 The Clarinet BBoard
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Author: KSCop
Date: 2016-12-19 21:52
I've been using a vapor-test method to check for leaks, but found myself a victim of Ebay and ended up with a couple of Magnehelic gauges.
I'd like to make my own Mag Machine from them and while I understand the principal of operation, I'm not sure I'm clear on the connections to the gauge / air supply, etc.
Does anyone have any information on how to connect the gauge? Or perhaps a pic of the inside of a Mag Machine?
There is a high pressure port and a low pressure port on the gauge
I'm a little out of my element but think I can get this done.
I'm too cheap to spend $400+...
Thanks in advance!
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Author: Bob Bernardo
Date: 2016-12-19 22:54
I know what you mean. I did spend the $500 for one. JL Smith has them. Maybe you can look at their catalog? I do a lot of repairs, also the dislike doing repairs immensely. The machines do work. You plug the holes with the rubber seals and you can isolate the leaks pretty fast.
It gets that perfect seal, if you are doing a complete overhaul, you don't need this expensive machine, just buy the rubber plugs, the kit. Take off all of the keys and add one pad at a time to achieve that seal. The plug kit comes with a tube and a plug so you can suck on it, without touching the horn, if you hate germs as I do and try to mess with each pad to get that perfect fit. Sometimes it is easier than the machine.
Designer of - Vintage 1940 Cicero Mouthpieces and the La Vecchia mouthpieces
Yamaha Artist 2015
Post Edited (2016-12-20 00:35)
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Author: KSCop
Date: 2016-12-19 23:03
I have the plug kit. I use an e-cig and blow vapor (no nicotine / no flavor = no odor) into the horn and can see the leaks.
I'm interested in the Mag Machine mostly for the education and a measurement that I can show people.
I do a lot of overhauls and pretty much do like you said, a key at a time.
I did manage to find a link that shows the build info I was looking for:
https://repairco.wordpress.com/
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Author: Dan Shusta
Date: 2016-12-19 23:04
Timothy, I used to manufacture Magnehelic testers around 5 years ago.
After looking at the one at https://repairco.wordpress.com/, I suggest putting that one together and using it.
Yes, it is nice to be able to show customers how airtight their instruments are.
Post Edited (2016-12-19 23:36)
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Author: KSCop
Date: 2016-12-19 23:53
Thanks. After seeing that one, I thought it looked like a plan to me.
I went ahead and ordered a few of the parts I was missing, but should have it ready to go in a few weeks.
All in, I figure I'll be under $200 and I can live with that.
Plenty of ways to check leaks then.
I do like the 'smoke' test that I do, but not something I can document as well as with a Mag Machine.
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Author: Bob Bernardo
Date: 2016-12-20 00:38
Nicely done! Beats $500!
Designer of - Vintage 1940 Cicero Mouthpieces and the La Vecchia mouthpieces
Yamaha Artist 2015
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Author: flyboy
Date: 2022-04-23 12:29
A bit late to the party and I am a relative newbie, but this looks very interesting. I also like the vape tester idea.
I'm very interested in making one but I am curious. Is it possible to use it with an assembled Bb clarinet or bass clarinet or do you have to disassemble it?
It seems like it would be worthwhile as I am a DIY type and the repair shop is 1.5 hour drive so a repair costs 6 hours of driving.
BTW I don't begrudge the maker of the device as he need to make a living.
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Author: clarnibass
Date: 2022-04-23 13:32
>> Is it possible to use it with an assembled Bb clarinet or bass clarinet or do you have to disassemble it? <<
Sure it's possible. It's just a matter of what you are trying to find out. I assume you mean assembled as in the keys are on it, rather than the sections are assembled for playing (since there's no reason for the latter).
If you want to find where a leak is, then it could be as simple as connecting the magnehelic and pressing various keys, and when you press the leaky key with more force it will seal or leak less. This works sometimes, just depends on what causes the leak and the number and type of leaks.
Disassembling the keys is good for finding where the leak is coming from, adding them one at a time, but there are often ways to find them.
For larger instruments like bass clarinets it's a bit different. Some people even use it on saxophones, but you never get it to read as low as it does on something like a soprano clarinet. Some who use it on saxophones just get the needle to move a little to consider it good. Like it is completely open in a room, it will gradually lose its ability to work the larger the space is.
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Author: SunnyDaze
Date: 2022-04-23 14:12
Would it work to use one of these manual blood pressure cuffs with the cuff cut off?
https://www.medisave.co.uk/premium-aneroid-sphygmomanometer-with-carry-case.html?sel=PM882PAS
This machine just pumps air into a blood pressure cuff and shows the air pressure on a dial. If the air instead went into the plug in the clarinet as the man shows in the mag machine video (https://www.youtube.com/watch?v=rTkFP3Mlzu0&list=PL1wI5pZnOCQvSZ9mD2YiK27bwgurbZ-l3&index=36) then it might have a very similar effect.
I'm just wondering in case this would be a cheap set up for people like me. Probably not suitable for KSCop if he needs something that requires fewer spare hands.
Thanks!
Post Edited (2022-04-23 14:14)
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Author: Peter B
Date: 2022-04-23 15:56
I'm afraid a blood pressure device isn't sensitive enough. Ideal blood pressure being around 120/80 mmHg, this is about 16kPa/11kPa. The gauge on a Mag machine has a maximum reading of 10 inches of water or 2.5kPa, and target pressure loss for a clarinet is below 1 inch of water or 0.25kPa.
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Author: SunnyDaze
Date: 2022-04-23 17:07
Gosh, yes, I see what you mean.
I just looked for videos about how pressure gauges work inside and this one is good. It seems as though we definitely need the right gauge for this level of pressure. There is no obvious way to adapt them.
https://www.youtube.com/watch?v=Ja_XCJAg_l8
Post Edited (2022-04-23 17:13)
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