Hey all!

I was planning a 1:35 reasonable governemental-like building for my Berlin '45 diorama. I always wanted to experiment with casting and making latex-molds myself so I desided I would cast me a building...
I turned in my gift-certifacates my boss gave me for Cristmas at a local hobby shop for latex and went to work.
I started with a little "study" before working on the Berlin dio.

First I made a "mother" model of a building part out of styreen and glued it on a piece of multiplex:



Than I place 4 little wooden "walls" around the building front, leaving at least 1 cm space between the model and te wood. I sealed the wood with glue to prevent leaking latex later.



Next step was to "paint" liquid latex (simular like Revell's "Color Stop") on the model. I made sure all details were "filled" thourougly. This is how it looked like after 2 layers of liquid latex:



Than I filled it all up with some thicker latex:



After drying (48 hrs.) the latex comes of very easy. Only on some places I had to use a knive cut the latex loose from the wood.
(The black lines were "copied" from the lines that were allready on the wood. These water-proof marker lines were allready on the piece of wood I used and are not related to this project).



I let the latex dry for at least another 48 hours (the mould is about 1,5 cm thick, so it takes a while to dry complete). The latex colour has changed to brown under influence of sunlight.
Than I poured in plaster, waited some time, crossed my fingers and:



Being my first self-made mould, I think I did pretty well...
Some inperfections, mostly holes made by airbubbles, can be worked away with plaster. This wave at the left upper window was the only thing I did not like:



Because of the length of the mould (almost 30 cm. long) the plaster would easely break at the middle row of windows:



OK, now the fun part of this little test, lets make a dio!!!
(BTW: the dio base is a plastic "plate" from IKEA, turned upside-down...)






Well, I found it good enough to use these castings for the Berlin dio, so I casted three more parts and placed them together.
You can see by the (darker) colour of the plaster where I had to use plaster to "glue" or smoothen places.





Well, this is how I made my building "basic", now I'm off to finnish both dio's.
I learned the following lessons for future projects:
- not make it too big/long, or with thin parts: the casted plaster breaks easy.
- reinforce the mould; this can prevent the "wave" like the on at the window.

The mould is re-usable, so perhaps I gonna use it in the future once again. For now I have to cast 2 parts from it again for a friend who wants to use it for a dio also. :-)

Paul

Hi Paul. A few things I learnt when casting plaster ...
Add some acrylic colour to the mix ... when this painted, if it gets scratched, the white shows through. It is also easier to work with and photograph. White glue mixed in the initial mix gives a lot of extra strength.
When designing your building add in extra features like columns or pillars. As well as giving a more 3D effect it gives extra strength.
I like the building you made, but maybe one of the windows could be cut out to ground level and look like a door?
One of the great advantages with plaster, is being able to scribe it. Lots of nice bare brick work could have been scribed in around windows and where the building is damaged! When completely built, give it good brushing with white glue/water mix. This will give a little extra strength and also give a surface for paint. The plaster how it stands now, will soak in a lot of paint.

Have you seen this ....
building a plaster base

Nice and cleaver job,
check this.

modelclub.gr

You can do a lot off thinks if you have imagination

Anthony that building is amazing. Are there any details on how it was done? (I can't read/understand Greek).
Paul, Yours turned out very good for your 1st time casting.

David is not my manufacture. The “eagle” is one from best in the IPMS of Greece, I asked him also how it makes. (sculpt of plaster) I wait for directives when it completes him

@:) Maybe you can use systran plus to translate. Sorry for my bad English

Paul, Very nicely done. I think Frank has offered up some very good tips to use in your next project. I look forward to seeing it. Cheers Kevin

Sadly it is not mine either.He didn't explain a lot just that he made molds,poured very diluted plaster(in order to avoid fractures while carving) for the walls and before it was completely dry he took it out of the mold left it 20-30 min before he carved the basic details.after several hours he made the lines on the rocks with a needle.amazing if not the best work i've ever seen!The patience and imagination this artist must have is enviable!hope he'll share more

Great job,
I am felling inspired, off to the hobby store I go
Robbo

Hoi!

Frank, thanks for all advice!
I'll practice them surely in my following project. And for the big building I'm surely taking your advise to "prime" it first wit water and whiteglue.
BTW: great article about the plasterbase!

Antony, David and Tasos; thanks for the "Greece connection". Great example.

Question:
Tasos translated the plaster was very diluted in order to avoid fractures while carving. Is that true? Is more diluted plaster "stronger" than less diluted?

Kevin and Robbo; thanks for the nice comments.


Paul

The quality of peoples diorama work never ceases to amaze me, for a first attempt Paul that looks great.

I've never done any plaster work and perhaps the more experienced builders will be able to answer me, but I was wondering if you're able add 're-inforcing' plastic rods to the plaster to provide added strength?

The brick work on your diorama Frank is brilliant!

I'm having the same problem with large structures and i thought of a way to make it stronger.I used many times orthopaedic plaster,the one used on fractured limps,which is combined with a form of a net.I use it for a base for rock formations.Since it is not any good for details why don't you try it as an intermediary layer or as a last layer.Just a thought,never tried it myself.As for the diluted plaster the creator of the dio didn't say the ratio but he said that a relatively thinner would remain softer for a longer period of time making it more elastic and therefore not as easy to break while carving thin or small parts.I'll give it a try.

Hi,
I only have one suggestion, thats get the hell away from the latex moulding process. latex sensitivity and full blown latex allergy is becoming a life threatening epidemic amongst all sorts of people, Doctors, Dentists,Nurses.and of course Model makers.
Damien.

MIXING PLASTER
If you do as Frank says and add some acrylic paint (I use dark brown) to the mixing water then that will slow down the curing time which will let you carve detail in without too much bother. An alternative would be to model your master in clay or the plastic card and cork method and make your mould from that. Then you could make your casts from a hard casting plaster which if mixed properly won't crack or break . A good description of how to mix plaster can be found here:
http://www.plastermaster.com/dandoesit/dandoesit2printer.htm
A longer process of making brick buildings is as follows:Roll out a sheet of plasticene to about 1/2- 3/4 cm thick cut it to the shape of your wall. Turn the plasticene sheet over. Now use a brick shaped object to impress whatever brick or stone pattern you want. I use different sized brick shapes carved from sprue. When you've finished making your pattern build a retaining wall around it. You now have a mould of the brick wall. Mix up some plaster of Paris adding a suitable brick colour, water based paint. Pour the plaster mix into the mould and shake it gently to make any air bubbles rise out. When it dries you can peel off the plasticene and there you have your cobblestone roadway. If you're careful you can reuse the mould a few times. The method is adapted from the book "Roy Porter's Model Buildings Masterclass" which is well worth getting.

Thanks for all the good advice again guys!
Try to make my further plaster of bether quality. I mixed it "to the eye" this time, but I can see there is more in it than I knew!

Damien, thanks for the good concerns, but I think it will be a low level health problem: you only have contact with the latex when it's dry and only for some short periods. As far as I know latex allergy / sensitivety is only with skin contact (correct me if I'm wrong) and by long use (like latex gloves). But it's good to remind this!