How to make Rochelle salt piezoelectric crystals

[coolguy701]

can some please tell me what i can do with one? seriously what are the practical uses of a piezo crystal? its such a cool thing but idk what to do with it.

[RimstarOrg]

@coolguy701 Good question. I read that old crystal earpieces used to be made with rochelle salt piezo crystals - something I'd like to try out. Also, I sometimes get emails asking for them for use in vinyl record players, apparently they're in the arm and activated by the needle. There's a video where someone used it a part of a speaker. For doing more cool stuff, I guess. Oh, and for competing in science fairs and learning about piezoelectricity.

[coolguy701]

@RimstarOrg oh if you ever get the earpieces made or speaker from a Homemade crystal please please please post a video.

[RimstarOrg]

@coolguy701 Will do... tough I think the earpiece one might be a long shot.

[onthecuttingedge2005]

use wax on the last cooling cup so the crystals don't stick to the glass when they harden. you could even shape some wax paper into the shape of a cup, if it still sticks then lightly warm the wax and the crystals should be free to lift out, you might get larger crystals this way since you would need to pry them out.

[RimstarOrg]

@onthecuttingedge2005 Good suggestion but prying it out didn't affect the crystals. The crystals are pretty solid and were surrounded by grain-sized crystals so it was really the conglomeration of grain-sized crystals that was broken apart by the prying. Of course that might be different if the whole thing was large crystals. I think taking out a few days sooner might have been better.

[ChozoSR388]

There's a video from Make Magazine that uses...I think it's soda ash instead of sodium carbonate, and he got quite large crystals, so, maybe you want to look into that. The soda ash is used as a dye fixer for ceramics, I think.

[RimstarOrg]

@ChozoSR388 I couldn't find the video you're talking about but soda ash is sodium carbonate. I started with baking soda which is sodium bicarbonate and then heated it to turn it into sodium carbonate. Maybe starting with soda ash would be better. I wish I knew for sure what the most surefire way is. Too bad the cream of tartar is so expensive otherwise I'd experiment more.

[Ryuuken24]

You're not supposed to have too much potassium bitartrate in the solution, that's why you didn't get a decent yield. It's an awesome crystal, but, boy, what a pain it is to grow it, specially when your country doesn't sell the ingredients in large amounts.

[RimstarOrg]

@Ryuuken24 That could be. The stuff's so expensive here it's hard to do a lot of experimenting. However, I would think that the amounts are proportionally correct once the sodium carbonate stops bubbling.

[widevan]

what if i don't have oven?

[RimstarOrg]

@widevan The oven is used to turn sodium BIcarbonate into sodium carbonate. You may be able to find some sodium carbonate and skip that step altogether. Sodium carbonate is found as washing soda or soda ash. Washing soda can be found as Arm & Hammer washing soda or Soda Solvay in Europe. Also try art stores where it's used for making tie dye.

[jasonve11a]

nice video ... 1 question: why do you need to bake 500g of baking soda ? I did not get the impression that you used more than 20g. Am I missing anything ?

[RimstarOrg]

@jasonve11a I actually measured it by weight afterward and it turns out I used 214g - which surprised me a little since it didn't look it, and keep in mind that in the video I didn't show the whole 50 minutes of putting baking soda in. But you're right, had I known ahead of time I could have prepared less. Better safe than sorry. I'll add an annotation to the video about how much I used.

[Wavefront101]

Just nitpicking, but the cream of tartar is potassium bitartrate, not bipartrate. Good video.

[RimstarOrg]

@Wavefront101 Good catch, thanks. I added an annotation to the video. Funny thing is, I had it right in the description and on my website.

[ElectricSparq]

I will try it.Thanks.

[RimstarOrg]

@ElectricSparq You're welcome. Let us know how it goes.

[RimstarOrg]

@luvintherawlife You're welcome! Thanks for the feedback.

[MichaelAChang]

Excellent. Thank you!

[RimstarOrg]

@MichaelAChang Glad you liked it!