Chris Groat on mon 22 jan 07
I'm currently trying to improve the recipe for a glaze that is beautiful,
but crazes.. a lot. I started by adding a little silica, decreasing the
amount of sodium, and increasing the magnesium. It looks like it helped a
little bit, but it's still not good enough. My next idea was to increase
the amount of Boron. I just couldn't make the formula work by adding
gerstley borate, but I was able to figure out a decent formula using
borax. When I went to the store to buy borax I found some Boric Acid Roach
Killer. It contains 99% boric acid and 1% random crap. Pure boric acid
seems like it would work better than borax. Has anyone ever tried this? Do
you think the roach killer would be a good source of boron? It was only
$1.99 so I thought I should at least try it.
Chris
Chris Groat on mon 22 jan 07
Just to provide a bit more clarification. The exact form of boric acid I
will be using is Orthoboric acid (B2O3=B73H2O). There are a few different
types, but I believe when it's fired they are all essentially the same.
Also, I am breaking a federal law by using this stuff. It says it's
against federal law to use it in a manner inconsistent with the labelling.
I suppose it will be good for doing tests, and when I decide to mix a
large batch of glaze I'll get the good stuff (you know, the kind that
isn't labelled 'Roach Killer').
Also, I know this stuff can be a bit reactive when mixed with basic
compounds. The reason I chose boric acid over borax is because I wanted to
stay away from the sodium that is in borax.
Hope the feds don't come after me...
Chris
Steve Slatin on mon 22 jan 07
Tried it, and it works, but there's a gotcha in the solubility department --
being a soluble, it had undesirable characteristics, primarily in the area
of being absorbed into/onto your pots at rates different than you would
expect from its concentration in the mix. (I suspect, but cannot demonstrate,
that it also goes deeper into the clay body for the same reason.)
-- Steve Slatin
Chris Groat wrote:
I'm currently trying to improve the recipe for a glaze that is beautiful,
but crazes.. a lot. I started by adding a little silica, decreasing the
amount of sodium, and increasing the magnesium. It looks like it helped a
little bit, but it's still not good enough. My next idea was to increase
the amount of Boron. I just couldn't make the formula work by adding
gerstley borate, but I was able to figure out a decent formula using
borax. When I went to the store to buy borax I found some Boric Acid Roach
Killer. It contains 99% boric acid and 1% random crap. Pure boric acid
seems like it would work better than borax. Has anyone ever tried this? Do
you think the roach killer would be a good source of boron? It was only
$1.99 so I thought I should at least try it.
Chris
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Taylor Hendrix on mon 22 jan 07
Chris,
Let us know how it works out. When I went borax hunting I noted that
my roach killer borax included a bit of sugar as a bait. I have no
idea if that is a universal case or not. I took the list's advice and
got a box of borax from the laundry section of the store. I was making
slip, but the laundry borax migh be good enough for glazes as well. I
plan on making some raku glazes tonight and will be using my borax.
I'll report the results as well. I do expect some funky stuff in the
slop over time.
On 1/22/07, Chris Groat wrote:
...When I went to the store to buy borax I found some Boric Acid Roach
> Killer. It contains 99% boric acid and 1% random crap. Pure boric acid
> seems like it would work better than borax. Has anyone ever tried this? Do
> you think the roach killer would be a good source of boron? It was only
> $1.99 so I thought I should at least try it.
...
Ivor and Olive Lewis on tue 23 jan 07
Dear Chris Groat,=20
The only problem with Boric Acid is that it is water soluble.
Possibly a better way to overcome your problem is to use on of the =
Lithium Minerals. I prefer, and have had good results using Petalite =
because it is rich in Silica.. Do a line blend using 5% increments and =
see where that takes you.
Best regards,
Ivor
Chaeli Sullivan on tue 23 jan 07
>
>On 1/22/07, Chris Groat wrote:
>
>...When I went to the store to buy borax I found some Boric Acid Roach
>> Killer. It contains 99% boric acid and 1% random crap. Pure boric acid
>> seems like it would work better than borax. Has anyone ever tried this?
Do
>> you think the roach killer would be a good source of boron? It was only
>> $1.99 so I thought I should at least try it.
>...
>
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Chris
Worked for Orkin Pest Control once. Basically, the roach killer you are
describing has sugar as the additive. The little critters are, believe it
or not, very "clean" animals who, like cats, lick the sugar off their
feet, thus ingesting the boric acid.
Haven't a clue yet, what sugar will do in glazes.
Best of Luck
Chae
sacredclay on tue 23 jan 07
Fellow Clayarters, Please note Chris's brand new e-mail address. Who
can figure out the visual take on the name? Give you a hint, it's in
NC.I think it's really quite clever! Other than that, I don't know
enough to offfer you sound advice for the roach killer thingie, but
as so many others have been encourageing me, test, test test and make
sure it's properly ventiliated. I'd say, go for it.Happy testing!
Kathryn in NC
Boric Acid Roach
> Killer. It contains 99% boric acid and 1% random crap. Pure boric
acid
> seems like it would work better than borax. Has anyone ever tried
this? Do
> you think the roach killer would be a good source of boron? It was
only
> $1.99 so I thought I should at least try it.
>
> Chris
>
>
______________________________________________________________________
________
> Send postings to clayart@...
>
> You may look at the archives for the list or change your
subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@...
>
iglasgo on tue 23 jan 07
Chris-
100% pure boric acid can be purchased from a pharmacy counter. I
don't know if all drugstores have it. I got some from an old-school
"formulating" pharmacy... one of those places that doesn't have
a convenience store in front, just a few aisles of crutches and
medical appliances.
-Ivy G.
--- In clayart@yahoogroups.com, Taylor Hendrix wrote:
>
> Chris,
>
> Let us know how it works out. When I went borax hunting I noted that
> my roach killer borax included a bit of sugar as a bait. I have no
> idea if that is a universal case or not. I took the list's advice and
> got a box of borax from the laundry section of the store. I was making
> slip, but the laundry borax migh be good enough for glazes as well. I
> plan on making some raku glazes tonight and will be using my borax.
> I'll report the results as well. I do expect some funky stuff in the
> slop over time.
>
> On 1/22/07, Chris Groat wrote:
>
> ...When I went to the store to buy borax I found some Boric Acid Roach
> > Killer. It contains 99% boric acid and 1% random crap. Pure boric acid
> > seems like it would work better than borax. Has anyone ever tried
this? Do
> > you think the roach killer would be a good source of boron? It was
only
> > $1.99 so I thought I should at least try it.
> ...
>
>
___________________________________________________________________________=
___
> Send postings to clayart@...
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@...
>
sacredclay on wed 24 jan 07
-Steve, In other words, does it make it an unsafe glaze because of
leaching possiblities? Kathryn in NC--,
primarily in the area
> of being absorbed into/onto your pots at rates different than you
would
> expect from its concentration in the mix. (I suspect, but cannot
demonstrate,
> that it also goes deeper into the clay body for the same reason.)
>
> -- Steve Slatin
>
>
claystevslat on thu 25 jan 07
Kathryn --
No, I was unclear in that message, I see. I was talking about
what happens in the glaze slop when you put a piece of bisqued
ware into it.
The bisqued ware is extremely dry, highly porous, and it absorbs
water at an astonishing rate. Because of this, any material
in solution with the water gets rapidly absorbed into the body
of the clay. The material in suspension (the clays, spars, etc.)
adhere mostly to the exterior of the pot, and do so more slowly
than the water itself.
This explains why if you start with a relatively small amount
of glaze slop and glaze a number of pieces at one go, you'll
sometimes find that the glaze gets too heavy by the end.
If there are no (or few) solubles in the mix, you just add a bit
more water and you're OK again. If the original water is carry much
of the soluble load from the slop into the body of the ware, adding
more water will not give you precisely the same glaze that you had
before -- it'll have a much lower concentration of the solubles.
Best wishes -- Steve Slatin
--- In clayart@yahoogroups.com, sacredclay wrote:
>
> -Steve, In other words, does it make it an unsafe glaze because of
> leaching possiblities? Kathryn in NC--,
>
> primarily in the area
> > of being absorbed into/onto your pots at rates different than you
> would
> > expect from its concentration in the mix.
Linda Hughes on thu 25 jan 07
Chris,
Try incorporating frit 3249 into your calculation. It is a low expansion leadless frit with the chemical formula (taken from CeramicMaterials.info on the digitalfire.com website):
Chemistry CaO 3.500 MgO 12.200 B2O3 28.900 Al2O3 13.300 SiO2 42.100
Works great
Linda
Chris Groat wrote:
I'm currently trying to improve the recipe for a glaze that is beautiful,
but crazes.. a lot. I started by adding a little silica, decreasing the
amount of sodium, and increasing the magnesium. It looks like it helped a
little bit, but it's still not good enough. My next idea was to increase
the amount of Boron. I just couldn't make the formula work by adding
gerstley borate, but I was able to figure out a decent formula using
borax. When I went to the store to buy borax I found some Boric Acid Roach
Killer. It contains 99% boric acid and 1% random crap. Pure boric acid
seems like it would work better than borax. Has anyone ever tried this? Do
you think the roach killer would be a good source of boron? It was only
$1.99 so I thought I should at least try it.
Chris
______________________________________________________________________________
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/
Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
Linda R Hughes
mamahug@yahoo.com
May you always be blessed
with a sense of wonderment
Chris Groat on thu 25 jan 07
Thanks for clearing that up Steve. I was left with the impression that the
boric acid being absorbed into the pot would somehow mess up the pot, but
now I see what you're saying. I spray a lot of my pots, so it shouldn't be
much of a problem. Thanks for the suggestion Linda. I played around with
my glaze calculation program and I think I have a formula that will work.
I'll add the glaze with the frit to my long list of glazes to test. The
kiln is firing right now, so I guess tomorrow will be like Christmas
morning... (or possibly a disaster)
Chris
Chris Groat on thu 25 jan 07
Thanks for clearing that up Steve. I was left with the impression that the
boric acid being absorbed into the pot would somehow mess up the pot, but
now I see what you're saying. I spray a lot of my pots, so it shouldn't be
much of a problem. Thanks for the suggestion Linda. I played around with
my glaze calculation program and I think I have a formula that will work.
I also think frit 3185 would work pretty well. It's composition is:
Na2O-7.70 B2O3-38.20 SiO2-54.10
I'll add the glaze with the frit to my long list of glazes to test. The
kiln is firing right now, so I guess tomorrow will be like Christmas
morning... (or possibly a disaster)
Chris
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