temperature limit for kiln wash?

[mpg]

Hi,

I tried a high-temperature firing last night (1700 for 45 minutes). It was a really simple experiment -- a pile of glass scraps on top of a piece of thinfire paper. During the soak, the glass pulled in upon itself (as expected) and appears to have wrapped up upon itself, as it left thinfire paper residue on the top of the piece in some places. I was thinking of repeating this using just a kiln-washed shelf, but was wondering if that would just leave a bunch of kiln wash stuck to the back of the piece? (I want to try higher temps and longer soaks, too.) I use BE kilnwash (it's orange, though, not pink) and system 96 glass.

Thanks!
Michelle

[Brock]

Kiln wash will work fine, although you will get kiln wash stuck to the back of your slab. Expect to have to deal with it in some way. Brock

[Tom White]

I have played with Bert Weiss' formula of 80% alumina hydride, 20% kaolin and have adjusted it to 85% alumina hydride, 15% kaolin. I have ground the alumina hydride in my makeshift ball mill to as fine as I can obtain for this release. I mix 100 grams dry ingredients to make 1 pint release. I also add a little CMC gum for green strength before firing. For normal fusing with system 96 or float glass I airbrush 3 or 4 coats on the shelf. For my mini pot melt pendants I squirt a puddle on top of a released shelf and spread it smooth with my finger. No need to dry for pot melts since the glass never touches the shelf before 1500 F. Fused float and cathedral S-96 glass seldom stick to the release at all. In fact, I can get as many as 3 to 4 firings from one application if I don't go over 1550 F in my quickfire kiln. Melts need scrubbing with plain water and a Scotchbrite pad then a quick going over the back with a Dremel flap sander to produce a smooth, pleasing texture.

Best wishes,
Tom in Texas

[Amy Schleif-Mohr]

I'm with Brock on this one.

I do a lot of high fire. I use BE glass and BE kiln wash on fiber and mulite shelves.

I mix my kiln wash to the consistancy of heavy cream and put 4 or 5 coats on. I only use it once before I recoat. It is going to stick to the glass so you will either have to sandblast it off or grind it off.

Amy

[Brian and Jenny Blanthorn]

Hi,

I tried a high-temperature firing last night (1700 for 45 minutes). It was a really simple experiment -- a pile of glass scraps on top of a piece of thinfire paper. During the soak, the glass pulled in upon itself (as expected) and appears to have wrapped up upon itself, as it left thinfire paper residue on the top of the piece in some places. I was thinking of repeating this using just a kiln-washed shelf, but was wondering if that would just leave a bunch of kiln wash stuck to the back of the piece? (I want to try higher temps and longer soaks, too.) I use BE kilnwash (it's orange, though, not pink) and system 96 glass.

Thanks!
Michelle

The kiln wash is OK well above 1000 c

But its the glass that wets the wash so it sticks more as temp increaces

Avoid enamels / fluxes near wash n fire slow n low / soak

Brian

[Lynne Chappell]

A lot of people use 1/8" fiber paper (not thinfire) for high temperature melts such as combing. It won't end up on top of your glass. It will leave some fiber stuck to the bottom, but it may be easier to get off than the wash. I just use wash, but I have a sandblaster to clean up any mess.

[Lauri Levanto]

> The kiln wash is OK well above 1000 c
> But its the glass that wets the wash so it sticks more as > temp increaces
>
> Avoid enamels / fluxes near wash n fire slow n low / > soak
>
> Brian

I have no doubts about your expertice Brian,
I just try to understand what happens

If the kiln wash conteins kaolin, it starts to sintrate
around 900 C. I expect it to react with glass at the same time. The AlO in kilnwash is refractory to higher temps.
Talc might be even better.

In casting temps I increase the AlO content, so that
kaolin particles has less opportunities to meet each other
for sintrating to a solid
or with glass.

Am I on a wrong track here?
-lauri

[charlie]

> The kiln wash is OK well above 1000 c
> But its the glass that wets the wash so it sticks more as > temp increaces
>
> Avoid enamels / fluxes near wash n fire slow n low / > soak
>
> Brian

I have no doubts about your expertice Brian,
I just try to understand what happens

If the kiln wash conteins kaolin, it starts to sintrate
around 900 C. I expect it to react with glass at the same time. The AlO in kilnwash is refractory to higher temps.
Talc might be even better.

In casting temps I increase the AlO content, so that
kaolin particles has less opportunities to meet each other
for sintrating to a solid
or with glass.

Am I on a wrong track here?
-lauri

i use talc on the bottom of my pot melts, and it never sticks. it does make the back lumpy though, as it moves with the glass movement.

this makes me wonder if talc could be used as a kiln wash if applied in a water medium though.

[Lauri Levanto]

Charlie commented:




i use talc on the bottom of my pot melts, and it never sticks. it does make the back lumpy though, as it moves with the glass
movement.

this makes me wonder if talc could be used as a kiln wash if applied in a water medium though.

Try it and tell the results.
I have used AlO slurry in pot and frit casting molds.
It gives a nice surface. In an open face mold
I burnish it in whhile wet.

-lauri

[Brian and Jenny Blanthorn]

> The kiln wash is OK well above 1000 c
> But its the glass that wets the wash so it sticks more as > temp increaces
>
> Avoid enamels / fluxes near wash n fire slow n low / > soak
>
> Brian

I have no doubts about your expertice Brian,
I just try to understand what happens

If the kiln wash conteins kaolin, it starts to sintrate
around 900 C. I expect it to react with glass at the same time. The AlO in kilnwash is refractory to higher temps.
Talc might be even better.

In casting temps I increase the AlO content, so that
kaolin particles has less opportunities to meet each other
for sintrating to a solid
or with glass.

Am I on a wrong track here?
-lauri

U can only try stuff

But give both a go separatly

N C which sticks more

Brian