Monday, 17 March 2014

WW1 General Service Wagon - Casting

Further work has been done to the bodies since the last post.   The strengthening ribs on the sides and underneath of the tray have been added as has the box which acts as a foot support for the driver.   The tail gates have also been added to the rear of the trays.

I decided to cast up the seat springs in resin as they are a fairly generic item that could be used for other projects.   Masters were made from styrene strip and rod.   The strip was gently curved before each strip was attached.   A simple box for the mould was made up from styrene sheet.

 The spring masters were then glued to the base of the mould box.   I should mention, this method of casting is a simple one piece mould, suitable for simple shapes that have a flat back.

The mould box was then given a spray of mould release, in this case Stoner's Rapid Release.   Theoretically the Silicon material used for the mould should not stick to anything but itself, but I err on the side of caution.

The actual material I used for the mould was PinkySil, an equal part, two part silicon medium.   When mixed you have a working time of six minutes in which to do your pour.

After you have poured the mould, tap/shake the mould box to release any trapped air bubbles in the mould.   Another tip is to blow gently through a drinking straw over the silicon as the carbon dioxide in your expelled breath will allow air bubbles to rise and burst.

After the silicon has dried off (usually between 20 and 30 minutes), the mould itself can be released from the mould box.   It can then be cleaned up if necessary and the meniscus around the edges can be removed with scissors/craft knife.    This allows the mould to sit flat on the table.

To produce the actual castings I used Easycast, an equal part, two part polyurethane resin.   Once mixed you have a working time of two minutes before it starts to harden off.   It is important to get the volumes of the two parts correct as any imbalance will affect the quality of the castings.

As the amount of resin required for the springs alone is quite small, it is a good idea to use the excess on other moulds you may have made.   In the photo above you can see the completed spring castings (just need deflashing) and also some small police cars for a game from many years ago called Jail Break. (I was missing some cars!) and also some plugs/rivets for Star Fighter maneuver dials for the X Wing Miniatures Game.   Any air bubbles/defects in your castings can usually be made good with two part epoxy putty.

Monday, 10 March 2014

The Wild West Town of Saw Butte Part 4

The Notchyaws Mine Office

The Notchyaws Mine Office is the administrative building for Notchyaws Mine, which is located a few miles out of Saw Butte at the foot of Callyer Bluff.   Though production of gold and precious minerals has declined somewhat, the Mine Office does handle assaying, claim licensing and gold shipments monthly.

Construction was as per the previous buildings i.e. foamcore shell with icy pole stick boards applied.   The windows were scratchbuilt from matchsticks and icy pole sticks and the roof was made from corrugated card.   The door was from the book of early Australian Pioneer buildings described in a previous post. 

The building signs were printed up on card stock with a wooden texture (off the internet) and suitably distressed.

The structure was painted with Folk Art Acrylics.

Saturday, 1 March 2014

WiP The WW1 General Service Wagon Part 2

The tray of the GS wagon is fairly straightforward.   20 thou styrene sheet was laminated to a thickness of 60 thou.   The inside and outside surfaces being scribed to simulate the planking.   The scribing was done with an industrial hacksaw blade that has had one edge ground to the shape seen in the photo below.
The floor of the tray was constructed in a similar manner with the exception that 20 thou and 40 thou sheets were laminated to provide a 60 thou thick floor.

The "Scrawker"in action!

Laminated sides and ends

Floors of the tray made up from 20 thou and 60 thou sheet.   Final trimming still to take place.

The Tray bodies.

A piece of 40 thou sheet was let into the sides at the front of the wagon body.   This will provide support for the seat and its springing arrangement.   Also the tiny hinges I intend to use for the rear tray flaps can be seen.   These were sourced from Scalelink in the U.K.   They will be attached with very tiny pins/nails that are supplied for the purpose.