Fitting a new leadpipe + fifth valve


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Posted by Dave Erickson on October 30, 2002 at 15:06:35:

I'm planning on adding a fifth valve to my project tuba
and simultaneously replacing the leadpipe. The fifth valve
will go above the first valve, offset by about 1.25" away
from the bell. The thumb linkage for the new valve may
end up being a custom fabrication. There are a few unknowns
still, so seeking the advice of the repair folk on this board:

I've never tried melting tar (or buying it for that matter). Is
the tar used when bending leadpipes the same stinky stuff used to
build up composition roofing (tar and gravel)? If so, it should
not be too hard to find. After bending the leadpipe, heating it
should melt the tar and get 90% of it out; what about the last
10%?

Do the port arrangements on rotary valves have standard terminology?
i.e. when I order the valve, I want to get it with an arrangement of
ports like the poor ascii drawing below, is there a standard way of
describing such an arrangement:


* ---
*/1 2\ ***
| TOP |
\4 3/
*** ---
*
*

1) is where the leadpipe enters and is angled 45 deg. upwards
2) is the port that leads to the first valve and points to the right
3) points down and will get a 90 deg. elbow which connects to an outer
slide for fifth valve
4) points to the left and attaches directly to one of the outer slides
for fifth valve

-Dave


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