Call for Artists, Making Money at Juried Art Fairs, Craft Shows and Festivals
After you cut the pipe into 4 pieces, put the test caps in one end and place them with that end down on a level surface. Fill each pipe half full of the dry Sacrete and add one cup of water. You can stir this with an old broom handle if you wish, I did, but am not sure it mattered.
After a quick stir, add more dry Sacrete till the level is about 6 inches from the top of the pipe. Add one more cup of water and wait for the level to fall. Add water and Sacrete alternatively in small amounts till the level of mix is up to the top of the pipe.
Insert the test caps, with the eyebolts and nuts, through the holes, into the wet mix and push the caps down tight. Then push the eyebolts down into the wet cement, stopping a half inch or so from the cap.
how heavy are they each? how sturdy are they to stand up to someone falling into them?
I have similar weights and they each weight about 40lbs. and work quite well. I would suggest adding a handle half way down to make it easier to carry. Use a large U bolt at least the width of your hand. http://www.championtrailers.com/SS_BOLTS_UBOLTS.HTM Drill a hole into the PVC and attached it before you pour in the concrete. The U Bolt also makes it so the weights won't roll around in your vehicle..
Here is another example linked from Larry Berman's forum. http://artshowphoto.com/pages/weights.htm (the handle is a bit wimpy but every thing else is nicely finished).