Paul Borian on sun 30 may 10
i have been using hardwood ash in one of my glazes for years and it is a
major part of my product line.
however, i have never like working with it because it is caustic and it
presents numerous glaze application problems.
i know there are fake ash glazes out there but it would take a lot of time
to seek them out and test them all and hope i find one that looks the same.
So, i was thinking to send a sample of the hardwood ash i currently use off
to a lab to get the chemical analysis. With that info, would it be possible
to reformulate it as a fake ash glaze by making the necessary substitions t=
o
get a glaze with the same unity formula?
Basically i just want to come up with a substitute for wood ash with the
same chemical analysis as the ash i currently use.
Possible or impossible?
anyone care to comment?
thanks,
Paul
David Beumee on mon 31 may 10
What I read is that the basic problem is that the ash is caustic, easily
remedied by washing out the soluble alkalis.Yes, it will change the look of
the glaze, but you have a better chance of retaining the subtle qualities o=
f
your particular ash by fixing the problem than by trying to reproduce natur=
e
through chemical analysis and the UMF.
David Beumee
Lafayette, CO
On Sun, May 30, 2010 at 12:17 PM, Paul Borian wrote=
:
> i have been using hardwood ash in one of my glazes for years and it is a
> major part of my product line.
> however, i have never like working with it because it is caustic and it
> presents numerous glaze application problems.
> i know there are fake ash glazes out there but it would take a lot of tim=
e
> to seek them out and test them all and hope i find one that looks the sam=
e.
> So, i was thinking to send a sample of the hardwood ash i currently use o=
ff
> to a lab to get the chemical analysis. With that info, would it be possib=
le
> to reformulate it as a fake ash glaze by making the necessary substitions
> to
> get a glaze with the same unity formula?
> Basically i just want to come up with a substitute for wood ash with the
> same chemical analysis as the ash i currently use.
> Possible or impossible?
> anyone care to comment?
> thanks,
> Paul
>
Eric Hansen on mon 31 may 10
Amen; before giving up on wood ash look at Aerni's site:
http://www.richardaerni.com/
Washing ash will remove the soluble alkalies, the caustics, yes. Washing
also allows finer screening of the ash. 40 mesh is good for me but some
might prefer 100 mesh. Ball-milling is even better. You might also want to
standardize each ash product. Such as, firewood, fruit tree wood prunings,
rice hull or rice straw, reed ash, bracken ash. Wood has the smallest retur=
n
percentage wise, most of it burns off. Grasses can yield many times the
amount of ash per pound. Also consider a standardized way of cooking ash.
Such as Gary Navarre's Koie Cooker:
http://www.google.com/search?q=3DKoie+cooker&hl=3Den&client=3Dsafari&rls=3D=
en&prmd=3Dv&source=3Duniv&tbs=3Dvid:1&tbo=3Du&ei=3DjCEETOWzAcWblgf_k-iBDQ&s=
a=3DX&oi=3Dvideo_result_group&ct=3Dtitle&resnum=3D4&ved=3D0CDMQqwQwAw
Also there are ways to tame the ash glaze using certain percentages of
feldspars and clays in addition to the ash.
h a n s e n
p.s. using the UPA to reconstruct a chemically identical formula will work,
however the results will be different with every substitution you make. How
different will depend on which substitutions they are.
On Mon, May 31, 2010 at 10:01 AM, David Beumee wrote=
:
> What I read is that the basic problem is that the ash is caustic, easily
> remedied by washing out the soluble alkalis.Yes, it will change the look =
of
> the glaze, but you have a better chance of retaining the subtle qualities
> of
> your particular ash by fixing the problem than by trying to reproduce
> nature
> through chemical analysis and the UMF.
>
> David Beumee
> Lafayette, CO
>
>
>
>
>
>
>
>
>
>
>
>
> On Sun, May 30, 2010 at 12:17 PM, Paul Borian > >wrote:
>
> > i have been using hardwood ash in one of my glazes for years and it is =
a
> > major part of my product line.
> > however, i have never like working with it because it is caustic and it
> > presents numerous glaze application problems.
> > i know there are fake ash glazes out there but it would take a lot of
> time
> > to seek them out and test them all and hope i find one that looks the
> same.
> > So, i was thinking to send a sample of the hardwood ash i currently use
> off
> > to a lab to get the chemical analysis. With that info, would it be
> possible
> > to reformulate it as a fake ash glaze by making the necessary substitio=
ns
> > to
> > get a glaze with the same unity formula?
> > Basically i just want to come up with a substitute for wood ash with th=
e
> > same chemical analysis as the ash i currently use.
> > Possible or impossible?
> > anyone care to comment?
> > thanks,
> > Paul
> >
>
phil rogers on sun 6 jun 10
Clayart Digest - 30 May 2010 to 31 May 2010 (#2010-145)BODY {=3D0A=3D09FONT=
-SIZ=3D
E: 13px; COLOR: #000000; FONT-FAMILY: Verdana, Arial, Helvetica, sans-serif=
=3D
=3D0A}=3D0ATD {=3D0A=3D09FONT-SIZE: 13px; COLOR: #000000; FONT-FAMILY: Verd=
ana, Ari=3D
al, Helvetica, sans-serif=3D0A}=3D0AP {=3D0A=3D09FONT-SIZE: 13px; COLOR: #0=
00000; F=3D
ONT-FAMILY: Verdana, Arial, Helvetica, sans-serif=3D0A}=3D0AA {=3D0A=3D09FO=
NT-WEIGH=3D
T: bold; FONT-SIZE: 13px; COLOR: #3366cc; FONT-FAMILY: Verdana, Arial, Helv=
=3D
etica, sans-serif; TEXT-DECORATION: none=3D0A}=3D0AH2 {=3D0A=3D09FONT-WEIGH=
T: bold;=3D
FONT-SIZE: 18px; COLOR: #cc0033; FONT-FAMILY: Verdana, Arial, Helvetica, s=
=3D
ans-serif=3D0A}=3D0AH3 {=3D0A=3D09FONT-WEIGHT: bold; FONT-SIZE: 17px; COLOR=
: #3366c=3D
c; FONT-FAMILY: Verdana, Arial, Helvetica, sans-serif=3D0A}=3D0AWashing ash=
wil=3D
l not remove all the alkaline =3D0Asoluble fluxes...washing twice or three =
ti=3D
mes is sufficient to remove enough alkaline to render the ash useful. If yo=
=3D
u are having =3D0Aapplication problems it is likely that it is because you =
ha=3D
ven't washed it all =3D0Aor not enough. All of these issues are dicussed in=
m=3D
y book ASH GLAZES. You will =3D0Asee that I recomend washing. I know there =
ar=3D
e potters who don't wash but there =3D0Ais always the risk of the glaze bat=
ch=3D
spoiling due to excess alkaline in =3D0Asolution. The effect is a jelly li=
ke=3D
formation that makes the glaze appear to be =3D0Athick. The addition of mo=
re=3D
water until the glaze looks like it is right only =3D0Aproduces a very thi=
n =3D
coating when a pot is dipped. There is far too much water =3D0Ain the suspe=
ns=3D
ion BUT it appears to look right. after this effect has happened =3D0Aone m=
ig=3D
ht as well throw the batch away as it is, to all intent and purpose, =3D0Ai=
rr=3D
eversable. Additons of acids like vinegar or Calcium Chloride can make a =
=3D
=3D0Adifference but it is temporary.
Washing ash need not be a huge chore...I have developed a method that is qu=
=3D
ick and only a minor inconvenience. If anyone is interested I can elaborate=
=3D
on that later.
=3D0A=3DA0=3D0AUnless you really want to do it there is no real =3D0Aadvant=
age in f=3D
inding the chemical analysis of your ash. Any ash can be used =3D0Asuccesfu=
ll=3D
y...it just needs to be prepared properly. Again, there is a chapter =3D0Ao=
n =3D
'fake ash glazes' in ASH GLAZES. ( I was reluctantly persuaded to include =
=3D
=3D0Ait!!)=3D0A=3DA0=3D0ATo me at least, the beauty of ash as a material is=
=3D0Athat=3D
it is a natural product and one should enjoy the slightly unpredicatble =
=3D
=3D0Anature of the material. If you require a standardised product then go =
ah=3D
ead and =3D0Aproduce a 'fake ash' but it is moving away from the very real =
ch=3D
aracter of ash =3D0Aand the reasons why I,at least,=3DA0use it.=3D0A=3DA0=
=3D0APHIL RO=3D
GERS
=3D0A=3D0A=3D0A
Lee Love on sun 6 jun 10
During my apprenticeship, one of my jobs was washng the wood ash.
I would wash the ash, 3 to 5 times a day for a month.
If you want to know about wood ash and glaze, get Phil's book on
the subject.
--
Lee, a Mashiko potter in Minneapolis
http://mingeisota.blogspot.com/
=3D93Observe the wonders as they occur around you. Don't claim them. Feel
the artistry moving through and be silent.=3D94 --Rumi
| |
|
