Wednesday, August 23, 2006

Norse Meat Spit - Period Fluxes?

Joel wrote:

> ... I was trying to reproduce a roasting spit artifact from the Lund
> It looked in the picture like the pointy end was tripled back on itself
> and "apparently" forge welded. We tried this, and it worked quite
> well, producing a replica that looks just like the picture. Here's the
> question. Assuming Viking Age smiths could forge weld, what did they use
> for flux? Borax wasn't found in Scandinavia was it? Do you know how
> they did it? ...

As it happens I have to make up one of these same sword spits latter
this week. (This as part of a package of Viking Age domestic ware and
tools being ordered for a film under production - more on that in an
upcoming post here!)

The object under consideration is a type of Viking Age meat spit called
a 'sword spit' . The artifact is from Lund, Sweden and is dated to 1000
- 1050. Its total length is 111 cm. Roughly the front quarter (about 30
cm) is flattened to a long rectangular sectioned point. There are two
short prongs which bend forward at the base of the blade, which look to
be round profile and end in points. The remainder of the shaft is square
cross section, all twisted in one direction. The far end is equipped
with a ring held by a simple loop.

Viking to Crusader (Number 62 page 244) describes it as having " the
prongs being cut from the shaft and bent forward"
Viking Artifacts (Number 46 page 17 / 201) describes it " At the base
of the blade the outside edges are cut and bent to form prongs parallel
to it."
Both the books have images too small to see this kind of detail.

I can see maybe three ways of doing this:

1 - shaft and sword are one piece, two smaller rods welded on for the
prongs (a pain to wire on the small pieces while heating)

2) sword is flat stock, slit back at one end for prongs. Shaft is lap
welded on to this. The long shaft could also have a short slit made in
it (Imagine the blade with a short taper between the barbs > >- and a
matching V slit on the shaft. This is how I intend to do it by the way)

3) one thicker piece. Two diagonal slits made that get lifted away to
form the prongs. The blade is forged (slightly drawn out). Then the
length of the shaft is drawn out.

I have never been able to find a close up image of the artifact, or have
never seen it in person. (if YOU have I'd really appreciate a jpeg of
the thing - especially at the joint!)

One general comment; In the Viking Age, the source material would be
shorter and thicker 'currency bars'. These are typically about 5/8 to
3/4 square and about 12 - 18 inches long. I doubt a single one would
provide enough material for the Lund spit. For the Norse smith, the more
obvious way to work would be at the least to make the head from one bar
and the shaft from another. ( If I was REALLY doing a high end
reproduction I would try working down from the thicker stock!)

A second consideration - which is going to lead to your second question.
Remember that this would have been WROUGHT IRON (technically bloomery
iron) rather than our modern mild steel. This changes how you make a lot
of things, as the material has a distinctive grain to it from slag
occlusions during its smelting from ore. This would assist you in
determining the actual method used originally - if you had detailed
photos or the object to look at. Things like welds and joined pieces
show up pretty clearly on the artifacts.

This relates back to the welding. Period iron is to a certain extent
'self fluxing'. Often no extra flux is required to weld it. I have to
admit that I always use borax - even on the few times I have forged
welded antique wrought iron. (Which frankly has not been all that often,
as I save the material I do have for layered steel work primarily.) This
mainly on the better safe than sorry theory. Borax is what I have always
used - the cheaper washing soda variety.
You are correct that Borax was not available to northern Europe
historically. (This came up as a discussion topic just this week on
ARCHMETALS - but in the context of bronze casting and smelting.)

I have read and heard that traditional English smithing uses 'fine white
sand' for flux. This is a silica sand? I can't imagine the quartz sand
more typical here in Ontario would melt at forging temperatures. Again
one of the things thats on the (too long) list of things to try!

Hope some of this helps



STAG said...

Nice to see what you are up to. I'll try to get into your archives later on. Have to work now though.


Weekend_Viking said...

On the flux thing, I tend to cut my borax about 50% with plain white quartz sand, and find it works quite well. I've also had some success using fine straw ash or wood ash, and wonder if this would work if cut with quartz sand as well. In general, any soda compound plus quartz will melt fairly easily at iron welding temperatures to form a glaze/glass.



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