Just want to share a little warning with you. I'm not sure if you had a simillar experience with this.

Be careful when you are using Plaster of Paris for your groundwork. I had a near disaster when I made my groundwork for my diorama.

Since we don't have Celluclay here, I decided to use Plaster of Paris for the groundwork of my 16 X 22 inch dio. My plan was to use Plaster or Paris as groundwork. While still wet, I was going to sprinkle finely sifted garden soil for ground texture.

I mixed up a bowl of PP to a smooth working paste. Then, I applied it to the base with a spatula.

But to my horror, the PP cataclyzed almost immediately....around two or three minutes. It was very hard to spread around because the paste becomes harder by the minute. There's almost no chance to "sculpt" it. I had to chip off the hard plaster little by little because I haven't had time to sculpt it.

Tonight, I'm going to attempt the groundwork again, this time, using finely sifted soil mixed with water and white glue. I think it would give me a better groundwork material.

For small dios, I think PP is okay since there is only a small area to cover, which means, lesser time to sculpt and spread it around. But for large dios, it's better to use Celluclay or something else.

I'm not sure if anyone here had the same experience.

Angela

Ooh yes! I gave up on Plaster years ago. It shrinks, it cracks, it makes a mess when you mix it, it runs from vertical surfaces (try to cover a styrofoam 'bank' with it. ). I have tried clay, but that shrunk aswel. Not impressed as I made all the tyre and trackimprints, which went from 1:35 scale to 1:72! :-) . I now use tile adhesive only, it's the stuff you stick tiles to walls with. Soft but not runny, takes textures very well, dries slow enough to do a large dio, doesn't shrink.
If you try the white glue method, which I use for small bases, remember to seal the wood first otherwise it will warp. Unless your base is three inches thick

Cheers
Henk

Hi Angela,

Why not just use styrofoam covered with wall putty. I did that in my dio...its lighter and cheaper. I used Bosny acrylic wall putty but you could actually use other brands.

First shape the landscape based on your preference, after which cover it with the wall putty...you could also countour the ground as you like. Once dry you could paint it with earth colors. Once the paint is dry, brush diluted PVA on the base then sprinkle your garden soil...wait for it to dry....

Just a suggestion

Hi there angie...

i have bad experience with PP before.... in fact the same scenario happen to me on my trial and the only attempt to use PP..the PP look like set immediately when i mixed them with water..after trying the 2nd attempt, i gave up...keep the PP inside a tight container until recently i met beachbum

well, we don't have celluclay or other modeling material that the lucky americans have...so we have no choice ...

last 2 week i was talking to beachbum about the base for my dio and he also learned the problem i faced with PP... and here's the magic word, what happen is the ration of water : plaster MUST be approx 70% plaster and 30-40% water... that's the ingridient he told me and i try it. It works!
sometime i mix white glue in the water and mix with PP.
Yes, they do crack sometime, but that's the only cheap alternative that i can found local. The carck wont be visible if i add a layer of sand on it.

Hi warthog,

Well, that is a great idea warthog.

The problem though is that admittedly, (oh this is so embarassing),I...ran out of patience. I've already sifted a lot of earth already and my arms were aching all over from sifting. I've sworn on my soul that that sifted soil will NEVER go back to hallowed ground without paying the price.

I'm going to try that sometime, though, when I make another dio.

Hi Silantra,

Thanks for the suggestion but I don't think I'm going back to PP for groundwork. It's just too quick.

Angela.

Plaster of Paris is not the same as plain plaster...... it's designed to cure at a rather fast rate. We use to make molds from Plaster back in the old days at college, had a fine working time, but it certainly wasn't Plaster of Paris.
If you can't fine regular plaster, try some good old fashion spackle, (Not this new light weight crap) comes premixed, you can thin it if you want, and has a longer working time than Plaster of Paris. Today I prefer using good old Durham's Water Putty.... dries rock hard, easy to mix, The thinner it is the longer the cure time, can add water saluable colors to it (the pigments add to the cure time though especially acrylics) You can carve it, drill it, and tap it, and if you sprinkle dry powder over the wet mix, you end up with a nice pebble, rock texture. Nice part is it doesn't stick well to plastic or polyurethaned wood, so you can form your ground work on the sealed base, and let it cure, and then you can remove it from the base, paint it, do what ever else you want to it, the just glue to back to the base for a perfect fit. Thin it is fragile, thick strong as granite. I usually try for a 3/8 to 1/2 thickness. Oh and shrinks very little. Of course the more water, the more it will shrink.

Ouch - no fun at all - I know what you mean about wanting to make progress after a long teadious task.

Honestly - I never knew the difference between plaster of paris and plaster. Thanks grump'.
I personally use celluclay (sorry you can't get it), or Woodland scenics plaster, it has a nice decent work time, not to long not to short. You can control it some with how wet you make it.
The other item I use a lot is house hold spackle (wall putty). You do need to be careful with this because some type will crack if they are to thick. Not a drastic deal if you have time to re-putty and fix the cracks.

Hmmm.... I tried mine in my 6 x 12 inch dio and it worked fine. Try this: use more water and less plaster. It would take long to dry but the spreading would be evenly.

Hi Ralph,

I did put more water. It actually has the consistency of cake batter. But it still dries to quickly.

Thanks for all the suggestions people.

Angela

Angela -

Definitely feel your pain. As with others, I like the styrafoam approach (especially with any "raised" terrain, or trenches, banks, etc.) then cover with either the Woodland's plaster or Spackle. As with all, I'm still trying new approaches and trying to learn better methods. Thanks to all for ideas/suggestions, I plan on trying some for my next diorama base.

Blade48mrd

Hi Angela,

Don't worry about the earth that you sifted...as mentioned earlier, you are still going to use that soil on top of the wall putty. You actually need the soil to cover the putty so that it would look realistic. BTW, I read somewhere that you sould put the soil in a microwave to kill some of the bacteria..

Cheers

Plaster of Paris has such a high water content (50% or more) that shrinkage and base warping should be expected. Wall Packle is a slower curing product, and has only about a 35% water content. You can also mix in acryllic paint to "pre-color" it before applying as ground cover. Better still, it is fairly inexpensive, and availalbe at most any DIY store...

Aaarrrgggghhhh!!!!

I used the technique in "making cheap basis and groundwork" in Missing Lynx (I think it's also here in this site) using fine sand/earth for my groundwork. I mixed it with white glue and water until it became a chocolate cake batter and spread the muck all over.

Damn! It's so messy. And now, it takes too looonnngg to dry. I placed quite a lot of groundwork last night but it still hasn't dried up when I checked it this noon.

If this won't dry out tonight, I'm going to throw that diorama away and burn all my models.....

...just kidding. I think I'll just scrape the muck off again, clean/scrub the base and put wall putty as advised for groundwork if the muck doesn't dry up tonight. But then I have to wait for next day to go to a DIY store to buy some wall putt....

This is soooooo frustrating.

I've been modeling for sometime now but this is my first attempt to put together a dio.

Angela

angela,

just a word of advise " be patient dear" ... when i try my first dio attempt it was so frustating... i never try those method before but my normal ground material are sand, PP, white glue and water.... after a while a friend suggested that the mixture should be like ice cream viscosity (before it melt )

anyway, good luck on your second attempt

thanks for the warnings and tips here as I am about to do some bases for most of my stuff and I would have fallen prey to the plaster of paris thing too

Angela,

Be patient, dilluted PVAs really take time to dry out. You are a girl...use your hair dryer it really helps a lot.

Hmmm...that reminds me.. I have to buy my own coz my wife does not want me to over use her dryer...
:-)

Cheers

HaHa..that reminds me too ..
about 4 years ago i bought a hair dryer then my then girlfriend (now wife) thought it was for her.. Naaa..it's for my hobby!!

Hit this post a little late, but Angela, I did my Tiger dio groundwork all in plaster, it was roughly the size of the one you're trying to do now...large! :-) Like your groundwork, the plaster started to dry pretty quick, but I managed to shape a rough design. I came back 15 minutes later, and touched the plaster to see how it was coming along, and whoa! It was hot to touch! When it fully cured, I had to chisel some areas to make my Tiger sit flat, then I added my dirt/grass to the plaster. I've made the dirt white glue batter for groundwork too, works really well, yes it does take a little time to dry, but don't worry, be patient, work on something else while it's curing.
Now I use either sanded/non-sanded tile grout for my groundwork. It has a little more working time, if I don't have any slopes in my dio, I simply just spread the grout powder over my base, then take a spray bottle with some water, and lightly spray the powder to make it slightly damp. Then I take my bottle of white glue/water mix and start applying it to the grout.
Let sit for a few minutes then you can start to shape the groundwork while it's curing, and when done, it dries rock hard and won't crack.

Angela, don't throw it out or scrape it as yet. Sounds like you may have added a bit too much water. PVA depending on the mix needs about 24 hours or so to gain full strength. It is also possible that the soil mix you used had moisture in it too making it even more mucky.

Trouble with us here in the tropics is that the humidity is too high making drying times longer. Try putting it outside but away from direct light and shaded from rain. Trying to blend in a soil/sand/glue into semi wet plaster is tricky. Its best you let the plaster dry first. Then apply a layer of PVA:water (50:50) mix over the plaster with a brush and sprinkle the sand/soil over it with a tea strainer in thin layers. The tea strainer helps to give a more even spread.

Wait to dry. Blow off any loose soil and add additional PVA:water mix to the bald areas and apply soil again. Mixing them altogether is not advisable unless you've played around with the soil:PVA:water mix before and know the right proportions vs drying times.

To get contours and high points use stryfoam to get the rough shape and then add plaster over it. Once the plaster is dry then apply the soil as above.

I use PP for years and had no problem. The best mixture of it is 2 parts of water for 3 parts of plaster. If you use it on a large area you must pour it in little sections. If you're pouring it on a wooden base, the wood will absorb the water from the plaster prep resulting fast hardening. Also the wood base can change its shape by bending when it' wet, result: cracking! Izolating the wooden base with varnish is a good solution.
The storage of PP is very important. If it catches some humidity the results are devastating. Much humified PP will harden so late and will retake the powder form after the complete evaporation of the water. Less humified PP will harden so easily which shortens your time of modelating..
At last here are the tips:
-For a longer hardening time add some bicarbonat in the mixture (baking soda)
-For a short hardening time add some kitchen salt in the mixture.