Oseberg Cauldron...

On 2020-03-07, D L wrote:

The group was wondering about the size of the cauldron. Do you think we will be able to cook for 10 to 20 people or so in it or will it be much smaller?

Under consideration is the large iron cauldron found in the Oseberg Ship Burial (Norway, dated about 824 ACE).
I freely admit that I have NOT personally seen the actual artifact being referenced here!

I'm also not having a lot of luck coming up with the exact measurements on this cauldron. Part of the problem is that even though I did have access to the full original excavation reports at one point - those are from about the time of the excavation (roughly 1900) and in Norwegian (!). ( 1 ) There are very limited illustrations included. Below is the field drawing showing the cauldron and tripod (only illustration of those in the report). If you attempted to work from this (scaled) drawing, you would come up with roughly 35 cm diameter by about 25 cm deep for the cauldron. Importantly, the legs of the tripod show as about 125 cm long.

I've also got a very slim book (1956), likely intended to be a museum guide to 'The Viking Ship Finds'. ( 2 ) It does not give any measurements, but lists TWO cauldrons in the burial.

So looking at this image, one of the few I've found (over the internet, ok?) showing the actual objects. ( 3 )
 The proportions of the height to depth are much different than the report illustration:
- Closer to ratio 3 : 1 (width to depth).
- It looks (?) like the artifact is 8 segments plus the bottom dish.

This image may prove a bit more useful to work with - as it is taken from a more flat position (less distortion on the leg lengths) ( 4 )

Now combine the two images:
- Take the measurement for the legs of the tripod from the report illustration, at 125 cm.
- Now make a rough scale from that length, placed against the images of the artifacts. (5)
- The resulting estimate for the cauldron seen is :
    width about 55 cm
    depth about 25 cm
- If you run those figures into a math calculator  you get a volume in the range of 90 L ! ( 6 ).

What is happening along the top edge of the rim is hard to determine from the images of the artifact that are (easily) available.
Typically, the bloomery (wrought) iron used for making the plates needed for shapes like cauldrons are massively thicker than expected by those used to modern industrially produced mild steel sheets. Norse material is in the range of 4 - 6 mm, modern steels normally used for replicas typically 1 mm or less. The point here is that with this thickness, there is no special need for extra re-enforcement of the cauldron's upper edge.
There is certainly some modification of the upper edge seen in the images.
- Is this a separate band of iron, circling the rim? On the inside or outside?
- Has the top edge been forged towards the outside and then folded over back against the outside surface? This would produce a rounded top edge. (In cases of objects made of much softer high copper alloy, sometimes a piece of round rod is placed into this 'pocket' before it is hammered down tight, as a further stiffener.
- Is this actually an extra piece of 'new' material, added during the initial conservation effort, to stabilize the ancient metal? Do remember this work would have been undertaken in the late 1800's, and standards of preservation were vastly different than today's.

Many modern replicas (see the final section) add a band of light weight metal, which has been then hammered over to make an upside down L shaped cross section. This results in a flat rim around the edge. If this method was used in the original construction of the cauldron, it would make it unique. (At least I am not aware of any other Viking Age iron cauldron that uses this method.) ( 7 )



I've got templates worked up for the cauldron seen below. I had made this for the 2008 film Outlander.

Strictly speaking, this is certainly more ‘vaguely inspired by’, than specifically a replica. (Much less to be considered a reproduction!) There are a number of definite differences from the artifact  (overall size / number of segments / lack of a rolled edge / attachment lugs / handle shape and detail). Note that this object is also made of much thinner modern 18 ga mild steel sheet. At roughly 1 mm thick, this material can be cold hammered to dish the plates to shape (so not forged.) Clearly some of the criticisms I apply to what is currently available commercially apply to this object! (Remember however, this was only ever intended as a visual prop for a *fantasy* film. Not either to be a duplicate of history - or actually to be cooked in!) 

I don't have the best notes on the finished measurements for this one. I remember that piece to be about 40 cm wide by 15 + cm deep. My original description on volume is "three gallons". (So roughly 12 L?). In retrospect, I think that might be more of a WAG than something I actually measured.  If you run those dimensions into that same math calculator you actually get a volume in the range of 25 L.

Still image capture from Outlander. You can see a copper cauldron and elaborate hanger I created.

So - although this is a long winded way to get back to the original question...

My best estimate is that, using the templates I have on hand, the final cauldron should run roughly 40 - 50 cm diameter and about 15 - 20 cm deep. (This actually results in a fair amount of volume variation!)
It should hold (to the brim!) at least 25 L, with the larger measurements, considerably more.
Given a 'good bowl full' at about .5 L (figure a normal yogurt container) per person? So 30 - 40 plus people should be easily possible.
My intent for this commission is to use significantly thicker mild steel plate, at 1/8 thick (so + 3 mm). This will require forging (hot dishing) the individual segments and base to shape. Along with creating an object more like the weight of the Norse originals, the thickness will assist in more even cooking heat, especially important for use over open fires.


‘Can you see a difference…’
(Ok - a bit of a rant.)


There are a number of people out there (typically on Etsy) selling what are described as ’the Oseberg Cauldron’ ( 8 ).
There are several aspects I find in almost all the things advertised as either 'replicas' or 'reproductions’:
- They all appear much smaller than the artifact. Significantly, the actual measurements are almost never given.
- All certainly appear to be made of thinner mild steel sheet, again thickness not specified.
- The finished metal colour and even surfaces suggests cold dishing method.
- Most use round rod starting material for the handles (a profile rarely seen in Norse artifacts).
- You see the top rim as separate narrow piece attached as a flat edge to the top of the body segments. This metal is folded straight back at 90 degrees, creating a flat surface along the upper edge.

The body of all of these versions offered for sale is so similar (almost identical) I have to wonder if there is actually a single source for the bodies (most likely offshore?) supplying all of these. That there is some variation on the actual handles suggest that the cauldron bodies are purchased, with individuals only adding handles? Despite all being described as 'hand forged' - the only hot work is in the handles and attachment lugs (and the level of complexity even there varies considerably).

Just sayin’…


NOTES:

1 ) Osebergfundet, A.W. Brogger, 1917

2 ) The Viking Ship Finds, Universitetets Oldsaksamling, 1956

3 ) Variations of this view of the artifacts as on display, are seen a number of times on 'Pintrest’. Itself a site I really hate for lack of context.
Including copies of the replicas I made for Outlander - described as ‘artifacts’. Which in turn have been used by my competitors as documentation for their own (usually lower detailed) ‘replicas’!

4 ) This image is poached from Alamy :

5) I actually did this for all these reference images to help refine the measurements.

6 ) Calculation for the volume of a spherical section
I found one (very derivative!) comment suggesting this artifact was actually at about 20 L (?) This offered in support of the some of the work referred to at the bottom of this piece.

7 ) I would be really interested for observation details from someone who has stood in front of the actual artifacts from Oseberg.
I dug into my (considerable) reference collection as I prepared this piece (plus the internet) and could not find better images than the two duplicated above. As suggested, NONE of the other cauldrons I had information on showed this 'top ledge' construction.

8 ) For your own interest, you might search ‘Oseberg Cauldron’ as images.
You will see a number of renditions of those same images of the actual artifacts.
You will find work by 'Torvald Sorenson' of Weland Smithy (with a web site that appears closed?)
You will find a number of images of my own work, mainly part of commentaries (seen on this very blog).

And the images I show here.
As I am highly critical of that last group of work - I am quite deliberately NOT linking back to the commercial web sites involved.