Update on my 'slow burn' layout.... Over the past 6 months I have made slow but steady progress on my rock face and tunnel and thought I would share my efforts.
I had hoped to use polyfilla powder mix as I had done on the other side of the layout but this proved problematic as even though I tried to build it in layers from the bottom up, it kept 'slumping' and was not firm enough for me to try and do some rough shaping before it set.
Therefore I opted for plan B as shown in the photo, a cardboard tiered structure which I then draped in plaster cloth. These steps then gave me a framework for using filler to make the rock face. I used ready made filler out of Tesco which was only about £2.50 a tub - I used two.
Once the rock face was set, I spent many weeks carving and shaping rocks using files, a Dremel and various carpentry chisels to shape the rocks.
Next came the painting and after an initial spray with Humbrol Acrylic grey, olive drab and dark brown I set to work with various mixes of Tamiya acrylic paints, applied by brush, often using a dry brushing technique.
I installed a small drain at the foot of the rock face, it should probably be closer to the rock face. After cutting out the polystyrene, I lined it with plaster cloth, painted it and then filled it with Woodland Scenic water mixed with murky water. I used some of this water mix inside the tunnel and dry brushed some onto the rock face in places.
A final touch was applying some static grass at top of rock face and some between rock and track to break up the scene a bit.
I can see many flaws but I'm pleased with the overall look and it proved a suitable backdrop as the trains trundle past.
What next? I am going to cut out the polystyrene on the other side of the line and make a river bank scene....or at least that's the plan!
Another few shots of the tunnel end, not much room to play with at side of tunnel before it meets the edge of the board!
A simple trick to stop pollyfiller from slumpling is to turn the layout on its side so the pollyfiler is on a flat surface.
It can also be mixed in such a way as to be more solid by adding more powder to the mix.
You can also leave it for a while to thicken up a bit before doing any shaping etc.
Many thanks Brian, I was a bit stuck as I couldn't turn layout into side but would consider applying this idea for creating ready made sections to slot into layout and then blend together with filler.
Far from perfect but I am pleased with it as a first attempt!
Not making the mix too 'sloppy' as Brian mentions is a good plan whatever the situation. If it cracks as it dries it is a sure sign it is too wet. If the underlying surface is very absorbent don't be temped to make the mix wetter but either mist the surface and let it soak in or 'size' the surface with diluted PVA glue.
For making moulded sections painting on a very thin coat of slightly wetter mix, stippling it into all the detail and then adding thicker (and stiffer) layers, and for large section perhaps with some sort of reinforcing such as strips of rag or paper, maybe J-cloth or bandage even, is an option. In traditional plasterwork horsehair was added for the purpose. A similar sequence is used in laying down glass fibre into moulds.
These days I tend to make the underlying 'hills' from expanded polystyrene fixed down and cut in to shape as required with a sharpe knife. I keep a quantity of polystyrene packaging for this use.
This does not 'sag' or in any way move when the pollyfiller is applied. As mentioned if the mix is too wet it will crack when it sets. I also always mix in brown powder paint so that if it ever gets knocked only brown will show through not white.