Plasters which one

 
  anzac1959 Chief Commissioner

Its time to get away from flat poly styrene and add hills and hollows (so too speak) . Ive been told plaster of paris is too brittle, and to use plasterboard cement with netting , liquid glue added and when mixing it add coloured paint . I have used this process but was wondering about the longevity once set . What do others use ?

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  a6et Minister for Railways

Its time to get away from flat poly styrene and add hills and hollows (so too speak) . Ive been told plaster of paris is too brittle, and to use plasterboard cement with netting , liquid glue added and when mixing it add coloured paint . I have used this process but was wondering about the longevity once set . What do others use ?
anzac1959
I use Cornice cement for the scenery.  I once tried the adding of glue to the mix but found it really did not achieve any benefit.  I colour the mix with brickies coloured mortar powders, which you can mix to make up various shades.

In the past I tried the plaster clothe & then netting over the styrene & found that it just added another layer of work to the process, although that is not saying it is something not to do.  So in order to simplify the work I use Styro foam boxes & break/cut it in pieces to form the basic shape I am after, then cover with the cornice cement mixture working it to the shape I am after.

In the mix I put vinegar to help with delaying the setting of the mix, also disinfectant, & washing liquid. the Diso helps keep mould at bay, with the dishwashing liquid seems to keep the plaster in a dampish state for a couple of days, even though basically set. That provides time to scrape & cut the plaster for rock cuts & any other working.

By covering the foam with at least 12mm of the mix it helps not having cracks.  Using this sort of mix, & application I find it sets quite hard, & the old layout prior to moving had some sections of the scenery moved here but I never used it & it survived that, & some was around 7 years old when we moved & it arrived in a trailer no worse for wear.

I also use the same mix to raise the levels on the layout by just pouring on the baseboard & no problems with cracking so far. In corners & layout edges such as low embankments, I use flat styro foam with the same mix over the top, cheap & I cut down the thickness of the mix on these locations, the foam under the mix provides the best method for me to plant trees into.

We live in an active soil area where there is a fair bit of movement created, that shows up more on the backboards but so far that movement has not affected any of the scenery, except some very narrow embankments which have been replaced.
  Donald Chief Commissioner

Location: Donald. Duck country.
I have used plaster bandage - the stuff hospitals use when you break a leg or similar - over the top of the styrene bits.   This saves on the amount of cornice cement you need to use.   It gives the basic outline that then needs the cement to give a bit of the rocky look.   If you are covering the hill in grass etc, then the plaster bandage may be sufficient.
  a6et Minister for Railways

I have used plaster bandage - the stuff hospitals use when you break a leg or similar - over the top of the styrene bits.   This saves on the amount of cornice cement you need to use.   It gives the basic outline that then needs the cement to give a bit of the rocky look.   If you are covering the hill in grass etc, then the plaster bandage may be sufficient.
Donald
By using the plaster bandage & the alternatives such as cheese cloth or Chux soaked in the cornice cement you need to ensure there is no air gaps between it & the Styrofoam, as over time the plaster cloth will crack up especially in areas of temperature extremes & movements such as I have experienced.

Likewise it can crack fairly easily once fully dry if you try to drill holes in it for tree foundations.

The aspect of having the clothe just as a base for grassing is not a bad idea, although just using the cornice cement mix usually is sufficient for that.

What I also do on hills with the cornice cement is before it dries (forgot to put this in before) is to cover the mix with brickies sand & rub it in, that creates a dirt like look for the ground, the sand also absorbs the colour of the brickies mortar powder to blend in, & often enough for a soil look, then add the grasses.

On the hills, the same sort of work does help in creating a better sandstone appearance.

When I went to get the sand I went to Bunnings, around $7.00 for a kilo or two bag, or $16.00 for 20Kg its a bit more corse than getting at a landscape supplies though, at landscape or builders suppliers you can get the sand much finer & in both Sydney White or Yellow.  The very fine white is excellent to use as "Bombo Dust" areas such as in depots & painted over.
  Hendo Deputy Commissioner

You could always try another method with little or no plaster. A big roll of the discount Chux cloth with diluted white glue, paint or brickies mortar colour. That way you keep the plaster where you want rocks and save the weight and cost. This method has been successfully used by a number of modellers. such as the Canberra N Scale Group on their portable exhibition layout, so it must be strong enough.


Cheers,
Hendo
  LaidlayM Chief Commissioner

Location: Research
Maybe it's time to move away from plaster as well.  Why not try Goop?  Google "Lou Sassi Goop".

My recipe in Australian terminology is:

1 cup of Papier-Mache mix from craft supply store.
1 cup of Vermiculite from Nursery.
1 cup of latex paint from paint shop.
1 cup of white glue from hardware shop.
Water as needed to create peanut butter consistency.
1 cap only of Lysol from hardware/supermarket.

Mark
  wolfpac Minister for Railways

Location: Over here...
You could always try another method with little or no plaster. A big roll of the discount Chux cloth with diluted white glue, paint or brickies mortar colour. That way you keep the plaster where you want rocks and save the weight and cost. This method has been successfully used by a number of modellers. such as the Canberra N Scale Group on their portable exhibition layout, so it must be strong enough.


Cheers,
Hendo
Hendo
This is what some of the guys at the club did on my module years ago, Chux over the top of carved/shaped white foam. (Came back one day to have it on one of my Free-mo AU modules)

Nice and light, can just shove trees into it and pretty resilient to knocks etc.

Saying that, naturally it soaks up EVERYTHING. You'll need a lot more glue and paint to cover it, naturally. It's kind of what Chux are good at doing, after all! Laughing

Wolfpac
  TheBlacksmith Chief Commissioner

Location: Ankh Morpork
This is all pussy stuff, build your scenery in concrete as Rick Richardson did on the Vulcan Vale layout. Then you can walk over it to get to the far corners.
  John_Bushell Chief Commissioner

Location: Brisbane
Provided you will never want to move the layout.
  danpickard Junior Train Controller

Location: Geelong
I use a thin layer of plaster bandage over a roughed in terrain shape (either from scrap polystyrene, or more better shaped in wire mesh).  The plaster bandage only needs to be enough to cover the shape, and not heavy multiple layers.  I then "skin" the layout with No More Gaps (or similar cheaper brands of acrylic gap filler).  Squeeze it onto the plaster bandage base in liberal blobs where you are working, put on some gloves, get your hands wet ( and keep getting them wet as you work), and smear the No More Gaps all over the surface.  You can also use an old paint brush to do the No More Gaps spreading, and again keep it wet as you work. It will end up being a couple of mm thick once finished, and create a slightly rubbery skin over the terrain.  The plaster underneath wont crack or chip with this over the top, and the No More Gaps skin is robust and fairly light weight (especially from an exhibition layout perspective, so the surface also has a slight flex to it to be forgiving during transport and movement...no unsightly whit plaster crack spots to fix all the time).

Cheers,
Dan Pickard
  wolfpac Minister for Railways

Location: Over here...
This is all pussy stuff, build your scenery in concrete as Rick Richardson did on the Vulcan Vale layout. Then you can walk over it to get to the far corners.
TheBlacksmith


Laughing

Wolfpac
  TheBlacksmith Chief Commissioner

Location: Ankh Morpork


Laughing

Wolfpac
wolfpac
And very few people are aware that Chuck did not have to touch that rock, he just spoke to it and gave it a choice......
  wolfpac Minister for Railways

Location: Over here...
And very few people are aware that Chuck did not have to touch that rock, he just spoke to it and gave it a choice......
TheBlacksmith
LaughingLaughingLaughing

Wolfpac
  barkfast Station Master

I use a thin layer of plaster bandage over a roughed in terrain shape (either from scrap polystyrene, or more better shaped in wire mesh).  The plaster bandage only needs to be enough to cover the shape, and not heavy multiple layers.  I then "skin" the layout with No More Gaps (or similar cheaper brands of acrylic gap filler).  Squeeze it onto the plaster bandage base in liberal blobs where you are working, put on some gloves, get your hands wet ( and keep getting them wet as you work), and smear the No More Gaps all over the surface.  You can also use an old paint brush to do the No More Gaps spreading, and again keep it wet as you work. It will end up being a couple of mm thick once finished, and create a slightly rubbery skin over the terrain.  The plaster underneath wont crack or chip with this over the top, and the No More Gaps skin is robust and fairly light weight (especially from an exhibition layout perspective, so the surface also has a slight flex to it to be forgiving during transport and movement...no unsightly whit plaster crack spots to fix all the time).

Cheers,
Dan Pickard
danpickard
I'm assuming that this would also work directly over some form of mesh material such as old fibreglass fly screen... or even cheap chux??

It sounds quite appealing because unlike plaster/spakfiller/etc it doesnt take 24hours to set....
  danpickard Junior Train Controller

Location: Geelong
Yup, will work over what ever material you use to create the initial terrain shape (be it a mix of small boxes, chicken wire frame, cardboard lattice, screwed up newspaper etc etc...doesn't matter, pick your flavour) as long as it creates a terrain base to lay the plaster and No More Gaps over the top of.

Cheers,
Dan Pickard
  yogibarnes Locomotive Fireman

I have a large layout.  Economies of scale rule.  
A time honoured and cheap method:  I use cornice cement (plaster) available cheap in bags up to 10 and 20 kg.  In thin layers it doesn't shrink when it dries.  I lay it on shadecloth (plenty of scraps in most backyard sheds) stapled to the woodwork framing.  The shadecloth is stiff enough to hold its shape but flexible enough to be shaped and stay in place once stapled.  If a large area requires "backing", stuff underneath with newspaper and after the subsequent plaster dries pull it out leaving only the plaster/shadecloth shell.
Rough squares of newspaper are dipped into cream consistency plaster mix and pulled across the edge of the ice cream container.  Resulting wet newspaper is placed onto the shadecloth and rubbed in.  By getting the plaster into the netting the resulting layer is strong.  After drying, repeat, two layers minimum for strength, more if you are going "plant" trees etc by piercing/drilling holes.  
After thorough drying and adding any rock mouldings etc, paint it all using household base colour acrylic paint, drab browns etc, watered down and proceed with detailing from there.
Used on quite a few of our club members' home layouts and works every time.

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