Effects of thread wrapping, Series 2:

A Plan



In our previous article, we developed some theories about what the bore should look like, and we think that the reconstituted tenons would still fit in the sockets at each end.  So how do we go about reconstituting?  Is there a plan?  Not just one, as it turns out...

Plan A

Plan A is that I should subject it to some normal playing, to see if, freed from its tenon wrapping constrictions, we might see it starting to move spontaneously towards one of the shapes we predicted in the previous articles.  I must say, given the degree of compression, and the time over which it has been built up, I'm not expecting miracles.

Plan B

If we see no sign of movement, we could try some deep humidity cycling to emulate the passage of the years. But not attempt to steam and reform it as I did with the two strangled flutes. The test would be aimed at finding out whether just removing the constriction is enough, if given time and seasonal variation (either in real-time or accelerated). If that doesn't work, it won't prevent me from following the steaming and reforming approach later. 

Plan C

If Plans A or B show no promise, I might ramp it up a bit by simulating the accumulated effects of much longer playing over a lot of time.  We found in the test tenon case, that applying a damp rag to the inside of the bore was a very efficient way of injecting moisture.  It's also interesting to speculate on the difference between presenting moisture inside and out, as the weather does, and just from the inside, as playing does.  One can imagine in the playing model that a wave of moisture propagates outwards through the instrument wall followed by a wave of dryness.  Whether this one-way propagation is enough to produce a different outcome is something we'd need to discover.

Plan D

Plan D, involving steam, might be resorted to if previous plans didn't produce enough movement.  I steamed the original boxwood strangled flute in the pressure cooker to make it limber enough to straighten out.  It might seem violent, but there is precedent.  Timber that has "collapsed" during kiln drying is sometimes recovered by steaming for about 6 hours.  Since cell collapse is a definite possibility in this case, this approach seems not inappropriate. 

Plan E

Plan E, might involve a "keeper".  Moisten the flute by one of the methods outlined above and, while it's swollen, introduce a keeper, tapered to the desired bore shape.  Allow the wood to dry out, and the keeper should prevent it from assuming its old collapsed state.  Repeat, gradually insert the keeper a little more each time, as hopefully it eases the bore back into the desired shape. 

Making the keeper of course requires making a decision between the various bore shape scenarios we talked about previously.  One could perhaps start with the most conservative, and if successful, then aim for a more ambitious target.  If I were going for a conservative scenario, like "fix the tenons" or "two slopes", I think this could be achieved in one treatment.  But, if I was holding out for something bolder, this might require a series of treatments.

We have to recognise that, by adopting the use of the keeper, we are abandoning hopes for miraculous self-cure.  But not quite abandoning hope for home or low-tech therapy - the keeper could be something as crude as a hand-whittled dowel.  You might cringe and say, but what about the precision of the bore?  Well, it could hardly be less precise than it currently is, could it?!

There are interesting practical issues in regards to use of a keeper.  Once the flute body has dried and tried to shrink onto the keeper, will I be able to get it out?  Hopefully, being tapered, it should just tap out.  Remind me about that word "just" a little later - I'll be the one wielding the sledge hammer!  Secondly, the keeper may only be needed in the areas under the thread wrap.  If compression caused by the wrap caused distortion to propagate through the section, presumably expansion in the same area will also propagate.  A sub-plot to be investigated.

Plan F

We're getting close to an "if all else fails" scenario by the time we get to Plan F.  We know from the experience with the cocus strangled flute that a "steam-bending" approach will straighten out even a thoroughly collapsed tenon back to the "fix the tenons" scenario.  But I don't think it will be enough to enable the bolder approaches - the body wood is probably a bit thick to bend much in a short time, even with steam to help.  Still, the flute has got to play better without those crumpled tenons!

Plan Z

If we can't at least correct the distortion in the tenons back to the orange "two slopes" line, we can always replace the tenons.  That remains an option even if our experiment goes horribly wrong.  And we're not risking a priceless relic - the Potters made vast numbers of flutes and they are well distributed around the museums of the world.  Most people would regard a flute in this condition as firewood. 

As Bob Dylan puts it in "Like a rolling stone", "When you got nuthin', you got nuthin' to lose...".  I hope we have everything to gain, and we won't come to Plan Z.

An interesting thought on Plan Z though.  Just replacing the tenons will take us beyond the conservative, "fix the tenons" scenario, perhaps even up to the red "join the flat bits" scenario shown above.  (A little reaming of adjacent body areas would pull them into line.)  But it would probably not get us as far as the the boldest scenario dimensions.  If we were serious about the "Ignore the shrinkage" scenario, we'd probably need to cut off the old damaged tenons, steam or whatever the body back into shape, and then graft on new tenons.  Woah, that's quite an undertaking!  But would anything less be "restoration", in the musical sense?  Sad too that a decision would have to be made between restoration in the musical sense and restoration in the artefact sense.  Which is the more important when dealing with a musical instrument?  Hmmm, might leave that one to the philosophers!


Whichever plans I am forced to invoke, I'll be closely monitoring changes.  Having carefully measured all the important dimensions (some of which are illustrated in the graph), I can easily detect variations as small as 0.01mm.  Since we are hoping for changes in the 0.5mm to 1.3mm range, that's plenty of resolution. 

I've also weighed the flute sections, with laboratory scales capable of 0.01gm resolution and calibrated to that precision.  Monitoring the weight will tell me how much water it has absorbed, and conversely, when it has re-equilibrated with local or low-humidity conditions. 

And I'm running a datalogger, which will automatically record temperature and humidity variations in the flute's environment, in case any dramatic changes there affect what we are doing.


So, we have a target shape, or at least a range of target shapes, identified in the earlier articles in this series.  And we have a plan, or at least a range of plans, by which we hope to coax our poor mangled flute back towards the target shapes.  So, I think the time for measuring and wondering and musing and planning is over, and the time for action is here.  In our next article we'll make the start.

On to Plan B, or

Back to McGee-flutes Index page...

  Created 8 May 2011