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Seating Pads

Martin

Member
Messages
212
Hi.

Today I started putting some new pads on my 'The Martin' tenor. They are black roo skin, from Musicmedic. I'm doing the job in stages, hopefully to avoid getting myself in too much trouble, so todays stage was to replace the upper five front pads, the group operated by the left hand. I'm putting the new pads in with stick shellac.

I noticed that the new pads are a little thinner than those that came out. This has resulted in the keys closing slightly further, so that the outer edge is pressing down more firmly than the inner edge. I don't think I have leaks and the sax plays OK, but I know it's not correct...the key has to be pressed down firmly...not ideal...I want to improve it.

I have a book on woodwind maintenance, by Ronald Saska, in which he recommends bending the keys by placing an old reed under the outer edge and pressing down on the inner edge. I tentatively tried this, but backed off...it feels far to brutal.

So what do I need to do to seat the new pads correctly? Remove them and place packing pieces under them perhaps? Or remove them and seat them on a lake of shellac, to allow them to take up an angle?

I would welcome your collective advice.

Looking forward to some ideas,
Martin
 

Stephen Howard

Well-Known Member
Messages
1,957
First up, it has to be said that one of the most important issues when it comes to replacing pads is getting ones of the correct thickness.

My article on testing leaky pads sets this out in detail:

http://www.shwoodwind.co.uk/HandyHints/LeakyPads.htm

It's certainly possible to bend key cups to some degree, but there are pros and cons.
I don't recommend bending key cups without the proper tools, because it's not the key cup that you want to bend...it's the key arm.
Using objects placed under the tone holes requires you to use the cup itself as a lever, which means you're using a relatively thin bit of metal (the cup) to bend a thick one (the arm). This often results in the cup distorting - and the golden principles of setting pads are a level pad in a level cup against a level tone hole.

The proper tools - be they special pliers or levers - allow you to bend only the key arm, leaving the cup untouched.
But when you bend a key you not only change the angle of the key cup but also it's position relative to the tone hole.
Bending a key cup arm down to accomodate a thinner pad will push the key cup forward. This will mean that there's less 'meat' on the pad at the rear of the tone hole...and this often leads to leaks.
Similarly, bending the arm up allows for a thicker pad...but at the expense of meat at the front of the pad.

Saxes aren't that well-built in the first place, and it's often the case that the key cups are already at the limit with regard to positioning.

So, you have a set of pads that are too thin - and you really don't want to throw them away.
Well, you can increase their thickness by 'backing them up'. This simply means gluing discs of thin card to the rear of the pad to increase the overall thickness.
Determining the required thickness of card is a matter or trial an error - you could measure the distance required, but by the time you've set the pad (thus compressing it slightly) you might find your measurements are off.
Old birthday cards are ideal material, as are sources of slightly thicker card such as cereal boxes.

Place the pad down on the card, draw round it with a pencil and then carefully cut the card just inside the line. This disc must now be glued to the pad. Ideally you should use the same glue as you're using to seat the pad - either shellac or hot-melt - but you can glue them on with contact adhesive...the pad glue will climb the sides of the key cup and further secure the disc..just make sure you get a good bond with the contact adhesive before attempting to glue the pads in the cups.

What most tech will do is try a 'dry run' - the backed-up pad is fitted to the cup without any shellac and the key is fitted to the horn. The pad is then checked for height. It should be just slightly too thick at this point (i.e it hits the back of the tone hole first). By how much is hard to say - only experience can tell you whether a pad looks like it will level out nicely or not, but it will at least point up any large errors.

The pad is then shellacked in place, the key fitted and the pad set.
You might now need to adjust the thickness, and this can be done by removing the pad (it starts to get a bit messy now) and either add more card or peel away some from the existing backing disc.
The first pad you set will serve as a rough guide for the rest...assuming someone hasn't beaten you to it and bent the key cups before.

Another method is to float the pads in...which means they sit on a bed of glue.
To do this properly requires some skill and patience - and it can get incredibly messy. I rarely use this method myself, and tend not to recommend it to home repairers.

Regards,
 

thomsax

Well-Known Member
Messages
3,805
I would mesure up every pad indvidually, so you get the correct thickness. You probably got correct pads. I would buy new in the same height as the ones who are installed. You can do more damage to bend back the keycups. So I recommend new pads.

I never "built" up pads. It's like paper in to big shoes!

We talked about your Martin sax before:

http://cafesaxophone.com/showthread.php?2671-Time-to-install-resonators…but-which-ones

Thomas
 

kevgermany

ex Landrover Nut
Subscriber
Messages
21,947
I'm guessing the Musicmedic pads come from Prestini. I used Prestini kangaroo pads when I did my sax recently. Had similar problems and ended up adding extra shellac, cos I didn't fancy trying to cut shims once the shellac was in the way, and like you didn't want to bend the keys. I'd dry assembled, but not with pads. My error. Adding the extra shellac was very messy, as Stephen says. I wish I'd done the dry assembly with pads, would have saved me a lot of time. Cos I'd have seen the problem beforehand. And I'd have shimmed with card/paper.

I've been working on a couple of flutes recently. It's taught me a lot about what works and what doesn't. And just how accurately the pads need to be for an instrument to play properly and quickly. And with the pads the way you describe them at the moment, you'll not only get very tired hands, but will struggle with whistles/bum notes/maybe octave jumps, especially in quicker passages. Those pads need to seal all round, with the very lightest touch of your finger. Stephen's cigarette paper method is good for checking this, as is a leak light.
 

Stephen Howard

Well-Known Member
Messages
1,957
I never "built" up pads. It's like paper in to big shoes!
Not really. Every pad has a backing disc, typically made of card. If you wanted to 'do it properly' you could peel back the leather, unfasten the reflector and replace the existing backing with a thicker one...then reassemble the pad.
Not much point really - if the disc is glued with shellac it'll present the pad with as stiff a surface as before.
There's even some slight advantage to the method as thicker pads will have a thicker felt core...and a thinner pad is more stable in the long run.


Regards,
 

Martin

Member
Messages
212
Wow, fast response. Thanks for some good tips, everyone.

I think I'll follow Stephens advice and add cardboard shims behind the pads, attaching them with shellac. I imagine it might get a bit messy removing the pads that I've already mounted.

My next opportunity to work on it will be Sunday...I have three gigs between now and then...I'll have to just stagger through them!

Thanks,
Martin
 

Stephen Howard

Well-Known Member
Messages
1,957
Find out the thickness of card you need on a new pad....then when you heat the key cups to remove the pads you've already fitted (put a little mark with a pen on either the front or the rear of the pad to help with realignment when you replace them...assuming they've got a tone hole impression on them) whip 'em straight out and press them firmly down onto the card.
Allow to cool and simple cut round the base.

Regards,
 

Martin

Member
Messages
212
Find out the thickness of card you need on a new pad....then when you heat the key cups to remove the pads you've already fitted (put a little mark with a pen on either the front or the rear of the pad to help with realignment when you replace them...assuming they've got a tone hole impression on them) whip 'em straight out and press them firmly down onto the card.
Allow to cool and simple cut round the base.

Regards,
Thanks Stephen...I'll do exactly that.

Martin
 

Martin

Member
Messages
212
Wheatabix to the resue

Find out the thickness of card you need on a new pad....then when you heat the key cups to remove the pads you've already fitted (put a little mark with a pen on either the front or the rear of the pad to help with realignment when you replace them...assuming they've got a tone hole impression on them) whip 'em straight out and press them firmly down onto the card.
Allow to cool and simple cut round the base.

Regards,
Job done.

Followed your method, Stephen, adding a shim of Wheatabix box (0.4mm) under some pads and some thinner card (0.2mm) under the rest. Adjusted the corks, etc to make the linkages work together nicely...and...it's playing well again now. Thanks again for your advice.

It did take me a long time though...most of Sunday...if I lived in a place where professional help was available, I would probably send it in for a sax tech to do the job, probably faster and better than me...unfortunately, it's not practical where I live.

Martin
 
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