[Henry D]

Great electro mechanical geezamaholistic device- sicncerely, from someone who loves such things. Is the difference in perceived quality in playablilty as an end result of the presumably improved leak detection audibly detectable when compared to the results obtained through the old "bung a stopper in the end of a clarinet joint and puff gently on the other end with your mouth" technique? I've no experience with flutes and my efforts towards stopping up anything larger than a soprano sax and puffing have been dismal at best (leak light as my current option) but I'm surprised that it is any better on the clarinet population.


Its shop utility on the larger horns appears like it would probably be pretty good as several experienced repairmen have commented. I'm not certain that it'd be enough of a differential to cause me to replace the leak light but if I ran a highvolume/ professional shop I'd certainly consider one.

 

[simso]

Yes its good but also frustrating,
I now re-check all my finished jobs with it and go Mmm yeh thats okay or it could be better, Ive found with the machine set up fas per JL Smith specs "reading of 8 open and flow of 1" that a clarinet plays just as well with a reading of 3-4 fully closed as it does with a reading of .6 "my best to date reading achieved".
It really just kind of confirms what you already know, but it puts a quantittive value to it.
One thing it does work well on, is I had a sopranino clarinet in that was reading 4.8 fully repadded by me, and I could not achieve a better reading, and it wasnt sounding quite right but I dont play sopraninos very often so It was more a guess then a fact. I decided to strip every key and plug the whole unit up and then reassemble the unit one key at a time to find out what was going on and locate the problem. Fully blocked off and tested it read 4.1. I still couldnt find the leak, so I immersed it into a bucket of water under pressure and low and behold the whole unit was frosting up from top to bottom, basically the material they used was slighlty porous " go figure ", so showed the customer who had purchased it brand new from the states on ebay, and told them to bin it
Would never have found this problem without it. And for the manufacturer of these instruments "weimar" YOU HAVE A PROBLEM, unless its a one off but I dont know

Becoming a very good final check tool for my own personal confidence

 

[tarynone]

Check your SOTW email account...Link posted to the picture..

Joe B

Dear Joe,

I have begun to gather the components to make my own mag machine (I am not a "real" repair tech, but am into it just for the fun of it) and was wondering if you wouldn't mind emailing me or posting that picture you had mentioned above. Thank you very very much!
Taryn

 

[stevesklar]

JBT,

since receiving my JL Smith MAG i've done a little testing (only a little so far).

this is only on clarinets

as a basis test - on a barrel I get a perfect 0 reading. I've also been testing the manual test vs the MAG. Of course the MAG is extremely visual where as the manual is more on "feel and experience"

After it goes through my feeler and manual testing to get to the end result --
i've consistently been getting .4 on bladder and leather pads on UJ or LJs (4 joints). I have yet to test an UJ & LJ together.

Now supposedly on an all cork joint I can get even closer to 0, per a buddy that uses one.

I've been plugging all the holes with rubber stoppers and using wedges to close the other keys via the mechanisms themselves vs using finger pressure for all.

This is a very interesting machine. I'll be fiddling with it more to learn more about it.

Additionally, Moennig had his own manual test (like ours) plus a test to test each pad individually before selecting and installing them.

 

[wilsaxo]

[/B] J.L. Smith recommends setting the inches of water pressure to 8 and the flow to 1 scfh in his instructions. Joe Butky wrote that he gets good results by setting his Mag to 4 inches which has also been my experience.

Coltman in his experiment to test the porosity of pads made the observation that the maximum air pressure inside a woodwind when played is equal to roughly 1 inch of water. My assumption then is that 4 inches of pressure is adequate to test the spring closed pads, and that 8 inches of pressure is probably overkill.

The real value of the Mag so far in my experience is the ability to diagnose leaks quickly in clarinets and flutes. Adding more finger pressure or putting a piece of plastic under a pad quickly tells if that pad is the source of a leak.

Thanks for the Coltman info. I had been using 5 inches but the Eb on the flute foot would put up a serious fight to get to "0". Flute players want this key sprung lightly. I started using 4 inches (and sometimes less) to test this pad, along with play tests from my customers, to get this spring tension and pad coverage its best.

For quick sax diagnosis I isolate from the high C# tonehole up (using an expansion plug described in my earlier post) and can quickly test the pads above and the neck socket at same time. The offending pads can all be replaced quickly while the plug is still in place using the Mag to verify the installation. I'll then proceed to plug below the G, or G#, tone hole. This section is more difficult, but still possible, to isolate leaks while the horn is assembled. If the sax is in the shop for playing problems this section will most likely leak like mad.

Forget about plugging the bell and testing the finished job through the neck like a flute or clarinet as you will only be disappointed. I have demonstrated, at several clinics that I 've given on using the Mag on saxes, a saxophone with all of the tone holes and bell opening plugged that gave a reading of "0" testing through the neck opening. This sax would play a beautiful, soft low Bb once a mouthpiece was added and the bell plug removed.

The biggest value that this testing device has is that it can reveal the only aspect in repairing that we can call perfect= Airtightness. All other parameters are to tolerances.

Please keep me posted on anything any of you develop to make this easier.

David

 

[hansmartini]

I've done a lot of flutes, but nobody has ever asked me to spring/seal the Eb lightly. I'm not doubting you, but I would appreciate you, and anyone else expounding more on this. (I hate Eb on flutes.)
Hans

 

[Gordon (NZ)]

Great electro mechanical geezamaholistic device- sincerely, from someone who loves such things. Is the difference in perceived quality in playablilty as an end result of the presumably improved leak detection audibly detectable when compared to the results obtained through the old "bung a stopper in the end of a clarinet joint and puff gently on the other end with your mouth" technique? I've no experience with flutes and my efforts towards stopping up anything larger than a soprano sax and puffing have been dismal at best (leak light as my current option) but I'm surprised that it is any better on the clarinet population.....

I concur with your ponderings (and I have done many flutes). I regard my experienced mouthahelic as a very sensitive instrument for both pressure and loss of air. Perhaps that is not the case for all techncians.

(Of course, 'testing' from the lungs rather than the mouth, as some technicians no doubt do, is nowhere near as sensitive.)

And that is why, although I am well known for my GAS, I have not bought a magnehelic.

 

[Blitzhild]

What model of needle valve would you recommend?

 

[ZonaSax]

I would also like to know what needle valve to use. I have the Dwyer parts, I'm just not sure about the needle valve.

 

[carolus]

I hope it's alright to revive this thread. I'm making a "Mag machine" and would like to know what pressure regulator others have used (or know of) that is appropriate for the task (specific product)? The only product I've head of is Airtrol 4104-1.5-w/k. Any other possibilities? Doing a Web search, low pressure regulators seem to be few and far between. Thanks.

 

[Gordon (NZ)]

This seems to be a modern way to go - digital.
It has had favourable reports by people who have used both types.
Possibly a lot cheaper to make.

http://www.digitalleaktester.com/

 

[carolus]

Thanks, I hadn't seen that before. I did however consider digital manometers; the $35 ones "appear" to be sufficiently accurate, but fitting them into an enclosure adds some complexity. I also considered a tube manometer (cheap or DIY and most accurate), but liquid spills and portability is an issue.

As to http://www.digitalleaktester.com, the factory presets solution sounds nice, but I think I would prefer adjustable settings. Also, there is no info on components used. So, I'm still open to suggestions for low pressure regulator products.

Separately, I noticed in a Mag video that when there is no leak, both pressure differential and flow go to 0. It then occurred to me that a differential pressure gauge is not needed. A regular low pressure gauge would do, though the operation would change a bit: instrument not connected; turn on machine; pressure = 0; set flow; plug output tube; set pressure; unplug tube. That's done once to adjust settings. To test: attach and plug instrument; if no leak, pressure stays up and flow goes to 0; if leak, pressure *diminishes* and flow stays elevated. With this system, the flow measurement is the relevant value. If someone sees an error here, please chime in. Thanks.

 

[saxoclese]

I hope it's alright to revive this thread. I'm making a "Mag machine" and would like to know what pressure regulator others have used (or know of) that is appropriate for the task (specific product)? The only product I've head of is Airtrol 4104-1.5-w/k. Any other possibilities? Doing a Web search, low pressure regulators seem to be few and far between. Thanks.

I originally built mine using a different pressure regulator and was not happy with how it performed. Later when I found a source for the "Airtrol" I purchased and installed that one and it made a huge difference. They cost a bit more, but in my experience the cost is worth it. The attached file has information that may be useful although the prices are probably not up to date. The photos below show how I chose to assemble and house the magnehelic I built. The plastic case is an electrical box from Home Depot that measures 8" x 8" x 4".

 

[carolus]

saxoclese, thanks for the info. I went ahead and ordered the major parts for the Mag Machine build (Dwyer magnehelic, flowmeter, and Airtrol pressure regulator); spent ample time doing my due diligence. That will be my reference machine. I'll explore other solutions and other products in the future. It's funny, there are surely several low pressure gauges and low flow meters out there; but the sellers sure make themselves hard to find and/or deal with. Cracks me up.

 

[Saxdaddy]

I bought a regulator with the wrong size nipples and machined some adaptors to get it to work. It was much cheaper than ordering it, but it's not near as pretty as J.L or MM's. I'm pretty proud of it regardless, so here's a few pics.

 

[carolus]

Very nice!