I want to slump an oval piece of glass ....

[Tamra]

I want to make a 7.25"  diameter wooden turning on a lathe.  

Split the turning into Quarters (you glue paper in between so you can split.

Then use 1/4 of the wood turning as the negative component of my mold that I want to create.

The plan was to create a plaster mold and then slump micro thin glass into the plaster mold. 

Micro thin glass measures 1/32"  thickness with calipers.  It is ordinary picture frame glass.

Suggestions are appreciated if this new person is way off.   

This might be a rectangle or an oval.  I have a 3d filament printer that I can use too, but prefer

to use wood for my model as it is heavier.

This is going to become a 1/12th scale curved window at the corner of two walls.

 

Thanks - Tamra

 

[Min]

15 hours ago, Tamra said:

The plan was to create a plaster mold and then slump micro thin glass into the plaster mold. 

So you would be firing the plaster mold to glass slumping temps?

[Tamra]

Hi Min, I think? I have to fire the plaster mold in order to get the glass to slump over or into it. 

I think it is likely that the plaster is going to shrink with firing, so I will likely make my turning a larger diameter, and then attempt to heat the mold up to see how much it shrinks.

The walls of the structure are not made, so what ever piece of glass that I get the wall can be curved around it, but I do need 4 pieces, or 1 for every corner.

I always try to do the hardest part first.   I should measure my kiln before I turn on the lathe!  I can get lazy and heat up some acrylic, but I love glass...

The only slip that I have is porcelain around here for dolls, but I'm open to ALL Suggestions or recommendations for videos or books.  

I don't have a large block of pottery clay, but can certainly buy.

Thanks - Tamra

 

 

 

[Tamra]

I do have a glass blowing torch, but I have not connected it to a fuel source, so I might be able to slump with a torch and just anneal the glass in a kiln...

I'm thinking, very thin glass will not take much time to slump....

Tamra

[Min]

1 hour ago, Tamra said:

have to fire the plaster mold in order to get the glass to slump over or into it. 

Yeah, no, pottery plaster will break down in a kiln firing. Would be better to make a clay form and use that after bisque firing it.

[Callie Beller Diesel]

You can make single use plaster moulds out of a combination of silica and pottery plaster (50/50 if I remember correctly, but if you want to go that route, ask me to look up the specifics). It doesn’t shrink appreciably. After one firing, the material will crumble and wash away from the glass. You can get some materials that will fire more than once, but they’re stupid expensive.

But. If you’re using 2mm picture glass, that’s going to take some very fine tuning on getting the kiln cycle correct due to the thinness. Heatwork is going to play havoc with that small of a thermal mass. I think your idea about torching it and annealing it is a much better one. if you can easily get your lampwork setup going, you could probably use the wood turning itself as a hump mould. Many glassablowing tools are charred wood. 

[Tamra]

Callie, thank you for chiming in... I don't think it is 2 mm thick glass... I will measure it, but I do like the idea of using wood and trying this first with a torch.  Likely 1/32"  thickness or .80 mm. 

I need 4 windows slumped... 

I need to go to talk to the local guys about getting fuel for my glass blowing torch...   and will try to find a glass forum.

Tamra

 

 

 

 

 

[Callie Beller Diesel]

If it’s thinner than 2mm then the principles above are even more applicable. Annealing, torching and annealing is sounding like the ticket. I’ll also ask a glassblowing friend to see if she’d be willing to advise. 

[Tamra]

I have made my 7.25" diameter wood turning that will be my negative,  I may put it back on the lathe tomorrow and sand it with even higher grit as I bought some 800 emory cloth today at the hardware store.  

  I will shrink wrap it in plastic and use the smoothest surface section for the negative portion of the mold.  It seems reasonable that any pine knots that are in the turning are going to show up in my glass, and  I really don't want texture in this glass project.

I ordered clay tonite and should receive it next week.  I'm thinking of a slab about 3/8" thick initially to allow clay to shrink in the drying stage - next week it might hit 80, so this is good timing for a slow dry...  I anticipate I will need to drape, and not slump because I didn't make my turning large enough, even though I do understand the properties of clay shrinking when drying and then shrinking again when it is fired.... 

While I'm waiting to receive my clay, I will try to do some modeling and 3d print something that is flexible and apply it to the turning as i hope to control the oval shape...  and to build this into my mold.  I think my Elegoo resin printer is large enough.

If this plan fails, will go the torch method, or may try the torch method anyway... just for fun, but I don't want to torch the turning yet; yes I do know it is soaked in water, did a intro glass blowing classes at Benton Harbor, MI.