When I lent my services to a collegue who was working on a film about 12 years ago, I was introduced to the world of cnc. I remember watching this huge machining centre milling out a slab of mdf and turning it into a fantastic set of gears. I knew that it would have taken me hours to achieve the same thing with traditional power tools. I decided then that I would invest in a cnc router for my own business Oxenham Design. At that time I could turn on a computer, but even to check email seemed like a crazy set of operations. I persevered and learned every piece of relevant software I could get my hands on. I am now fortunate enough to be using Vectric's ASPIRE software, and Techno cnc routers, which has helped us to create some amazing projects, both in part, or in full. I thought that this blog would be a great place to share "behind the scenes" adventures with the software, materials and equipment we use, as well as the projects we build.

Monday, 25 March 2013

Finishing the Un-Finished!

While we're working on our current show, we've also been working on finishing alot of the small self-projects that are piled up around the shop. A while ago we started the number 8. This was going to be hung up at the back door of the shop, so our unit could be easily found amongst all the other loading doors!
This was cut from 2" HDU, and was double sided machined. I only had to draw 1 side in Aspire. I just ran the file, then flipped the part, and re-ran the same file. Pretty straight-forward.

Once it came off the machine, we put on 2 coats of primer, painted it copper, and did some patina to the recessed portion. Unfortunately, that was awhile ago, and I can't locate the photo's :(

But fear not..........we're picking up from that point now.
The main reason for this particular piece, locating our shop aside, is to test out our metallic powder treatment outside-facing south. A good test for sure, as south is the toughest facing location for a sign. It can change over 10 degrees in a couple of hours in the winter, then bake and fry all summer long. The plan is to created the sign as usual, do the powder thing, then only clear-coat the bottom half. Then we can keep an eye on it as it ages. We use this treatment quite a bit for film props, but it would be a great alternative to gold leaf on a sign. Especially as the Pearl-X powders claim not to tarnish outside. Finally, polished copper letters outside, staying bright forever!

I always get asked how we do the powdered metallic treatment on our different projects. It's really quite easy, once you try it!

 I decided to shoot a short video of Jody using the technique, so you could get a good clean idea of the process.

Before the video was shot, we applied a good couple of coats of gloss black enamel. We use Tremclad gloss black for this. The process doesn't work nearly as nice with water-based paints, as they dry WAY to fast. The smoother and glossier the enamel coat is, the brighter and shinier the metallic finish is. This process works with all metallic colors.
The other major player is WHEN to apply the powder. The paint has to be dry enough to not come off on your finger, but still a bit grabby. The stickiness is what glues the powder down. And as this is a  polishing kind of application, it lays the metallic powder particles down flat, becoming as much like real metal as possible. This is why metallic paints like copper and gold don't look like the real thing, when they spray out of the can or spray gun, the micro-flakes get deposited randomly, not uniformly, resulting in loss of real metallic sheen.
If you find that buffing the powder isn't resulting in a super shiny metal, try letting the paint set up a bit more. 20 minutes can make all the difference!

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