Incredible sets of medieval moulds found in France

A few years ago at Mont San-Michel, a lot of stone moulds for pewter casting were found.
Here is the link

http://www.inrap.fr/preventive-archaeology/Events/Virtual-exhibitions/Virtual-exhibitions/Making-Pilgrim-Badges-at-Mont-Saint-Michel/The-site/p-1475-lg1-The-site-and-the-discoveries.htm

They are 14th and 15th century pilgrims badges, often showing St Michael, or the Virgin, or a sword. The detail and artistic skill is wonderful to see, far above my own. 260 fragments were found,

Quote:
“This excavation is exceptional in that it has revealed a workshop for the making of pilgrim badges, the first to have been found in France to date. Exceptionally, the activity is clearly shown by the objects found, the cast-offs, and the archaeological structures, even if the latter are incomplete.
It was not only a workshop for the making of finished objects for pilgrims, but also for the making of moulds for this activity, as indicated by the numerous waste products, rough mould shapes and reworked examples. The whole chain of production was on one site.

However, it is not clear why certain faultless intact moulds were abandoned, especially when it is clear that this type of object was considered to be precious and was transmitted from generation to generation. “

The above indicates a problem similar to that I have mentioned to do with the Coventry moulds, that is, why were they dumped? Many of the Coventry ones are not obviously damaged. What the article doesn’t specify is how faultless the dumped moulds were. It is entirely possible that still usable moulds would have been dumped when fashion changed. Or maybe one part of them broke.

It is interesting though that the moulds were made on the site they were used. What is unclear from the historical records and finds in the UK is whether the pewterer carved his own moulds. I think they may have done so in some occasions, but in others purchased them from stone carvers, but I am not aware of any definite evidence either way. It has been suggested that engravers did the carving, and even that some carved bronze moulds for pewter casting, although none of them have survived. Somewhere more isolated like Mont San Michele would not be conducive to a division of labour, whereas in a town it would be easier to find a good carver.

The website says:
“The quality of the engraving, characterised by great attention to detail, bears witness to the work of craftsmen in full possession of their art, but who were also dependent on the wishes of the monks of the abbey. Written sources inform us that the moulds were the property of the monks and were made at their demand. The monks then entrusted them to metalworkers for the manufacture and sale of the badges, an important part of the profits being paid back to them.”

which still leaves it a bit unclear who the monks had make the moulds and sits oddly with the fact that the casting and the mould making happened in the same workshop.

The photos of moulds that they have made available indicate the usual methods of manufacture, but what is interesting is that they are made of schist and limestone. The limestone is probably from the same source as the Caen limestone, but the schist is not so easily located, perhaps coming from Breton quarries. According to the website the most detailed carving is in the finest grained schist, which makes sense. But oddly the geology book I just consulted says that schist is a moderately metamorphosed rock, made up of very platy minerals, such as mica, which in a schist are large enough to nearly be visible to the naked eye. Which would to my mind make it not very good for carving. If it is so fine grained that it isn’t obviously so wavy and platy, then it isn’t a schist. Certainly some of the Coventry moulds are highly metamorphosed mudstones and the like.

They have the usual holes for locating pins, vents for air etc. One has a clear saw mark in it, proving that they cut the stone up using saws.

Some day I’d like to have a look at these moulds.

A problem you run into when making buckles using stone moulds

I have had the ambition for years now to make good pewter buckles, of the sort in use in the 14-15th centuries for holding shoes shut. Numerous examples can be found in the Museum of London book “Dress accessories” and other books of finds.

The mould I am using is is made of soapstone, which I am using purely because I don’t have access to easily carved limestone or siltstone.

Note that I’m cramming quite a few items into one mould, which was done in the past. Good stone isn’t so cheap and easy to find, and it makes sense to use it for several objects, or use two sides for different objects, as seen in some of the Coventry moulds.

The slight problem is, how do I make sure that both sides have the correct half on them? Dan Towse (http://pbsn3.pbworks.com/w/browse/#view=ViewAllObjects), an experienced SCA caster, reckons they squared the mould sides off and measured. That would work well enough I think; being a cheapskate I don’t always use squared off moulds in order to maximise the amount of stone I can use, yet most moulds I have seen are squared off which certainly strengthens his hypothesis.

So, given the situation I was in, how should I mark either side? I tried using damp red clay in the already carved side, but it did not stick very well and rather marked one side of the stone as you can see at the bottom left:

soapstone buckle moulds in the making

Then I tried pouring wax in, hoping it would stick to the appropriate area. It did, but also spread a little beyond, so it was not as accurate as I would have liked. Still, it was a start.

Next I tried casting metal into it, hoping the white stone would be marked by it. No luck, the white soapstone remained unmarked.

When test casting into the mould though, I found that a partly complete cast could indicate the other side of the mould easily enough:

soapstone mould half done with test casts soapstone mould half done without test casts

So perhaps they did it that way? It would be nice to find some objects that are clearly half made, and that show both sides of the mould. Once you have carved the edge of the area to be carved out, you can carry on carving with the occasional test casting in order to see how you are doing:

I would expect real half-done moulds to show some evidence of this or another way of carving, although if the carver is sufficiently good and artistic they could do it virtually freehand I am sure.

I’m pleased a couple of my castings look like the originals they are based on

All I did was carve the stone mould based on the period design and I made what is probably the same mistake that the original mould maker did, in that neither are quite symmetrical, simple though that is to do when you have a ruler. Maybe he didn’t have a ruler and compass and protractor.  All I used was a ruler to measure the lengths of the sides and width, but didn’t concern myself with getting the angles precisely correct, and unsurprisingly the result was not symmetrical.

Here is a photograph of the belt spangles: Continue reading

Being a blog, I can ask questions that professionals won’t go near due to lack of evidence

For instance, who made stone moulds used to cast pewter and perhaps bronze items? Having had a skim through several sources of information about stone moulds, such as the Museum of London books, the Historical Metallurgy Society journals and excavation reports, I can’t find anything about this question. Of course being a proper careful archaeologist you can’t go beyond what the artefacts tell you, and they mostly don’t come with labels or engravings saying “Made by Bob”.

Obviously carving stone is a specific skill associated with masons, but the moulds are quite small and were probably carved using small sharp tools and files. My experience of making them suggests that with a modicum of artistic ability and fine motor skills you can carve moulds reasonably well, but the complex ones for pewter badges will take quite a lot more practise and real artistic skill.

Which therefore does not mean a stone mason is required.

One suggestion, in “English Medieval Industries” (page 78 of the paperback edition) is that many of the more detailed pewter badges were cast in metal moulds, the metal being cut by seal engravers. Who would indeed have the requisite skills, but I would need more evidence that they actually used metal moulds for this sort of thing in the first place, given the stone moulds that we know of from Britain and Germany, and the fine detail you can get in any fine grained rock.

I did read somewhere that the earthen moulds for casting bells and cauldrons and suchlike in, were made by a specialist on making them, referring to some records from medieval York, but those were single use moulds and he would have made scores every year, whereas a good stone mould can make 300 or 400 pewter castings and thus last for years of use.

Certainly engraving metal moulds would be harder for foundrymen to learn and do than simply outsourcing the work to someone else, but on the other hand they might, especially in smaller towns, encompass engraving within their skill set, as it is in a way related to the finishing of small items.

Turning to “A History of British Pewter”, we find mention of moulds in wills, but unfortunately it does not say what the moulds are made of. Some will be bronze, for plates and the like, and maybe they all are, or maybe some are stone. The authors write that metal moulds were widespread in England in the 15th century, attested to by references in the London Pewterer’s records, in Welch, i, 14-15, 105, 120, 175, 179. Welch is “History of the Worshipful Company of Pewterers of the City of London, 2 vols, 1902. (Note to self, the NLS and St Andrews and Glasgow have it) They also assume that the pewterer would make his own moulds. It would be comparatively simple for a pewterer to cast their own moulds (Or got a foundry to do it, but in smaller towns they were often both the same person and workplace), and spend time finishing them off. It would certainly negate the need for an engraver.

In fact, having been spurred on by this question to read more, I have an answer in the book “Pilgrim souvenirs and secular badges” by Brian Spencer, one of the Museum of London books. It says in the introduction that “Little is known about the men who made the moulds, an operation that called for skill in small-scale precision work as well as a degree of artistry and iconographical knowledge.” It seems some records in York and Cneterbury mention mouldmakers, i.e. people who carved the moulds, whether stone or also, as is shown in the book, cuttlefish bone, but it is not always clear in the records whether they made their own mould or hired them. The introduction also mentions the use of seal engravers in mould cutting and goldsmiths and that bronze moulds for casting pilgrim souvenirs are also described.

So we have more of an answer than at the start of this post. With any luck there is more information available; I shall certainly be chasing up the excavation reports of the moulds mentioned in the book. Cuttlefish bone is one substance I haven’t really looked at, but will surely be the subject of a blog post in the future.

How not to make a stone mould for pewter spoons

Four years ago at Kentwell Hall I spent ages trying to make a stone mould for casting spoons in. It failed in a somewhat spectacular manner – I accidentally carved one side of the mould at the wrong angle, so the pewter ran out the bottom. An understanding of the shape required to make a spoon should make it clear why this would happen. soapstone spoon mould both sides Here are the two parts, on the left the male, the right the female with the indent for the bowl of the spoon. The male side has to fill the bowl, whilst leaving enough space for the metal to run between both sides. But I couldn’t see how to get both sides to match up perfectly when I was carving, and the result was as said. The white stuff in the photos is plaster, put there to try and block up the gap, but it didn’t work. This view from end on should make it clearer, the white plaster being on the right hand side: soapstone mould top view of male part You can see that the metal enters from the top of the bowl, and there are clear grooves cut to allow air out of the mould.

What I have just realised now, a few years too late, is that looking at the medieval stone mould pictured in this book:
http://books.google.co.uk/books?id=PDLPX7J8kW8C&lpg=PA144&vq=spoon&pg=PA66#v=snippet&q=spoon&f=false

, the bowl is sunk somewhat into the stone, i.e. the rim of the spoon is below the level of the upper face of the mould. This will firstly help give a good seal when the two parts are pressed together, and secondly might also allow room for manouvre in carving the bowl. Of course without the other half it is harder to be certain, but I think that indenting the female part and raising the male part above the level of the joining plane would perhaps make carving it a little easier. Ahh well. At least there is enough stone to spare that I can try to remake the mould and this time make a better job of it.