23 replies to this topic

[Chris Ghent]

If anyone is replacing valves that have been glued on using PVA, here's how to do it.

Pull the old valve off and put a drop of new pva on top of the old PVA. Stir the new PVA gently with a small screwdriver. Very soon you will find you are stirring the old PVA as well and you can scrape the whole lot off leaving the wood clean.

Caveat: there are a lot of different sorts of PVA, I have tried this with only one, Selleys Aquadhere.

[Steve_freereeder]

I've found this Staples liquid glue very good for attaching valves. I think it may be gum arabic based. Just don't try to apply it with the glue pen it come in!

Since Gloy Gum has disappeared, the only other alternative that I know of is the gum arabic crystals. You can get them from the wicca sites, just dont put a hex on the concertina, although the are already hex-agonal, or at least most are. (sorry)

Dave

You can also obtain Gum Arabic from artists' suppliers, e.g. Winsor and Newton:
http://www.winsornewton.com/products/oils-solvents-mediums-varnishes/water-colour-mediums/gum-arabic/

[jrintaha]

I've found this Staples liquid glue very good for attaching valves. I think it may be gum arabic based. Just don't try to apply it with the glue pen it come in!

Since Gloy Gum has disappeared, the only other alternative that I know of is the gum arabic crystals. You can get them from the wicca sites, just dont put a hex on the concertina, although the are already hex-agonal, or at least most are. (sorry)

Dave

You can also obtain Gum Arabic from artists' suppliers, e.g. Winsor and Newton:
http://www.winsornewton.com/products/oils-solvents-mediums-varnishes/water-colour-mediums/gum-arabic/

Do you know how well Gum Arabic holds to metal? Does it "string" easily? Shellac strings a bit, which is somewhat annoying when trying to finish a big block of accordion reeds fast. Might try buying a bag of gum pearls, make my own mix and see how it feels. I'm guessing the watercolor thinner solutions are too thin to be used as glue, and you'd have to let them dry a bit first. Also I'm a bit concerned about the shelf life of such solutions, as I think they're mixed with glycerine, and at least shellac goes bad pretty quickly after it's mixed with alcohol.

Cheers,
Jori

PS. Do not ever ever ever try using burnt shellac as a valve glue, unless you've somehow discovered a magical leather that will never have to be replaced again. I once tested burning shellac in a teaspoon (I think it was one of Pietro Deiro's accordion handbooks or some such old manuscript that suggested it) to see how well it would stick to metal. Well, after scraping it first with my fingernails and then with a knife, and after 20 or so rounds in the washing machine, the spoon is still coated with burnt shellac. Holds just a bit too well!

[Frank Edgley]

I have found that school glue, in stick form works well. It hold the valve securely, is easy and not messy to apply using a toothpick, and easily scrapes off. It is also easy to get and inexpensive. White glue is not a good idea.

[apprenticeOF]

Was shellac or gum arabic originally used? The few I've worked on I thought appeared to be hide glue. So I used liquid hide glue when replacing the valves.

Where I ran into PVA on previous replacements, I used a very sharp 1/4" chisel AS A SCRAPER (NOT as a chisel) and removed it fairly easily, leaving just a thin "slick" and not removing any wood. More work than when removing originals, but with care and a steady hand seemed to work ok.

Any comments on these practices?

Thanks

Doug

[malcolmbebb]

You can also obtain Gum Arabic from artists' suppliers, e.g. Winsor and Newton:
http://www.winsornewton.com/products/oils-solvents-mediums-varnishes/water-colour-mediums/gum-arabic/

Just search on Ebay - lots of sellers.