Copper work hardens, but how fast. If my friend was hammering copper to
"sculpt" it, how much depth/stretch could he do before it would have
to be annealed? To avoid cracking. I'd guess that it depends upon the
thickness of the copper, so is there a multiple of the thickness that he
could use as a rule of thumb?

Thanks,
Bob

On Sat, 25 Jul 2009 21:16:25 -0400, Bob Engelhardt
wrote:

Copper work hardens, but how fast. If my friend was hammering copper to
"sculpt" it, how much depth/stretch could he do before it would have
to be annealed? To avoid cracking. I'd guess that it depends upon the
thickness of the copper, so is there a multiple of the thickness that he
could use as a rule of thumb?

Thanks,
Bob
=======
Why reinvent the wheel?

Here is a guy that made a weather vane
http://www.appaltree.net/aba/repousse.htm


Many good books available on weather vanes. See
http://www.amazon.com/American-Antiq.../dp/0486243966
http://www.amazon.com/Moving-Metal-A.../dp/0970766491

on repousse
http://books.google.com/books?id=hW1...l t&resnum=11


Lindsay http://lindsaybks.com/prod/allbks.html has several
reprints detailing the exact processes/techniques required.
Key word is plate which was used for sheet at that time.

Hasluck-Metal Plate Work
21591
$10.95

also see
http://www.artmetal.com/blog/walker/...pousse_methods
http://en.wikipedia.org/wiki/Repouss%C3%A9_and_chasing
http://www.eric.ed.gov/ERICWebPortal...cno =EJ052558

http://www.youtube.com/watch?v=Cs4bMGhHruI

Good luck and let the group know how you make out.


Unka' George [George McDuffee]
-------------------------------------------
He that will not apply new remedies,
must expect new evils:
for Time is the greatest innovator: and
if Time, of course, alter things to the worse,
and wisdom and counsel shall not alter them to the better,
what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman.
Essays, "Of Innovations" (1597-1625).

F. George McDuffee wrote:
snip
on repousse
snip

Ah, "repousse", that's it. It's so much easier to find stuff when you
have the right search word.

Thanks,
Bob

On Jul 26, 10:39*am, Bob Engelhardt wrote:

Ah, "repousse", that's it. *It's so much easier to find stuff when you
have the right search word.

Bob

That's a good word for a copy of a cat.

On Jul 25, 8:16*pm, Bob Engelhardt wrote:
Copper work hardens, but how fast. *If my friend was hammering copper to
* "sculpt" it, how much depth/stretch could he do before it would have
to be annealed? *To avoid cracking. *I'd guess that it depends upon the
thickness of the copper, so is there a multiple of the thickness that he
could use as a rule of thumb?

Thanks,
Bob

Maybe this can help: a chart of “temper vs. reduction of area” for
drawing copper wire from the Southwire Company:
http://tinyurl.com/mepj7e

Denis G. wrote:
Maybe this can help: a chart of “temper vs. reduction of area” for
drawing copper wire from the Southwire Company:
http://tinyurl.com/mepj7e

Thanks - that's a useful link. Bob

The work hardening of copper is highly overrated.
as long as you avoid putting stress risers in, you can pound 12ga into foil
without cracking.

7 or 8 years ago I was commissioned to make a copper weathervane. It was a
dancing cat, patterned after one the customer saw in Prague.
Finished size, about 18x 24. about a foot wide across the brisket.
Made it out of 16oz sheet. Took a sheet about 24x36 annealed it and
sandwiched it into a die jigsawed out of 5/8 mdf, sunk each side to about 3"
across the brisket in one go. After removing from the die, I sawed one side
off at the edge of the die, and the other side about 5/16 larger. I tinned
the flange with an iron and folded it over.
I put the second piece inside the flange and closed it.Then I used a
prestolite torch and rosin core solder to lock them together.

Be sure to put weep holes in the low spots. Water will find a way in. If it
has an easy way out it won't harm anything.

Paul K. Dickman

"Bob Engelhardt" wrote in message
...
Copper work hardens, but how fast. If my friend was hammering copper to
"sculpt" it, how much depth/stretch could he do before it would have to be
annealed? To avoid cracking. I'd guess that it depends upon the
thickness of the copper, so is there a multiple of the thickness that he
could use as a rule of thumb?

Thanks,
Bob

Paul K. Dickman wrote:
The work hardening of copper is highly overrated.
as long as you avoid putting stress risers in, you can pound 12ga into foil
without cracking.

Great - I didn't like the idea of having to do repeated annealings.

7 or 8 years ago I was commissioned to make a copper weathervane. It was a
dancing cat, patterned after one the customer saw in Prague.
Finished size, about 18x 24. about a foot wide across the brisket.
Made it out of 16oz sheet. Took a sheet about 24x36 annealed it and
sandwiched it into a die jigsawed out of 5/8 mdf, sunk each side to about 3"
across the brisket in one go. After removing from the die, I sawed one side
off at the edge of the die, and the other side about 5/16 larger. I tinned
the flange with an iron and folded it over.
I put the second piece inside the flange and closed it.Then I used a
prestolite torch and rosin core solder to lock them together.

That's clear and you make it sound so easy, but I'd bet that there was
considerable experience behind it.

Do you have pictures?

Be sure to put weep holes in the low spots. Water will find a way in. If it
has an easy way out it won't harm anything.

Good point. I know how devious water is!

Thanks,
Bob

"Bob Engelhardt" wrote in message
...
Paul K. Dickman wrote:
The work hardening of copper is highly overrated.
as long as you avoid putting stress risers in, you can pound 12ga into
foil without cracking.

Great - I didn't like the idea of having to do repeated annealings.

7 or 8 years ago I was commissioned to make a copper weathervane. It was
a dancing cat, patterned after one the customer saw in Prague.
Finished size, about 18x 24. about a foot wide across the brisket.
Made it out of 16oz sheet. Took a sheet about 24x36 annealed it and
sandwiched it into a die jigsawed out of 5/8 mdf, sunk each side to about
3" across the brisket in one go. After removing from the die, I sawed one
side off at the edge of the die, and the other side about 5/16 larger. I
tinned the flange with an iron and folded it over.
I put the second piece inside the flange and closed it.Then I used a
prestolite torch and rosin core solder to lock them together.

That's clear and you make it sound so easy, but I'd bet that there was
considerable experience behind it.

Do you have pictures?

Be sure to put weep holes in the low spots. Water will find a way in. If
it has an easy way out it won't harm anything.

Good point. I know how devious water is!

Thanks,
Bob

The only pic I had was a 4x5 the home owner took after it was mounted.
That's stuck in a drawer somewhere.
I don't even remember the street it was on. I stored the patterns for about
4 years. I told a guy helping me clean up after a flood to pitch them out (I
didn't even look at them). About 3 months later somebody called asking if I
could make some more for him. That's the way it always goes.

The real trick was using the dies. It was a trick somebody came up with when
I was in college. We called them masonite dies because we made them out of
plywood and tempered masonite. I haven't seen tempered masonite in years.
They work great for shallow hollow shapes where you need to seam two halves
together.

You saw out the outline in the center of two sheets of mdf.
Then you mount your sheet metal between them with screws around the
perimeter. The screws must go through the metal to pin it in place. You can
then emboss the sheet to the outline leaving a nice flat edge. Then you
remove it and put in the second half and emboss it in the other direction.

The skill comes in keeping the tension even as you hammer. If you draw one
area to hard, it'll start to tear around the screws.

Paul K. Dickman

On Jul 25, 9:16*pm, Bob Engelhardt wrote:
Copper work hardens, but how fast. *If my friend was hammering copper to
* "sculpt" it, how much depth/stretch could he do before it would have
to be annealed? *To avoid cracking. *I'd guess that it depends upon the
thickness of the copper, so is there a multiple of the thickness that he
could use as a rule of thumb?

Thanks,
Bob

You can tell by feel when to anneal it. Beat up a sample piece first.

jsw

On Jul 26, 4:14*pm, Jim Wilkins wrote:

You can tell by feel when to anneal it. Beat up a sample piece first.

jsw

And when it doubt, anneal. It does not take long and it is so much
easier to work when annealed.

Dan