Conn 70h restoration

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Savio
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Conn 70h restoration

Post by Savio »

I have two Conn 70h in a restoration shop. They say they are finished 10. August. Im very excited to see what they have done. They have used long time so maybe they have waited for parts. One of the slides was very bad so maybe they try to get new parts, but when I speak to the repair man he told they try without changing anything. But is it possible to take out dings in the inner slide? Anyway, Im very exciting now, days go slow without the 70h.

Leif
boneagain
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Re: Conn 70h restoration

Post by boneagain »

Savio wrote: Thu Aug 02, 2018 12:25 pm I have two Conn 70h in a restoration shop. They say they are finished 10. August. Im very excited to see what they have done. They have used long time so maybe they have waited for parts. One of the slides was very bad so maybe they try to get new parts, but when I speak to the repair man he told they try without changing anything. But is it possible to take out dings in the inner slide? Anyway, Im very exciting now, days go slow without the 70h.

Leif
Of course, we'll need pictures!! :)

I'll also be curious if they refurbish the valves in any way. I just did the F valve on my Duo Gravis last fall. Some folks plate and rehone. My mentor walked me through sleeving instead. Valve now has the best compression ever. The wear and damage on the F valve had made it quite leaky. I find it hard to imagine the 70h would NOT have leaky valves; so I'm curious if they reworked them.

I'll also love to hear about the inner slides. For me there is a big difference between keeping a wrinkle there from bothering the action and being smooth. Turns out being smooth has a high chance of causing the slide to bend away from the side being smoothed, and that increases the likelihood of poor action. But, each brass tech has his/her own secrets, so I bet SOMEONE can make an inner smooth AND straight.

Only 8 days to go.... too bad you don't have a nice vintage Holton to help ease the pain... OH WAIT... you DO have a nice vintage Holton :)
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Savio
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Re: Conn 70h restoration

Post by Savio »

boneagain wrote: Thu Aug 02, 2018 2:43 pm
Savio wrote: Thu Aug 02, 2018 12:25 pm I have two Conn 70h in a restoration shop. They say they are finished 10. August. Im very excited to see what they have done. They have used long time so maybe they have waited for parts. One of the slides was very bad so maybe they try to get new parts, but when I speak to the repair man he told they try without changing anything. But is it possible to take out dings in the inner slide? Anyway, Im very exciting now, days go slow without the 70h.

Leif
Of course, we'll need pictures!! :)

I'll also be curious if they refurbish the valves in any way. I just did the F valve on my Duo Gravis last fall. Some folks plate and rehone. My mentor walked me through sleeving instead. Valve now has the best compression ever. The wear and damage on the F valve had made it quite leaky. I find it hard to imagine the 70h would NOT have leaky valves; so I'm curious if they reworked them.

I'll also love to hear about the inner slides. For me there is a big difference between keeping a wrinkle there from bothering the action and being smooth. Turns out being smooth has a high chance of causing the slide to bend away from the side being smoothed, and that increases the likelihood of poor action. But, each brass tech has his/her own secrets, so I bet SOMEONE can make an inner smooth AND straight.

Only 8 days to go.... too bad you don't have a nice vintage Holton to help ease the pain... OH WAIT... you DO have a nice vintage Holton :)
:hi: Yes, the old good Holton is here :good: I just hope the Conn's dont get jealous when they get home :biggrin:
Dave, I hope its possible to make the inner slides straight again and make them synchronized with the outer slides. And make the valve on one of them. I asked him also about the valve and suggested maybe change it. He told no, we try without changing. I dont have a clue how they can do it. :idk: But he told they can do it. Both slides and the valves. Soon 7 days.... :shuffle:

Leif
mrdeacon
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Re: Conn 70h restoration

Post by mrdeacon »

Boneagain, what do you mean by sleeving?

The valves on my bass are leaky, not unusable leaky, but leaky enough where I'm going to have to do something about it in the next few years.
Rath R1 2000s, Elliott XT
Bach 42 1974, Elliott XT
Holton 169 1965, Elliott LB
Minick Bass Trombone 1980s, Elliott LB
boneagain
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Re: Conn 70h restoration

Post by boneagain »

mrdeacon wrote: Thu Aug 02, 2018 3:20 pm Boneagain, what do you mean by sleeving?

The valves on my bass are leaky, not unusable leaky, but leaky enough where I'm going to have to do something about it in the next few years.
Not to hijack Leif's thread, but perhaps an overview would be ok.

George McCracken, who was head designer at King for many years, has been building horns and doing repairs on his own since retiring many years ago. He doesn't like plating for leaky valves because he has seen too much plating get honed too thin and flake off.

Mr. McCracken prefers to turn down the old valve body, the turn a sleeve to fit over the reduced valve body. He carefully cuts away the metal over the air passages, paying special attention to preserving the shape that will mate with the valve port. For tapered rotors (the most common kind), after turning to approximate size, he hones the valve into the case with successively finer grits until it just fits the case freely with no leakage.

For cylindrical rotors (like on the Duo Gravis) he makes internal and external hones for both the valve shell and rotor core. Both are honed until a tight fit, then final honing goes with the finest grit in the cylindrical core (VERY little honing done this way!)

Side note: before any of this all aspects of the valve are very carefully measured. Usually if the valve leaks, the leaks are because either: 1) the shell was warped by some damage, and operation after the damage reduced the size of the outer edge of the rotor, or 2) the valve lacked oil many times, and the axle portion swaged (swedged... pick your favorite spelling) the hole in the bearing plate open, letting the circumference rub against the shell. This all shows up in the measurements. If a tapered shell has been warped, that will need a hone made to re-establish roundness. If the bearings have been swaged large, it MAY be possible to swage them back to proper size, and that would have to be done before honing could be done (or we'd just hone the old problem right back in.)

Believe it or not, this is the short description. Takes quite a bit of time and skill. I would not have been able to sleeve mine if Mr. McCracken hadn't been within a few feet the whole time.

So, knowing what I went through with my horn, you can see why I'm REALLY curious about what the tech did to Leif's treasured 70h!
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Savio
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Re: Conn 70h restoration

Post by Savio »

I speak to the repair man today, and what he told is not making my expectations too high. He told dents on the inner slides of the old 70h are difficult to straighten out. Not like modern slides. But he told he did his best and also used some "silicon" treatment. Whatever that is. He also told there was a missing part in the valve he made some custom things to fit. He told in this old horns you cant just swap from another similar valve, they have to fit to make it tight in that specific horn. Well, maybe he was a little humble or its true its not easy to fix this old horns. It will arrive some day next week….I'm excited like a child!

Leif
boneagain
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Re: Conn 70h restoration

Post by boneagain »

Savio wrote: Fri Aug 10, 2018 6:15 pm I speak to the repair man today, and what he told is not making my expectations too high. He told dents on the inner slides of the old 70h are difficult to straighten out. ... Well, maybe he was a little humble or its true its not easy to fix this old horns...
Probably repeating myself here, but what most people don't realize is that repairmen cannot remove dents. The dent stretches the metal. The metal can't be "unstretched" by ordinary means. "Ordinary" includes use of heat below the melting point of the metal. The repairman pushes the stretched metal around, redistributing that metal until the surface gets back to an eye-pleasing shape.

On a badly dented bell the pushing can make it so the large end of the bell no longer sits flat on a table. For most of us, that is better than a big dent in the bell.

If you think about a slide dent in terms of pushing metal, you can see that the kind of warping that is OK on a bell is FAR from OK on a slide. Let's exagerate the effect as a thought exercise: assume that getting the inner slide dent perfectly smooth would make THAT side of the slide 3mm longer. Now the slide would take on the shape of a banana. That wouldn't play very well. The repairman would need to find a way to stretch the REST of the slide to match the stretching of the formerly dented spot. AND all of this would have to be done underneath a relatively brittle chromium plating.

Now if, on the other hand, the repairman only made it so the dent restricted less than, say, 10% of the acoustic passageway, there would be little acoustic effect, and it MIGHT be possible to get the outer to pass pretty freely over that dent with a little rounding of the tube (unless the dent is in the stockings, in which case... oh, let's just not even THINK about that :( )

I'm really curious about what part(s) were missing on the valve. Since many of them (the valve body, the rotor stop arm) are tapered fits, even if you COULD get a brand-new part, it likely would not fit (because of decades of wear on the matching part) it is reassuring to hear your tech's approach to custom fitting!

The tech DOES sound a little humble, AND it IS true that it is not easy to fix horns this old! :)

Looking forward to pictures even MORE now!!
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Savio
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Re: Conn 70h restoration

Post by Savio »

Thanks Dave, is the inner slide made of harder stuff than the outside slides? He told it was extremely hard on this 70h. And I wonder how long this silicone treatment will last?
Leif
boneagain
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Re: Conn 70h restoration

Post by boneagain »

Savio wrote: Sat Aug 11, 2018 6:09 am Thanks Dave, is the inner slide made of harder stuff than the outside slides? He told it was extremely hard on this 70h. And I wonder how long this silicone treatment will last?
Leif
Don't know about this particular 70h. In general, the plating will be relatively hard and brittle. For my own purposes, I like a little extra hardness on the inner material, especially on a bass. Hardness can help minimize bending on the longer positions. Slide designers have, for centuries, done and amazing job of balancing hardness, wall-thickness, weight, lubrication retention, and more, all so we can saw back and forth from 7 to 1 on sixteenth note runs :)

On treatment longevity: all depends. If you clean the outer with brass cleaner, not long. If you keep the outer swabbed with a soft cloth and are regular with normal day-to-day lube, a while. I HAVE noticed improvements from treatments of the outer, but not enough that I depend on them.

BTW: Slide Doctor was VERY specific about cleaning and lubing for every use of the horn immediately following his treatments. Took a while for things to sort out, but they did by following that advice.
boneagain
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Re: Conn 70h restoration

Post by boneagain »

Well, August 10 came and went... any word?
The anticipation is killing me.... it's like waiting for that last octave leap the bass trombone and bottom trumpet get to play toward the very end of the Meistersinger overture!
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Savio
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Re: Conn 70h restoration

Post by Savio »

Should be here any time. Think he sent it on monday, I sent a sms but he doesnt answer. Hmmm...waiting...
Leif
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Savio
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Re: Conn 70h restoration

Post by Savio »

Image

The loved ones come home today! Hope you can see the picture. The left one is from 1955, the right one is from 52. The first thing I noticed, the left one was so much better to play. It was a dog before, but now its like a dream! The repairman has done a lot on it. The slide was 2 out of 10 before, now its 8 of 10. Not perfect but much better than I hoped for. The response is amazing, its delicate to play. I can see the repairman have made something inside the valve. Some of the soldering are new both on the bell and slide. Looks better.
Spit valve is changed, and even he told its impossible to remove all dents from the inner slide, I cant see any dents at all.

The one to right was alrady good before he got it, but all small dents are gone, spit valve is like new, slide is better but not like a new one. Still its the same as the another one, 8 of 10. I noticed both slide are even in all positions, even out to 7nt.


Well, Im very pleased with the result! Im just home from a band practice, and its amazing to feel how fantastic the 70h is in an ensemble. Everyone should have tried that in their life. When you put it out on the long 7nt and blow a low C. Wow what a feeling. :D

Anyway, I was a little afraid when he told its hard to make the slides, but I was surprised. Much better than I thought they should be. I wonder why Conn have different lacquer on these two, the one to left is more light yellow.

Im going to play the hole day tomorrow, so good to have them home again... :good:

Leif
boneagain
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Re: Conn 70h restoration

Post by boneagain »

Images did not paste in.
REALLY glad to hear how well they BOTH came out!!
The "delicate" aspect you mentioned leads me to believe he DID rebuild the valve (at least one). Losing leaks that were in the wrong places makes a huge difference in being able to nail delicate articulations/slures, etc.
Congratulations!
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Savio
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Re: Conn 70h restoration

Post by Savio »

Thanks Dave! I try post the picture one more time. Naah, tried but it doesnt work. Does it work with dropbox or Onedrive?
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BGuttman
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Re: Conn 70h restoration

Post by BGuttman »

Savio wrote: Fri Aug 17, 2018 3:18 pm Thanks Dave! I try post the picture one more time. Naah, tried but it doesnt work. Does it work with dropbox or Onedrive?
MattK (Matt Kingsbury) would be your best reference. I think most ways of "pointing" to on-line pictures work. You should also be able to upload them using the "attachments" tab in the full editor.

Glad you have two lovely new "babies" to enjoy.
Bruce Guttman
Merrimack Valley Philharmonic Orchestra
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Savio
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Re: Conn 70h restoration

Post by Savio »

Image

https://1drv.ms/u/s!AnFhNyFesmcYhPEV3tn_QrBcC8xD6g

Wonder if this image will show up?
Leif
pompatus
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Re: Conn 70h restoration

Post by pompatus »

The URL works, but not the embedded image. Those are some great looking horns, Savio!
boneagain
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Re: Conn 70h restoration

Post by boneagain »

Nice pictures Leif!
Thanks!
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