Gather your supplies. Make sure you have everything you need ready to go. Once the mix is well, mixed, you have to be quick.
Cover everything in a 50 foot radius with newspaper. Okay, that's just how I would do it if I were doing it again. You can cover your immediate work area only if you want to. I'm warning you though! Don't come commenting back here telling me that your dog is concreted to the floor tomorrow.
Mix the plaster according to the package instructions. I sprayed my form with Baker's Joy just to be on the safe side. I had this feeling the plaster wasn't going to release. It may not have helped. I don't know.
Once your plaster is mixed well to the consistency of pancake batter, pour it into your mold.
I know you think that you need to wait and let it sit for a minute before you add your insert (I used a votive cup) but you don't. Maybe a minute, but no more. Sit the votive cup centered in the top of the form and let it sit there.
My first 2 batches I thought I needed to wait because I just knew they were going to sink. Turns out it was already hardened and it ruined that batch... and the next one too. I'm obviously not a quick learner. So the third batch I immediately put the votive cup, well, by this point I'm using tea lights because my votives were concreted in another form by now.
While I'm sitting here, browsing my Google Reader, I had this bright idea to try to remove the first 2 batches from their forms just to see how hard that task was going to be. I tapped on it a few times and I couldn't get it to release. I'll give you the dialog from here...
Me: Babe, can you come here for a minute, please?
Mr. Messy: Sure, whatcha need?
Me: Will you see if you can get this thing out of here? It's stuck!
Mr. Messy proceeds to squeeze, tap, jiggle, tap some more
Mr. Messy: Crap, where's the broom?
I gasp, put my palm to my forehead and try to keep the dog from eating semi-hardened plaster.
I'm going to go out on a limb here and say that if your package says you can remove from the form in 20-30 minutes, don't. It might be hard, but it's not cured and a little bit of pressure will make it crumble. Just wait until morning, just sayin'.
The next morning I popped them from their forms, sanded down the edges just a tad and put fresh tea lights in them. I have no where in particular for them to go, but after all that, I feel like they need a glass case to be proudly
I found a tutorial to make a cardboard form of a monogram and plaster a giant letter that I might try when I get the kitchen cleaned back up in 2014.