Wednesday 21 December 2016

She who increaseth knowledge decreaseth sorrow

Since "finishing" my Assassin's Creed II costume two years ago I have been researching how to construct the non-fabric accessories to the outfit.
For the belt buckle/insignia I first looked into 3D printing. ACT libraries have a Makerspace with 3D printers available to the public so I went in for an introductory session. Unfortunately, the printers they had did not do as fine detail as I was looking for. I was also put off 3D printing by the university course I had just finished which included 3D animation. I was quite looking forward to not spending more hours with 3D modelling software – especially not on a project that involved an intricate design.

I did a brief experiment with carving foam but found I couldn't carve at all precisely. So on to the next method on my list: resin casting.

I bought some air-dry clay, ignored it for a few months and then decided to be brave and give it a go. I printed out a picture of the buckle at the size I wanted, sticky-taped it to a cutting board and then covered the whole thing in glad-wrap. The picture became my guide for sculpting. To get the pattern in the badge at the top I printed out a picture of the original and stuck pins through it into my sculpt and then joined the dots in the clay with the pin.
I was expecting to last maybe 10 minutes before adding clay-sculpting to the list of things I can't do – alongside drawing, colouring in, and playing the clarinet. I was rather astounded to find, in almost that amount of time, that sculpting was, in fact, something I CAN do. I found the air-dry clay much easier to work with than sculpy, the clay I have used for smaller projects.
The first sculpt I did took about five hours divided into 2 or 3 sessions over the day. Whenever I took a break I wrapped what I'd done in more glad-wrap to stop it drying out.

I was very happy with the first sculpt but it had a few issues that made it unsuited for making a mould. I had made each leaf individually which left gaps in between them that the mould medium would fill in, making it impossible to remove the clay or a cast. The badge at the top was too thick, making the buckle unbalanced and unlikely to sit well. Other parts of the sculpt were too thin.

So, armed with my new-found confidence in my sculpting ability, I made another one.
While I don't think the second attempt is as good, it was better suited for making a mould.This time I carved the leaves out of a lump of clay, which worked quite well. It was a bit more difficult to follow the outline from my guide but I'm pretty certain the non-matching up of the leaves was exacerbated by the clay shrinking. (I don't know if clay shrinks or not – but there were a few time when bits of the picture were visible that I was sure had been sculpted over the day before.)

I decided to use this sculpt for my mould. I used an arm from the first sculpt to test all of the following steps before I did them for real. I used brush-on latex to make the mould. (I bought each of the key ingredients to the process only when I knew the previous stage had succeeded.) I kept painting layers of latex on until I was confident the mould was sturdy enough.
Once the mould was done I filled in the back of it with playdough to make a solid base and messed around with a level ruler until I thought it was sitting flat. Then I detached the glad-wrap from the cutting board and flipped the mould over.
Some of the latex had dried under the clay and the edges of the sealant I used on the clay was generally getting in the way so the next step was to trim around the edges of the mould with a scalpel.

[Note: before making the mould I used sealant on the clay to stop it sticking to the latex. I wasn't careful to stay on the clay so around the edges of the sculpt the sealent formed a plasticky layer on top of the glad-wrap that was wrapped around the cutting board. When the latex was applied the sealant pulled away from the glad-wrap which meant in some places the latex did not get the full depth that it was meant to. So once I turned the mould over I masked off some of the edges of the clay with playdough and put another layer of latex on to make the mould deeper. I don't recommend doing that, but it's better than having a cast that's too shallow. I then went round the mould with the scalpel again (and a chisel, to remove the now dry play dough masks).]

The last step was to remove the sculpt, which required breaking up the fragile clay to leave the latex secure in the play dough base.
The resin was mixed and poured:
And removed from the cast (this time I broke up the play dough).
The cast has got some flash around the edges where the resin spilled over the edge of the mould which will need to be removed, and it will need sanding in places. Even so, if I made another one I would use more resin as some places are a bit sunken in and thin, only rising to proper thickness where it was in contact with the mould edge.
What I am most impressed with is how well the pattern showed up in the badge. The pattern was visible in the mould but the ridges were not very high so I wasn't sure it would come out at all in the resin.

Next steps: sanding and painting.



Assassin’s Creed belongs to Ubisoft.

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