Has anyone on the board had any experience of using P.E.G (polyethylene glycol) treatments for stabilising wood, and its effect on tonal properties?
Not too much talk about it here…
David Daye’s e-mail based message board (Heanet) has extensive discussions about PEG, especially with reed treatments.
Geoff Wooff talked with his wood merchant about it once. The man said the ebony would desintegrate in time, it was not a good idea.
I was interested in this very subject for pipe building. I knew that gun smiths use Polyethlyene glycol (PEG)s to stabilize wood (typically walnut) for stocks on high-end target rifles. A friend of mine has two guns made this way for biathlon (cross-country skiing, that is). What PEG treatment does is stabilize the green wood and prevent dimensional change do to water loss after treatment. The PEG polymer permanantly replaces water in the wood. Therefore, the treated wood does not undergo dimensional changes like untreated wood do to water absorbtion and loss from seasonal changes in humidity, or spilt Guiness and what not. There is a very good treatise on the subject in a book called ‘Understanding Wood’ by Bruce Hoadley. I can get you the ISBN # if you like. It is a fantastic and thorough reference book in general, but he also deals with PEG stabilization, it’s uses and limits.
I found that there are a few reasons why this method is impractical for pipe building. First, one needs to treat freshly cut wood - once the wood is dry beyond fiber saturation point (~30% water in most species) it has already suffered from dimensional strain (whether it shows or not) do to water loss and PEG treatment will do nothing to reverse it. So if you are not in Tanzania when they cut that Blackwood you’re out of luck. Second, PEG is mostly adsorbed through end grain, and then only an inch or two in depth. Since you need a billet of wood 14.25 inches long for a D chanter (measured end-grain to end-grain) you would not get very effective or uniform penetraion of the PEG into the wood before you pilot bore and ream the blank. Also, PEG is not supposed to penetrate most tropical woods very well because of their density and the amount and constitution of the extractives in the heart wood. Finally, the PEG at the surface of the wood is hygroscopic (binds water) and it is said that it can make the wood feel slimy on humid days (yuk!).
As a side note, I have treated dried Ebony blocks with WD-40 and it readily wicks through the wood along the vasculature for quite a distance. I do this to make lubricated guide blocks for my bandsaw blades. So it might be possible to at least permeate seasoned wood with something that could possibley stabilize it when it is being worked down, like polymerizing glue or somethig, I don’t know.
Well, hope some of this helps.
~John.
It certainly does! Thanks for the input (and Peter Laban), I think i’m fairly certain now that it’s not the greatest idea for Uilleann pipes/chanters.
Oh well, there’s no harm in asking… 