Thursday, June 14, 2012

Moulding For Dummies

I've been busy this month working on the God Being Killed painting that will feature an elobrate frame. I thought I'd share the process I used for making it. I've enjoyed working with a few new materials so far, and today I've been playing with silicone mould making material.

The first stages of the frame were quite straightforward. As with any frame I began with a wooden frame that fitted the painting. On top of that I added an arch, which I made by layering lots of sheets of MDF. to make a thick block of wood, then jigsawing the arch hole from it. Then I glued it to another piece of MDF to make the back.

When fitting it, it was essential that it remained flat and in the middle so I attached it in two stages. First I painted the top of the frame and the bottom of the arch with dilute PVA. The plan was to make it less absorbent and make a good hold for the next step, an idea I got from wall plastering. Then I glued the two halves together using acrylic mouldling paste, which is essentially acrylic plaster. I thought that acrlyic would make a good glue and act like a filler too, making the imperfect join fit well by filling in any gaps. It worked as planned and a few hours later I found I could lift the frame without the heavy top falling off, which is important!

However I'd be foolish to rely on glue to hold something that heavy so I then drilled and screwed the top. It was important to glue first because If I'd have drilled and screwed first it might not have been straight.

Here it is at that stage...

Next, was an easy but messy step, to pour plaster all over it. After that, and trimming off the edges it looked like this...

That's pretty much how it is now. I've painted it with epoxy casting resin today, which will toughen it up a bit and help stick it to the frame (I covered the wood with PVA first to help the plaster stick, but every little helps). I'm not 100% sure about the epoxy being ideal, although it must surely toughen things up. In tests it seems to sink into the plaster and not toughen it too much, at least I've managed to smash it when trying! More tests are needed I think...

I want to add some moulded shapes of chess pieces and other bits so I got some silicone to make moulds from. It was really gloopy stuff. It's mixed with a catalyst with a simple 10:1 weight ratio so I used my trusy digital scale to measure a plastic cup full out and stirred it up with great difficulty! It pours slowly, but sets just like rubber. I wonder if I can make rubber stamps with it? It might repulse the ink. Maybe that's a good thing for a stamp?

I began with some chess pieces and set them half in plaster in plastic boxes. I topped these up with the silicon and the results were great. The only problem was removing the lot from the box! I also wasted quite a lot of the stuff, casting a big block of rubber for some quite small objects.

For a second bacth of objects I improved the process by using Lego walls to hold the silicone. That was much easier, and the stuff wasn't so fluid that it seeped out of the walls (unlike the watery epoxy, which would have I just know it!). Another advantage with Lego is that you can build the shape you want, saving waste and it's easier to dismantle.

I'll use epoxy clay to make my mouldings, because I want to bend them when setting them in place. The rippled frame would make it awkward to stick a solid flat object down with ease too.

For now I'll leave this for a few days. Tomorrow I'm painting the last stages of the tiger (if it's dry enough), off on Saturday to see the Shrewsbury College end of year art show, then some more end of year shows in Manchester on Sunday, back in time to paint the second layer on this god painting next week... if the last layer is dry enough. We have the light but this summer has been so cold that it feels forever autumn (now if this was a radio broadcast then it would be time for a song).

Ta ta for now.

2 comments :

John Salmon said...

Bravo! I love reading your frame making adventures Mark. Interesting stuff indeed.

Mark Sheeky said...

Thanks John. This one is moving on apace. I'm using Milliput epoxy clay for the first time and enjoying it.