So today I was very encouraged with the first trial with copper plumbing joints to extend the small finger and also the thumb. This became more interesting because the small finger extension reaches as far as I want sideways but the thumb ,being a little short too allows the hand itself to settle too low . This means the small finger although reaching the octave easily is just moving the next lower note slightly . If I place my left forefinger below the thumb and raise it about one centimetre the octave can be played perfectly cleanly .
The reason I am pleased with today`s effort is the type of silicone rubber I have used inside the copper tube. It`s CT1 which is a popular diy glue/sealant . It sets as a firm flexible material but has a lot of tactile drag on the skin which makes it ideal to hold on the finger tips. The playing action continually pushes the "thimble " into the desired position and is unlikely to need any further attachment.
The CT1 as a material for the fingertip is ideal . It does not slide off the black keys and being silicone it will be very durable. The surface can be renewed indefinitely by applying the same material to itself .
Now that the metal shape seems so suitable I can already see a plastic version would be even better . That would make it much lighter .
When I began this topic I had not seen CT1 close up and it looks a better alternative to stretching my thumb joint and getting painful hands .
I have lowered the small finger tip to cater for the key dip but the thumb needs a little extra attention . Each thumb is used on it`s side when playing so the angle of the piano key is at odds with the line of the extended thumb . So the copper thumb extender is fitted like a wide ring from the end joint and a small part of the copper extends past the thumb about one quarter inch to add on the silicone "blob" to act as the fingertip. This small addition is angled to suit the line of the piano key , rather than running across it too much .
Because the thumb joint is not "contained" or restricted it feels quite natural .
An odd thing about this metal and silicone combination is the way it "feels" the key . You get instant feedback on the lightest touch which is an improvement on using all silicone and flexible materials . I googled to see if anyone else had tried to make " finger extension for piano "and only found one question from 5 years ago . He received no encouragement at all poor chap . Anyway I have put the phrase in inverted commas so the magical internet may reach back to him one day .
Apart from these copper pipe "reducers" (correct technical description ) there are some plastic ones available which will be much easier to work (or play) with . Also the variety of silicones , medical or otherwise , should produce a workable result for not a lot of pennies .
One negative was suddenly realising that silicone will not adhere to CT1 glue. So CT1 is officially dropped.
The most important change is for the small finger. The silicone is difficult to shape after it sets (or cures ) so to get the shape of a finger pad on the keys I carved out a nice smooth divot in some soft wood .I used the end grain and was able to rotate the gouge to get a smooth surface at the right depth . Then I rubbed beeswax into it to act as a release agent for the silicone. The copper "thimble" had a tiny spoon shaped extension soldered on and this was designed to be embedded in the silicone blob . The top of the blob being "loose" needed some shaping and I laid on a small patch of clingfilm and used a 1/2 inch brush to shape and coax it into a tidier form .
Looking at the one inch extension , the small finger first joint ,nearest the nail , needed some protection against bending backwards . This was done with a piece of copper 1/4 inch wide soldered on the top and reaching back to the second joint with another piece of silicone as a cushion against the skin .
I tried to use the minimum material to keep the weight down .This version seems to be very stable .
Padding the internal was a teaser. If you wrap the finger in clingfilm it gets wrinkley and ends up setting into the silicone. One way round that is to build the padding up in strips. Laying the flat clingfilm inside first , then squeezing in the silicone , pull the clingfilm over that and then place the finger inside for a few seconds , seems a nice dry way to go .
Checking the thumb addition I altered the position of the blob 10 degrees to be below the copper extension . It was facing a bit sideways as the hand was stretched over the keys . So just that tiny change gives a wider reach .
Drilling holes in the metal will be a final plus to make it as comfortable as possible .
This is to create a layer of silicone between the copper and the finger. There is an opening at both ends so I started by wrapping my small finger in cling film to estimate the width needed. Then rolled that clingfilm round a marker pen . This was inserted in the copper tube .There was enough room to add the silicone and rotate the marker pen. Then the pen was withdrawn and carefully I inserted my finger inside the clingfilm. I imagined that would be difficult but it was very easy. I had enough time to get the extension centralised and then released my finger . Today the film was removed and I have a superb fit with a very stable feeling.Just wiggle the finger inside and it`s ready to go .
This is looking like a seriously practical solution for small handed players .