 The Clarinet BBoard
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Author: KSCop
Date: 2017-01-05 06:58
Attachment: 20170104_202036.jpg (88k)
I finally got the last part delivered and finished my Mag Tester build. Counting the oak for the case, I have about $120 into it. A lot better than $400 or so.
It works perfect, but I am already considering a different design for the case and putting in a smaller footprint air pump. I'm a little anal..
The current case is 3/4" Red Oak, Dovetail joints with the 1/4" Oak plywood front and back in a rabbet. Front and back are screwed on using threaded inserts.
I works really well. Used it on the upper joint of an old rebuild and got a reading of 2. Adjusted 1 pad and got it down to 0. Awesome deal!
Post Edited (2017-01-05 07:00)
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Author: jbutler ★2017
Date: 2017-01-08 01:18
I set mine to .45 to .5 Setting it all the way open to towards 1.0 puts too much air pressure inside the instrument for my liking but it will work where it's set in your picture. Nice job.
Just noticed your gage is different than mine. Mine registers 0 to 1.0 I see that yours has a much higher capacity.
jbutler
Post Edited (2017-01-08 01:25)
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Author: Roxann
Date: 2017-01-08 21:12
Curiosity is not going to kill this cat. What in heaven's name is this device used for?
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Author: Maddmatts
Date: 2017-01-08 22:52
Roxann: It will show if an instrument has leaky pads and help in finding which one is leaking. You typically don't see these machines outside of repair shops.
Sealing the keys and holes with your hands and pulling the air out with your mouth can do something similar, but is awkward and less hygienic for professional repair.
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Author: KSCop
Date: 2017-01-08 23:07
'Sucking air' to test for leaks is moving the air in the opposite direction than when playing. I like to test by bkowing air in; hence the 'vapor injection' testing that I do as well as the magnehelic,
The vapor injection is nice because I can inject it at low pressure, similar to playing pressure and visually see any leaks.
The Magnehelic is more scientific and I can actually see the reading go down as I heat a pad to float it in.
My usual procedure is to pull all the keys, then plug the body and test with the magnehelic. This gives me a base line for the body. Plastic horns usually read 0 unless there is a crack. Wood instruments vary but should be below 1.
Then as I install the newly padded keys, I install one key at a time, plugging the other holes. I get a reading (usually high since the pad isn't seated). I then float the pad and get the best reading I can (usually the same as the body reading). Then I move on to the next key and repeat the process. Once a joint is done, I test it as a unit. Then once the horn is done, I assemble it and test the whole thing.
The Magnehlic gives a nice clear reading.
I work on a lot of OLD instruments doing restorations and some have been sitting in some questionable places. Much nicer to have a more sanitary approach.
The machine has made my repair process much easier. I'm still pretty anal about testing and getting the best seal possible but it has helped my turn-around time quite a bit.
A simple re-pad is down to 60 minutes including cleaning & polishing keys. I don't know if that's quick or not, but it is for me.
My last two overhauls had MAG readings of under 1 for the whole horn. They were both plastic bodies - A Vito Reso-Tone 3 and a V40.
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Author: KSCop
Date: 2017-01-08 23:11
In terms of my mag build, I may have over-sized my air pump as I can't get it down to less then 6 on the gauge. For some instruments with older springs, it would be nice to have it lower, say to 4 or so.
I could replace the pump, but I'm going to try a needle valve to restrict the airflow before it hits the regulator. Then I'll have a bit more adjustment.
I'm also working on a Version 2. This one will have a smaller, 12v air pump and be in a smaller, lighter case made from PVC board.
I just like building things..
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Author: Mojo
Date: 2017-01-09 00:23
FYI, Magnehelic is the product name for a line of (very nice) pressure gauges made by the Dwyer company. They come in many ranges and scale units. It looks like a scale up to 10 inches of water column is useful for this rig.
I used to buy many flow meters and pressure gauges from Dwyer when I worked as a process engineer.
MojoMP.com
Mojo Mouthpiece Work LLC
MojoMouthpieceWork@yahoo.com
Post Edited (2017-01-09 20:02)
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Author: KSCop
Date: 2017-01-09 02:48
Yep. They are used in HVAC work a lot. I have a few of the lower resolution ones as well.
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Author: adszperacz
Date: 2020-05-06 09:22
I'm just building my tester as well. Could say what pressure your air pump has?
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Author: Dan Shusta
Date: 2020-05-06 11:39
Oh my! This thread brings back so many memories!
Around 7 to 8 years ago, I designed, built, and sold around 10 Magnehelic testers from my home under the name "Simplicity Instruments" using that well known auction site. Tom Puwalski bought one of them and I believe he still uses it.
For a number of good, solid reasons, I closed the business.
However, it sure was fun for a while!
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Author: Johan H Nilsson
Date: 2020-05-06 13:07
KSCop,
"My usual procedure is to pull all the keys, then plug the body and test with the magnehelic. This gives me a base line for the body. Plastic horns usually read 0 unless there is a crack. Wood instruments vary but should be below 1."
Wood bodies should show 0 as well. A leak of 1 in the upper body of a clarinet makes a difference for the player. Often there are pores in the wood that go through to the bore, cracks in the sockets/chimneys or thumb/register tubes that leak at the sides. All these leak sources can be filled to make the body seal completely.
While it does work to have 1 as a basis when starting putting the pads on, it feels bad to start with giving the dreaded leakage a handicap...
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Author: tarynone
Date: 2020-05-11 18:56
Re: which pump to use:
I’m not sure what the Pumps the commercial devices use, but mine uses the small aquarium style pump that sells for around $10. It works great and I have used it off an on for about 12 years. (I am just a hobbyist.) I imagine the commercial devices use one with slightly more pressure, but not by much. Mine takes about 3 seconds to “fill up” after turning it on, while, if I remember correctly, the professional ones are ready to go after about a second.
Post Edited (2020-05-11 19:10)
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Author: Steven Ocone
Date: 2020-05-11 19:07
"Wood bodies should show 0 as well. A leak of 1 in the upper body of a clarinet makes a difference for the player."
I definitely agree.
Steve Ocone
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Author: Bob Bernardo
Date: 2020-05-11 22:57
If you can't afford a mag machine, use these plugs. Actually, I can afford anything, but really see no need in it. I'd rather spend the money deep sea fishing for tuna out here at the Pacific Ocean!
http://www.jlsmithco.com/plug-bung-sets/master-testing-plug-assortment these are plugs I use.
The meg machine - http://www.jlsmithco.com/leak-locating/the-mag-machine
They also sell the mag machine (above) for about $700 after shipping, taxes, all of that.
I studied repair with one of the very best, Hans Moennig. Downtown Philadelphia.
In the old days, and I do the same now, is take all of the keys off of the horn. Then use the above rubber plugs and place them in all of the open holes on the horn. Once you get that air tight seal, about 1 minute, or use the mag machine, and hit zero, you can now mess with replacing each key pad one at a time. I don't use the mag machine. I've seen them of course.
Some repair people, are sloppy, I can say Levi at RDG woodwinds in Los Angeles could be a lot better. A 1 to 2 reading on the mag machine is OK for him, this equals to about a 1 second seal at best. It's not for me. Needs to be at least 30 seconds or more. I like Levi a lot. A VERY nice man. A very busy guy as well. So perhaps he just doesn't have time to repair new Buffet horns, fix them correctly, without getting paid extra by Buffet or RDG. Nancy is also very sweet, the owner. You will surely score a Buffet at the very best prices in the country. I surely can't blame Levi as none of us want to work for free, fixing defective horns.
When you buy a Buffet you are lucky if you achieve a 1 second seal. You really can't play these horns in new condition. They require repair. Yamaha uses very fine quality leather pads. The horns don't leak. They tune really well too! You can surely play a concert the same day you buy the horn. Yamaha's are exciting horns! Amazing workmanship. If Yamaha can do this so should Buffet!
I feel with the invention of synthetic pads there's no reason a repair person can't get a perfect seal. Back in the old days I made plugs out of wine bottle cork. The JL Smith rubber plugs are so much better.
Hitting zero on the mag machine shouldn't be a problem. With these great leather and synthetic pads repair is so much better. So repair people should never accept anything other than ZERO!! And players should only accept zero on these machines as well. When horns are sealed it's so much easier to adjust horns, find issues with horns, tune them, and be able to pick out the finest horns on the shelf at the stores.
Designer of - Vintage 1940 Cicero Mouthpieces and the La Vecchia mouthpieces
Yamaha Artist 2015
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Author: tarynone
Date: 2020-05-12 18:50
Well, I’ve always found Levi’s work to be quite good and would recommend him without hesitation. But I believe he hasn’t been at RDG for a while now and has his own shop back East.
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Author: Bob Bernardo
Date: 2020-05-13 08:07
Wow, had no idea he left. I wish him well. Yes a good guy. As I said I don't think he got paid for setting up new Buffets. I'm sure that's why my experience with him wasn't the best.
Thanks for telling me.
Designer of - Vintage 1940 Cicero Mouthpieces and the La Vecchia mouthpieces
Yamaha Artist 2015
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Author: marsheng
Date: 2020-07-16 06:04
The question was posted before but what pressure is ideal ?
See here https://www.aliexpress.com/item/4000249049295.html
Cheers Wallace.
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Author: seabreeze
Date: 2020-07-16 07:11
Levi Traci moved to McLean, Virginia in 2018, and Melanie Wong, who trained under Marc Jacobi and has much experience setting-up and repairing Buffets, moved from the Buffet showroom in New York City to RDG in Los Angeles to join the clarinet servicing team there.
Post Edited (2020-07-16 07:45)
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Author: marsheng
Date: 2020-07-17 07:36
I found this page..
https://flutopedia.com/breath_pressure.htm
This indicates that the breath pressure to play a clarinet is 20-50 mBar or 2000-5000 pa or 0.3 to 0.7 psi.
So if we are looking for leaks, 0-1000 pa probably would be in the right range.
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Author: Peter B
Date: 2020-07-17 09:32
The Magnehelic dial on the "original" mag tester ranges from 0-10 inches of water, which is 0-2500 pa or 0-25 mBar. That's the one shown in the picture from the OP in this thread. The readings referred to in some of the other posts refer to this 0-10 range.
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Author: marsheng
Date: 2020-07-17 09:41
Thanks for that. I've seen the increments on instruments before but didn't know they were inches of water. I attached photo clearly shows the figures and units.
Post Edited (2020-07-17 13:53)
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Author: Steve Z KC
Date: 2021-01-31 04:23
Does anyone have a picture of the innards of a machine or have a routing diagram for one. I was at a local equipment sale and found the proper parts except for an air pump which I am purchasing a small aquarium air pump from amazon but have no idea how to route everything.
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Author: Ken Lagace
Date: 2021-01-31 18:58
If you want to just get one -
https://www.jlsmithco.com/product/the-mag-machine/
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Author: Peter B
Date: 2021-01-31 23:07
On https://repairco.wordpress.com/ you'll find a full description of a DIY magnehelic, and there's a picture clearly showing the tubing as well. I used this page to build my own one. Over here in Europe, getting the components was my main issue. I ended up replacing the Dwyer air flow regulator/gauge with an alternative one, which has a higher max flow rate, so regulation is a bit more coarse.
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Author: Mojo
Date: 2021-02-01 18:28
There may be more than one way to pipe these up. You would just need to get a feel for how your system numbers change to indicate leaks.
I don’t have one, but I have worked with a lot of flow meters and pressure gauges. From the photo it looks like this pressure gauge is piped up to give the differential pressure across the flow meter. I would have looked for a way to measure the pressure from inside the clarinet to outside (atmosphere). Maybe it is more sensitive the way it is shown in the photo.
But making changes to the regulator knob vs the flow meter valve might give different pressures readings at the same flow rates. Maybe you are supposed to just fiddle with one of the knobs (or neither) during leak testing.
MojoMP.com
Mojo Mouthpiece Work LLC
MojoMouthpieceWork@yahoo.com
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