Re-hydrating a dried-out instrument

[Steve Bliven]

The question came up on a bagpipe forum but seems to apply equally to flutes. Some thoughts from you folks with restoration experience would be greatly appreciated.

If you have a flute that hasn't been played for a long while, how do you go about re-hydrating it? How can you tell when it's "wet" enough to be ready for playing? How much do you play it during the initial stages? Do you oil a dry instrument or do you wait until it's re-hydrated (which leads back to the previous question)? Any additional thoughts?

And, most importantly, is there already a thread on this that my search missed?

Thanks and best wishes.

Steve

[MikeS]

Good advice here from Rod Cameron:

http://www.gruk.net/lars/rodflutecare.html

Rod says, "Remember that a flute which has remained un-played and allowed to dry out needs to be played in again just like a new flute!!" Follow the break-in schedule on the sheet and you should be fine.

[Sillydill]

Hey Steve,

When you receive a parched flute, it is an opportunity!

Now is the time to make repairs...mend cracks, glue rings.... The wood will absorb oil like never before.

When you put the flute in a humidor, it will start to expand and seal its wounds. If they are already mended all the better, puts force upon them to keep them closed.

2 or 3 days in the humidor will work wonders, then start to play it in like a new wooden flute.

Good luck and Enjoy!

[Terry McGee]

Steve, if you happen to have a set of scales with fine enough resolution (eg 1gm or ideally better), do measure its weight at various stages, including for a while after its gone into service. Its on my agenda to do, but I'm still a bit overwhelmed to get on to it.

Terry

[Jon C.]

Steve, if you happen to have a set of scales with fine enough resolution (eg 1gm or ideally better), do measure its weight at various stages, including for a while after its gone into service. Its on my agenda to do, but I'm still a bit overwhelmed to get on to it.

Terry

That is a great idea Terry, I will have to try that, I have a nice triple beam scale that i use for casting, should work. I guess I would have to wait for the next Santa Ana wind climate to bring the humidity down to 5%...

[Terry McGee]

Argghh, a triple beam balance, you make me profoundly jealous. I have a great little digital jewellery scale that goes in the pocket and measures to 0.01gm resolution. Fabulously useful, but absolutely zero romance!

I should have expanded on what I said above. When we find an old flute that hasn't been played in yonks, it does feel dry and dessicated. But there is no reason I can think of that the wood in it is going to be out of equilibrium with the air humidity in its environment. Here's a typical table:

0% RH = 0% EMC
19 to 25% RH = 5% EMC
25 to 32% RH = 6% EMC
32 to 39% RH = 7% EMC
39 to 46% RH = 8% EMC
46 to 52% RH = 9% EMC
57% RH = 10% EMC
65% RH = 12% EMC
74% RH = 14% EMC
80% RH = 16% EMC
91% RH = 21% EMC

Where RH is Relative Humidity of the Air, and EMC is the equilibrium moisture content in the wood. So if your local indoor humidity is a nice comfortable 50%, and the flute has been unplayed but lying around in that environment for a month or more, we should expect its moisture content to be around 9%.

But what happens when we start playing this flute regularly? It soaks up some of the moisture when we play, and so gets heavier. In the gap between plays, it slowly releases that moisture back into the atmosphere, or at least the atmosphere inside the case, which will slow down the weight loss. But presumably it averages a higher moisture content than it did when it was just lying around. The question I'd like to be able to answer is, what is a typical value for that increased level (it's obviously going to depend on a lot of things including whether it's in a case, what the weather is like, how often you play and for how long). Secondary questions include does the flute play better with that extra water on board, and if so, can we work out why?

I do remember doing an experiment weighing my flute just before and after the weekly session, but then noticing it actually gained weight during the week between sessions! That turned out to be the fact that I stored the damp mop rag inside the case, and some of that moisture was finding its way back into the flute. A lot to think about here.

We also expect the flute to gain a bit of weight when oiled, but not much if it's blackwood!

Terry

[jemtheflute]

Yeah, contrary to some views here and pending objective data, I very much doubt that a cocus or grenadilla flute will actually truly absorb any significant amount of oil or that giving it an oil bath will achieve anything much. If it is dessicated, sure it will absorb water, and pre-oiling will affect that process, but how helpfully?

Ok, I live in moist old Wales, so the issue may be different here, but I have not experienced any significant problems in this aspect of restoring old flutes. I ususlly just clean them, surface oil them and play them in with moderate caution.

[Steve Bliven]

Thanks all for the input — and feel free to keep it coming.

As I mentioned to begin with, my questions were spawned from a bagpipe forum discussion regarding how to address long-dormant chanters and drones. Some of the discussion came from bellows pipers and so had little application to flutes, but mouth-blown pipes seem to have at least some issues in common with flutes (mostly blackwood, lots of moisture, questions/strong opinions about when to oil and with what, etc.)

It also happened that I recently got a new (to me) antique boxwood flute. I live near the ocean and our relative humidity is near 100% this time of year. I don't know when the flute was last oiled and what humidity it was used to in its previous home. So the questions of how long to allow the flute to acclimate to a (potentially) higher humidity and whether to immediately oil it or wait for it to adapt to the new humidity still stand.

Let me add that I continue to be impressed both by the assembled knowledge found on this Forum and the willingness to share what others might consider "trade secrets". For those of you who make your living—in whole or in part—from making and restoring flutes; sincere thanks for sharing. A special bow to Jon C. who has recently patiently endured and politely and clearly answered a barrage of questions from me.

Continuing thanks and best wishes.

Steve

[Steve Bliven]

[[Apologies for a duplicate message. My computer burped.]]

[Terry McGee]

Yeah, contrary to some views here and pending objective data, I very much doubt that a cocus or grenadilla flute will actually truly absorb any significant amount of oil or that giving it an oil bath will achieve anything much. If it is dessicated, sure it will absorb water, and pre-oiling will affect that process, but how helpfully?

Ok, I live in moist old Wales, so the issue may be different here, but I have not experienced any significant problems in this aspect of restoring old flutes. I ususlly just clean them, surface oil them and play them in with moderate caution.

I reported some results on this forum quite some years back on weight gain in new flutes of various timbers (that I was making) when oiled. Maybe Denny or some other internet-foraging super-hero could dig them up? Gidgee was one of the woods I think, so that might help. From memory, new blackwood hardly absorbed any, but the other wood types absorbed a few grammes. This was in a one-day oil bath. Second dunking, carried out a week or so later, absorbed considerably less, which is encouraging, as the water absorption rate is probably equally reduced.

What we can't know of course in the case of old flutes, is what their oiling history is. So weight gain in an oil bath might tell us something, especially if we got enough data. For example, if it soaked up a similar amount of oil to that I reported, would that tell us that the original oil has now lost its usefulness?

I wonder what happens in the very long term to "non-drying" oils like sweet almond soaked into wood. Does it stay there, finally polymerise, degrade to something useless, wash away, evaporate away, or what? Bring me a chemist!

Terry

[Terry McGee]

Wow, I found it myself. This seems to be the fullest listing of absorptions:

------------------------

Well, this one won't interest many people, as I think I'm the only maker who uses the Australian wood Gidgee. Gidgee is a very dense and fine timber from inland northern New South Wales. It's a legume, and a member of the Acacia family.

Flute is a 6 key Rudall Perfected model. Before oiling weighed 252.8, after 254.9, an increase of 2.1 grams. Allowing for the extra surface area of a 6-key compared to a keyless, it's probably 3 times more oil take-up than blackwood, and a bit less than cocus.

Adding it to our rough graph where one dash equals 0.5 gm, we see:

- Blackwood
--- Gidgee
---- Cocus
------ Mopani
------------- Cooktown Ironwood

Interesting to speculate on why Cooktown Ironwood is so different. My guess is that it alone grows in the presence of large amounts of available water (unusual in a dense timber). The others grow in very dry climates.

So, in the light of the current discussion, it would be interesting to see if an old cocusflute absorbed anything like 2gms of oil.

Terry

[Denny]

ya, if ya can guess a couple of the words and know the author it makes a short list to splunk.