OK, this is mostly to start the begin the thread for my series of tests, but I wanted to start with some examples also. Now you'll have to keep in mind that this first part was purely an experiment, just to get my feet wet.
Here is the picture of the expoy I received.
Then I went to Home Depot and bought some aggregate. I bought .5 cubic feet of marble rocks. It was about $4. I bought a 50lb bag of playsand, that was white and small. It was also $4. I also bought a toilet bowl ring. It's made of bee's wax. I'm going to try it as a mold release agent. I also use it in my woodworking, so it serves two purposes. I also went outside my place and gathered a few handfulls of medium sized rocks. I just wanted a good mix of sizes. Here is a pic of all three categories.
I also bought a 12x12" granite tile. It's about 3/8" thick, and seems very flat. It also has a very smooth surface. It will serve for some testing purposes.
So then I washed the rocks. I used a straining bowl, and washed them with water. For the sand, I would fill the bucket up half way with water, then empty out the cloudy water. I did this about 10 times, and it was pretty clear. I would definetly want to streamline that process, a larger slab would take FOREVER!
I had already set the over to 400F, and put the aggregates on a cookie sheet.
It didn't take long at all for the bigger rocks to dry. But I had to spread out the sand some and it took about 20 minutes. I really don't think this is how I'd normally do it, but I just wanted to do something tonight.
I decided to try the 1:1 epoxy first. So I mixed a table spoon of each in a mixing bowl. Once it was mixed well enough, I added some of each aggregate. Of course I only used a few of the big rocks, more of the middle rocks, and filled the rest with the sand. The sand absorbed the sand surprisingly well, and definetly made a semi-pourable mixture. The 3:1 epoxy has a hardener that is thinner than the 1:1. So I'm sure it will be even more pourable.
Here is a picture of the mound I made.
This weekend is when I'll be at my shop and doing some real testing. I already learned an important lesson about wearing latex gloves. I wasn't wearing any, and got some epoxy on my hands. It's tough to get off! I'm also going to buy a whole set of bowls and utensils to use, instead of my wifes. I will be making some square molds this weekend, and making some 1" thick, 8x8" blocks.
Some more observations. There was really no heat involved. The rocks were still warm from the oven, but the epoxy generated no heat. After i mixed everything, I used a thermometer to measure the temp, it was 114F. After thirty minutes, is was DOWN to 105F. After 3 hours, it was at room temp which was 77F. It's definetly getting harder, and I'm going to give it until the weekend to do some strength analysis. I'll probably break it in two and see about voids and how hard the center is. I have plenty of woodworking tools at my shop, and am going to use the ideas about sanders and other things to vibrate the molds. I have an old scoll saw that will vibrtate the thing to pieces! Finally found a use for that thing!
So again, this is really just to get the thread started, and get more ideas flowing. Again, if there's anything I'm missing, or a better method of experimentation, please let me know. I've never really dealt with epoxy, so this is all new.