Paul on sun 16 feb 03
Hello,
I was trying to extrude some 4" cylinders to make bird feeders with and
would like to know if there are any suggestions on how to do this. I made an
expansion box for my extruder and made a die for a 4" cylinder with 1/4"
thick walls. I could not get it to come out straight and it was very
difficult to handle once i cut it off. The only thing i can think of is
maybe the walls need to be thicker or maybe the clay was too soft. Can
anyone with experience doing this sort of thing offer any advise? Thanks,
Paul B
David Hendley on sun 16 feb 03
Most likely, your clay is too soft. 1/4" walls is plenty thick
for a 4" cylinder.
Extruder manufacturers always stress that you should use soft
clay in their machines. This is because they don't want to be bothered
with the possibility that using stiffer clay might bend or break
something on the machine.
The truth is, you should use clay that is similar in consistency to
throwing clay, if you want the form to hold up after you extrude it.
If you are concerned about having really straight cylinders, extrude
the cylinders, let them set up for a little while, and then insert a
newspaper covered pipe or rolling pin in the cylinders, and roll, to
true them up.
David Hendley
Maydelle, Texas
david@farmpots.com
http://www.farmpots.com
----- Original Message -----
> I was trying to extrude some 4" cylinders to make bird feeders with and
> would like to know if there are any suggestions on how to do this. I made
an
> expansion box for my extruder and made a die for a 4" cylinder with 1/4"
> thick walls. I could not get it to come out straight and it was very
> difficult to handle once i cut it off. The only thing i can think of is
> maybe the walls need to be thicker or maybe the clay was too soft. Can
> anyone with experience doing this sort of thing offer any advise?
Logan Oplinger on mon 17 feb 03
Hello Paul,
In addition to what Dave Hendly has said, be sure the spacing between the
inner and outer plates of your cylinder die is equal all the way around the
die. Any difference in spacing will cause the extrusion to curl. Also,
anny difference in the smoothness of the die wall will also affect the
resistance to clay forced through the die. You do not say what your die is
made of. The thickness of the die, and the radius or chamfer at the edge
of the die will also affect how the clay passes through the die. A smooth,
uniform radius or chamfer will promote a more uniform extrusion.
One way I have used to control or limit distortion is to first extrude a
short length, about 3 inches, and cut this off at the surface of the die.
Then I hold a small board up against the die and continue extruding,
allowing the board to move with the extrusion as I hold it under the
extrusion.
Logan Oplinger
Another Pacific Island
Latitude: 13.5 Longitude: -144.7
On Sun, 16 Feb 2003 11:50:15 -0500, Paul wrote in part:
>Hello,
>I ... made a die for a 4" cylinder with 1/4"
>thick walls. I could not get it to come out straight and it was very
>difficult to handle once i cut it off. The only thing i can think of is
>maybe the walls need to be thicker or maybe the clay was too soft. Can
>anyone with experience doing this sort of thing offer any advise? Thanks,
>Paul B
Concepts in Clay on tue 18 feb 03
Here's another idea for keeping the cylinders straight coming out of the
extruder, provided your extruder is on the wall. I used those foam water pipe
insulators that you get at Home Depot or..., and as the extrusion is coming
out I hold the foam cylinder under the extruder and let the extrusion go
inside of it. I used foam cylinders that are about 3" diameter for a 4"
extrusion. You can gently keep it straight as it comes out, but it also makes
it easy to move to a table with the foam inside.
Bobbi in Central PA
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