24 September, 2015

Props for LARP and Cosplay (Part 5)

The foam I'll be using for the shaft is the same stuff I've previously used for coreless LARP throwing knives and a metal-cored swordstaff. There are a few consistencies of foam available. If a foam is too hard it doesn't compact when the weapon hits someone, that hurts. If a foam is too soft, it compacts too much and and core within the weapon impacts the target, that also hurts. A moderate foam somewhere between these extremes collapses just enough but not too much. The designation of foam I'm using from Barnes is called S-Foam 50. It mixes in a weight ratio of 100 to 45, so I pull out the kitchen scales and wrap them in a freezer bag to prevent foam getting on them (after all, these scales are normally used to handle food). I turn them on with the mixing cup already on the scale, which means the scales will only measure the chemical, not the cup.

The two parts are measured separately, then the two are mixed together.    

The mixture takes a minute or so to start foaming up. In this time, I put the polycarbonate core into the PVC plumbing pipe (which has been bound back together with duct tape), holding it roughly in the middle with one hand while I pour the slowly foaming mix into the pipe with the other hand.

The mix sticks to the inside of the pipe...well, more accurately it sticks to the SR92 which is stuck to the inside of the pipe. It stars clogging up in the pipe which shows that the foam is starting to form. Eventually it starts to overflow the top...luckily I didn't mix too much and the overflow isn't too bad.

I touch the top of the foam every couple of minutes to see if it has solidified. Once the foam is dry to the touch, I wait about another 15 minutes before pulling the duct tape off the pipe and separating the two halves.It actually looks pretty good. I'm happy with the results of the SR92.

The clogging occurred halfway up the pipe, so the bottom half didn't fill with foam. I reform the pipe around the foam shaft and core, tape it back together and turn it upside down. I measure and mix some more foam solution, pouring it in before it has had the chance to foam up at all (I pour some more into my throwing dagger mould). The liquid starts to foam up after a few minutes. 

When I peel away the pipe mould, I now have a 12mm polycarbonate core, surrounded on all sides by at least 12mm of flexible foam. 

The next stage is to paint the shaft with a flexible metallic finish acrylic paint. It doesn't give a mirror finish, but it does give a decent anodized look.

The same metallic paint is applied to the hammer head once I've pushed the head down over the polycarbonate core.

Now I leave it to dry overnight while I think about the extra detailing for the piece.
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