How do you use plaster??

Model Railroader General Discussion (Model Railroader)
1

I bought some plaster today and used a little but it hardend in the bowl after about 7 minutes. I was wondering if I did something wrong. Im using plaster of paris and it says it hardends in 20 to 30 minutes.

Victor

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2

If this is a serious question, then here is an answer. If you use water that is too warm or put too much powder into the mix or even if you over mix it you will end up with a hardened lump. Maybe you can paint it and use it for a rock face or something…

Scott

3

Use cold water and mix it a bit thinner even them you want to work quite quickly, I’ve heard that if you mix in a little white vineger it will extend the work time some but I don’t know as I’ve never tried it.

bill

4

Some plasters are suppose to set up really quick , such as Plaster of Paris. When I did my layouts mountians I used joint compound, the stuff used on drywall in houses. I put some in a bread baking pan( my wife was less than pleased with this) and deluted it with water , about 2 to 1 plaster I think but best to experiment. Then I dipped brown paper strips, about 2 inches wide and laid it on the mountian. The set up time was well over 10 minutes. And this stuff dries really hard and has been on my layout for over 18 years, no cracks etc. If you put it on to thick , it will crack , but you can just fill the cracks the next day. Hope this helps.

5

I started a post on this very same topic a few days ago. Check it out, it may help you. It did me!
http://www.trains.com/community/forum/topic.asp?TOPIC_ID=57355

6

Thanks for the info. Im using the hardend plaster for rock castings. I will just mess around with it. I used 2 parts plaster to 1 part cold water. Thanks again guys.

Victor

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7

I had the same problem! Igave up and just used Woodland Scenics plaster cloth, works great and low mess factor.
Peter

8

I have a little plaster cloth left but wont be able to get any for a while.

Victor

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9

I know this all too well ,lol ,I use about 5- 6 towels worth of plaster.mess with it with my fingures till i can feel it setting up then i moved quik.the nice thing is when you get to nitty gritty you make rocks with it hope this helps

Carl,

10

Thanks carl. It does help.

Victor

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11

If you ar dipping paper towels in the plaster to layer over scenery forms, try dampening the towels with a spray bottle filled with water. This causes the towels to pull less moisture out of the plaster and allows you to work with it longer.

Ron

12

This is a very good point. Of course, there is a tradeoff; the plaster that you retard for setting that way will also have that much longer to sleek and sag off the carefully arranged pieces of cloth or paper towel, and to pool around the base of the structure where you don’t necessarily want it.

13

Thanks guys. I havent had time to work on the layout since I posted this topic but I should be able to work soon.

Victor

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