Saturday, March 05, 2022

Cloning sheep

Having constructed an open topped cattle wagon from an IP Engineering kit and repainted a secondhand Tralee & Dingle open topped cattle wagon in PLR livery, I decided to give them both sheep loads. 
Having acquired my own 3D printer (see How I assembled my Anet A8 clone printer), I printed out a dozen sheep using files downloaded from the Thingiverse website - and loaded them into the wagons.

However, someone with more knowledge than me about transporting livestock, pointed out that sheep were usually crammed into wagons to prevent them from falling over and injuring themselves or getting trampled-on and so I needed a whole load more sheep. I reckoned I needed around 20 per wagon. I didn't fancy printing out that many (they are a bit fiddly to print effectively and take three or four hours each to print out) so, being a bit impatient, not to mention, penny-pinching, I looked for another way of filling the wagons more quickly and cheaply.

Why not make castings using plaster, I thought?

The first job was to make a casing for the mould. This was made slightly smaller than the internal dimensions of the wagon from five pieces of corriflute. The base was the size of the internal dimensions minus 10mm to take account of the thickness of the sides of the mould box.

The sides were 35mm tall. These were fixed to the base with hot glue.

Some cheap PlayDoh was acquired from my local Bargain Store and this was squidged into the mould box to about half its depth,

A couple of my 3D printed sheep were then carefully pressed into the PlayDoh and removed, leaving an impression.

When the entire surface had been impressed with sheep backs, a sloppy mix of plaster was poured into the mould and left for an hour to set.

The sides of the mould box were then prised off and the PlayDoh removed.

The cast was then scrubbed under the tap with a pan-cleaning brush to remove the more persistent pieces of PlayDoh.

The false floor was then painted black with acrylic paint.

The sheep were then painted a yellowy cream colour ........

..... and then dry-brushed with white so the cream colour showed through in the depressions. Their faces were painted black.

 Their bums were painted brown, leaving their tails white. They were test fitted into the wagon and, although they looked OK, they did give the impression they were swimming in molasses.

Furthermore, when the sheep were removed from the PlayDoh, some of their heads became misshapen.....

So, I decided to have another go. 

I had noticed that when pushing the back of the sheep into the PlayDoh, there was a tendency for the previous adjacent impression to become distorted, causing some of the sheep to have narrow ridged backs. So, for my second attempt, I used six sheep, varying their size slightly (in my slicer - Cura), I left most of the sheep in the PlayDoh while I made the new impressions.

This helped to prevent the adjacent impressions becoming distorted. I was also very careful when removing their heads from the Doh to try and preserve as much detail as possible. Eventually, the mould was finished ........

...... and so was filled with plaster, paying careful attention to ensure it was poured into the head cavities.

After an hour or so, the cast was removed and cleaned-up.

This was a big improvement. Before the plaster fully hardened, I carefully removed unnecessary pieces of plaster from around the edges and tidied up some of their heads with a craft knife and the blade of a small chisel.

I then painted them as before.

As the sheep are more tightly clustered, there is less impression of them swimming in treacle and, providing they are not given close scrutiny, I think they could pass for a load of sheep.

I think the PlayDoh cost less than £4.00 (though you could make your own from flour, water, salt and oil) and the 1kg of plaster was £6.99 on eBay. There was enough plaster in the bag for three castings - hence £2.33 per casting as the PlayDoh is reusable.

A word of warning! Don't mix the plaster too thickly. It needs to be about the consistency of whipping cream so it can flow freely into all the nooks and crannies. I made the mistake of making one batch too thick (more like rich double cream) and it simply wouldn't flow. In fact it was starting to set as I tried pouring. The result was headless sheep with no surface detail.

If the sheep were clustered even more tightly, so little if any floor was visible, then I think the casting would be even more effective. I am sure some of you will be far more patient and skilled than me!

An added bonus of using plaster is that it provides much needed additional weight in the wagons - not to mention keeping costs down in filling wagons. I am beginning to wonder what other loads could be cast using this method: packing cases, stacks of timber, stacks of bricks, stacked slates, coal, minerals? The possibilities are endless!