[sdiy] Reproductions of Vintage Synth Parts (how are they made?)

[Bob Weigel]

I don't know why mold make is so expensive for some parts.  Especially 
if you have a pattern and it's a tapered part that can be jammed into 
the clay w/ a little silicon on the surface...and pulled out.  The two I 
poured last night...one was pretty good and one had a major bubble but 
that was because I was using epoxe and it was hard to 'knead' it into 
the holes :-).  But I think I got a useable one when it dries 
completely.  Overnight it's still pretty plastic feeling.  When it 
hardens to where I can machine it I should be able to just drill a shaft 
hole and goop it onto the shaft and nobody will ever know the different 
unless they tear it off :-). -Bob

ASSI wrote:

>On Tuesday 09 December 2008, Ken Elhardt wrote:
>  
>
>>I'm wondering how it appears so easy for the Technology Transplant
>>guy on ebay to make reproductions of vintage synth knobs, buttons,
>>switches and so on.  I was under the impression that getting some
>>custom plastic part fabricated from scratch was expensive, but he's
>>got all kinds of stuff.  Does anybody know the process a private
>>individual would have to go through to make a reproduction of a
>>Jupiter-8 knob in quantity for example?  Are the costs reasonable?
>>    
>>
>
>Making the mold is most expensive (especially if it requires more then 
>two pieces), then comes keeping it in storage and setting up for 
>production.  You would probably look at low four-figure numbers for 
>simple knobs.  Once set up for production the shop will probably 
>require you to make a few hours worth of production or else charge 
>extra for setting up and taking down.  Assume one shift worth of 
>work, setting you back another $1000 or so and landing several 
>thousand knobs in your lap.  Most shops will have a few mold makers 
>at hand to fork that work out.  You can skip a few dollars if you 
>don't specify too long of a mold life, which is generally measured in 
>how many shots you expect to get from it (this allows the mold maker 
>to use cheaper and more easily shapeable material).
>
>For most knob designs resin casting (into silicone or powder casts) 
>would probably be a cheaper alternative especially if you only need a 
>handful.  The downside however is that the form is much more 
>restricted and the parts need more work to get the surface finish 
>right.  If you expect bubble free results you also need a vacuum box, 
>otherwise you can easily do this in your garage if you don't mind a 
>few chemical smells.
>
>
>Achim.
>  
>