Author Topic: Wurlitzer 700 cracked reed bar casting  (Read 200 times)

Offline velo-hobo

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Wurlitzer 700 cracked reed bar casting
« on: March 22, 2019, 05:42:43 PM »
Greetings all, been a long time since I posted.

I sort of took a break away from doing Wurlitzer repair but recently started taking on a few projects again, and trying to make progress on a few old ones.

I have a model 700 in for the typical damper felt replacement, along with a cleaning, action lube, and general setup work

When I went to reinstall the reed bar after working on the dampers, I noticed the two small braces that go from the front to the back were cracked. Either the casting had internal stresses that eventually fatigued (or it was dropped, or the reed bar screws were mis-adjusted and twisting it at some point in its life)

It seems to have less sustain than another 700 I used to own, and several 120s that I've worked on, although none of those pianos ever seemed to have a remarkable amount of sustain compared to the later models. Still working on setting up the action so maybe that could change, as the let-off is still way out of adjustment.

I'm inclined not to worry about fixing it (not a primary instrument or major studio piece for the client) but curious to know if anyone's ever encountered this or attempted a repair.

My guess is it could be carefully TIG welded (I am a welder), but I have no idea what the alloy is, and am concerned the casting might be somewhat porous leading to difficult welding. Dirt/oxidation is the enemy of a good Alu weld.

Physical distortion might also be introduced during the heating and cooling cycles, and the last thing I'd want is to warp the reed bar even further.

Offline cinnanon

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Re: Wurlitzer 700 cracked reed bar casting
« Reply #1 on: March 23, 2019, 01:41:27 PM »
If you C-clamp it does sustain restore?

Offline velo-hobo

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Re: Wurlitzer 700 cracked reed bar casting
« Reply #2 on: March 23, 2019, 03:30:00 PM »
That's a good question, and a good experiment to try, thanks for the idea!

I'm not sure how much clearance there is for a c-clamp in there but I'll check it out when I go to work on the action setup.

Offline cinnanon

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Re: Wurlitzer 700 cracked reed bar casting
« Reply #3 on: March 23, 2019, 07:40:56 PM »
If clamping it does bring sustain back, and you don’t want to weld it, you could drill some through holes on either side of the broken rib (in between reeds of course) and put some all-thread through those holes with nuts on the end to merge it back together. I bet 8-32 all thread would be good enough. I have no other ideas on how to do it.

Offline pianotuner steveo

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Re: Wurlitzer 700 cracked reed bar casting
« Reply #4 on: March 27, 2019, 03:10:45 PM »
What is all thread? I've never heard of it
1960 Wurlitzer model 700 EP
1968 Gibson G101 Combo organ
1975 Rhodes Piano Bass
1979 Wurlitzer 206A EP
1980 Wurlitzer 200A EP
1980 Wurlitzer 270 Butterfly Grand
2000 Yamaha acoustic piano
2004 Hammond XK3
2009 73A Rhodes Mark 7
2009 Korg SV-1 73
....and a few guitars...

Offline velo-hobo

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Re: Wurlitzer 700 cracked reed bar casting
« Reply #5 on: March 27, 2019, 03:24:11 PM »
It's another name for threaded rod - like a machine screw with no head.

I thought about this approach a bit and I'm not sure I'd be into drilling new holes in the harp casting.

But if it would fix the sustain issue, then maybe that's the way to do it.  It would certainly avoid the heat warping issues that are possible with welding.

In any case I haven't had time lately to investigate further. The client isn't in a hurry to get this back so I have time to think about it.

Offline pianotuner steveo

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Re: Wurlitzer 700 cracked reed bar casting
« Reply #6 on: March 27, 2019, 05:07:53 PM »
Or, you could replace the harp...
1960 Wurlitzer model 700 EP
1968 Gibson G101 Combo organ
1975 Rhodes Piano Bass
1979 Wurlitzer 206A EP
1980 Wurlitzer 200A EP
1980 Wurlitzer 270 Butterfly Grand
2000 Yamaha acoustic piano
2004 Hammond XK3
2009 73A Rhodes Mark 7
2009 Korg SV-1 73
....and a few guitars...