Depends on the depth of the mold, but 24 hours would be a minimum.

Hmm.. if the temp is cooler, they need to be in longer, I usually try to wait at least 36 hours, 2 days if I can stand it. They should drop right from the molds, otherwise your mold release isn't working properly.

I'm sorry you had the problems. I always seem to screw up when I'm all proud that I made 4 or 5 in one day....

I'm not sure what a planter liner is, but still, the concrete should not have broken on it's way out. Was it soft in the center?

Gina

Premix can be poor for stones.
Because of the size of the agregate your stones should be a minimum of 2 inches thick.
If you used a bit too much water 24 hours might not be enough time.
Premixes are often not a strong mix.
If you want fool proof stones add a quart of Portlands cement to each bag of premix.

Do you hate carrying those stones around after they are made.
Try adding a poly rope handle in the edge.
1/4 or 3/8 inch rope, tie a knot in each end of a foot long chunk and bury each end in the concrete an inch from each side of the stone leaving enough rope sticking out to form a handle.
When you are done packing these stones around cut the handle off or just hide it underneath for easy moving next time.

For big stones try two handles.

What a great idea to pull them to the spot designated for the stones. My main problem would be to find portland cement in a more manageable size. The supply store only carried it in 90 lb. bags. Neither my husband or I can carry it. Any other suggestions?

Vicki

Vicki
Most any place that sells to bricklayers etc would be happy to transfer the cement to buckets for you.

5 gallon buckets are free at Burger King with nice tight lids
Get the cement transfered to three or four of those pails and it will last you a long time.

Most bulk food stores give away the 3 gallon buckets which are even better. 3-4 of them will hold a bag of cement and take less room.

I too am wondering about if it is possible to get portland cement in smaller quantities. It has been my experience that even in buckets cement mix of any sort does not make it through the winter. I am no longer making the quantity I once was but would like to make one or two a season. I would prefer to buy it 10-30lbs at a time. Does anyone know if this is possible at a foundry even.

arcy the problem is most places won't sell you $3 worth of cement.
It costs more in labor for the guy to shovel it into a bucket than it's worth.
Buy the big bag and throw away whatever goes bad.
Or share with a neighbor.
Almost everyone has a little project in their yard that needs doing.