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Bronze coating on medieval iron bell


#1

Researchers at the National Museum of Scotland are working on
creating replicas of the medieval monk’s bells, that were made of
iron sheet and somehow given a bronze coating. Apparently the
bronzing part is giving them trouble. Does anybody in Orchidland have
any experience with this sort of thing?

BBC Scotland did a little report on the project that can be seen at

Stephen Walker
Andover, NY


#2

Hi Stephen,

Ive an antique Austrian cow bell here thats made this way, tho the
coating is brass.

Looking at the surface its obvious that the brass has been fused to
the iron sheet AFTER its been bent up and riveted.

Bells on bovine and other stock have been used since the earliest of
times, for identification and finding them in mist and fog in the
alpine regions of Europe and elsewhere in on the African continent.

Im fairly certain how it was done, given the level of technology of
the metal smiths who made the bells, wether for 4 legged or 2 legged
users.

Given that the Edinburgh researchers are on substantial salaries,
they should really work it out for themselves.

My guess is that they are academics who havnt much hands on
experience.

Tho Id be happy to act as a consultant for my usual fee.


#3

I saw an interesting technique a while back.

An open steel cable grip was created, heated to hot, then plunged
into a crucible of molten bronze.

Looked awesome.

Maybe something along these lines may work, heat the bell and dip it
into molten bronze. Try small scale first.

Regards Charles A.


#4

I agree with Charles on researching medieval techniques and in the
practice of making replica armor the ‘dip bath’ on iron was the
easiest way depending on the size of the bell. Just bit of ctual
research would lend invaluable Tell them to contact
their local S. C.A.{Society for Creative Anachronisms) armorers and
farriers group. There are group archives going back decades
discussing all manors of metal work and foundry techniques.

Teri


#5

I can tell you the method used then is still used in Spain and other
countries for cattle and sheep bells. The steel bell is enveloped in
clay and a small piece of bronze or brass is placed in with it. The
item is them placed in a fire when the clay has dried and heated to
about orange-yellow heat and then when cooled the bell is broken out
of the clay. The bronze or brass melts and coats the bell by
wicking, the seams are brazed with this process as well as the
rustproof coating. Very cheap as done onan open fire rather than in a
proper furnace. No volatolisation or oxidation. Larger pieces have
straw in the clay to bind and bulk fill it andthis turns to carbon.
Nick Royall


#6
Maybe something along these lines may work, heat the bell and dip
it into molten bronze. Try small scale first. 

In the news piece, they show a crucible of bronze, but they don’t
really say what they did with it. I would suppose that dipping it
would be one of the most obvious things to try. But I see a reason to
suspect it was done some other way.

If the culture that produced these bells (early medieval Scotland
and Ireland)could bring together enough molten bronze to immerse an 8
to 10 inch bell, it would seem that they would also have very likely
produced some bronze castings using a similar volume of bronze. You
would need at least a hundred pounds of bronze to fill that crucible.
But I am unaware of any bronze castings coming from that culture that
are anywhere near that large.

Steve Walker


#7
I can tell you the method used then is still used in Spain and
other countries for cattle and sheep bells. The steel bell is
enveloped in clay and a small piece of bronze or brass is placed in
with it. The item is them placed in a fire when the clay has dried
and heated to about orange-yellow heat and then when cooled the
bell is broken out of the clay. [snip]

Hmmm. that’s really interesting, and I can see some applications for
it in the work that I do.

Thanks Nick.

Regards Charles A.


#8

There is a commercial application being used by Bathsheba, a
mathematician working in 3D geometry. She describes it as liquid
bronze wicking into the interstices of a steel printed model. It may
be related to the ancient process. Her description is in the middle
of the 3d process on this page.

http://www.ganoksin.com/gnkurl/ep80kv

Her work with cad/cam and solid geometry is stunning.

Judy Hoch