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Mokume expansion


#1

Hi everyone-

Just need some advice- I am just starting to work with mokume and I
have a nice piece of 5 x5mm square stacked wire-

I will be reducing this to approximatly 1.5mm.

Is there a rough standard ration on the expansion of the metal ?

I will be feeding it longways through a flat rolling mill. I am
going to buy an expensive piece of wire and need to estimate how
many inches to buy

Thanks,
Paul


#2

i think the ratio is based on the reduction capacity of the mill as
opposed to the billet since each billet is variable-the one
consideration or rather, influence on that statement would be:
Depending on the metal you use on the outside of the billet it may
or may not effect the outcome since you may or may not begin with
equal weights of the total of all metals used for the whole…and as
removing random or pre-planned (patterened) areas or quantities is
just that, random, you can’t predict exact expansions of a given
billet as it is changed from the original weights and amount of or
kind of fusion (solder, electro, eutectic bonding, etc.) you choose
to unite the billet…for instance if you use 14kt white gold on the
outsides it is what is at the point of contact with the pressure of
the rollers.So that may always expand at x ratio relative to the
reduction your mill exerts on that particular material- 14kt white
gold being harder than 18kt yellow golds.It will expand a slight bit
differently than say using an outer layer of silver or brass or 24kt
gold but the layers inside the billet and the method used to bond
will make the entire thing vary from billet to billet.There is a
book that does have a table (or appendix) that lists various
combinations in making billets. by Steve Midgett- I haven’t looked at
it in a while but you may or may not find more info there…rer


#3
Just need some advice- I am just starting to work with mokume and
I have a nice piece of 5 x5mm square stacked wire- I will be
reducing this to approximatly 1.5mm. Is there a rough standard
ration on the expansion of the metal ? I will be feeding it
longways through a flat rolling mill. I am going to buy an
expensive piece of wire and need to estimate how many inches to buy 

Are you buying pre-patterned material or are you going to pattern it
yourself? If it is pre patterned then it is a simple volume
calculation the product of the height, width and length of the
starting object will equal the product of the height, width and
length of the final piece.

for example a piece of material 5mm x 5mm x 25 mm that equals 625
cubic mm so if you flat roll that piece it will end up as 83 mm long
(625 cu mm divided by ( 1.5mm x 5 mm))

if you are going to pattern it you have a somewhat more difficult
question but still not hard. A typical patterning process will
remove somewhere between 30 to 50 % of the starting material so you
would end up with 30-50% less length than the above example.

James Binnion
James Binnion Metal Arts