Marvin Bartel on thu 25 apr 96
>If anyone has a waterproof raku glaze please let me know!!!!
>Steve Branfman
I don't have a water proof Raku glaze, but Raku can safely be waterproofed
to be used as flower vases. I heat the pot to about 200 F. in the kitchen
oven. While the pot is hot, I pour melted paraffin into the vase. Pour
it back out the same way we glaze insides of pots. Having the Raku hot
keeps the wax liquid long enough to soak into the pores of the clay. I
don't recomment this for food containers, but at least it is a non-toxic
material in case somebody does put food in it. You can buy the wax at the
supermarket with canning supplies. They sell it to seal preserves.
To be safe, wax must not be melted directly over a heating unit,
but in a double boiler arrangement or in a thermostatically temperature
controlled vessel turned just hot enough to melt wax - no hotter. A friend
in grad school nearly lost a hand from burns suffered from a wax blow up.
Never let it get hot enough to cause serious burns.
For the interior of food containers we use a glaze of 3 parts
Gerstly Borate and 1 part feldspar. It will craze and seep liquids, but
you can serve lots of food from a pot that has very slow seepage. Just
don't store liquids in it. Actually, milk may be good to store in it, as
it tends to clog the pours in time. Tribal cultures still cook in
unglazed porous pots as they have for thousands of years. Some people may
be concerned about the bacteria in the craze lines. High heat would likely
take care of that. Also, never put any colorants or other stuff in the
glaze that might cause illness or worse. It can even taste bad.
* * * * * * Marvin Bartel * * * * * *
Art Dept., Goshen College
Goshen IN 46526
marvinpb@goshen.edu
phone 219-535-7592
fax 219-535-7660
http://www.goshen.edu
* * * * * * * * * * * * * * * * * * *
See Goshen College Alumnus
Dick Lehman on Ceramics Monthly Cover
* * * * * * * * * April, 1996 * * * * * * * * * *
Peter Powning on sat 27 apr 96
I've been making my living mostly with raku for about 15 years and have made
amny flower vases that don't leak. It acts more like earthenware and sweats,
some vases more than others. I use a low or no grog throwing body, I glaze the
insides of pots with clear commercial, food safe glaze (which presumably means
that the glaze is tested to current standards). For work that is not for food
I have tried various liners. One of the easiest, even for a very pourous pot
is put a plastic bag inside the pot and fill it with water when using a piece
as a vase. This works with even the funkiest pieces, even pieces that you can
see daylight through. Another solution is to fill the vase with milk and let
it sit for a few days in the fridge. Not very practical but it works.
Laquer/sealer should also work but gives off bad fumes. I should think there's
be many safer solutions than hot wax. Ask Monona Rossol about the fumes from
hot wax before you spend much time working around it. It's probably the
biggest cause of studio fires and burns in our profession and the potential
health effects of the fumes are worth being informed about.
Peter Powning
NB, Canada
Lari Ward on mon 12 jun 00
I just use glass liners inside my raku vases. You can also buy plastic =
ones that florists use that are different sizes and shapes. It takes =
the hassle and worry out of trying to find a solution. I buy the glass =
liners wholesale. Everything I used to waterproof the vases changed the =
colour of the copper glazes. =20
Lari=20
In Poulsbo, WA. where the sun is shining>>>>for the moment, and I am =
rakuing wall hangings for a show. =20
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