Need help with niello

[Jeff Mack]

I've been wanting to make, and use niello for some time. In my research, I've talked to people that say the sulfur fumes will kill me, others say don't worry about it. Anyone have suggestions for methodology and safety in making niello. I've got some recipies, just making sure I don't kill myself off. I'd like to use the stuff on a seax i'm hammering on now.

Thanks!
JDVM

[Jeff Pringle]

Dude! worry about the lead, not the sulfur!
And check out: http://www.jloose.com/thesis.html
From our moderator, all you wanted to know about recipies and more.
As far as safety goes, ventilation and more ventilation, if you have a respirator make sure it's cartridges are good against metal fumes and still go for the extra ventilation.
Jeff

[J.Arthur Loose]

Jeff,

The sulphur fumes won't kill you, but they are profuse & acrid. Jeff P. is right... worry about the lead fumes. The best way to make niello is to make a good ventilation box, just big enough to get the crucible & the torch into comfortably, with a good strong draft that takes the fumes away from your shop. A wooden box, some 3-4" flue pipe & a squirrel cage blower should suffice. I make niello in a jewelry melting/pouring crucible with a handle that is about a foot & a half long. I like Phil Fike's recipe and methods the best, here's a section from a study I did of niello in college:

Fike:

6 parts Silver,2 parts Copper,2 parts Lead, Sulphur in excess

The Making

Phillip Fike, as a modern niellist, describes the making of niello in a much more relevant manner than most sources. Fike recommends using an ordinary Burno crucible into which copper and subsequently silver are melted with an oxy-acetylene torch. When the two metals are fully blended, Fike adds the lead and swirls the crucible to mix the '...alloying mass gently.' (p.5) At this point Fike suggests that the proper swirling motion requires an accompanying sway of the backside. Once the alloy has been properly swirled, Fike introduces a '...heaping tablespoon of sulphur onto the alloy,' (ib.) This should be done '...without hesitation or timidity, as the sulphur is immediately afire, and so may be the spoon, which you might return to the bottle, possibly afire without knowing it...' (ib.) Fike then uses an iron stirring rod to '...'muddle' everything that is melting and burning,' (p.6) After burning off all of the sulphur '...the niello will be at about 1200? F a medium red color if you can read it.' (ib.) The alloy is now rotated as before in order that '...it [washes] over itself in a circular flow. A cinder of residue will form as the mixture cools.' (ib.) Fike maintains that this cinder is a '...critical point,' (ib.) as it '...might in fact have a cleansing effect on the balance of the melt.' (p.5,) When this cinder has formed from about 1/3 of the original mixture, the niello is poured in the angle iron (coated with carbon.)

The Application

Fike first states that the metal to receive the niello be carefully cleaned by abrasive scrubbing, pickling & degreasing, sandblasting or electro-cleaning. The work is fluxed with white pasting flux diluted 25%; Batterns flux (full strength) or as I recall from a workshop I attended, a 50/50 mix of handy flux & Prip's [and then heated with a torch.] If using the rod straight from the pour, the work is '...lightly fluxed,' (p.7) using one of the aforementioned mixtures. When the flux is '...fully active and glazing the surfaces,' (ib.) the rod is put to the hot metal. If using a powdered niello, it is '...mixed with the flux, and then fired such as with enamel in a kiln...' (ib.) According to Fike, '...niello is a quick moving liquid at 1000 degrees. It becomes firm [at] about 875?' (ib.)

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One thing to note: Fine (or "pure," or ".999,") silver works best since Sterling is alloyed usually with copper and sometimes with who-knows-what. Copper tubing (like for gas-lines... usually available in the bladesmith's shop,) works best due to it being "oxygen-free," according to Fike. As for the pour, tilt the angle iron (about 3 feet long,) at about 15 degrees and use your torch with the oxygen cut off to coat it with carbon. Make sure there's something to collect the niello should it run off the bottom of the angle iron. The rod created thus is really the most convenient way to apply niello, and impurities often run out toward the end of the rod. I also use wet/dry sandpaper, rubber gloves and a plastic dishwashing pan (like you use in your sink,) filled with water to finish the fused niello. That way the shop isn't getting niello powdered-lead dust everywhere.

[Jeff Mack]

Thanks! I think I've got a spare blower in the shop. I'll have to attempt to remember some wood working skills and build a exaust box. Your thesis is awesome!

Thanks again. If I'm sucessful, I'll post pics.

Jeff