Strength training uses a piece of equipment called an atlas stone.It can be difficult to buy in a store because it is so heavy.An atlas stone can cost a lot.Basic supplies can be found in a hardware store and a sporting goods store.
Step 1: If you can find it, use a stone mold.
It looks like a clear, acrylic globe with a hole in the top, if you buy an Atlas stone mold online.Atlas stone molds come in two parts.If you want to prevent the concrete from sticking, you need to wipe down the inside of the mold with a damp cloth.If you can't find an atlas stone mold, learn how to make your own.Click here to continue if you are using a store-bought mold.
Step 2: If you don't have an atlas stone mold, use a rubber playground ball.
Purchase a rubber ball from a sporting goods store and inflate it with an air pump.The atlas stone will be heavier if the ball is larger.Atlas stones range in size from 8 to 24 inches.The weight range will be between 23 and 586 pounds.Don't use rubber balls that have seams.Don't use balls on the beach.
Step 3: The ball should be on the bed of sand.
Set the ball on top of the tray with 6 inches of sand.As you coat the ball with plaster of Paris, the sand will keep it in place.The ball's plug should be facing down.It will be easier to deflate.You can use small pebbles if you don't have sand.The next step can be messy.You can cover your floor with newspaper if you work in a garage.
Step 4: There is a 6-inch (15- cm) gap between the coat of the ball and the plaster of Paris.
Prepare a small amount of plaster and apply it to the ball.Use enough plaster to make a thick shell.There is a 6-inch gap between the bottom of the ball and the sand.You can use this gap to fill the mold and remove the ball.Don't prepare too much at once because plaster of Paris sets up quickly.Before applying the next coat of plaster of Paris, let it set.
Step 5: The plaster should be dry for 24 to 36 hours.
The plaster ball should be left in the sand.When the plaster turns white, flip the ball over.Pull the plug out of the rubber ball to deflate it.The ball needs to be pulled out of the shell.It takes a long time for the plaster to dry.You can expect to wait between 24 and 36 hours.If you can't find the rubber ball's plug, you'll have to deflate it and pull it out.
Step 6: If needed, reinforce weak spots in the shell.
Make sure that there are no air bubbles in the shell.Next, look for weak or thin areas.Let them dry if you see any, fill them with more plaster of Paris.If the opening in the shell is not perfect, don't worry.
Step 7: Prepare the concrete according to the instructions.
Follow the directions carefully for each brand of concrete.If you want the best results, use a 5000 psi concrete.Adding concrete fibers to the mix will give it extra strength.Next to the concrete is a hardware store where you can find these.
Step 8: The mixture should be put into the mold.
You'll need a trowel to fill the mold because concrete has low-viscosity.If you fill the mold with concrete, you can reduce the amount of air bubbles.The sides of the mold should be tapped to make sure there are no air pockets.There is a 6-inch gap in the top of the mold.Make the concrete follow the curve of the ball.Pour the concrete through the hole in the top if you are using a 2-part Atlas stone mold.
Step 9: The time recommended on the package should be set for the concrete.
It can take as little as 24 hours to 4 days.Follow the instructions that came with your concrete.You are ready to go to the next step once the concrete has set.The ball should be covered with a damp cloth.It will help keep the concrete from cracking.
Step 10: The mold is around the ball.
To chip the sections away from the concrete ball, use a chisel and hammer.Start by pouring the concrete into the mold, then work your way towards the other side of the ball.The plaster of Paris should come away easily.Pull the halves of the mold apart.
Step 11: Remove any rough edges.
Even if you used a store-bought mold, there is still a chance that your stone will have some rough spots.To smooth them down, use a grinder or sander.If you see air bubbles or pits, fill them with concrete.
Step 12: If needed, let the concrete finish setting be used.
Check the instructions that came with the concrete.Once the concrete is taken out of the mold, some brands have an additional curing time.It could be as little as a couple of days.The concrete cure needs to be let go.The concrete will be prone to breaking if you don't let it cure.
Step 13: If you want, seal the concrete.
It's a great way to give your stone a smooth texture, but you don't have to do it.Simply coat it with a layer of concrete.Let it dry according to the instructions on the package.If the concrete is too smooth, buffing it with a sander or grinder will give it more texture.It will be easier to hold.