Sunday, 28 February 2016

Press-moulding shields

So in the process of finally coming close to finishing my Nightmare Legion, I decided they needed to all be bearing the classic coffin-shaped shield from the 80s. Unfortunately I only owned about six, but I would need 17. I'd made overtures in the Oldhammer Trading Company Facebook group about sourcing some, but I'd never managed to close a deal. Then I read about press-moulds using some stuff called Oyumaru. Basically a reusable heat-malleable plasticy stuff for making moulds.



 So off I went to ebay and found the cheapest single stick of Oyumaru I could find. I didn't want to invest too much in my early experiments as I really had no idea what I was doing. Turned out to be from some French seller. It turned up within about three weeks.

I did a little Google research, read a few articles on dakka and other forums, skipped through a YouTube video in dire need of editing (much like this post), and figured I knew enough to have a crack at it. The shields were good candidates for simple press moulding as they really only needed to be one sided moulds, and that is even less than half the effort of a double sided mould which has a bunch of extra difficulty.

First up I put a mug of hot water into the microwave to boil. Pulled it out, and dropped the stick of Oyumaru in there for a few minutes. Fished it out with some tongs so I didn't burn myself on the water. The Oyumaru itself was warm but not too hot to hold.


Just using my fingers I flattened it out into a circle and put it on a ceramic coaster. I then arrayed the six shields on it, face down, and covered it with another ceramic coaster and squished it together with all my might.


After holding it for about 10 seconds, I opened the coasters.


Looking good so far! I popped it in some cold water to cool down and set for a minute or so, then carefully picked the shields out of it. The Oyumaru is still a little flexible so they popped out nicely.


Next I cut off a small length of greenstuff, and kneaded it together. I then portioned it out into little blobs for each shield slot. Make sure you have some cold water in a dish nearby to keep dipping your fingers in when kneading greenstuff. It'll stick to your fingers otherwise. Why did no one ever tell me that before?!


Then I put the other coaster back on and squished with all my might again. The second batch I did I actually used a woodworking lever clamp to press the two coasters together. It worked a bit better than hand squishing.

Lift the coaster off and the greenstuff will stick to the coaster but not the Oyumaru. Except that one lone shield but it popped out easily as the Oyumaru is flexible and the greenstuff doesn't stick to it. I had splashed a little water on the Oyumaru to make sure the greenstuff didn't stick, but it was unnecessary as it will not stick anyway and all it did was create a little bubble in one of the pressings.


After four hours I carefully scraped the shields off using a long boxcutter blade (they were still a bit flexible). I'm going to leave them overnight before I trim the excess and paint them up. But in the mean time the mould was free as well as both coasters, so I pressed a second batch.

Next time I think I could use a quicker drying epoxy putty. I don't need the extended malleability time of greenstuff, and I'm not trying to capture too much detail with these, so regular milliput or something is probably fine.

Update: 5th March 2016

The original batch of them all ready to go.


Trimmed up just one to start with, painted it in halved purple and grey to match the Nightmare Legion's uniforms. Used a hobby blade to make the first cut into the boss hole, then a dremel with a drill bit to widen it out.


Then on to the rest, started painting them while they were still on their flattened "flash".


That was kind of silly so I trimmed them all up using a hobby knife.


Then used some double-sides sticky tape to stick them to some popsicle sticks.


Update: 7th March 2016.

The double-sided tape was a bad idea. Lots of little spots of adhesive got left behind. Next time, blutack!

But the painting is done, just time to mount them now.


7 comments:

  1. This is pretty brilliant, and thanks for taking the risks and sharing the process. I've done a similar thing (but not as good of detail or re-usability) by press molding into super sculpy. The big difference my process though was I used two part resin, that set up quickly. Maybe something you might want to try?

    cheers!
    Ths

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    1. Resin for the moulds or for the shields? Sounds like an option.

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  2. I can recommend milliput for making to shields - I've used it with my press moulds and it works fine!

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  3. I can also recommend adding some milliput to your green stuff to get a harder end mix, or just adding the yellow part of greenstuff to milliput to create a slightly flexible but still sandable mix. I'm going to try your method this evening first!

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  4. Another little useful bit is to press one of your original shields into some lightly oiled green stuff. This will give you a negative, much like a mould cavity which you can use to hold your castings whilst you file the backs. It'll allow you to get uniformity of thickness and if you glue it to a stick or something like that it'll make your castings much easier to hold while you work on them. Great post!

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  5. Top stuff. An honest gamers experience. I always found that Greenstuff to stay flexible so would consider milliputt. But this is a great post.
    cheers

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    Replies
    1. Yeah if I make another batch it would be milliput. But greenstuff is what I had on hand. They're currently in the freezer trying to make the damn double sided tape residue harden up so I can scrape it off. >:(

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