Johnny, ....I got the jello egg molds, too, & molded up a set of plaster of paris eggs.   They weigh almost exactly 80grams each, which is a nice weight for me, tho a little light for the sturder lads who prefer 100-150gram ammo.  Getting the thick liquid plaster into the closed mold was hard & messy.   To do it again, I'd use a heavy-duty ziplock bag.   Fill it with plaster.   Clip a corner to make a nozzle & squeeze the bag to inject the plaster into the egg molds.   I greased the molds, too, but I'm not sure it helped a lot.   Finally, it's tuff to open the mold with the hardened eggs inside, so I dont know how many sets of eggs can be gotten out of one mold.     mgreenfield

Johnny, I'd use sand mix. Cement and sand without the aggregate (stones). It will pour into a mold better. You can buy this premixed in a bag. Sometimes it is called patching concrete, too.

I suppose you could if you added enough water.

If the molds are two parts, then why not fill each half of the egg and 'slap' them together before the concrete and fall out?

Or, go the other way. Use only enough water to make the mix sticky and roll a whole egg in your hand first, place in the mold, press together so the concrete takes the shape, and set aside to cure. Technically, the latter will make stronger concrete.

Johnny,

Get the strongest concrete mix you can find.  High Early Strength should be printed on the bag.  This stuff hardens quicker and gets much stronger than the normal stuff. 

Additionally, get a grout bag.  This looks like a cake icing bag used to decorate cakes.  Mix the concrete as instructed.  If it looks a bit thick, add some water.  Then spoon it into the grout bag and fill the eggs.

Remember, no aggregate larger than sand, unless the concrete mix has fibers in it which would be good.

jeff <><

Most of the stuff should be available at any large home store like Lowe's, etc.

You may have to make your own grout bag, though.  Any thing will do, like a zip-lok bag, as mentioned earlier.

Make sure you let the concrete harden sufficiently before throwing.  Even the high early strength stuff could take weeks to get to full strength.  So, be nice to the for a while.

jeff <><

Johnny,

Yes, another great use of the empty 5 gallon bucket!
My son and I are on our third one. We use them for the head of "George the Roman" --one of our fasvorite slinging targets.

Yurek
What is sand plaster? Sand and plaster mixed together?
Thanks