Casting kiln

[Lauri Levanto]

When I begun with glass, I expected to do mainly slumping.
Therefore I wanted a fairly large bell kiln:
50x70 cm with 40 cm height.

That is enough for many castings, but with flowerpot method the height is restrictive.

I'm deaming of a two chamber kiln. A side door kiln, with
more height than width. On top of tha a separate toploading chamber for the flowerpot. ( and a small hole between to drip the glass of course.

That way I could preheat the mold slowly, then melt glass in the flowerpot, adding more when needed, without opening
the main chamber.

Two questions:
A. Does that sound feasible?
B. Someone said that a casting kiln needs elements on
all six surfaces. Why is that?

-lauri

[Bert Weiss]

When I begun with glass, I expected to do mainly slumping.
Therefore I wanted a fairly large bell kiln:
50x70 cm with 40 cm height.

That is enough for many castings, but with flowerpot method the height is restrictive.

I'm deaming of a two chamber kiln. A side door kiln, with
more height than width. On top of tha a separate toploading chamber for the flowerpot. ( and a small hole between to drip the glass of course.

That way I could preheat the mold slowly, then melt glass in the flowerpot, adding more when needed, without opening
the main chamber.

Two questions:
A. Does that sound feasible?
B. Someone said that a casting kiln needs elements on
all six surfaces. Why is that?

-lauri

Lauri

You can get many different designs to work for you.

Elements on all 6 surfaces is ideal for plaster/silica molds because the heat drives out moisture from the plaster. Plaster has chemically bonded water that is difficult to remove. If you have any gasses coming from the plaster when the glass is soft, it will bubble.

What about adapting a regular round top loading pottrery kiln with side elements. You could make a hole in the lid with a removable hard brick. Place everything in the kiln and when you are ready to load in glass, remove the brick and drop your glass in.

I recommend designing your own rig and building it. The vitrograph kiln is a great example.

[Lauri Levanto]

hanks, Bert,

Fortunately I do not have to build my next kiln. A local manufacturer makes custom design kilns at a reasonable price.

The chemically bonded water (released around 700 C =1300F, is that right?) was the reason I wanted to heat up the mold before melting the glass.

My slumping kiln has a hole in the top, unfortunately
my kiln maker made it too small. I'm going to enlarge it.
( it has the vitrigraph hole in the bottom, too. I wanted to pot melt into a water bucket to make frit. *It does not work*)

-lauri

[rosanna gusler]

so who's the manufacturer? rosanna

[Lauri Levanto]

The manufacturer is

Varnia Oy
Kisko
FINLAND

if it helps you Rosanna
may be a little far away.

-lauri

[John Kurman]

The two-chamber kiln sounds cool, but why not a kiln with two controllers? You can stack four half-shelves or some such arrangement to hold the pot, and just use one kiln with two firing zones.

Just my two cents, but I always go with maxim "The more you rig up the plumbing, the easier it is to stop up the drain".

[Lauri Levanto]

Yes I know,
that I'll need two conttrollers for the dual chamber kiln.

What I have in mind is
That the upper chamber serves as a small testing kiln, too.

And I can first rig it on top of my current kiln.
In stead of down payment, I buy it stepwise.

My final goal is to be able to cast 2-3 feet tall sculpures.

-lauri

[charlie holden]

I think you could build this type of kiln pretty easily. There are a couple of ways I can think of going about it.

You could just take a normal ceramic kiln with three detachable rings and remove the top ring. These kilns often have a three zone controller, one zone for each ring. Plug the top ring into a seperate controller, lay four inches of rigidized fiber board with a hole cut in the center on top of the second ring and put the top ring back on top of the fiber board. You could add a new third ring back to the bottom section to make it taller since there is room on the controller for three zones. The problem with this system might be that you couldn't get into the bottom of the kiln without completely removing the top ring and the board.

At Pilchuck they have some custom kilns that have a bottom section with wall elements and a lid that lifts straight up on a frame like a bell. There are elements in the lid as well. You can disconnect the power from the bottom section and slide a shelf onto it. The shelf is insulated, so you now have a shallow kiln with lid elements only. If someone cut a hole in the middle of the shelf, they would have essentially what you describe, only without the doors and with a shallow top section.

The most ideal set up would be a car kiln unerneath a front opening kiln. A car kiln allows you to do huge stuff, since you load the mold on the car and roll it into the kiln. See "Glass Notes" for plans on how to build a car kiln.

ch

[Lauri Levanto]

Thanks again for encouragibg ideas.

There are some practical limits, like money and space. My studio has no room for a car kiln.
My studio is at a rented space, where I am limited to a total of 12 kW of power.
The ring kiln construction has a point. If it is a fiber kiln,
then lifting the rings without damaging the mold
seems possible.

As my current kiln is of bell type, I appreciate the
second to have a door to make it easier to play with
hot glass.
-lauri