I will be taking a sand casting class this month, and would like to try some of the buckles shown in the
buckle image thread
Some of these would seem to be hard to cast, with all the tiny curliques. Does anyone know the mechanics of casting these things? Would they have cast a bigger part and filed the fine part down?
Quote:Some of these would seem to be hard to cast, with all the tiny curliques. Does anyone know the mechanics of casting these things? Would they have cast a bigger part and filed the fine part down?
We know quite a lot about the casting of equipment from the archaeological evidence. Nearly all military copper-alloy stuff in the 1st century AD was produced using the lost-wax technique, with a one-off, one-piece mould (of clay, formed around the wax model) that has to be destroyed to retrieve the object. The plus side is that it produced an item requiring little finishing. In the 2nd century, the two-part mould (of clay and sometimes stone) starts to be used, allowing copying of existing equipment and reuse of the mould, but at the expense of requiring more finishing, usually removing the 'flash' that seeped between the halves of the mould. Both methods require casting sprue removal. There are plenty of half-finished items in museum collections that demonstrate these two techniques rather nicely. So far as I know, there is no evidence yet for sand casting except for lead slingshot from Velsen (and that was under exceptional circumstances!).
Mike Bishop
Thanks! I know from taking classes with the instructor before that he uses "delph clay" in place of sand, and it is a very fine consistency. The one time he demonstrated in a jewelry class he cast an impression of a US quarter which came out with a lot of detail, but did look as I remember as if it would need some finishing work, including of course taking the sprues off.
Thinking about it I can see where you could put in a lot of was sprues and not damage the casting, whereas with sand/clay you are digging a sprue and can damage the detail. Will try out.
I try to find how that type of buckles was made too, but already have the equipment to cast.
I think that the pelta buckles with the fine scrolls were cast as a rough version. The detail is added by hammering certain parts flat and then bending them in the wanted form. Most probably tongues were used, but I have never seen a Roman example.
In my collection I have a buckle that is clearly not completely finished because a part of the casting sprue and other excess material are not removed at all. The buckle is cast as a whole and does not have fine bent scrolls; it`s the other heavier type. Based on the lack of finishing it is clear that it is made using piece moulds.
Looking forward to your progress. We need more reenactor made belt parts in the US!!
This is rather where I hope 3D scanning happens: scanning such small parts and being able to 3d print them in casting wax, or even printed in bronze. At least giving an accurate picture.
Hi Rich,
Just noticed your postcounter seems stuck at 2999 :-) The material he uses is probably Delftse aarde (or clay), which is great for high detailed casting.