manufacturers, but anyone who knows anything about glycerin, please chime in.

Now that's an interesting one. The only thing I know about glycerin is that it's sometimes used to make semi-liquids smooth. I think that's why you'll see it in cosmetics and lotions. Maybe there's something about that characteristic that lets it soak in or something. You know - surface tension and all that.

[pkr2]

Glycerine is a form of glycol that is derived from vegetable matter. It's non-poisonous. Ethylene glycol (automotive anti-freeze)and propylene glycol, both forms of glycerine, along with glycerine has been used for a good while to keep lumber from checking and splitting as it dries. It's also used to soften warped veneers to flatten them. Ethylene glycol has been pretty much abandoned because of its toxicity.

It works by slowing the evaporation rate of the moisture in wood.

It doesn't maintain that moisture indefinitely, however. If it were used to swell the wood, in turn decreasing the size of the screw hole, it's effect would only be temporary untill the wood restabilizes.

I've never attempted to use it to refurbish a stripped screw hole, but it doesn't seem that it would work very well for that purpose. It's so easy to plug a screw hole that I don't see any advantage in its use.

[JimmyM]

Yeah, I'm a toothpick/Elmer's guy my own self. But this guy on AGB swears by it, so I thought I would run it across you guys to see what you thought. I would never trust a screw hole that was stripped and revitalized by glycerine. When it gets stripped, you need to add wood, not soften it with liquid. But I always give people the benefit of the doubt when they come up with something I never heard of. That'll learn me.

[BassChuck]

Glycerine used this way is an old trick of piano tuners. If the wood block on a piano used to hold the tuning pegs dries or splits then putting some glycerine to decrease the size of the hole works better (and cheaper) than fixing or replacing the tuning block.

How long it lasts probably depends on the density of the wood, but in the case of guitar repair I would imagine that a toothpick works far better.

[pkr2]

Originally Posted by BassChuck

Glycerine used this way is an old trick of piano tuners. If the wood block on a piano used to hold the tuning pegs dries or splits then putting some glycerine to decrease the size of the hole works better (and cheaper) than fixing or replacing the tuning block.

How long it lasts probably depends on the density of the wood, but in the case of guitar repair I would imagine that a toothpick works far better.

That's a good tidbit. I must be overlooking something (nothing new there) because it just seems that when the glycerin eventually dries out the hole would return to its original size.

Who's gonna be first to strip a screw in a piece of scrap and try it?

[joeyl]

you would be better off filling the hole with baking powder, drop some super glue in it, wait a little, add more baking powder, and more super glue, and wait for it to dry, then you can redrill or if you have some space, you can just tighten the screw back

[The Craw]

I've never heard of using glycerin but if there isn't an adhesive, I wouldn't regard it as permanent. Same thing with Chair-Loc. There is a product called Wonderlock'em you can buy at some hardware and home improvement stores, it swells the wood and has glue in it. But for anything critical like a strap button, I'd much rather use the toothpick and glue method.

[Zooberwerx]

Originally Posted by joeyl

you would be better off filling the hole with baking powder, drop some super glue in it, wait a little, add more baking powder, and more super glue, and wait for it to dry, then you can redrill or if you have some space, you can just tighten the screw back

Hey, I've heard of this. Supposed to work really well. I can understand the super glue but what's the purpose of the baking powder?

Riis

[Hambone]

Originally Posted by Zooberwerx

Hey, I've heard of this. Supposed to work really well. I can understand the super glue but what's the purpose of the baking powder?

Riis

The powder and CA mixture makes a quasi-plastic material that has good body and can be worked with hand tools. Lots of guys use this to build up nut slots that have gotten too deep.

[joeyl]

Originally Posted by Hambone

The powder and CA mixture makes a quasi-plastic material that has good body and can be worked with hand tools. Lots of guys use this to build up nut slots that have gotten too deep.

I got that trick from the Dan Erlewine book, good book but very oriented towards guitars and acoustic guitars

[Zooberwerx]

Originally Posted by Hambone

The powder and CA mixture makes a quasi-plastic material that has good body and can be worked with hand tools. Lots of guys use this to build up nut slots that have gotten too deep.

Hmmm...that gives me an idea. All we need is bucketloads of superglue, baking powder, and some molds to create a cost-effective alternative to graphite composites.

Ah, never mind....Ibanez has already done it.

Riis