Jason Russell on wed 1 feb 06
I'm looking for somewhere in Oregon where I can dig my own clay. Does anyone know of any
places that are particularly well-suited for functional pottery, i.e. close to workable straight out of
the ground? Any info would help. Thanks!
Jason
nsmheralds@netzero.net on thu 2 feb 06
>I'm looking for somewhere in Oregon where I can dig my own clay. Does =
=
anyone know of any
places that are particularly well-suited for functional pottery, i.e. cl=
ose to =
workable straight out of
the ground? Any info would help. Thanks!
Jason
The news associated with this is both good and bad. The good news is th=
at the entire Willmette Valley is filled with alluvium, some of which is=
stream deposit, some deposited by the Bretz Floods. Obtaining it seems=
to be another matter entirely. I usually consider roadcuts to be fair =
game, whether it be for collecting plant seed, picking up rock for the l=
andscaping, or gathering geologic samples for testing in the kiln. Unfo=
rtunately, there are few roadcuts through this alluvium and almost all t=
he ones I've seen are either on heavily-travelled raods, choked with veg=
etation, or on the edge of someone's private property to the extent that=
removal of more than a couple of shovels full might lead to erosion iss=
ues. Further bad news is that you'd actually want to dig down further t=
han a foot, as the topsoil has too much organic material in it.
The good news is that it throws pretty well, even when a bit over-hydrat=
ed. Keep in mind that the only stuff I've thrown came from my back yard=
and had a considerable amount of chunks of stuff in it--bits of wood, s=
mall gravel, stuff like that. The larger particles probably acted as so=
me form of grog, but also got in the way and made throwing anything but =
the most primative-looking forms difficult at best.
Your best bet for getting a decent amount of the good stuff is to keep y=
our eyes peeled for excavations. The surface-skimming housing developme=
nts don't count. You're looking for utilities digging trenches or someo=
ne excavating for a basement or possibly for road construction if you ca=
n tell they're working more than half a meter below what used to be the =
surface. The clay you want will be really stiff and a sort of gunmetal =
grey. I noticed this several years ago when I was replacing my sewer li=
ne. The soil in the top foot or so was a darker, coarser material, no d=
oubt from the presence of organics. While this is normal and is the stu=
ff you want in your garden, it's not what you want for making pots. I n=
oticed that after I dug deeper, the color and texture of the clay change=
d abruptly. The deeper stuff was stiffer, a ligher shade of grey, and c=
lung to my shovel like star-crossed lovers. That's the stuff you want. =
The stuff I'm throwing right now came out of a fence post hole, but I t=
hink it still had too much of the upper-level material in it, as it has =
all the coarse stuff I mentioned before.
It won't take cone 10. I tested a small bowl at cone 10 reduction and i=
t turned into a puddle; fortunately it was sitting in a stoneware bowl s=
hard. I think it'll take cone 6, possibly cone 8, but further testing i=
s required.
I hope that helps. Where do you live, by the way?
Nathan Miller
Thistillium Pottery
Newberg, OR
=
Michael Wendt on fri 3 feb 06
Nathan mentions a local Oregon clay that fires into a puddle at cone 10.
This kind of clay is a perfect candidate for a blend with a high refractory
clay like Helmer. A simple line blend can bracket the clay body firing
range using fluid slips of the same specific gravity. Once melting point and
porosity issues are measured, the area of interest is further refined with
small scale throwing tests which include glazing and firing.
Getting a workable body then means finding the correct additives to control
shrinkage cracks and dunting and you are off to the races with a local
clay.
I still think this is the real answer to local interest. It really helps
sale to both tourists and locals when they learn that they are getting a
piece made with local clay.
Regards,
Michael Wendt
Wendt Pottery
2729 Clearwater Ave
Lewiston, Idaho 83501
USA
wendtpot@lewiston.com
www.wendtpottery.com
Nathan Wrote:
The good news is that it throws pretty well, even when a bit over-hydrated.
Keep in mind that the only stuff I've thrown came from my back yard and had
a considerable amount of chunks of stuff in it--bits of wood, small gravel,
stuff like that. The larger particles probably acted as some form of grog,
but also got in the way and made throwing anything but the most
primative-looking forms difficult at best.
Your best bet for getting a decent amount of the good stuff is to keep your
eyes peeled for excavations. The surface-skimming housing developments
don't count. You're looking for utilities digging trenches or someone
excavating for a basement or possibly for road construction if you can tell
they're working more than half a meter below what used to be the surface.
The clay you want will be really stiff and a sort of gunmetal grey. I
noticed this several years ago when I was replacing my sewer line. The soil
in the top foot or so was a darker, coarser material, no doubt from the
presence of organics. While this is normal and is the stuff you want in
your garden, it's not what you want for making pots. I noticed that after I
dug deeper, the color and texture of the clay changed abruptly. The deeper
stuff was stiffer, a ligher shade of grey, and clung to my shovel like
star-crossed lovers. That's the stuff you want. The stuff I'm throwing
right now came out of a fence post hole, but I think it still had too much
of the upper-level material in it, as it has all the coarse stuff I
mentioned before.
It won't take cone 10. I tested a small bowl at cone 10 reduction and it
turned into a puddle; fortunately it was sitting in a stoneware bowl shard.
I think it'll take cone 6, possibly cone 8, but further testing is required.
I hope that helps. Where do you live, by the way?
Nathan Miller
Thistillium Pottery
Newberg, OR
Leland Hall on fri 3 feb 06
Jason,
Many years ago, I was fooling around up above Foster Resevoir, up in the
hills out of Sweet Home. I was on a dressed out Harley Road King, camping
and fishing and such, noticed that all the cut banks seemed to be clay,
Dug up maybe 25 lbs., bagged it and brought it home in the bikes saddle
bags.
I'm sorry to be of such little help, cause I never got around to doing
anything with it. But I made a few little pinch pots, and some coil pots,
right there on the riverbank, left them on a rock for the deer to wonder
at. It was quite plastic and handled nicely. It might still be around
here somewhere.
Oh, you said "functional". The clay was light orange, I remember thinking
probably an earthenware/Terracotta type clay.
Someplace out of Tillamook area is a lighthouse where pioneers built
woodfired kilns on or near large clay deposits near the beach, and fired
bricks, and built the lighthouse of them. It is a historical site and
museum now, and opent to the public.
I think you will do better on the west side of the Cascades, as the East
side volcanoes are so young. Not much is broken down yet, Except the
Ochoco are much older mountains as are the Blues and Wallowas. Coast range
has much clay, and are ancient. Wallowa mountains are dated with the
Rockies, and part of the same geologic phenomena I am told.
There is clay at base of Cape Lookout. I made pots to leave on the beach
there. Again, don't know fireing range, but it was plastic, though gritty,
and needs screened.
Good luck in you search, have fun!!
Leland Hall
Before The Wheel Enterprises
La Pine, OR
PS. I just remembered reading in a little book about the history of the La
Pine basin, that the pioneers had found a "huge" clay deposit in the basin
of the Little Deschutes river, and were advertising back east that folks
should emmigrate to Central Oregon, since there was bound to be a booming
clay mining industry eventually in the La Pine area. (never happened)
I've been here over fifteen years on the banks of the Little Deschutes, and
have yet to seen sighn of it. Maybe I don't know where to look.
Subject: Oregon Clay Deposits...
I'm looking for somewhere in Oregon where I can dig my own clay. Does
anyone know of any
places that are particularly well-suited for functional pottery, i.e. close
to workable straight out of
the ground? Any info would help. Thanks!
Jason
nsmheralds@netzero.net on sat 4 feb 06
>Many years ago, I was fooling around up above Foster Resevoir, up in th=
e
hills out of Sweet Home...I'm sorry to be of such little help, cause I n=
ever got around to doing
anything with it. But I made a few little pinch pots, and some coil pot=
s,
right there on the riverbank, left them on a rock for the deer to wonder=
at. It was quite plastic and handled nicely. It might still be around
here somewhere.
>Oh, you said "functional". The clay was light orange, I remember =
thinking
probably an earthenware/Terracotta type clay.
It sounds like this might be ferruginous bauxitic laterite. It's a redd=
ish soil that forms on top of basalt. The rock weathers and gradually, =
one is left with mostly silicates, aluminates and iron. The laterites o=
f the Redding terrane are composed mostly of kaolinite clay, alumina and=
iron. I threw a bowl from Redding laterite and found that it didn't ha=
ndle well. I once tried wedging laterite from Chehalem Mt., the basalti=
c ridge that lies north of Newberg, and found that it doesn't adhere to =
itself too well and has a lot of lumps in it. It is, however, highly re=
fractory and does interesting things as a slip, both raw and under a rut=
ile blue glaze. It seems to have a very high expansion/contraction rate=
and when used bare over bare clay, it has a rough, alligator texture--e=
ither that, or it just doesn't melt enough at cone 10 to fully and evenl=
y spread over the suface on which it's applied. But even as a slip, I f=
ound it lumpy and difficult to handle, probably a result of surface weat=
hering and the binding properties of various organics (worm castings and=
such).
>Coast range has much clay, and are ancient...There is clay at base of C=
ape Lookout. I made pots to leave on the beach there. Again, don't kno=
w fireing range, but it was plastic, though gritty, and needs screened.
This and the clay with which they built the lighthouse would be either m=
udstone or sandy shale. There's well-exposed mud-stone along US 20 betw=
een Newport and the seafloor basalt west of Philomath. This mudstone, w=
hen test-fired to cone 10, closely resembled Willamette Valley alluvium =
when used as a glaze: a darker brown with a satin finish. Most other r=
oadcuts in the northern Coast Ranges are probably shale, sandstone or sa=
ndy shale. I collected some material near Hebo Mt. that had a sort of g=
ritty clayey texture to it. When I made a slip out of it and test fired=
it to cone 10, its apearance closely resembled that of ferruginous baux=
itic laterite. It did seem to melt better, suggesting a bit more silica=
or less alumina. I haven't tried throwing with it.
=
Going with Michael's statements, I might have interesting results combin=
ing Willamette Valley alluvium with ferruginous bauxitic laterite and/or=
Coast Ranges sandy shale.
>PS. I just remembered reading in a little book about the history of th=
e La
Pine basin, that the pioneers had found a "huge" clay deposit in the =
basin
of the Little Deschutes river, and were advertising back east that folks=
should emmigrate to Central Oregon, since there was bound to be a boomin=
g
clay mining industry eventually in the La Pine area. (never happened)
>I've been here over fifteen years on the banks of the Little Deschutes,=
and
have yet to seen sighn of it. Maybe I don't know where to look.
Might this be similar to the reworked volcanic alluvium found in the vic=
inity of Madras? I collected some of this, but have yet to test it. I =
would suspect the upper Deschutes material to be relatively recently ero=
ded volcanic material and probably resembles its parent rock much more c=
losely than does the alluvial material in western Oregon.
=
Nathan Miller
Thistillium Pottery
Newberg, OR
=
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