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ready for rivets and antiquing |
This is a follow-up post to the ulu reproduction mentioned in the previous blog post. Despite the time crunch that I'm feeling, I'm really regretting not building a second ulu alongside this one for myself. I'm sure that I'll attempt it, or a similar one again someday so I want to record some of the steps while its fresh in my mind.
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Muriatic acid accelerates rust |
For the blade, I used a stainless steel cleaver that I bought at the Magic Wok on Duckworth Street. It has just the right dimensions and gave me a nice, clean steel blank to start with. I cut the corners off with an angle grinder and used the grinder and hand files to finish shaping and sharpening the blade. To mimic the pitted and rusted surface of the blade I covered the blade with a very fine sawdust and sprinkled a bit of muriatic acid solution into it. It only took a few hours on each side to create the antiqued pattern. I then soaked the blade several times in tea to help turn the reddish pink rust a darker blackish colour, to mimic the look of a conserved metal artifact.
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Antler stem |
The neck of the handle is caribou antler. The general shape is a natural flare, where a tine starts to flare out into a flat palm. When I had the rough shape cut out, I soaked the antler for about 24 hours in white vinegar to soften it. I wanted the slot for the blade to fit inside the soft spongy part of the antler without cutting through the dense outer layer. Softening the antler in vinegar first let me bend out the slight irregularity in the shape of the palm.
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Cut musk-ox horn for the handle |
The small grip across the top of the antler is musk-ox horn. I used the smallest part of the horn that I could that matched the dimensions of the original artifact. I think there are still 2 or 3 more similarly sized handles inside this small horn. I cut the horn with a scroll saw and shaped it with an electric sander. Its comparable to soft wood or antler and shapes very quickly and easily with sanding, although it was that distinctive, unpleasant burnt hair smell as you cut or grind it. Its predominantly held in place with friction, although I also added some hide glue to fill up any gaps and to make it even more secure. I left the antler neck a little longer than necessary and sanded to top down flush with the musk-ox handle when it was fit in position.
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drill the antler and metal apart |
I needed to drill holes through the antler and the ulu blade for rivets. I marked the position of the holes on the antler and drilled through the antler first. I put the undrilled blade back into the slot and marked the position of the holes on the blade, through the drilled antler holes with a pencil. Then I drilled the pencil marks out using diamond abrader bits on the dremel tool, plus water to keep from burning through the blades. I don't really have a steel working shop, so this was the step with the most room for improvement. I'm sure a drill press would have done a much quicker and better job. The main thing is to not to drill through the antler and the metal together. Its too easy to shred the antler when the bit hits the harder steel inside and starts to dance around.
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tea staining works on metal and the organics |
After I drilled the holes, but before I but the rivets in, I antiqued everything in tea. I wanted the tea to stain the antler and horn a reddish brown, and the blade black. I didn't quite get as much red from the tea as I was hoping, so I touched it up on the surface with a bit of red ochre.
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Annealing the copper rivet rod |
The copper rivets were slightly more laborious than they needed to be because I started with a a heavy copper ground wire that was much thicker than I needed. I hammered, ground and filed it down until it was thin enough to fit through the holes. If I had it in the workshop I would have started with a narrower gauge of wire. Since I was hammering I needed to periodically anneal the copper with the blow torch to soften it again and prevent it from becoming brittle and fracturing while I worked it.
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Ready to cut to length |
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Starting to tap out the rivet head |
When the copper was thin enough to fit through all the way through the antler and blade I would cut it off and move on to the next hole. I worked on all the rivets at the same time. The wires in the photos are a little longer than necessary. Next time I'd make each on a millimetre or two shorter. If the wire is too long, it will want to bend over rather than flare out as you hammer it. I'd hammer the rivets on the anvil, being sure that the opposite end of the rivet was supported by the anvil.
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Finished rivets flattened out |
Even one light hammer tap on the antler can leave a dent that is impossible to remove. I hammer very slowly. Alternating filing the heads down and drilling small dimples into the ends to help the metal flare out and create the rivet head as I tap it down. When all the rivets were pounded flat, the ulu was pretty much done. All that was left to do was touch up the colour and and antique the copper with the red wine vinegar and miracle gro solution.
The photo sequence below shows the progress of the ulu next to the original 1:1 blueprint that I drew from the reference photo.
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The cleaver made a perfect blank |
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At this stage the antler has had very little work done to it, its naturally shaped like that |
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The blade has been cut and I started trimming the antler |
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The blade has been antiqued in muriatic acid and the musk-ox horn handle is planned out |
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I made the first cut on the musk-ox horn and started thinning out the antler part of the handle |
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All of the major shaping is done, it just needs to be antiqued and riveted |
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The finished ulu next to the original pattern |
Photo Credits: Tim Rast