Tin and building works – what is it for?

I was having a quick look through “The Welsh castles of Edward I”, by Arnold Taylor, when I found mention of the purchase of 160 pounds of tin for use in the building of Beaumaris castle in Anglesey in the late 13th century.

This naturally had me wondering what use tin was in building works. Tin is a weak metal, and not much use by itself. Almost every use requires it to be alloyed with something else. Lead and tin make pewter, tin and copper make bronze. Actually quite a few nice shiny pilgrim souvenirs and ampullae used nearly pure tin because of that shinyness. But you don’t make them for building a castle, gold and silver are much more popular with the workmen.

You certainly don’t put it in the lead for roofing, that would make it stronger but also less able to be beaten out into shape and around corners.

The last use I could think of would be tinning iron nails or other ironwork. Not only does this make it shiny it also helped inhibit rusting.

Theophilus, writing in the 12th century, recommended tinning iron nails and sheet iron used to bind wood together for making an organ. Biringuccio in the 16th century uses tinning on the inside of bronze or copper vessels to ensure that they do not taint food. He no doubt would have tinned iron as well had it been his job.

I also think that some small or large copper alloy castings were tinned to make them look like silver.

So I think the most likely use of the tin was for tinning nails. I have tinned nails before, using Theophilus’ recipe, but it is trickier than you would think, I really should have another go at it.  This photo shows the tinned nails.

tinnednailslanark08

You need a deep crucible for the liquid tin, nice clean iron nails, and to get the temperature of the tin and nails just right, as well as a steady hand when dipping them.

 

Since I wrote this wee post, I have found a mention of using tinned nails in buildings, but cannot recall where I read it.

What I did on my holiday this year – bronze casting

Once again, I was on the foundry at Kentwell hall in Suffolk.

This time, I was the master of the foundry. Unfortunately there was a slight lack of assistants, so there were 2 of us most days. Still, I managed to get a few things done and refine my understanding of the processes and equipment.

Last year, which I meant to write up and publish but never really did, involved a group of us trying to make cannon. We failed, due to lack of time and lack of appreciation of the difficulties. Replicating the techniques of 16th and 17th century foundry work, even with at least 3 of us having a great deal of expertise, was something that would have taken more than the 8 days that we had, and so we failed. Just two more days would have been enough though. Which isn’t bad, all things considered.

For those who don’t know, this is the foundry at Kentwell, first the bellows end and then the furnace end:

bellows end of kentwell foundry 2016 furnace of kentwell foundry 2016

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What I hope to do at Kentwell 2015 next month

This year (If all goes well) I am being a foundryman at Kentwell hall, in the year 1588. This is a good opportunity to try various things out, most of which I shall blog about afterwards. So I shall be sure to take a lot of photographs.

Things I intend to do/ show:

Finish my stone pewter spoon mould

Cast pewter buckles which will be used to try and make the next items

Cast bronze and brass buckles, purse bars, scabbard chapes, and pestle and mortar

Experiment with dry powder casting as mentioned in Biringuccio

As well as helping out with attempts at making small cauldrons or a cannon or a bell.

The trick will be preparation, so the week before I shall be mixing up lots of muck for moulds and trying to finish off a couple of pewter buckle moulds. Once there I shall also be discussing foundrywork with a couple of people who know a lot about it, and trying to keep the newbies who don’t, right. And get the younger ones working the bellows.

Yes, I am aware that having a foundry at a 16th century manor house in the countryside isn’t really accurate. It’s one of these irritating compromises that helps keep both the public, the site owner and us re-enactors happy and interested. Ideally we’d have a replica town, but that requires some millions in investment to make happen.

(And don’t say that early medieval association or group has managed it, because I’ll just laugh at you)

My philosophy of manufacture of reproduction stuff

Sorry about not posting for a while, I’ve been busy and progressing lots of things at once so nothing is quite finished yet.

I decided ages ago that I would make not direct copies of medieval and Tudor stuff, but attempt to make similar objects. Not only because starting from scratch gives a better understanding of the processes and knowledge required, but also because given the massive variety of surviving objects, I think it pointless to try and produce an exact match to one specific one. Yes, all buckles are buckles, but when you look more closely there are many variations between them, due to the use of many different moulds in different towns over a century or many different copies made. It is the latter I am aiming towards, i.e. how a craftsman would replicate something that is, say, new to town or seen as the latest fashion coming from London. Or that a competitor has designed. Therefore my replicas are often a bit different in size or precise shape.

An example of such variation can be found in the MoL book “Dress Accessories”, where they list 39 medieval pewter buckles excavated in the city of a similar design, i.e. “raised, bevelled band along centre of frame and beading along edge”.. Their diameters range from 21 to 24 mm, which suggests to me at least 3 different stone moulds or else one mould slightly recarved after every few hundred castings due to erosion of the stone, in which case the depth of the buckles should change quite a bit as well. I have trouble believing that each design of buckle would be proprietary to one pewterer or girdlemaker; that they are not helps explain the variation in shape and size. The two they do illustrate have different numbers of beads around the edge and a slightly different cross section.

There is another very geeky reason not to make your reproductions identical to originals, otherwise people might mistake one for the other or try to pass them off as originals. This has accidentally happened to a reproduction potter I know, although it didn’t involve any money, just mis-identification.