sticking molds to plaster

i am making basic molds and having trouble getting them to "stick" as i apply
them to the mountain that is covered in a thin base of plaster for structure.
just curious as to what works better.
thanks
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Reply to
AndyPaul
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Wet the thin plaster base. What is happening is that the dry plaster base is drawing the water from the mold and is making the plaster that you are applying too dry to cure fully. If you later go and wet the plaster mold down and make sure that the water gets down to the base, it will also allow the plaster to cure for the stuff that you have already done although a full one shot cure is the best.
-- Bob May Losing weight is easy! If you ever want to lose weight, eat and drink less. Works every time it is tried!
Reply to
Bob May
Dry plaster acts as a sponge and soaks up water from the plaster you're trying to use as "glue" for the castings. Wet it down. If you want to know if you wet it enough, drop a little of the "glue" plaster on it. If the "glue" gets water soaked up from it, it's not enough on the shell. Add more water. Once you've done it a few times, you'll get the feel for it.
This method can be applicable to wall plaster and drywall repairs also, so it's useful to know.
Jay CNS&M North Shore Line - "First and fastest"
Reply to
JCunington
Right. ANY time you're putting fresh plaster over old plaster, whether it's adding a mold, or a wall repair, or adding another layer of hardshell, fixing a crack, WHATEVER.
ALWAYS wet down the old area first.
Don
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Reply to
Trainman
Wet down the base plaster you are trying to stick your fresh rock mold to. Then load a mold full of fresh plaster and hold it in your hand. Work it a bit until you can see the palster *trying* to crack. At this point the plaster is still wet but not as soupy. Transfer the whole thing to your prewetted area and hold your hand on the mold until you feel it getting hot. The heat is the plaster setting up. After about a minute, pull the mold off and you should have a nicely detailed rock face staring back at you. Good luck. Doug
Reply to
Doug
The only time I haven't done it is when I'm fixing air bubbles in a casting. Then I just mix the plaster a little thin and pack it in with a dental pick. Of course, if I were a little more careful not to trap air in the mold...
Jay CNS&M North Shore Line - "First and fastest"
Reply to
JCunington

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