first sand cast project

[Dean Hubbard]

Thanks Fellows,
I learned a lesson the hard way once before, in regards to health matters. Years ago, I got involved in kinetic sculpture racing, (human powered) vehichles that had to be able to negotiate sand, mud and water, besides asphalt. I unknowingly zapped my lungs real bad with a toxic vapor, because I brazed galvanized conduit in a confined area for an extended period. I came down with pneumonia really bad. For about the next 5 or 6 years, I got pneumonia every year and I had to be real careful because it was real easy to relapse into another bout of pneumonia. All because I picked up a set of torches and "went to town" without proper instruction or knowledge. Thankfully, my lungs have gotten better over the years.
I am glad this message board is here, because I probably would have tried that fine silica flour mixed in dry with the mix.
At this point, I will try bentonite all by itself first, just to see the results.
In my excitement, it would be easy for me to get into a bad situation.
Thanks Again.

[Brian and Jenny Blanthorn]

Thanks Fellows,
I learned a lesson the hard way once before, in regards to health matters. Years ago, I got involved in kinetic sculpture racing, (human powered) vehichles that had to be able to negotiate sand, mud and water, besides asphalt. I unknowingly zapped my lungs real bad with a toxic vapor, because I brazed galvanized conduit in a confined area for an extended period. I came down with pneumonia really bad. For about the next 5 or 6 years, I got pneumonia every year and I had to be real careful because it was real easy to relapse into another bout of pneumonia. All because I picked up a set of torches and "went to town" without proper instruction or knowledge. Thankfully, my lungs have gotten better over the years.
I am glad this message board is here, because I probably would have tried that fine silica flour mixed in dry with the mix.
At this point, I will try bentonite all by itself first, just to see the results.
In my excitement, it would be easy for me to get into a bad situation.
Thanks Again.

U need 2 check up on bentonite

I has silica in n is realy fine

So I dont know wether it is any safer than flour silica

Brian

[Dean Hubbard]

Doesn't that sheep ever trip?

[Dean Hubbard]

Thanks Brian,
I will be using a dust mask when I'm working with the bentonite. I'm just doing a test in a small kiln. I'm going to take a 15" diameter steel ring 2 1/2" tall, place it on a kiln shelf and fill it with bentonite. I will tamp it down just a bit, then make a pattern impression. Then I'm going to set a piece of 3/8" float on the bentonite and see what happens. I did a similar test with compressed dry plaster, but it separated in places during heating, allowing the glass to flow into the small fault lines.

P.S. I'm just begining my journey of learning "sneaky things" with warm glass.

I really like reading your responses.

Wanna-Be-Sneaky Boy

[Bert Weiss]

Thanks Brian,
I will be using a dust mask when I'm working with the bentonite. I'm just doing a test in a small kiln. I'm going to take a 15" diameter steel ring 2 1/2" tall, place it on a kiln shelf and fill it with bentonite. I will tamp it down just a bit, then make a pattern impression. Then I'm going to set a piece of 3/8" float on the bentonite and see what happens. I did a similar test with compressed dry plaster, but it separated in places during heating, allowing the glass to flow into the small fault lines.

P.S. I'm just begining my journey of learning "sneaky things" with warm glass.

I really like reading your responses.

Wanna-Be-Sneaky Boy

Dean

Thinking outside the box could yield innovation or be a big waste. Who knows. Go for it. See and adjust.

[Brian and Jenny Blanthorn]

Thanks Brian,
I will be using a dust mask when I'm working with the bentonite. I'm just doing a test in a small kiln. I'm going to take a 15" diameter steel ring 2 1/2" tall, place it on a kiln shelf and fill it with bentonite. I will tamp it down just a bit, then make a pattern impression. Then I'm going to set a piece of 3/8" float on the bentonite and see what happens. I did a similar test with compressed dry plaster, but it separated in places during heating, allowing the glass to flow into the small fault lines.

P.S. I'm just begining my journey of learning "sneaky things" with warm glass.

I really like reading your responses.

Wanna-Be-Sneaky Boy [img]

http://www.stopstart.fsnet.co.uk/mica/face.gif[/img]

Here R some thoughts on

Shrinkivity

My guess is first fire bentonite will shrink as its a clay

But next should B OK I guess same is true of dry plaster

May B fire slightly over ur temp first fire

Stuff like alumina should not shrink

The Sheep is a highy trained stunt animal n does not trip

Do not try this with normal sheep

Please note no animals were hurt during intensive training

Also he gets regular breaks when not being watched

Has a ciber field n big holes in the fence so he can stick his head through n eat grass from the other side

And a larger flock of sheep 2 hang out with

Brian

[Brian and Jenny Blanthorn]

Thanks Brian,
I will be using a dust mask when I'm working with the bentonite. I'm just doing a test in a small kiln. I'm going to take a 15" diameter steel ring 2 1/2" tall, place it on a kiln shelf and fill it with bentonite. I will tamp it down just a bit, then make a pattern impression. Then I'm going to set a piece of 3/8" float on the bentonite and see what happens. I did a similar test with compressed dry plaster, but it separated in places during heating, allowing the glass to flow into the small fault lines.

P.S. I'm just begining my journey of learning "sneaky things" with warm glass.

I really like reading your responses.

Wanna-Be-Sneaky Boy [img]
Got this today from http://www.stopstart.fsnet.co.uk/mica/face.gif[/img]

Got this today from handmade-glass.com

Msds info site

http://msds.pdc.cornell.edu/msdssrch.asp

Brian

[Bert Weiss]

The Sheep is a highy trained stunt animal n does not trip

Do not try this with normal sheep

Please note no animals were hurt during intensive training

Also he gets regular breaks when not being watched

Has a ciber field n big holes in the fence so he can stick his head through n eat grass from the other side

And a larger flock of sheep 2 hang out with

Brian

Brian

If you can get the wool from this sheep it would surely make you a fortune. You could retire, live on jam, and be warm and fuzzy.

[Brian and Jenny Blanthorn]

The Sheep is a highy trained stunt animal n does not trip

Do not try this with normal sheep

Please note no animals were hurt during intensive training

Also he gets regular breaks when not being watched

Has a ciber field n big holes in the fence so he can stick his head through n eat grass from the other side

And a larger flock of sheep 2 hang out with

Brian

Brian

If you can get the wool from this sheep it would surely make you a fortune. You could retire, live on jam, and be warm and fuzzy.

In Feb 04 I will B grafting some plums on2 my existing plum trees

If all goes well will have about 20 different plums

Should last about 6 months or so as some early mid late

Some of then R 4 jam

I do have a lot of interests but knitting is not one

One thing tho

What is Olivine sand did do a search on it but could not find out what it actualy was ??

Brian

[Bert Weiss]

The Sheep is a highy trained stunt animal n does not trip

Do not try this with normal sheep

Please note no animals were hurt during intensive training

Also he gets regular breaks when not being watched

Has a ciber field n big holes in the fence so he can stick his head through n eat grass from the other side

And a larger flock of sheep 2 hang out with

Brian

Brian

If you can get the wool from this sheep it would surely make you a fortune. You could retire, live on jam, and be warm and fuzzy.

In Feb 04 I will B grafting some plums on2 my existing plum trees

If all goes well will have about 20 different plums

Should last about 6 months or so as some early mid late

Some of then R 4 jam

I do have a lot of interests but knitting is not one

One thing tho

What is Olivine sand did do a search on it but could not find out what it actualy was ??

Brian

Olivine sand is magnesium sand. There is some silica in it but no free silica. If I get some spare time when I get home I'll look it up in the Ceramics Monthly material issue.

One of my strangest unrealized projects is to make slivovitz, plum brandy. First you make plum wine, then distill it. You'd love the still. It's a stainless steel pressure cooker with a long copper tube coming out of the top. Starts out wine, ends up firewater. I have had one made in Croatia and one made in New York (with california plums). The New York bottle, made by Sloime's Slivovitz is actually the better tasting one.

[Paul Tarlow]

Bert - the table is very, very cool.

I hate it when people post pics that make me wish I had a bigger kiln.

Have you ever thought about fiber carving a recess into the bottom to prevent the glass from sliding?

- Paul

[Bert Weiss]

Bert - the table is very, very cool.

I hate it when people post pics that make me wish I had a bigger kiln.

Have you ever thought about fiber carving a recess into the bottom to prevent the glass from sliding?

- Paul

Sliding where? I actually do the opposite. The sand bed is smaller than the glass by at least it's thickness. The edge rolls over creating a strong and aesthetic edge.

[Dean Hubbard]

Here R some thoughts on

Shrinkivity

My guess is first fire bentonite will shrink as its a clay

But next should B OK I guess same is true of dry plaster

May B fire slightly over ur temp first fire

Stuff like alumina should not shrink



Brian

Brian,
Good call. I aborted my first attempt, because I noticed, not only was the bed of bentonite cracking and separating, but steam was also excaping from under the glass. As soon as the glass is cool enough to remove from the kiln, I'm going to fire the bentonite by itself to eliminate any remaining moisture content and hopefully shrink it into submission. One thing I did notice, even when I compacted this stuff and made a very simple pattern in it, the weight of the glass placed on top of the bentonite did eliminate much of the pattern. I'll keep you guys posted and let you know what happens on second attempt.

[Bert Weiss]

One thing I did notice, even when I compacted this stuff and made a very simple pattern in it, the weight of the glass placed on top of the bentonite did eliminate much of the pattern. I'll keep you guys posted and let you know what happens on second attempt.

Dean

You have stumbled on to the need for larger particles in the matrix. Welcome to the club.

[Dean Hubbard]

You have stumbled on to the need for larger particles in the matrix. Welcome to the club.

Thanks Bert,
I am honored to be the newest member of the NSCGA, or is it the NSBA?
BTW, The bentonite was showing that in its "green" state. Now that I've fired it, the binding quality is totally gone (that sticky clay feeling). Trying to make a pattern impression with it now is of no use whatsoever.

National Sand Box Association Rule #1: Bentonite is used as a separator, not a casting bed.

[Dean Hubbard]

Bert,
It looks as if playing in the sand box will require some knowledge and use of physics. I'm a bit lacking in the knowledge department. (that's why I'm here) I understand the principle of adding larger granuals to the mix to create a more stable bed to support the glass. I think I read a thread about this in the archives. It seems to me that the granual structural make up would play an important role also, i.e. sharper edges and interlocking capabilities. I had this preconcieved notion that the bentonite might be the magic ingrediant. In its unfired state, when rubbed between two fingers, feels somewhat greasy. It was this property, I felt, would hold the material in place acting as a binder. Unfortunately, the temperature of the kiln vetoed that and it shrunk way too much, right off the get go.
I don't know of a liquid that would remain unchanged from the heat of the kiln, if there is such a thing and oils would burn off. I read that thread about the guy that made that "special sand", described by one writer as spongey. Unfortunately, it said that the guy blew his studio and himself up. Do you know what he was doing when that terrible accident took place? Do you know of any type of additive that would make the sand bind together in a dry application that could be reused?
I haven't gotten my hands on any olivine sand yet. Does olivine seem to change at all after firing?

Does anyone care to share their own recipe for open face sand casting?

[Bert Weiss]

Bert,
It looks as if playing in the sand box will require some knowledge and use of physics. I'm a bit lacking in the knowledge department. (that's why I'm here) I understand the principle of adding larger granuals to the mix to create a more stable bed to support the glass. I think I read a thread about this in the archives. It seems to me that the granual structural make up would play an important role also, i.e. sharper edges and interlocking capabilities. I had this preconcieved notion that the bentonite might be the magic ingrediant. In its unfired state, when rubbed between two fingers, feels somewhat greasy. It was this property, I felt, would hold the material in place acting as a binder. Unfortunately, the temperature of the kiln vetoed that and it shrunk way too much, right off the get go.
I don't know of a liquid that would remain unchanged from the heat of the kiln, if there is such a thing and oils would burn off. I read that thread about the guy that made that "special sand", described by one writer as spongey. Unfortunately, it said that the guy blew his studio and himself up. Do you know what he was doing when that terrible accident took place? Do you know of any type of additive that would make the sand bind together in a dry application that could be reused?
I haven't gotten my hands on any olivine sand yet. Does olivine seem to change at all after firing?

Does anyone care to share their own recipe for open face sand casting?

Dean

The molten glass sand casting recipe uses water, olivine sand, and bentonite. The moist sand is sifted in to the box and an object is pressed in to the lofty sand. The mold is coated with carbon and hot glass is ladled in. The hot glass drives the moisture through the sand. It works.

I have been dry casting with sand and plaster. Part of the trick is to place the glass on the mold with a suction cup so as not to press finger prints in to the mold. You then have to clean the glass to remove invisible rubber residue. This approach is simple, fast, and fun. Except I lied about the fast part.

I imagine that you cold go to the trouble of making a moist mold, prefiring it, dusting with plaster or bentonite, and using the mold.

The guy who blew himself up, had a gas explosion.

[Brian and Jenny Blanthorn]

Bert,
It looks as if playing in the sand box will require some knowledge and use of physics. I'm a bit lacking in the knowledge department. (that's why I'm here) I understand the principle of adding larger granuals to the mix to create a more stable bed to support the glass. I think I read a thread about this in the archives. It seems to me that the granual structural make up would play an important role also, i.e. sharper edges and interlocking capabilities. I had this preconcieved notion that the bentonite might be the magic ingrediant. In its unfired state, when rubbed between two fingers, feels somewhat greasy. It was this property, I felt, would hold the material in place acting as a binder. Unfortunately, the temperature of the kiln vetoed that and it shrunk way too much, right off the get go.
I don't know of a liquid that would remain unchanged from the heat of the kiln, if there is such a thing and oils would burn off. I read that thread about the guy that made that "special sand", described by one writer as spongey. Unfortunately, it said that the guy blew his studio and himself up. Do you know what he was doing when that terrible accident took place? Do you know of any type of additive that would make the sand bind together in a dry application that could be reused?
I haven't gotten my hands on any olivine sand yet. Does olivine seem to change at all after firing?

Does anyone care to share their own recipe for open face sand casting?

Dean

The molten glass sand casting recipe uses water, olivine sand, and bentonite. The moist sand is sifted in to the box and an object is pressed in to the lofty sand. The mold is coated with carbon and hot glass is ladled in. The hot glass drives the moisture through the sand. It works.

I have been dry casting with sand and plaster. Part of the trick is to place the glass on the mold with a suction cup so as not to press finger prints in to the mold. You then have to clean the glass to remove invisible rubber residue. This approach is simple, fast, and fun. Except I lied about the fast part.

I imagine that you cold go to the trouble of making a moist mold, prefiring it, dusting with plaster or bentonite, and using the mold.

The guy who blew himself up, had a gas explosion.

Here's some Cheetin Technology 4 U Bert

Just 4 U, so dont tell anyone else OK

Try

No Mark tm

Although complex this cunning technique is well worth all the effort

Wrap the rubber sucker in cling film

Keep in plastic bag

But check the suction is Ok

I get stuff set up in by the kiln so I only gotta move it over a bit

There is a sucky thing with an indicator on it which showes suckivity

Getting back 2 the bentonite

Mixed with other none shrinking stuff it will probably B binding but shrinkage not B noticabble

Another tip which may B OK is spraying with gum aribic which will harden top coat

This technology may give smokey problems

Brian

[Nelson Tan]

Brian

Brian,
One thing I did notice, even when I compacted this stuff and made a very simple pattern in it, the weight of the glass placed on top of the bentonite did eliminate much of the pattern. I'll keep you guys posted and let you know what happens on second attempt.

Hi Dean.

I also had the same problem. Most of our project involves framing the glass in windows or doors. So what we did is to glue 3 mm fiber paper around the perimeter of the glass. The perimeter takes much of the weight of the glass.

Our recipe is 50% plaster and 50% alumina.

We also invested on a lot of textured rubber paint roller. It comes in many designs and we only have to press roll onto the sand to get a nice impression of the textures.

hope this helps
Nelson