Making Rochelle Crystals

[VintagePC]

Saw this just now. Wonder if it's possible to rebuild a crystal cartridge with this??

http://blog.makezine.com/archive/201...rew-piezo.html

I've got a dud TC8-S cartridge, maybe I'll give it a shot.

-VintagePC

[ctc17]

Interesting and worth a try. I would be interested in what the crystals taste like.

[bob91343]

Well I have two or three 'dead' crystal cartridges, including one that is in a cutting head. I wonder...

[Findm-Keepm]

Bob, lemme dig through my stuff. I seem to recall seeing that cartridge in my stash of stuff. I've got stuff from several repair shops and one distributor. Does your original cartridge look like the one on eBay, item # 250760246787 (no affiliation, used as a reference only)

Cheers,

[VintagePC]

Seems to me if you can get a nice clean crystal, and make good electrical contact to it, there's no reason it shouldn't work.
It will probably involve a 2-stage step, the second to re-grow a single crystal.

This page describes how to use baking soda as an alternative to the dye fixer:

http://www.seawhy.com/xlroch.html

followed by a recrystallization for purity:

http://www.seawhy.com/xlone.html

Originally Posted by ctc17

Interesting and worth a try. I would be interested in what the crystals taste like.

One of the pages says they have a saline, cooling taste. Wouldn't eat too many though, Wikipedia says that the salt is used as a laxative :P You'd be better off trying it with sugar if you want something to eat... hehe.

[bob91343]

Nope these cartridges are much older. They have metal cases painted brown. One is large, the cutting head. The other is about half the size. If you have something close, I'll get the part numbers and post them.

Bob

[jeyurkon]

Originally Posted by VintagePC

Saw this just now. Wonder if it's possible to rebuild a crystal cartridge with this??

http://blog.makezine.com/archive/201...rew-piezo.html

I've got a dud TC8-S cartridge, maybe I'll give it a shot.

-VintagePC

Pretty good production values!

[mbates14]

just have to figure out how to form it, shape it, and make secure electronic contact with it. He shows how to make it, but it just forms in its own way.

my guess, is sanding?

[bob91343]

I think they use a saw to slice the crystal into small sheets, then fasten a contact to each side. Of course, you have to consider lattice orientation. One way to fasten the wires is to make a little (non conducting) clamp to squeeze the contacts against the crystal.

[Electronic M]

Dumb idea, before it does much crystalization drop a frozen or chilled mold with one or two openings in to speed the cooling/xtalization process and get the shape.

Tom C.

[VintagePC]

Originally Posted by Electronic M

Dumb idea, before it does much crystalization drop a frozen or chilled mold with one or two openings in to speed the cooling/xtalization process and get the shape.

Tom C.

The problem with that is you get very rapid crystallization, which produces a lot of small, irregularly shaped crystals (think a sugar cube). You want slow crystallization, which gives a lot of time for the incoming molecules to align, and gives you a nice, large crystal - think rock candy type ones or larger).

Originally Posted by bob91343

I think they use a saw to slice the crystal into small sheets, then fasten a contact to each side. Of course, you have to consider lattice orientation. One way to fasten the wires is to make a little (non conducting) clamp to squeeze the contacts against the crystal.

If the crystal has straight, perpendicular cleavage planes, you wouldn't need to saw it - you could just split it in to blocks of the right thickness (provided the crystal is not majorly flawed)