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Friday, July 27, 2012
Wrath of Kings Diorama: Part 4
There must be about 1000 shingles on this city, and even though they were mostly glued on in strips, I think the shingles took up more time than any other single element of the construction. But they look beautiful, so it was worth the effort!
With the shingles finished, I could move on to the resin casting.
One way to speed up the construction of a large table like this is to resin cast small parts like windows and doors. This is much faster than scratch-building dozens of window frames and doorways.
As I mentioned last time, I built a few windows and put them in a mold box, made from PVC sheets.
Tap Plastics makes a line of RTV silicone and resin that I've used in the past, and have found to be pretty reliable. The RTV is mixed at a 10/1 ratio, so it's important to have a scale for precise measuring.
I use an old trick of pouring dry rice into the mold box to see how much material I will need. The rice goes in the mixing bucket and that tells me how high to fill it. Then I dump the rice and mix up a batch of RTV.
Since I don't have a pressure pot for eliminating bubbles, I place the mixed silicone on a table with a power sander running. The vibrations of the sander help bring the bubbles to the surface.
Before pouring the RTV, I use an old brush to paint it into some of the recessed areas that are likely to trap air bubbles. (This kills the brush, by the way, so use one that's already ruined and useless for painting.)
I pour the RTV into the corner and let it gradually flow over the parts.
Once the RTV is poured, I run the sander again to eliminate more bubbles.
You can see them rising to the top.
The RTV cures overnight and then I can peel away the mold box, revealing the impressions of the parts.
I use Tap Quick Cast resin. It uses a 50-50 ratio mix. I stir it for 60 seconds, and then have enough time to pour it and poke out any bubbles before it starts to cure. To poke out the bubbles, I use a stirring stick to carefully poke into the recessed areas in the mold to knock out the air bubbles. It takes a little finesse because you want to work quickly before the resin hardens, but don't want to damage the mold by poking too hard.
The resin cures in 10-15 minutes (I set my timer for 12 minutes), and out come the parts. They are still a little soft when I pull them out, which makes it easy to cut away the flash, and modify the parts, like cutting the stone trim off of the door, for example.
I only needed a few of these window boxes, so I cast them first and added them to the roofs. A simple basswood sill below the window finishes off the piece.
Because this will be a battle scene I decided to have the foreground buildings ruined and burned, as though the attackers are working their way toward the main city. As the windows were multiplying, I built the two ruined structures. They are made from a foam core framework with insulation foam "stones" on the outside. The rafters and floorboards were finished off with basswood strips and card shingles.
The trees are Woodland Scenics plastic tree armatures. To attach them to the table, I removed the pegs on the bottoms of the trees and replaced them with long wooden skewers that could sink into the foam hillside.
To attach the windows, I cut the shape out of the foam and sink the window into it. They are not glued at this stage. For efficiency, I'll take them out and paint them separately in a single batch and then glue them into the finished buildings.
One of the final steps was to cover the table with a mix of play sand and gravel.
Here's the finished assembly. The elemental head was cut from layered foam, sanded and covered with wood filler putty. It just needs its eyes and a little (well, a lot) of paint.