Sciencemadness Discussion Board

Etch-a-Sketch

Jager - 27-4-2003 at 12:59

http://www.howstuffworks.com/question317.htm

"Also inside is a mixture of extremely fine aluminum powder and beads. The beads help the powder to flow evenly"


Does anyone know what mesh the aluminum powder is inside a etch-a-sketch?

Jager

I know this is my first post and its a new topic, I didn't see any rules posted up against it, like the E & W forum

etch7.jpg - 17kB

Haggis - 27-4-2003 at 13:40

Hearsay says the aluminum powder is around 325 mesh. However, I also hear that the tiny beads are difficult to remove without losing much Al powder.

DDTea - 27-4-2003 at 13:44

We're not like E&W, notice the less tense atmosphere here :). Not that I have anything against E&W though...

However, I believe you have made an excellent contribution with this topic! I now have a reliable source of Aluminum Powder. I just love using toys for my plans :D

Do you know how many grams of Al there usually is in an Etch-a-Sketch?

Jager - 27-4-2003 at 13:54

I dont know how many grams are in there, I'll try to think of a way to get those tiny balls out without losing too much powder


Jager

Haggis - 27-4-2003 at 13:57

I was thinking that you could find out what the balls are made of, find a solvent and dissolve the balls. Then just filter out the Al and throw away the filtrate. Or you could (depends on how big the balls are) screen the powder through a mesh that is larger than the aluminum, but smaller than the beads. Then just use water to wash the 'sticky aluminum' away.

Jager - 27-4-2003 at 14:17

I just looked on the back of my etch-a-sketch and it said that there was alumium powder and plastic beads. I think I will break it open and squirt/pour acetone on the inside to get the aluminum out and in the process the plastic should dissolve in the acetone

each of those etch-a-sketchs are around 15 dollars so I dont know how economical this would be to make flash powder

[Edited on 27-4-2003 by Jager]

Darkfire - 27-4-2003 at 14:25

Make sure to wear a mask, or you will know that you forgot...

CTR

theh0ser - 20-2-2004 at 18:33

if they're plastic beads, you can just use magnets to get the Al powder out

The_Davster - 20-2-2004 at 18:53

theh0ser: Aluminum is not magnetic.

theh0ser - 20-2-2004 at 20:01

i'lle just shut up now

IgnorantlyIntelligent - 20-2-2004 at 21:46

If you have a mix of AL and plastic beads, what about putting it in water. Might the AL sink? Probably not.
Or what about taking a balloon and rubbing it on a piece cloth then holding it over the mix. Might the AL or the plastic seperate by one or the other lifting up and clinging to the balloon? Sorry if neither idea would work, I didn't know for sure.

I wouldn't add acetone to it in order to disolve the plastic as one of two things will happen. One: the plastic won't even dissolve and you now have a big sticky 15 dollar mess. Two: It does dissolve completely and now your 15 dollar 100g of AL is coated with a plastic layer rendering it useless for any pyrotecnic mixtures.

[Edited on 21-2-2004 by IgnorantlyIntelligent]

Saerynide - 21-2-2004 at 01:26

You should sift out the beads using a few layers of screens (like the stuff on windows used to keep out mosquitos) :D

Ramiel - 21-2-2004 at 01:31

IIRC, balls are soluble in phosgene.

IgnorantlyIntelligent - 21-2-2004 at 09:11

I don't think the plastic balls are big enough to solve the problem by simply sifting them out. Im just guessing there but if it were that easy then the "problem" shouldn't have been mentioned at all.
Anything you use to disolve the plastic beads is still going to leave a layer around all the AL. You will have a liquid of plastic/solvent with the AL either floating in it or at the bottom of it(probably floating) There will definetaly be a small layer of plastic left on the AL. Maybe it wont be enough to matter but it will be there.
If the plastic beads are a different size than the AL then of course screening is the answer like Saerynide said. Jager, for the sake of not wasting 15 dollars just try sifting it first.

Saerynide - 21-2-2004 at 09:53

Or... what about dumping it all in water, and decanting off the Al powder and water, leaving behind the beads? You can wash the beads and decant repeatly to get all the Al that sticks to them. :D

IgnorantlyIntelligent - 21-2-2004 at 10:41

But then the plastic beads must sink in the water. I think they'll float on top with the AL.
Wheres vulture to shed some light?
Just try sifting it with a small screen. Theres no way in hell the plastic beads are as fine as the AL. If they are, they'd be great for AN compositions to reduce desnity of the mix:) A nice comp could be abtained from the AL/plastic beads int hat case and you wouldnt even need to extract the AL or the plastic. But thats off topic.

Saerynide - 21-2-2004 at 21:26

No, they dont have to sink for them to be undecantable. If you decant very slowly and carefully, and let only a small amount of liquid down the stirring rod, only the Al powder should get down the rod.

Think about it as decanting soup off instant noodles when youre trying to get the noodle scraps. The soup and collodial stuff gets decanted off, and youre left with floating scraps of noodles and chives. But, if youre not careful and let too much water down the fork/chopstick/spoon, you lose the scraps.

So, just adjust how much liquid to let get by :D

IgnorantlyIntelligent - 23-2-2004 at 17:11

So did it work? Several people had ideas of how to seperate it and said they were going to soon try it. Its been a couple of days has anyone done it??

Saerynide - 24-2-2004 at 01:36

I dont have an Etch a Sketch, nor do I have any tiny plastic beads to test in water with, but i know it works with instant noodles :D

But I still think sifting is the least troublesome if its feasible :)

vulture - 24-2-2004 at 03:55

I would not use water. Fine Al can be pretty reactive to water, even if it's cold.

I suggest using xylene and/or acetone.

Did you try a PVC stick that's been rubbed with wool yet?