wallace myers on mon 13 apr 98
Hi Folks:
I made some oil lamps out of stoneware, glazed them
inside and out and fired them to cone 6. I gave them to
friends, who now tell me that they leak. What's going on?
I thought that clay vitrified at cone 6 and should not leak
even without glaze. If someone has a clue would you please
inform me.
Wallace
LOWELL BAKER on tue 14 apr 98
I just responded to a CM question concerning the same thing. Oil
will pass through the lamp body. The solution is one of several
things. Wash the inside of the lamp base with a thinned Elmers Glue
or a polyurathane varnish. allow to dry thoroughly (this may take a
week or more). Then test with lamp oil.
Interestingly enough water will not pass through the same clay body
because the water is sets up a kind of surface tension which dams the
small (minute) passages.
Read your CM questions section in the last edition for more on the
subject.
W. Lowell Baker
the University of Alabama
P.S. I had to call the Chemestry guys for the answer to this one.
Caroline and Hedley Saunders on tue 14 apr 98
I had the same problem with some little glazed stoneware oil lamps, oil
seeped through the unglazed base. I ended up coating this area with
super-glue which seemed to provide a seal. Though I still warned users to
beware! I never did find out why it happened but it did, it is a while ago
but I expect I used a grogged body, I wonder if a smooth body burnished
would make a difference?
Caroline Saunders
delphin@eclipse.co.uk
>----------------------------Original message----------------------------
>Hi Folks:
> I made some oil lamps out of stoneware, glazed them
>inside and out and fired them to cone 6. I gave them to
>friends, who now tell me that they leak. What's going on?
>I thought that clay vitrified at cone 6 and should not leak
>even without glaze. If someone has a clue would you please
>inform me.
>Wallace
>
Mike Flood on tue 14 apr 98
wallace myers wrote:
>
> ----------------------------Original message----------------------------
> Hi Folks:
> I made some oil lamps out of stoneware, glazed them
> inside and out and fired them to cone 6. I gave them to
> friends, who now tell me that they leak. What's going on?
> I thought that clay vitrified at cone 6 and should not leak
> even without glaze. If someone has a clue would you please
> inform me.
> Wallace
My partner and I have tried to seal cone 6 fired oil lamps with no
success. We tried glazing both inside and out, and we tried a lampliner
product. The lampliner product works about 50% of the time. We finally
gave up and are using glass globes to hold the oil on top of a clay
base.
The reason for the problem has something to do with the chemical
composition of water versus the composition of oil and the way the
molecules bind together. All I know is that we tried for several years
to solve this problem with no success.
Bridget MCDermott Flood
fireworks pottery
St. Louis, MO
Mark Issenberg on tue 14 apr 98
Hey Wallace i make cone 10 lamps and i would think they would leak also
so buy lamp sealer from Axner. You could make RAKU lamps as long as they
are sealed. So go buy some sealer.
Mark in Miami
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OWL POTTER on wed 15 apr 98
The problem with unreliable oil lamp liners might be not letting them dry long
enough.
I have had a lot of problems with leaky lamps until I learned to let them dry
thoroughly. Keep in mind, that is a very closed space trying to get rid of a
lot of moisture through a small opening. For mine, 5-7 days of drying is
necessary during the humid months here in Michigan. I've tried to hurry this
time by placing them on top of cooling kilns, but then they were sometimes
getting too hot and the liner was disappearing!
Carolynn Palmer, Somerset Center, Michigan
Cindy on wed 15 apr 98
Wallace,
If you don't want to use shellac or glue or lamp sealer, or whatever to
keep your lamps from leaking, you might experiment with different clay
bodies. According to a recent CM, glazes don't necessarily prevent oil from
getting to the clay body. I use many different glazes of different
formulations, however, and none of them leak so far--even one commercial
one (which I no longer use) that tended to craze never leaked. I use
Brownstone with grog from Dakota Potter's Supply (605-673-332-1946), for
those of you who live close enough to Sioux Falls to make that knowledge of
any use.
Cindy Strnad
Earthen Vessels
Custer, SD
USA http://blackhills-info.com/a/cindys/menu.htm
Cheryl L Litman on thu 16 apr 98
I made a few oil lamps with rounded bottoms which sit in a separate ring.
In any case I glazed the bottoms and fired the pot upside down on it's
top rim. I guess since they're glazed on the bottom, I've never had a
problem with leaks.
Cheryl Litman
Somerset, NJ
email: cheryllitman@juno.com
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