I can vouch for that stuff Brian, Iused it all over my previous layout,great for all sorts.

:doublethumb:cool:

What a great idea guys. :cheers:cheers:cheers    I'd never thought about plasterboard glue and you're right - it does stick to everything.  Watch out "Point P" (our local builders merchant) - I'm on my way - the French arm of B & Q is called Castorama and the nearest to me is an hour away !!!!

Re the cleaning out of bowls . bendy ones are best similar to tupperware. I look out for the xmas pud plastic bowls at xmas .they are about right . just squeeze the sides and residue plaster pops out. :thumbs

I'm going to need something like this when I start my scenic work and I'll probably be using polystyrene as a former.

Just to clarify - will it dry OK over polystrene??

How long will a bag last - 25kg seems a lot to me (for a 10ft x 7ft layout), perhaps a 10kg bag would be better.

The bit I did yesterday with plaster & Chux has dried out overnight in a cold room. I will get some photos a bit later ( some housework to do now )

All my scenic work these days is done with Styrofoam shaped to requirements then coated with a thin coat of casting plaster with a little white glue in the mix painted on with brush.

The white glue helps the plaster stick to the Styrofoam.

 Winter or summer it usually goes off in about 1/2 to 1 hour.

Ian

My own experiences have had the following results:

Home-made plaster bandage over gap-filling expanding foam substrate:   Done in winter but took forever to dry - over a week.  The bandage was made by cutting up pieces of cotton shirt and soaking in a plaster sludge - not an easy thing to do.

Commercial plaster bandage over polystyrene substrate:  Polystyrene carved to shape then plaster bandage soaked and laid over the landform.  Summer conditions, around 30C but relatively humid (not "tropical" but still "close")  3 days down the line and still not properly hard.

Commercial plaster bandage laid over chicken netting:  Virtually identical climatic conditions to the above - Dry in around 30 minutes, hard in about an hour.   My future choice.

I'm only speaking from my own experiences but my assumption is that, because the foams are watertight, all drying has to take place via the open (top) surface of the bandage.  Maybe I soaked it too long, maybe I used too much water, maybe the atmosphere was too humid / dry / hot / cold but whatever, with the exception of the expanding foam which I did last year, the other two were done under the identical conditions and the chicken wire was so far ahead that I'll leave the polystyrene to those who use it for it's correct function.  It will also be a mighty relief not to have to cope with the mess !!!  I'm referring to the white expanded polystyrene which leaves all those statically charged bubbles everywhere - not "styrofoam" the "crunchie" cored extruded foam board which is both harder and leaves very little mess after cutting.

To answer your question Jeff - yes it does dry over polystyrene but took forever.  My personal advice would be to go for an alternative.  Others clearly have different experiences - I have no idea why that is but that's life for you !!  There's never a right way nor a wrong way, there's just "your" way. :cheers

I've used it over polystyrene on my layout and it dried properly within about 36 hours. Mind you, this was in a conservatory in early summer.

I was really asking about the "Gyproc" product when I asked my two questions - wil it dry quickly and does it have a good "shelf life".

If those are positive answers, I'll use expanded poly and paint on gyproc after forming with a hot wire cutter.

I have used a great deal of poly, Jeff and always finish off with plaster of some sort. I use whatever I have to hand - plaster bandage, Mod-Roc, Plaster of Paris, Woodland Scenics Hydrocal (which I think is a Gypsum product) - and they all set pretty quickly - couple of hours at the most - and in many cases, I have had them knocking around for well over a year.

[user=6]Petermac[/user] wrote: 

  I'm going to experiment with other grades of plaster to see if I can find one that gives me enough time to work with it before it sets hard. 

G'day Peter, I have been told by an old timer [ lol] that if you mix in 1/2 teaspoon of Baking Powder to each 1/2cup of plaster & 1/2cup of water, it will extend drying time by 20 - 45 minutes. Jeff.
ps. I haven't tried it yet.

Hi,

I have just lately bought some plaster bandage and one thing that I'm sure I read was that you can alter / accelerate the drying time by adjusting the temperature of the water that it is soaked in. If you want it to dry quicker, you use hotter water. It's all down to the chemical process apparently.

Worth a bash though I'm not ready to use mine as yet.

Cheers

Toto

Even using watery PVA helps to slow the setting time down.

Just my opinion for what it is worth!
I have been using plaster cloth and Mod-Roc on polystyrene, chicken wire and all the other stuff that I could get out of skips etc!
The only difference being that I do not drench the cloth in water by dipping but merely spray it with a very cheap sprayer filled with rain water.
Even in the depths of this wet winter it goes off after a couple of days and is still as hard as a rock!
Regards Peter.

Hi Peter,

I have to ask - why? High density foam board (blue, pink or green, not the fluffy white stuff) takes paint and ground cover quite nicely. Latex-based construction adhesives (Liquid Nails or similar) if you want to glue rocks, etc. Cut it to shape with a hot-wire (not the bread knife or Surform), light sand with 800 paper (outside, otherwise you'll never hear the last of it), that's all that is required. Plus it's adding weight, the whole purpose of using foam board.

It does sound to me that the plaster cloth has passed its due date. Once opened it has to be used up rapidly, as it sucks moisture out of the atmosphere. Technically it's hygroscopic, and once sufficiently hydrated to gypsum will never set. If it doesn't heat-up when moistened and applied it's gone off. Store in a moisture-proof container. If you must use it roughing up the surface of the foam board helps, as the flat sides are impervious to water or air.

Nigel

In my experience Nigel - and I have tried both "Styrofoam" (the Dow Chemicals version of extruded foam board) and expanded polystyrene (the fluffy stuff you refer to) - incidentally, completely different beasts - but I would always go for the "chicken" mesh option - or any smallish mesh, whatever it's original intended use or whatever it's made from - provided it can support it's own weight plus a little more whilst the surface coating is drying.

It's infinitely easier to shape into land forms than any "flat" board and can be either wedged, pinned, stapled, taped, screwed or nailed to your baseboard frames.  You can "kink" it to make sharp hillside ridges where water has run off, you can curve it to make gentle moorland, you can bend it into steep valleys  - in fact, you can very easily shape it into virtually any form you are ever likely to see anywhere on the globe (or beyond ……:roll:)  That is just not possible with board materials although I agree that the broken edges make fantastic cliff (rock) faces and strata forms.

Board material does have a place in scenic modelling but, IMHO,  it's a very poor relation to small mesh wire.

Hi Peter,

Styrofoam is high density, closed cell polystyrene, the light, fluffy stuff is open cell, low density. "Styrofoam" cups are a different beasty.

With the exception of rocks, cliffs, etc., I don't use plaster at all. When I started modeling I tried plaster cloth over chicken wire, cardboard, balsa and thin plywood formers stuffed with newspapers, and of course HD expanded polystyrene, for terrain modeling, with and without a skim of plaster. If I have to the material of choice is open cell foam used for model airplane construction -  rigid, light, takes CAA (which the others don't), and comes in a range of thicknesses (0.5 cm up).

Most railways try to avoid gradients, for modeling in OO a 4 x 2 baseboard comes out to around 100 yards x 50 yards (or 100 meters x 50 meters), not really much real estate for anything but the start of a decent hill. Even a small tunnel (say 100 yards) is a 4-foot long hill. Modeling ravines, river gorges, etc. is probably best dealt with by dropping the baseboard, something I'm doing with my HO layout.

Exceptions of course - the station at Ventnor (Isle of Wight) would be one (see below). Vertical cliffs on 3 sides and a tunnel at the station throat as well.




(BTW, all I did for this was to copy from the source and then paste, thanks to Wikipedia. Easiest way to post a picture).

Having tried hills, vales, a tippler bank with a 1:20 gradient, and an open-caste mine or 2, I try and keep the terrain as flat as possible, as I have operation and viewing from both sides (no scenic board), and even a skim of plaster makes a big difference re weight. I'm partial to a raised bank along the sides, as it makes it a bit more difficult for the stock to leave the track and go flying. Foam is ideal for this.

Nigel

Nigel

Hi Peter,

I find that "Plaster of Paris' or general 'Builders Plaster' for patching up, works well. I cut up small (3" x 3") pieces of Chux clothe and dip into the plaster mix, coat all clothe both sides, then lay over the styrofoam. Even on a cool day, it will takes a few hours to cure properly. I do always leave it for 24 hours before painting another coat over the top to hide the patchwork of the clothe. 

I have read that you have purchased your plaster, but I found that a small bag (3KG) of 'Plaster of Paris' wasn't that much cheaper than a 15kg bag of Builders Plaster (down under that is)… Head straight to the builders section of your hardware store. Seriously though, 'Plaster of Paris' can't be that hard to find in France, can it…??

Question, why is it that people in the northern part of the world don't seem to like driving for an hour ?? :hmm ie, "the French arm of B & Q is called Castorama and the nearest to me is an hour away !!!!" ;-);-)

Cheers, Gary.


 

 

[user=878]Gary[/user] wrote:

Question, why is it that people in the northern part of the world don't seem to like driving for an hour ?? :hmm ie, "the French arm of B & Q is called Castorama and the nearest to me is an hour away !!!!" ;-);-)

Cheers, Gary.


 

 

Yes Gary  , one of those weird things living up north of the equator.

I guess on average I have 6 operate sessions a month to go to, each a half hour 35-40 km drive  to get there so one hour plus 70-80 kms a night

and then once a month, a 2.5 hour drive there & back for another modeller & his layout.

I'm sure the "driving" thing is more to do with Britain than with the "Northern hemisphere".

Living in Britain, one gets used to having a town every few miles.  We lived in the North East and within an hours drive, we had a huge choice of "shopping" towns and our nearest "decent" town with an excellent range of shops was about 15 minutes away.

Rural France simply isn't like that and the "Shopping experience" here is very different from UK - probably the thing we Ex-Pats miss the most about "Blighty".

I suppose also, motoring, even here in France, isn't cheap anymore and, unlike in UK, we pay to use the motorways.  A trip from here to Bordeaux - 70 miles each way - will cost around £8 in motorway tolls and you have to time it right because most shops close from 12 noon until 2pm.

I ought to add that, having driven to Bordeaux, the chances of actually finding what you need are in the lap of the Gods - the French are certainly NOT a nation of shopkeepers ………….  Something akin to a Bunnings would be like arriving in heaven ……….:roll::roll:

It's far, far easier to use your motoring costs to pay the Postman and order online - you know you'll get it, it will probably be cheaper and, instead of flogging up the motorway, you can sit by the pool and "do your bit" for the French winegrowers until Postie delivers your package…………. :cheers