Ben Shelton on sun 18 jun 06
I am in the planning phase of a new extruder. I'd like to use it with white
clays so I am investigating aluminum and stainless steel for the barrel.
Man, that stuff is expensive.
Online metals has stainless pipe with a .13" wall thickness.
4" pipe is about $46/foot
5" pipe is about $95/foot
Aluminum
3.5" round tube is about $50/foot
What have you used and what were the results? What are good sources?
Are there some premade items that could be scavenged to make a nice extruder?
How big of a barrel is needed? Is 5" diameter overkill?
My current extruder is a hand me down home made job that has seen better days.
It is terrible for white clays as it is rusty as all get out.
Thanks all,
Ben
Des & Jan Howard on mon 19 jun 06
Ben
Our extruders, 105 mm dia & 155 mm dia were made from galvanized
steel cylindrical pipes. A cylinder hone was run up & down the pipes
to give them smooth interior surfaces. The dies are made from sheet steel,
ply & plastic. The plungers have wooden plates attached to the steel
plates.
We have used them for our white porcelaneous stoneware for
yonks without any staining.
Essential! Empty & clean the barrels & dies after use.
Des
Ben Shelton wrote:
>I am in the planning phase of a new extruder. I'd like to use it with white
>clays so I am investigating aluminum and stainless steel for the barrel.
>Man, that stuff is expensive.
>
>What have you used and what were the results? What are good sources?
>Are there some premade items that could be scavenged to make a nice extruder?
>
>How big of a barrel is needed? Is 5" diameter overkill?
>
>My current extruder is a hand me down home made job that has seen better days.
>It is terrible for white clays as it is rusty as all get out.
>
>
--
Des & Jan Howard
Lue Pottery
LUE NSW 2850
Australia
Ph/Fax 02 6373 6419
http://www.luepottery.hwy.com.au
William Melstrom on mon 19 jun 06
----- Original Message -----
From: "Ben Shelton"
>I am in the planning phase of a new extruder. I'd like to use it with white
> clays so I am investigating aluminum and stainless steel for the barrel.
> Man, that stuff is expensive.
Ben, when I made my extruder, I ued galvanized steel. I use nothing but
porcelain, and I have no problems with rust or staining.
I made a direct copy of the Brent-style extruder, but I made the barrel
extra-long, 20 inches, which is very handy.
Galvanized steel pipe is used by electricians, and is called "rigid
conduit." The basis of the Brent extruder is 4 inch trade size rigid
conduit. It has an inside diameter of 4 inches, and an O.D. of 4-1/2
inches. If you have the time to search, you should be able to get a 20 inch
piece for free at a construction site that has huge power requirements, such
as a power plant, a substation or a big factory or mall. Rigid conduit
comes threaded on both ends, but industrial electrical contractors just
throw away small cut-offs. You also might try going to a big industrial
electrical contractor in your city, and seeing if they will give you a piece
for free from their boneyard.
I know all of this because I used to be an industrial construction
electrician. I'm not sure, but I think that plumber's and pipefitters use
the exact same pipe, only it is not threaded. You can also try your local
metal salvage and recycling yard. They sell "used steel" for about 50 cents
a pound.
By the way, the key component of a Brent-type extruder is a simple shackle,
trade size 3-1/4, that can be found at a wire rope or rigging supply house,
or, if you want to pay a lot for it, Grainger probably has them, and Brent
will probably sell you one too.
William Melstrom
http://www.handspiral.com/blog.htm
Crystalline Glaze Forum:
http://board3.cgiworld.dreamwiz.com/list.cgi?id=Crystal
David Hendley on mon 19 jun 06
If you want a non-rusting extruder and cost is a factor, plastic PVC
pipe is the way to go. It's cheap.
The easiest-to-make design, which works great, is the bumper jack
extruder. It requires very minimal welding. The plans show it with a
steel barrel (the plans were written in 1975, when PVC was not so
common), but the barrel is not fixed in place, so a PVC pipe (or stainless,
or aluminum) can be used as well. The barrel is simply set in position
and can be changed at any time.
The plans for the bumper jack extruder are available from several
sources:
Old issues of Ceramics Monthly are available on CDs, so the original
article is again available in that form:
"Making a Bumper Jack Extruder", Ceramics Monthly, September
1976, pages 50-53.
The plans were republished in Pottery Making Illustrated magazine,
"Making a Bumper-Jack Extruder", Pottery Making Illustrated, Winter
1999, pages 30, 31, and "Homemade Dies", Pottery Making Illustrated,
Winter 1999, pages 32, 33.
Republished again in the book,
"Pottery Making Techniques", (articles from Pottery Making Illustrated)
American Ceramics Society, 2004.
Also published in the book,
"The Extruder Book", by Daryl Baird, American Ceramic Society, 2000.
The "Pottery Making Techniques" book also has plans for a non-welded
PVC pipe extruder.
Of course, the best place to shop for extruder components is the scrap
metal yard. Short pieces of pipe, which are worthless scraps to the
folks running pipelines, but perfect for extruders, are very common
at scrap metal yards.
There are scrap yards that specialize in aluminum and stainless steel,
so check them out if you want to go that route. I go to such a place to
buy the aluminum plate for my extruder dies.
You could very well find a perfect SS or aluminum barrel for $20 or less.
Remember, if you use a design which requires welding the barrel or
other non-steel parts, special welders and rods will be needed.
Optimal barrel size depends on what you will be extruding.
It is probably best to keep the barrel diameter at 4". The force
required to move the clay increases dramatically as the barrel gets
larger. The Randall extruder, with a 6" barrel is notorious for being
too hard to use. But, if you will be using it only for large extrusions,
it is a good size.
For an all-purpose machine, it is better to keep the barrel at 4"
and add an expansion box for larger extrusions.
David Hendley
Maydelle, Texas
david(at)farmpots(dot)com
"EXTRUDE IT! Getting the Most From
Your Clay Extruder" available at
http://www.farmpots.com
----- Original Message -----
>I am in the planning phase of a new extruder. I'd like to use it with white
> clays so I am investigating aluminum and stainless steel for the barrel.
> Man, that stuff is expensive.
>
> Online metals has stainless pipe with a .13" wall thickness.
> 4" pipe is about $46/foot
> 5" pipe is about $95/foot
> Aluminum
> 3.5" round tube is about $50/foot
>
> What have you used and what were the results? What are good sources?
> Are there some premade items that could be scavenged to make a nice
> extruder?
>
> How big of a barrel is needed? Is 5" diameter overkill?
Ben Shelton on mon 19 jun 06
I actually ordered The Extruder Book on ILL at the local library this weekend.
We'll see what I can glean from it when it arrives.
What is your opinion on stainless vs aluminum?
I have seen mention that aluminum is not a good choice in the long run due
to oxidation of the working surface. Any experience with this?
I did have the idea that I could coat the inside of the tube with paint or
epoxy to prevent rust if I used a plain steel tube BUT I would rather stay
with a material that is rust resistant on its own. Seems les troublesome in
the long run.
Great info so far, Thanks
Ben
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