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One of the things that I like about papier-mache the most is my ability to make something out of nothing. I love the feeling of recycling something that would be thrown in the trash.
A friend explained to me a little while back that egg shells were a good source of calcium and that you could dry them in your oven and grind the shells up into a powder for a cheap source of calcium - so I have been keeping eggshells in my freezer because I didn't want them to go to waste.
It is only today when I was working on my papier-mache project that I realize that I could use the ground shells in my papier-mache for a substitute for buying ground chalk!
I am just brainstorming and I am not sure if the idea will actually work or not. I'll have to try it for my next project. I just thought I'd share the idea before I went off to experiment.
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I had never considered egg shells before! Wikipedia says that bird eggshells are 95% calcium carbonate with a little bit of protein to hold the CC together.
If you could powder them fine enough, I don't see why it wouldn't work.
I would dry the shells in a warm oven before trying to grind them, to make them more brittle. After you've taken your food from the oven and turned it off, put your shells in there.
Get back to us if you try it, okay?
Sue
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Well, I've tried this and it didn't work as well as I hoped. You must, of course, remove the inner membrane, which is probably easiest when the shell is still fresh. I dried the pieces and then ground them for some time with a pestel and mortar. It might be that electric grinders would make it finer but I doubt whether the blade would last too long with that abrasion.
I had hoped to post a picture here but haven't found out how to do it. The result was that ground chalk is a very fine powder; the ground eggshell was like coarse sand. It will work as a filler with pulp but gives a roughness so would be unsuitable for really fine work.
DavidO
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Wow dopapier, you are really on the ball! Thanks for doing this experiment.
I am sorry to hear that it didn't work though. It sure would of been nice if it did. 
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I would think you could let them absorb paint and mix the grains in; or sprinkle them on the pulp surface, and press in, painting either before or after. The ground egg could certainly give a roughish texture.
David
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Why not ball mill the eggshell to get a very fine powder? They can be easily improvised.
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What is a ball mill???
sue
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Sounds like it could be a bit like a flour mill ?
You could try using an old coffee grinder.
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A ball mill is basically a jar filled about 1/2 full with some kind of weight, like steel balls/nuts/fishing sinkers/marbles, and the rest filled with what you want ground up. It is then either shaken vigourously or rotated using a motor.
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Rotated sounds safer, like a rock tumbling machine.
Shaking steel balls in a glass jar doesn't sound very safe.
Sue
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Hi people
If you have a rough stone pestel mortar you should be able to grind down to a powder.
When we use to keep chickens we baked and ground down the shells to mix with the food and fed it back to the chickens.(It's good for them) 
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Today I came across this forum: (http://healthiertalk.com/viewtopic.php? … 6fe7a35c6d)
And someone mention that they used a rolling pin to turn the shells into a fine powder.
I wonder if it will work, I guess I'll just have to collect some egg shells and see. 
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I have some egg shells that I collected to break up for the compost bin. I dug out my old coffee grinder (electric) and ran them through it after mashing them up with worcestershire sauce bottle. Some came out fairly powdery, but had to be sifted out from the larger pieces that wouldn't seem to break down any further.
IMHO, it isn't worth the effort. Just get a cheap box of kids chalk and mash that up, as it's probably easier.
Sue
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One of the things that I like about papier-mache the most is my ability to make something out of nothing. I love the feeling of recycling something that would be thrown in the trash.
ME TOO! I have very little disposable income. Using recycled stuff is very affordable and very appealing too. Materials for the structure and the PM is cheap! The expensive stuff is the glues and the paints, but I'm hoping this stuff will go a long way (I'm just getting started).
Re: calcium carbonate from eggshells. Well, this seems a bit too much work. Tis much easier to sand a chalk stick and recover the powder. Getting the eggshell fine enough would be too much work for me.
I bought some chalk sticks today. I got 8 of these for $1 US. I'm pretty sure this will last a long long time!
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IMHO, it isn't worth the effort. Just get a cheap box of kids chalk and mash that up, as it's probably easier.
Sue
I know you are right Sue. I am just so obsessed with making my garbage go as far as I can make it go. (What can I say, I am a strange, strange
girl.) 
I will take your advice, because let's face it - your advice hasn't failed me yet and get a cheap box of kids chalk to mash up and make things easier on myself. I'll just use the egg shells for a calcium supplement for myself so it doesn't go to waste.
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Butterbee, a few chickens would go far to help you use up unwanted stuff. If you mash the eggshells very well, you can recycle them back to the hens. Not to mention your veggie leftovers and trims.
Hey, is this O/T or WHAT?!
Sue
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Hey, is this O/T or WHAT?!
Sue, well we have been really good lately. I think we deserve at least one O/T thread. 
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