OldSynths

Marv

You and I are in the same boat - we need something idiot-proof if we want to 
mould our own.

I reckon the only way I can do the insides of my Korg knob is to use a 
process similar to that used in car tyre "re-treads"; you take a part-worn 
tyre and coat the outside in fresh rubber into which you cut the tracks.

My "plan" is to find a knob whose mating mechanism is suitably similar or 
identical to the spline approach that my Kog uses. I'll take it to work and 
get it turned down on a lathe if necessary. Then I will make a mould of my 
existing knob, try to find a suitable plastic to cast a replica, and then 
suspend my donor knob in the middle of the mould and cast it into the middle 
of a new copy.

If you can find something that fits your DMP11, even if it is wrong, I think 
a similar half-way house approach might work.

As far as moulding is concerned, there are "alginate" based (seaweed) 
jellies that give very high resolution, and also the silicon-elastomer type 
that you refer to. The tricky but for me will to find a thermosetting 
plastic that is self coloured and looks just right. If I am going to make a 
copy it *has* to be perfect. Otherwise I might as well just stick some 
bakelite knob off a 1942 valve wireless on the front!

if I do get anywhere with making a mould, I will let you know. Thanks for 
getting in touch - at least we both know we aren't alone in our feeble 
quest!

Cheers

Richard Craven
England

----- Original Message ----- 
From: "Marvin Kaye" <marv@...>
To: <oldsynths@yahoogroups.com>
Sent: Sunday, January 16, 2005 6:27 PM
Subject: [oldsynths] Re: WTB: replacement knob for Korg MS-10 or 20 etc.


>
>
> Hi RMC,
>
> I saw your post about the missing knob on your Korg. I wish I was
> writing you with good news, like I have one for you, but alas, that
> is not the case. Instead I am writing to commiserate with you, as I
> have a pair of Yamaha DMP11 mixers, one of which is missing a slider
> knob, a part which is not available from the Yamaha legacy hardware
> support depot here in "the colonies". It occurred to me as well that
> I might have to wind up molding my own, if one can't be found from
> the Yamaha factory in Japan (still awaiting reply to that post.) If,
> in fact, you do find yourself molding a knob, if you would be kind
> enough to share your method and materials selection with me, I would
> be happy to do the same. I have been considering creating the mold
> from that rubber-like molding material (much like silicone sealant,
> only a bit harder on the Rockwell C-scale of durometer), and have the
> same issues as yourself... getting a mold of the outside is simple,
> but the internals (being a slot surrounded by a pair of square
> depressions rather than a circular opening) are a bit more
> challenging. Do you have any further thoughts on the matter? If so, I
> would enjoy hearing from you. Good luck with your search and/or other
> solution. Thanks for your time.
>
> <Marv>
>
>
> --- In oldsynths@yahoogroups.com, "RMC" <rmc@r...> wrote:
>> Hello All
>>
>> I need to get one of the MS-10 or MS-20 "large" knobs (small style
> will do
>> at a pinch), as used on the VCO waveform select or filter cut-off
> etc.
>>
>> If I can't buy one I might have a go at trying to mould one. the
> outside
>> shouldn't be too difficult to get right but the inside "spine" hole
> might be
>> beyond my meagre skills.
>>
>> Has anyone got one for sale please?  If so, could they contact me
> off-list.
>>
>> Thanks
>>
>> RMC, England
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