kkeerroo
Experienced Roboteer
Joined: 17 Jun 2004
Posts: 1459
Location: Brisbane
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Brass instrument repair
And now for something completely different:
A couple of years ago I bought this really nice 1903 C.G. Conn 3 valve trombone from ebay.
As soon as I saw it I had to have it. The problem is that with brass instruments before the 1930's is they are all tuned to C while modern music is written for B flat trombone. This means the instrument was pitching almost a semitone too high. While I could always transpose all my music to use the instrument as is this was a hassle.
To lower the pitch of the trombone I would need to lengthen the total amount of tubing in the instrument. So I did some research and did the maths on how much I would need to lengthen the tubing and decided to make extensions for the main tuning slide. The next problem was that this old instrument has a smaller then standard bore, that is that the tubing is slightly narrower than you would see on an equivalent trombone today. This made it a little challenging to find suitable brass tubing.
I ended up using two sizes of stock brass tubing from a hobby shop. the larger size would be the outer tubing and a smaller size that just fitted inside the larger would be the slide. I had to lathe off .5mm from the smaller tube to get it to match the bore of the trombone. I then soldered the pieces together, polished them and then coated them in clear acrylic lacquer.
Add to all this a new mouthpiece and I ended up with a usable trombone.
We also have a couple of other instruments here that are not much good so I have decided to pull them out and see what I can do.
To start with I thought I would have a look at my brothers old Blessings student model bone.
It has a lot of lacquer removed, some dents and the slide is a little rough. I will start by removing the remaining lacquer and putting on a fresh coat. This is going to be a little hard in some places.
I will put up more pics when I get around to doing more. _________________ Get Some!!!
Secretary of the Queensland Robotics Sports Club inc.
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