First attempt at a rock mold
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Thanx Roy, I forgot to mention that little tidbit!
I do that and get it into all the nooks and cranies (especially the cranies) with a soft brush. Makes the rock come out much better.
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wheeler1963
Wheeler's Trains
Thanks Rick!! Just got them washed with Quick Age. they look so much nicer now.
Roy Buchanan
Member
Molds
Make sure you use a release agent like water with a drop of soap or alchohol. this will prevent the casting from sticking to the mold. Looking good.
Roy
Make sure you use a release agent like water with a drop of soap or alchohol. this will prevent the casting from sticking to the mold. Looking good.
Roy
wheeler1963
Wheeler's Trains
Roy, thank you for that, I'll try it tonight.
Rico
BNSF Modeller
Thanx Roy, I forgot to mention that little tidbit!
I do that and get it into all the nooks and cranies (especially the cranies) with a soft brush. Makes the rock come out much better.
wheeler1963
Wheeler's Trains
i'm using hydrocal
Roy Buchanan
Member
I use plaster of paris. Just make sure you jiggle the mould to ensure that any bubbles in the casting medium get out.
Roy
Roy
Trussrod
Well-Known Member
A lot of good info guys, adding rock castings does add a lot to your layout.
I've always used Hydrocal and made the mixture on the soupy side, using a slim semi-stiff brush to ensure the the plaster gets into the nooks & crannies is a very good idea too.
There is still a couple of other tricks yet you guys can try that I've used. Sorry for not having any castings to display at present.
1st. You don't have to by ready made molds, you can make your own by purchasing some liquid latex and after cleaning the surface of a rock or portion thereof you want to make a mold of you can. Also molds don't have to be thick and or stiff. Some very interesting designs can be obtained by overlapping over rock castings even if only on the edge. Also the same mold can be rotated at whatever angle you like to give a different effect, as long as it will look believable.
I often create a generally shaped hillside from crumpled heavy paper shopping bags that I've somewhat flattened out and attached to the cardbord webbing used to form the general shape I want and then mix up a soupy batch of hydrocal and paint it over the paper bags to form a thin hard shell. Then I also take some of the same soupy mixture and pour it in the mold I have and let it just start to set-up where it isn't runny any more and then after wetting the area I want to apply it to with some water and a couple of drops of dish soap I lay the still wet mold against the hillside and hold it there for thirty to forty-five seconds to allow it to adhere good and then let it set for about another minute before pealing off the flexible rubber mold to show the casting perfectly conforming to the irregular shaped hill side in a very natural fashion. The same process can be repeated with the same mold of if you made others you can add some variation and don't forget to leave some open space here and there for dirt to show up.
Often along the road there will be a cut through a rocky area and often you can find some very interesting rock surfaces to make a mold from.
HTH
I've always used Hydrocal and made the mixture on the soupy side, using a slim semi-stiff brush to ensure the the plaster gets into the nooks & crannies is a very good idea too.
There is still a couple of other tricks yet you guys can try that I've used. Sorry for not having any castings to display at present.
1st. You don't have to by ready made molds, you can make your own by purchasing some liquid latex and after cleaning the surface of a rock or portion thereof you want to make a mold of you can. Also molds don't have to be thick and or stiff. Some very interesting designs can be obtained by overlapping over rock castings even if only on the edge. Also the same mold can be rotated at whatever angle you like to give a different effect, as long as it will look believable.
I often create a generally shaped hillside from crumpled heavy paper shopping bags that I've somewhat flattened out and attached to the cardbord webbing used to form the general shape I want and then mix up a soupy batch of hydrocal and paint it over the paper bags to form a thin hard shell. Then I also take some of the same soupy mixture and pour it in the mold I have and let it just start to set-up where it isn't runny any more and then after wetting the area I want to apply it to with some water and a couple of drops of dish soap I lay the still wet mold against the hillside and hold it there for thirty to forty-five seconds to allow it to adhere good and then let it set for about another minute before pealing off the flexible rubber mold to show the casting perfectly conforming to the irregular shaped hill side in a very natural fashion. The same process can be repeated with the same mold of if you made others you can add some variation and don't forget to leave some open space here and there for dirt to show up.
Often along the road there will be a cut through a rocky area and often you can find some very interesting rock surfaces to make a mold from.
HTH
RW&C
N Scale with Stone Tools
Jony, sounds like a weak mix/old plaster. Try another batch of plaster, thicker mix, let it cure a little longer. Mold release will also help. It doesn't have to be the good stuff, I've made decent castings from hardware store Fix-All patching plaster.
If it's a large or thin section you might try sinking some screen or wood scraps or something in the plaster to give it a little strength, but make sure whatever you use doesn't touch the mold or it'll make the casting look funny.
If it's a large or thin section you might try sinking some screen or wood scraps or something in the plaster to give it a little strength, but make sure whatever you use doesn't touch the mold or it'll make the casting look funny.
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