Search found 27 matches
- Tue Feb 19, 2019 2:26 am
- Forum: Techniques and Tools
- Topic: kiln elements
- Replies: 8
- Views: 26919
Re: kiln elements
Been a while since I took Electricity and Magnetism. If it used to have twice the voltage, then cutting the resistors in half will give you the same amps it used to have. Check the circuit breakers of the new house to see if they will handle the amps. But thar only helps a bit. Power is proportional...
- Sun Feb 17, 2019 2:37 pm
- Forum: Business Topics
- Topic: Does annealed glass bring liability?
- Replies: 1
- Views: 41569
Does annealed glass bring liability?
Many cups are now tempered. If I sell art that is annealed and not tempered, and a customer breaks it, am I at high liability for differing from the norm, which is using tempered glass on most other objects? What can we do to minimize our losses, and also not give some types of people ideas?
- Sun Feb 17, 2019 2:28 pm
- Forum: Techniques and Tools
- Topic: Drilling
- Replies: 6
- Views: 9175
Re: Drilling
I tried looking at the bail tutorial but was prompted for a user name and password. I don't want to create more for more sites since memorize too many. I want to drill a conical shallow hole into soda lime glass, about 1/8th inch wide and 1/8th inch deep. The piece I'd drill into is 1/2" wide, ...
- Thu Feb 14, 2019 4:21 pm
- Forum: Newcomer Forum
- Topic: I need castable mould materials to melt plate glass into a disc.
- Replies: 36
- Views: 101333
Re: I need castable mould materials to melt plate glass into a disc.
I doubt I can cut tempered glass. But I can split it. I also saw videos of splitting circles from squares. I think that is much less difficult with 1/4" glass than with 1/2". So, my task is to fuse two 1/4" pieces of glass together and slump them, hopefully in the same cycle. Freeing ...
- Thu Feb 14, 2019 4:05 pm
- Forum: Newcomer Forum
- Topic: I need castable mould materials to melt plate glass into a disc.
- Replies: 36
- Views: 101333
Re: I need castable mould materials to melt plate glass into a disc.
I also just found out that chalk is calcium carbonate, not magnesium oxide. Also magnesium oxide has high conductivity, as do most metal oxides. It is the carbonates that are thermal insulators. And the CO2 is driven off at very low temp. So that scratches my MgO thermal shock protectant idea. I sti...
- Thu Feb 14, 2019 3:52 pm
- Forum: Newcomer Forum
- Topic: I need castable mould materials to melt plate glass into a disc.
- Replies: 36
- Views: 101333
Re: I need castable mould materials to melt plate glass into a disc.
I'm going to level with everyone. I'm making a front surface mirror. Bubbles won't block the light, but they can change size with temperature pressure and deform the surface, which needs to be exact. The reason I'm against crystal is not the price so much as the density: 3 vs 2.5. That can make the ...
- Thu Feb 14, 2019 2:48 am
- Forum: Newcomer Forum
- Topic: I need castable mould materials to melt plate glass into a disc.
- Replies: 36
- Views: 101333
Re: I need castable mould materials to melt plate glass into a disc.
Schott likely has heavier tougher bricks that stay about the same temp in their flow through set up.
As for the temperature their shelf/mould can handle, their shelf is molten tin.
I can not copy them.
As for the temperature their shelf/mould can handle, their shelf is molten tin.
I can not copy them.
- Thu Feb 14, 2019 2:20 am
- Forum: Newcomer Forum
- Topic: I need castable mould materials to melt plate glass into a disc.
- Replies: 36
- Views: 101333
Re: I need castable mould materials to melt plate glass into a disc.
I just learned that clay pottery is hardened with mineral fusing. There is no mould, so water initially holds it together till other crystal bonds can form. It is a very gradual, well controlled process.
- Thu Feb 14, 2019 12:43 am
- Forum: Newcomer Forum
- Topic: I need castable mould materials to melt plate glass into a disc.
- Replies: 36
- Views: 101333
Re: I need castable mould materials to melt plate glass into a disc.
Well, since stainless steel has a melting point of 2550 and max working temp of 1600, I guess that means working temps are half of melting temps on average, but depending on the loads. I wonder how reflective titanium is in the infrared, compared to stainless steel. Titanium is not what shiny. I'll ...
- Wed Feb 13, 2019 10:01 pm
- Forum: Newcomer Forum
- Topic: I need castable mould materials to melt plate glass into a disc.
- Replies: 36
- Views: 101333
Re: I need castable mould materials to melt plate glass into a disc.
I found the name for dental stone. Hydrocal. Melting temp is 2650 F, but upper working temp is 900 F. I wonder why it does not work higher. Remember that mold and glass must be compatible. That means that the glass would need a higher expansion coefficient so it will shrink more on cooling. Otherwi...
- Wed Feb 13, 2019 9:55 pm
- Forum: Newcomer Forum
- Topic: I need castable mould materials to melt plate glass into a disc.
- Replies: 36
- Views: 101333
Re: I need castable mould materials to melt plate glass into a disc.
I found the name for dental stone. Hydrocal. Melting temp is 2650 F, but upper working temp is 900 F. I wonder why it does not work higher. Plaster has 2 kinds of water in it, the water you mix it with and chemically bonded water. Both need to exit the mold. Solid Hydrocal, will just crack. So you ...
- Wed Feb 13, 2019 5:03 pm
- Forum: Newcomer Forum
- Topic: I need castable mould materials to melt plate glass into a disc.
- Replies: 36
- Views: 101333
Re: I need castable mould materials to melt plate glass into a disc.
I found the name for dental stone. Hydrocal.
Melting temp is 2650 F, but upper working temp is 900 F. I wonder why it does not work higher.
Melting temp is 2650 F, but upper working temp is 900 F. I wonder why it does not work higher.
- Wed Feb 13, 2019 2:52 pm
- Forum: Newcomer Forum
- Topic: I need castable mould materials to melt plate glass into a disc.
- Replies: 36
- Views: 101333
Re: I need castable mould materials to melt plate glass into a disc.
Also, old glass may have contamination that can seed devitrification. Brand new glass is cheap. I can get 1/2" for $10 per square foot. Vastly cheaper than $70 for a 10" disk that has to be ground to the curvature I want. Coarse grinding is noisy, and the machines likely cost as much to bu...
- Wed Feb 13, 2019 2:43 pm
- Forum: Newcomer Forum
- Topic: I need castable mould materials to melt plate glass into a disc.
- Replies: 36
- Views: 101333
Re: I need castable mould materials to melt plate glass into a disc.
I wrote a post a couple of days ago but I must have forgotten to hit the submit button. You need to get hold of a kiln and try firing some glass. It doesn't behave the way you think it will. If I were you, I would cut some rounds, stack them and fire them for the first experiment. If you use old wi...
- Wed Feb 13, 2019 1:35 am
- Forum: Newcomer Forum
- Topic: I need castable mould materials to melt plate glass into a disc.
- Replies: 36
- Views: 101333
Re: I need castable mould materials to melt plate glass into a disc.
WoW You are in for an extremely steep learning curve. First of all, float glass has a relatively high melting point. Second, refractory molds don’t fare well above 1400ºF. Third you will never get bubble free stacking glass. You would do best starting out with a piece of glass thicker than you want...
- Tue Feb 12, 2019 2:14 pm
- Forum: Newcomer Forum
- Topic: I need castable mould materials to melt plate glass into a disc.
- Replies: 36
- Views: 101333
Re: I need castable mould materials to melt plate glass into a disc.
I plan to make the kiln light weight so that the walls don't absorb or store as much heat and cause the air temp to lag behind the set temp.
- Mon Feb 11, 2019 12:54 pm
- Forum: Newcomer Forum
- Topic: I need castable mould materials to melt plate glass into a disc.
- Replies: 36
- Views: 101333
Re: I need castable mould materials to melt plate glass into a disc.
Thanks for informing us on what we don't understand because we just don't. :lol: I was merely listing what I had to go find or read between the lines due to the silence here. I never said you did not know it. Thank you for telling me that clay kilns go up to 2300 F. I also read that Crystal uses le...
- Mon Feb 11, 2019 2:49 am
- Forum: Newcomer Forum
- Topic: I need castable mould materials to melt plate glass into a disc.
- Replies: 36
- Views: 101333
Re: I need castable mould materials to melt plate glass into a disc.
Well, I read up on devitrification. Basically need to keep the glass and kiln clean and follow firing schedules so the glass does not crystalize. Also, high temps wear out kilns in several ways. There are lots of firebrick formulations on the market, each attempting to get improvement. Artists buy g...
- Mon Feb 11, 2019 12:44 am
- Forum: Newcomer Forum
- Topic: I need castable mould materials to melt plate glass into a disc.
- Replies: 36
- Views: 101333
Re: I need castable mould materials to melt plate glass into a disc.
I still don't understand. Are you going to cut out rounds out of thin float glass (windows) and then stack it and fuse it, hopefully without bubbles? What thickness of glass are you starting with? Why do you want to cast it and not just fuse it? Heating window glass that hot to make it more liquid ...
- Sun Feb 10, 2019 5:09 pm
- Forum: Newcomer Forum
- Topic: I need castable mould materials to melt plate glass into a disc.
- Replies: 36
- Views: 101333
Re: I need castable mould materials to melt plate glass into a disc.
I still don't understand. Are you going to cut out rounds out of thin float glass (windows) and then stack it and fuse it, hopefully without bubbles? What thickness of glass are you starting with? Why do you want to cast it and not just fuse it? Heating window glass that hot to make it more liquid ...