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Re: Cracked Plastic Bass Clarinet

Author: Chris P
Date: 2022-07-26 20:31

While plastic instruments are 'not supposed to crack', that only means the top joints won't develop cracks when subjected to sudden or extreme temperature and humidity changes which wooden instruments often suffer.

Only those cracks or splits run along the natural line of the grain and not against it and mostly affect the upper end of the top joint from the top end and can run through and terminate in toneholes.

While plastic or composite instruments (including Greenline as it's essentially wood dust mixed with glue) are impervious to this kind of cracking/splitting as they don't have the same natural grain structure that wood has, but they do have an inherently weak area which is the middle tenon where the plastic is at its thinnest and subjected to a lot of undue stress.

Some plastic basses (eg. some Vitos) have metal reinforced middle tenons to give this weak area the strength it needs, but on an unlined/non-reinforced tenon, it doesn't take much for them to shear off through stress either through a simple knock or from a fall.

One-piece body plastic basses will be stronger as they don't have the weak middle tenon or socket, but they do have a couple of weak points where the three Eb/Bb toneholes (side and LH3 Eb/Bb toneholes and the LH2 tonehole), or where the two F# toneholes (LH thumb hole and side F# key) are located which are in the same plane.

The options are a replacement tenon and preferably one with a metal reinforcement extending several inches along the length of the bore, or replacing the top joint (and transplanting the existing keywork onto it) depending which is more cost effective. Simply gluing the snapped tenon back on won't work, unless it's pinned with several stainless steel or carbon fibre pins which has also been done successfully and is the least costly repair compared to the last two.

Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.

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