Curtis Nelson on mon 7 may 07
Here's an easy one. . . I'm checking out how to spray kiln wash on new shelves.
I have the new shelves that came with a new L&L kiln.
I'm using 25% ball clay with 75% alumina hydrate.
The two ingredients (25 g ball clay, 75 g alumina hydrate) were blendered in one
quart of water. Then I used a garden-type sprayer to spray the damp-sponged
shelves.
That resulted in what seemed like an awfully thin application. The shelves were
propped up on edge for spraying. By the time I got a shelf covered, rivulets of wash
were running down.
Should the wash be made thicker to start with? Perhaps 200 or even more grams of
ball clay and alumina hydrate per quart of water?
Is one thin coat enough, or should I do two? Should the first coat be fired before
additional coats?
And another thing . . . should newly kiln washed shelves be fired first without any
furniture or pots on them? That is, should I bisque fire all the shelves by themselves
before using them for firing pots?
Curtis Nelson
Asheville, NC, USA
Dale Neese on mon 7 may 07
Last week I re-coated my bottom floor shelves in my updraft. I used a kiln
wash formula posted on ClayArt, 1/3 cup silica, 1/3 cup kaolin, 1/3 cup
alumina hydrate. I sanded off the old flaking kiln wash and wiped off the
shelves with a damp sponge. Then I put the kiln wash mixed to the
consistency of milk in the HVLP sprayer from Northern Tools. Set the shelves
up off the ground on their sides on a piece of 2x4, stood away, lightly
sprayed them lightly with kiln wash. I avoided putting on too much wash at
one time. Waited a good 10 minutes and re-sprayed them lightly again
avoiding getting the shelves too wet. I used only the kiln wash I mixed,
building up in layers on the shelves.
Cleaned the edges of the shelves with a wet sponge and replaced the shelves
in the kiln. I let the shelves completely dry. Next day I loaded pieces to
be bisque fired on the freshly kiln washed shelves. Spraying the kiln wash
seems to give the surface of the shelf a durable pebbly texture and the wash
seems to last longer through many firings than brushing or rolling it on.
Key is not getting the wash on too thick or overly saturating your shelves
with moisture.
Dale Tex
"across the alley from the Alamo"
San Antonio, Texas USA
Ron Roy on wed 9 may 07
Hi Dale,
I don't recommend silica in kiln wash because it will combine with well
vitrified clays - especially porcelain. The result is bit of the clay foot
staying on the shelves - a hazard to the potter and the ware is unsalable.
I just use ball clay and alumina hydrate (20/80) - I do agree that spraying
is a good way to apply it.
RR
>Last week I re-coated my bottom floor shelves in my updraft. I used a kiln
>wash formula posted on ClayArt, 1/3 cup silica, 1/3 cup kaolin, 1/3 cup
>alumina hydrate. I sanded off the old flaking kiln wash and wiped off the
>shelves with a damp sponge. Then I put the kiln wash mixed to the
>consistency of milk in the HVLP sprayer from Northern Tools. Set the shelves
>Dale Tex
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Ron Roy on thu 10 may 07
Hi Curtis,
Yes - just too thin - make it thick and thin it down till it goes
through your sprayer - and keep it shook up!
I'd fire them with a bisque load but go slow to make sure any
impurities get burned out.
RR
On 7-May-07, at 12:56 PM, Curtis Nelson wrote:
> Here's an easy one. . . I'm checking out how to spray kiln wash on
> new shelves.
>
> I have the new shelves that came with a new L&L kiln.
>
> I'm using 25% ball clay with 75% alumina hydrate.
>
> The two ingredients (25 g ball clay, 75 g alumina hydrate) were
> blendered in one
> quart of water. Then I used a garden-type sprayer to spray the
> damp-sponged
> shelves.
>
> That resulted in what seemed like an awfully thin application. The
> shelves were
> propped up on edge for spraying. By the time I got a shelf covered,
> rivulets of wash
> were running down.
>
> Should the wash be made thicker to start with? Perhaps 200 or even
> more grams of
> ball clay and alumina hydrate per quart of water?
>
> Is one thin coat enough, or should I do two? Should the first coat be
> fired before
> additional coats?
>
> And another thing . . . should newly kiln washed shelves be fired
> first without any
> furniture or pots on them? That is, should I bisque fire all the
> shelves by themselves
> before using them for firing pots?
>
> Curtis Nelson
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