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[Student Talk] "Bowling"


#1

Well, I have had my first day in school. I was given a square
piece of copper and told to make a bowl. I cut, I torched, I
pickled, I pounded, torched again, pickled again, pounded again,
and VOILA! I now have a 6" dimpled amoebae! Bowl? Ha!

What must I do to pound it into a bowl shape? So far it is not
"bowling" too well.

Help!

Trudy


#2

There are two way to do this, you can “dish” it into a bowl, or
you can “raise” it into a bowl. Raising will produce a more
pronounced shape, but is more difficult to do. Dishing on the
other hand will give a shallow bowl rather quickly. Both
techniques are cold techniques, the metal does not need to be
heated, just annealed. I don’t think I can describe raising, but
I’ll give dishhing a shot.

Dishing uses a rounded faced hammer (like the ball end of a
ballpeen) to stretch the metal into a supporting form. The form
can be a sand bag, a tree stump or other large piece of wood
formed to act as a giant dapping block (the depth of the hole
should be shallow at first, then deeper as your bowl begins to
take shape and the edge should be rounded and smooth).

The technique is as follows: start with the metal centered over
the hole and strike it with the hammer(a small dent will appear).
Then move the metal slightly and strike it again (another small
dent touching the first). Continue moving the metal, always
striking over the hole in the form, so you make your dents in a
very gentle spiral, with dents slightly overlapping their
neighbors. Do this to the entire surface, anneal, and repeat the
process until you get the depth of bowl you want.

In the end you will have a rough bowl. If you want to make it
pretty you will have to “planish” it. For this you need a ball
stake and a planishing hammer (flat face with a mirror finish).
the technique is to hold your bowl against the stake and strike
the spot where the bowl and the stake meet. this will leave a
small spot with a mirror finish. Continue by moving the metal in
a spiralling motion with a slight overlap. Always move the
metal, not the hammer. The hammer should always strike exactly
the same spot (same is true for dishing). Once you have
completed the spiral you should have a bright mirror hammered
finish(not smooth, but with little tiny flat faces, almost like
facets).

Another important thing for this kind of work is how you hold
and use the hammer. You should not be taking big, full arm
swings, but rather short sharp, very controlled blows. Your body
should be slightly angled from the work (30 to 45 degrees), your
upper arm and elbow should be kept firmly against your rib cage
so all the motion is in your elbow and forearm. You should hold
the hammer so your thumb and index finger should be placed
opposing each other on the sides of the hammer, with the
remaining fingers wrapped around the hammer (I know i sounds
awful, but it should feel very natural and comfortable). This
position give great control, but makes the hammer stick out a a
slight angle from your hand (hence the reason the body should be
angled slightly away from the work). Your arm should just move
up and down from the elbow, only the forearm in motion. One last
thing, and this is the hardest part, your grip should be relaxed
(no white knuckling). Play with it for a while and when things
start to flow and feel very smooth you are doing it right.

I hope you can understand my descriptions, but if you have
further questions contact me off list at mehodgson@aol.com

Michael


#3

Did they not give any instructions about how to do this or are
you supposed to be creative and do things like cutting and
folding to get the bowl shape?

Marilyn smith


#4

Er, are you raising the bowl or sinking it? What is your
inventory of hammers, mallets, stakes, stumps, anvils, irons and
sandbags? How thick is it? Did you file the edges to get rid of
irregularities? Have you made any creases or cracks? Did you mark
the center? When you annealed it did you miss places? Are the
lumps ‘innies’ or ‘outies’? Do you have any reading knowledge, a
teacher or a plan of attack?

Georgie


#5

Trudy, It has been a while since I did any raising but here is
how I think it worked the best: - use a compass to draw circles on
the outside of your bowl about 1/4" apart, starting at the
outside edge of your bowls base ( you need a flat section in the
middle for it to sit on) and working all the way to the edge

  • begin striking with your raising hammer along the first
    line(nearest the cente) and slightly overlap your strikes as you
    go around the bowl, you should be able to get into a rhythm that
    will be quite natural.

  • when the hammer strikes the metal the metal should be
    positioned on the stake so that the curve you are looking to
    create is in contact with the metal - I think this is the hardest
    part

  • the key is consistant striking, listen to yourself and you
    will know if it is right or wrong

  • Good luck to you, wear hearing protection, be patient. The
    first raising projects can be pretty ugly.


#6
   What must I do to pound it into a bowl shape?  So far it is
not "bowling" too well. 

The usual process is called angle raising. Easiest is to first
create radial crimps, like the accordian folds of a Mr. Coffee
filter, which will pull the metal into sort of a funnel shape.
Now, using a raising hammer, over a raising stake, you hold the
crimps against the end of the stake and hammer the ridges between
them down to the stake. The essential part is that the lip of
the stake is located just behind (towards you, and of course,
underneath the metal) where you’re hitting with the hammer, and
that the angle of the crimps/ridges is kept constant to the
stake. Don’t try to take too big an angular bite at a time, or
it will just flare out as you work towards the edge. Don’t let
it fold over as you drive it down. You’re compressing the metal,
not just flattening it, and it’s getting thicker. Work in
concentric circles from the inside to the outside, and when
you’ve finished a course of this, the metal will now be slightly
cone shaped. And irregular. Now use a soft mallet to beat the
whole side against the stake to even out the waves, so the thing
becomes again more truely conical instead of warped and
ameabalike. The whole point is to keep the profile/cross section
uniform, whatever it may be, so that you can continue working in
concentric circles doing the same thing to similarly shaped
metal as you work. Then you anneal, and again create crimps in
the metal with an appropriate crimping stake (can made of wood).
You can do this without the crimps, but it’s harder to learn and
control. Each successive course depends the angle of the cone.
You develop a bowl by starting successive courses of angle
raising farther from the center, so the bowl grows up in angular
steps. Once it’s reached the overall depth, width at the top,
etc, of the bowl you desire, you then “bouge” it out to curved
surfaces with your mallet over a round or suitibly curved stake,
removing the angles. Then planish the surface to hammer out the
crude markes left by raising…

The other way to get a bowl is called stretching or sinking,
depending on the exact variation used. For this you start with a
circle of thick metal. Hammering hard in the center portion only,
you stretch it, expanding it to a dome. The edge isn’t hammered,
and holds the circumference in while the center of the disk
expands down. That’s stretching. Sinking is similar, except
you simply hammer a circle down into a suitably shaped
depression…

Pick up a copy of Murry Bovin’s “silversmithing and art metal”.
It shows the process clearly. So do several other books. One of
the best illustrations of how to move the metal is the diagram on
page 10 of “silversmithing” by Rupert Finegold and William Seitz,
a superb book. It doesn’t clearly show crimping, though, until
later in the book. But for showing you what to do, So SHOULD
your instructor. Figuring out just where the metal is held
relative to the stake is important, as well as the angle to hold
the metal, and the angle at which the hammer must strike the
metal. Once you figure this out, you’ll find the process will
"click" with you, and suddenly you’ll find you can move a lot of
metal just exactly where you want it to go in a surprisingly
short amount of time. Once you’ve built up the suitable arm and
wrist muscles, that is (grin)

Hope this helps.

Peter Rowe


#7

Trudy

Depending on the assignment specifics, the equipment to which
you have access and the appearance you want the finished piece to
possess you have several different options. You could make a
shallow bowl shape by dapping with the appropriate
hammer/hammers, a deeper form by hollow raising, a very deep form
by tradition raising with a hammer and block (usually made from a
hard wood) or by spinning.

It’s hard to respond to this question in anything other than
book form. If you weren’t given a demonstration of techniques,
my best guess is that you’ve been given the assignment to assess
your level of expertise, creativity and or perseverance.

Without anymore my suggestion would be to: Dap a
hollow form by holding the copper at about a 30 degree (?) angle
on a solid surface (wood or metal). Start in the center. Use a
6 or 8oz. planishing hammer or heavier forming hammer. Hammer
the copper while moving out from the center in a spiral. Make
sure to angle the cooper more steeply as you reach the edge. Or,
find a large wooden depressed surface (time permitting, you could
carve out the center of a log) or a sandbag. Put the copper over
the opening (drill holes and nail it down if you have to) or over
the bag. Choose a likely hammer and hammer the tar out of the
thing. Linda M


#8

Trudy, In addition to hearing protection, protect the palm of the
hand that is holding the piece while the other hand pounds with
the hammer. I have found that the best way to do this is to buy
an inexpensive pair of cotton gardening gloves that have rubber
"nubbies" on the fingers, little spots of latex that give grip.
Then get a pair of weight-lifting or cycling gloves; these gloves
protect the palm, but have no fingers. They should have a thick
leather pad running from the base of the hand across the fleshy
part of the thumb, continuing around to protect that web of skin
between the thumb and the first finger. Put on the cotton glove
first, then slip the weight-lifting glove over it. Now your
fingertips have the advantage of the rubber nubbies for gripping
and your palm – especially the area near the thumb – is a lot
safer. If you are right handed, it’s helpful to go glove shopping
with a left-handed friend in the same class, so you can share the
cost of both pairs of gloves and split of the pairs accordingly.

Have fun!

Anne in rainy Massachusetts, who just found out she IS going to
Tucson!!! [bank balance quivers in anticipation of killing
blow…]