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Dave Leggett

TITANIUM REEDS (a cautionary tale?)

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About 15years ago, I used to play a rather good Jones metal-ended C/G Anglo. I had often hankered after the lower and richer tone of a G/D instrument. I found one which I liked but foolishly sold the Jones in order to finance the G/D. I almost immediately regretted parting with the C/G but realised that the only way I could afford to replace it was to try and make one!

I had the totally decrepit remains of a 39 button Lachenal McCann duet concertina (which I had bought, along with 3-tea-chests-full of other diverse decrepit musical instruments and parts, for £50 at a sale). The steel reeds were all rusted out.

Being a designer/jeweller with a penchant for experiment and having by me a small quantity of thin titanium alloy sheet  ( grade of alloy unknown: in 3 different thicknesses (0.3, 0.6, and 0.9mm), which an aero-modelling friend had obtained for me, I thought that this might be fun to experiment with as reed-making material re-using the old McCann reed frames (suitably cleaned-up and refined). It certainly seemed 'springy' enough!

I sought the opinion of two eminent concertina makers. The first one said, 'out of hand' that titanium reeds was a bad idea without offering any cogent reason. The second was kind enough to take some samples and make a couple of experimental reeds. He also said that Ti was a bad idea because (a) the relatively low density(s.g.4.5) of Ti would give problems in getting sufficient mass distribution within the vibrating reed to give the necessary range of notes in a limited range of frame sizes. (b)You can't weight a Ti reed-tip with solder (it won't stick!) and (c) It's a really tough metal which is hard to work and blunts files.

Not being then the sort of person who is easily discouraged, even by Sage advice, I did persevere with the project in a spirit of curiosity (or obstinacy) and eventually, after much aggravation, made myself a playable instrument. I think the project was probably spread over a year or more.

BUT!! - 1) I had to increase the range of reed-frame slot-lengths by silver-soldering little brass blocks inside the narrow ends of some of them, (2) Some of the longer reeds are perhaps too thin at the belly, giving them a bit of a 'mushy' tone. Some of the small reeds are maybe too thin at the tips. (3) The damned stuff is a real pain to file!

Surprise, surprise: Sage no. 2 was right!!!

The overall result is that I may have a concertina (I've named him Ti'm) which is perhaps(?)  unique but which doesn't sound that wonderful (though better, I'm sure than the old Lachenal reeds that I replaced).

In pursuing this frivolity, I learned a lot of hard lessons and gained more knowledge, practical skills and confidence about reeds and other aspects of concertina-making than I probably would ever have had should I have kept 'the Jones'.

Was it worth it? In the following years I've had endless enjoyment in making a few more more-conventional instruments, so the answer is 'Yes' and I still take Ti'm out sometimes to Pub music sessions.

 

 

 

 

 

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I hope you will bring it with you for a demonstration Well done Dave

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Hi Dave, thanks for explaining the efforts you made and congratulations for finishing such an interesting project.  It usually takes a lot of work to improve our understanding of nature and there are always lessons learned.  I don't think we can say that your experience is definitive on whether Ti is a suitable tongue material because there are many subtle issues in this kind of application, although I well understand that you may feel that you've adequately explored these unknowns.  

I'm interested whether you've come to any conclusions concerning the musical tone of these reeds.  I have a theory that the musical tone of a free reed is primarily dependent upon material properties of the tongue, everything else being equal.  In particular, all material properties are determined by the ratio of Young's Modulus to density.  I make this claim because that ratio is the only way in which material properties enter into its equation of motion, determined by the Euler-Bernoulli equation.  Experiment has verified that this equation is very accurate in normal playing of the reed. 

If this theory is correct, there's chance that we might be able to predict the sound of a particular material, when compared to the sound from other materials we have more experience with.  Two common materials for concertina reed tongues are spring steel and brass.  If we calculate the ratio of Young's Modulus to density for these materials, we get that the ratio for brass (Alloy 260) is 0.497 that of the ratio for spring steel (AISI 1095) (making the latter = 1.00).  

You mention that the Ti alloy you used is unknown, and that will complicate any conclusions we can make here now.  However, the most common, every day Ti alloy that is used is Ti-6Al-2Fe-0.1Si.  There are others of course, but it's my impression they are used for the more exotic applications and they normally don't find their way on scrap heaps accessible to average humans.  The ratio of Young's Modulus for that alloy is 1.11, still with that of spring steel normalized to 1.00.  Other alloys of Ti can be much different, and I attach a table that shows this calculation done for a variety of materials.  If there's any way you could find out what your alloy is, it would help to have that critical information.  Going solely by these results, however, I'd suggest that the Ti tongue has a sound closer to that  of a spring steel tongue than a brass tongue.  Most comments I've heard comparing brass to steel say that brass is more mellow, or steel is more bright (perhaps helped because of higher volume), so I'd further predict that Ti is at least as bright as steel, maybe even brighter.  

Finally, I do realize that it takes a long time and much experience to know how to work with any material and to fashion it into a reed tongue in a way that would optimize whatever it has to offer.  I don't know how far along you came in this process, though I hope your results can give us a useful "data point" in this kind of experiment.

Best regards,

Tom   

 

Free Reed Tongue Materials Survey Table.doc

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