Tuesday, February 22, 2011

Japanese alloys rule!

Got to hand it to the Japanese. They never cease to amaze me with their exquisite taste.
I just finished a silver-shibuichi-shakudo mokume gane plate, and the colors that came out after patinating itare gorgeous. 
The photo does not do them justice...
The silver appears almost white in contrast tto the alloys, and the alloys themselves display such warm colors, its amazing. 

By the way, this is a completely self-made piece, 
I alloyed and rolled the 15% shibuichi, and 2,5% shakudo. 
Anyway, I'm just going to cut it up, twist it and give it to a jeweler friend of mine to make a few seamless rings. Feeling I've reached a good point at mokume gane technique, I guess I can now relax back into some swordsmithing...

Thursday, February 17, 2011

New (actually pretty old) machines.

This post could also have the title "Buying used machinery in a recession". The recession that is hitting my, IMF and ECB stricken, country is so severe, that several jewelry workshops are going out of business. Their old machinery, being too heavy to ship elsewhere, and not wanted by other struggling professionals, end up in scrap heaps. 
That is where I found the ones shown here. I am ashamed to quote the price I got them for. 
Suffice it to say that basically they were bought by scrap iron weight.

A huge powered rolling mill. First thing I need to do is install some finger protection...

Water-cooled precision table saw, and old electric kiln.

Basically all the heavy machinery needed to make mokume gane professionally, 
for the price of a few crates of beer...

Wednesday, February 16, 2011

Silver-copper mokume gane pictorial.

Just came back from the shop, where I made my first silver-copper mokume gane billet. It turned out really good, which probably means this combination is hard to mess up...
So here is a short pictorial of what I did.

You need pretty hefty torque plates made out of stainless steel. Paint the faces with yellow ochre so the metals don't stick to them.

11 layers of fine silver and copper.

Cleaning the faces and exposing fresh metal with a scotch brite pad. Works just fine, and is pretty quick.

 Clean off any grease by dipping them in acetone, then rinse with water and dry.

Making sure you don't touch the faces, stack them up between the torque plates.

Compress them as much as you can, and tighten the bolts again, to keep this pressure on the billet. 
In this case the pressure was over 1 ton/cm2!

Stick them in a small forge or kiln, with a small burner... you need to keep the temp below 778 C, where the eutectic alloy between silver and copper melts, and everything turns gooey. 

Let it soak for about an hour, turning it around occasionally to even out the temperature. Also try to keep a reducing atmosphere in the forge as much as you can (I found out it's important but not critical).
What is important is to closely monitor the temperature, hence a pyrometer is needed. Try to insert the probe between the steel plates, as close as possible to the billet.

Finally after some trimming and sanding here is a healthy billet without any delamination. Oh, I also presssed it once more after it dropped down to black heat.

Good Luck!

Tuesday, February 8, 2011

Propane burners, old and new.

I have been pretty busy trying to find and negotiating used power rolling mills. A lot of jewelry workshops are sadly going out of business in this country, and there is a multitude of used machinery that if not resold will go for iron scrap. I think I managed to clinch a deal on an old massive power mill with 9cm thick, 20cm wide rollers for 500 Euros, which is quite a deal, if it goes through...

I have also been building new forges, one for melting wootz steel, and another which will be able to hold a steady 750 C temperature for silver mokume gane. The first one is easy, just build it as massive as you can; the second one is a lot trickier, as most forges and burners will easily overshoot that temp.

Another ongoing project is casting some shibuichi and shakudo. I cast an ingot of both, and have been running to and fro a guy with a rolling mill to flatten them out to 0.5 mm sheet. I will make a silver, shibuichi, shakudo mokume billet, once I have managed to make the 750 C forge...

Anyway, just to keep this blog going here are my two propane burners. My old sidearm burner, with a 1.0mm (ignore the 0.8 in the photo, it does not work) gas port. The cast iron nozzle has to be switched with a proper stainless steel one, as it is deteriorating fast.

Here is my second, more powerful burner I finished today. It is a forced air burner, using the same gas feeding head as the previous one, but built out of 1.25 inch plumbing tube, and a 2 inch blower (I really like the BLOWER stamp on it; as if it looks like it could be anything else).
The whole thing look like a huge faucet, only, it shoots out fire!!!

Here is a useful and necessary detail, a flame holder made out of a 0.75 inch tube held inside the bigger tube by radially arranged screws. Some people go without it, but I could not keep a steady flame without one. 
The flame of this one is massive, and by controlling the blower speed one can easily switch between an oxidizing and a reducing flame.