Friday, October 12, 2012

Remember those Labels!

- So I says to meself, ya have that ReArc conference coming up in less than a week. Ya got a course this weekend, so actually its only all of two full and two half days for shop work remaining. Since yer gonna be demonstrating the Aristotle Furnace, it might be nice to have at least one working bar forged out from one of that pile of Aristotle 'pucks' ya got layin' about.
And being so lazy, I don't want to change back out of boots to head back into the house (again) to grab the camera. Best not to use one of the carefully recorded and documented test samples.
Here, see that one? Nothing noted on the bag. Use that one.

But what the heck *is* that piece anyway?

Two fairly crumbly looking fragments (sorry, no starting image, see above)
One at 223 gm, other at 75 gm.
These kind of fitted together, so stack, bring up close to welding in the coal forge, attempt to 'press weld' in the hydraulic press.
Ok, not really welded. So heat again, hand hammer weld. Try to press the edges in (again at welding heat), which does not work so well.
Cut in half and stack. Press weld. Repeat weld with the hand hammer, working the edges in (another couple of weld sequences)
Cut in half at 90 degrees to last cut line. Stack and press weld. Repeat weld with hand hammer, again working over the edges in another couple of weld sequences.
Draw to a rectangular bar on the air hammer, starting each sequence at welding heat.

Ok, that is a lot of welding heats taken.

Grind flat one face (angle grinder), polish to 80, cross direction at 120.

Total elapsed time : 2 hours at the forge

 (Images expand to considerably larger than life size - same surface in both)
Size : 3/4 x 1/4 x 6 1/4 inches 
Weight : 157 gms

Polished surface etched in Ferric Chloride.

A couple of things:

1) I'm not entirely happy about the 'yield' - at roughly 50% from bloom to bar.
This is primarily due to the source material, which I expect had considerable slag contained in the mass. There may certainly be a certain 'lack of skill' involved. I will note that only a couple of quite small fragments broke off the piece during the welding processes described.

2) What are those bright lines?
Given the position, I would think these are boundary lines between actual welding steps. However, Ferric Chloride normally etches carbon content, and bright areas like that are seen in billets where nickle is present. All the carbon leached out from a weld boundary? You can see the texture of the metal in the expanded views.

3) Source material?
During the polishing, few sparks were visible. Those that were had the 'dull red ball' effect normally associated with a low carbon 'wrought' iron. The normal product of this particular Aristotle furnace is a *medium* carbon.

Overall conclusion:

I think what I started with here was actually small bloom fragments instead of material from the Aristotle furnace.
The material did weld relatively easy, although there was some trouble blending in the fragmented edges.
The low yield is balanced by recovering metal from fragments around the outside of the sold bloom.

Although the carbon content shows as low, there is enough material to make two standard sized (3 - 4 inch) Norse styled belt knives. My intent is to do this, making one male (seax) and one female (long point) blades.


Remember to label those pieces!

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February 15 - May 15, 2012 : Supported by a Crafts Projects - Creation and Development Grant

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