TedFab Faber on fri 2 apr 04
Building an extruder is easy, if you can or know someone who can weld. =
You may want to check local school. I have built several from plans in a =
late 70's CM. Sorry I don't know which one. If anyone wants, I can make =
a drawing of my model. I have used round and square. I think there is =
less resistance with a round barrel. I used marine or 7 ply plywood for =
dies. Of course the real problem is finding a bumper jack.=20
Ted the Tech
David Hendley on sat 3 apr 04
Ted the Tech -
I wrote the article about building the bumper jack extruder.
It was in Ceramics Monthly in September 1976.
Since then, the article has been updated and published in
Pottery Making Illustrated, Winter 1999, "The Extruder Book",
by Daryl Baird, and "Pottery Making Techniques", a just-published
collection of articles from Pottery Making Illustrated. This book
also has an article by Mary Kate Sullivan showing how to make a
variation on the bumper jack extruder that does not require
any welding. I would still recommend the welded variety -
very little welding is required, and any small-time welding shop
could easily do it for non-welding builders.
I don't own or use a bumper jack extruder myself - I have a
couple of homemade models of different designs, but you
can't beat the bumper jack extruder for ease of construction.
Bumper jacks are getting harder to find, but they are still around
at junk yards. Of course, the Cadillac model BJ extruder
uses a 2-way (push and pull) tractor jack. This makes for easier
removal of the plunger after extruding. Tractor jacks are
commonly available, but kind of pricy at about $50.
My step-by-step instructions for making metal two-part dies
are also in these books and magazine. Recycled aluminum
street signs are my material of choice for extruder dies.
The books are available to buy, borrow, or check-out from libraries.
The American Ceramic Society published and owns these resources,
and they are available to buy at http://www.ceramics.org
If anyone is seriously interested in building an extruder, I strongly
recommend that they buy "The Extruder Book". Included are several
plans for building your own, and they might find a plan they like better
than mine. You will save $300 by building your own, more than enough
to justify the price of the book, and then you will also have all sorts
of information about using extruders. Diana Pancioli's book "Extruded
Ceramics" is also well worth checking out, if you are interested in
extruding, building with extrusions, and die design.
David Hendley
david@farmpots.com
http://www.farmpots.com
----- Original Message -----
Building an extruder is easy, if you can or know someone who can weld. You
may want to check local school. I have built several from plans in a late
70's CM. Sorry I don't know which one. If anyone wants, I can make a drawing
of my model. I have used round and square. I think there is less resistance
with a round barrel. I used marine or 7 ply plywood for dies. Of course the
real problem is finding a bumper jack.
Ted the Tech
Jim Tabor on sun 4 apr 04
David Hendley wrote:
>Ted the Tech -
>I wrote the article about building the bumper jack extruder.
>It was in Ceramics Monthly in September 1976.
>
David-
Design matters when it comes down to an extruder's function. On my first
"U Built" I was a little too eager to weld it together and made a
slight error of about 1" which leaves about 2 inches of clay in the 5"
dia. barrel. It has followed me around the past 30 years and is still
being used by my students and me. I understand you had the advantage of
John Miller at TWU for guidance using the bumper jack; however, I had
not ever seen an extruder and don't remember ever seeing one for studio
use when I made mine in 1973. I was aware of pipes and tiles extruded by
industry.
The barrel is an 18 inch X 5" pipe and cap I bought at an oil field
supply company in Dallas. It is welded to 2 pieces of 2.5" angle iron
that has a series of matched notches machined to take the plunger which
is made from 1.25" and a 3/4" pipe pivoting with a steel plate to fit
inside the barrel. I also use an extra 14" pipe inserted into the handle
when extra leverage is needed. Dies are held by screwing on the cap to
the barrel (never a problem of clay leaking there). The cap was solid
and had a hole machined as wide as would allow a small lip to hold the
dies. My first hollow die is a machining marvel from a block of
aluminum and 1/4" plate (beveled edges). Other dies have been made out
Plexiglas, plywood, steel, and brass.
I doubt if I spent more than $20 to build that extruder but I don't know
how much it would cost now to get the same machine work done. That part
was free because I had the help of a convict learning to be a machinist
in a prisoner training program at Skyline H.S.'s. night school. I was
still teaching there and didn't start the magnet school's ceramics
program until 1976 where we had good use of the extruder for 15 years.
Of course I took it with me when I left in '91. It is industrial
strength and holds a lot of clay.
We start extruder projects next week at school and it will get used as
much as the Northstar extruder mounted next to it. Students have been
hard on the Northstar with too many bent Z-braces, nuts in recycled
clay, and broken dies. At NCECA, I bought a dozen more braces to glue to
the dies in hopes to overcome some of the problems students cause by
that system.
Jim Tabor
Tulsa
http://www.members.cox.net/taborj/index.html
>
>
>
| |
|
