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Hi All, have been having trouble finding out how to melt crushed bottles. I have crushed some and put a pile of glass in my kiln but have not figured out a proper way or schedule to just make a puddle of glass. Am simply using crushed blue bud light platinum bottles, am not sure if I didn't heat to a high enough temp or what. Am a bit tired from Googling. Thank You All again.

in my med scutt kiln i use 1515-1530f to puddle bottle glass. crushed stuff i fire at 6oodeg/hr untill done. usually a 15-20 min hold. all kilns do heat work differently so your milage may vary. rosanna. edit. you will also have to put an anneal segment in there. i use 1000f to anneal bottle glass.

Scotty wrote:Hi All, have been having trouble finding out how to melt crushed bottles. I have crushed some and put a pile of glass in my kiln but have not figured out a proper way or schedule to just make a puddle of glass. Am simply using crushed blue bud light platinum bottles, am not sure if I didn't heat to a high enough temp or what. Am a bit tired from Googling. Thank You All again.

I have found that blue bottle glass (the dark cobalt-ish blue, and the pale Bombay Sapphire blue) is prone to devitrification (which can be fine, if that's what you want to work with). I sometimes mix powdered bottle glass with borax when milling powder. If you are crushing to large frit or lumps, you could probably do fine with a bath in borax solution (and let dry thoroughly before putting on kiln shelf!) to minimize devit. In my experience the bottles also want higher-than-float fusing temperatures... it's stiff glass.

thanks rosanna, i fired to 1650 for an hour but must be some stubborn glass, just looks like broken glass stuck together in a pile. all in all though i am happy to hear from you again and am still using some of the bullseye frit you sent to me years ago, thank you for being one of the best. scotty.

yes blue bottle glass is stiff. try putting really clean glass in a pile and lightly spraying with borax dissolved in distilled water. you really do not want the borax to get under the glass as that will make the kw stick. 600dph is fast enough to soften with out mush if any devit. i just must be lucky or something as i have few problems making various types of bottle glass do pretty much what i want. or maybe i make things that the glass wants to do. whatever. if you take plenty of notes you will dial it in. just do not change more than 1 or 2 things at a time whilst trying to figure it out. rosanna

thank you all, kept searching and bing sent me in the right direction as well as you all did. am going to do alot of experimenting and having a blast.

Can you assume that identical bottles (same shape and color) have the same COE?

These bottles would be mass produced in batch runs. Correct?

1650 for an hour and still not getting results makes me think something is off with the kiln. You may not get a 'puddle' of blue but certainly more action than just chunks stuck together. Ya think?

I will check out my kiln this weekend, was wondering the same and need to watch it closer. i trust it too much. thank you all.

Peter Angel wrote:Can you assume that identical bottles (same shape and color) have the same COE?

These bottles would be mass produced in batch runs. Correct?

Bottles are not necessarily compatible with one another. They are produced with recycling capability in mind, but there is an essential difference between a furnace and a kiln. In a furnace when you melt bottle glass, it can be stirred and homogenized. This will make a glass with a new COE/viscosity profile.

Heatwork is dependent on more than just temperature. Once you figure out a schedule for your kiln, it should be repeatable, but each kiln could be different. Repeatability will depend on exactly how much mass (combination of molds and glass) are placed in the kiln, as well.

I was able to cast float in my kiln at 1700 - no problem. I have a Skutt GM1414. In my experience, blue bottle glass is a PITA. Brown bottle glass seems to flow better. But, like Bert said, there's no guarantee than one bottle is compatible to another. If you're just playing around, go ahead and experiment. But, if you plan to sell these, please make sure your glass is compatible.

Hi Scotty,

I hope your project's off to a good start.

Full Disclosure: I've never used float glass, nor bottle glass in a kiln-forming project!

But I do have a question regarding heat-work. Why fire so fast to 1600-1700? Okay, perhaps to avoid devitrification. But if I need some of my stiffer Bullseye glass colors to flow more, I use slower ramps to reach my top temperature; and often, I'm even able to lower my top working temperature because of the slower ramps.

Would a slower approach to 1650-ish temps allow more time for the glass to melt, and therefore, puddle?

Again, I'm completely inexperienced with other types of glasses other than Bullseye, so take my questions for what they're worth, but would a slower approach be worth a try? Maybe try a ramp up of 200-300 deg./hour, thereby doubling the heat-work achieved by the kiln, and measure the resulting changes to the end state of the glass and/or devitrification?

Just my two cents, because that's about all the sense I have to spare...

warm regards,

Eric

Eric Baker wrote:Hi Scotty,

I hope your project's off to a good start.

Full Disclosure: I've never used float glass, nor bottle glass in a kiln-forming project!

But I do have a question regarding heat-work. Why fire so fast to 1600-1700? Okay, perhaps to avoid devitrification. But if I need some of my stiffer Bullseye glass colors to flow more, I use slower ramps to reach my top temperature; and often, I'm even able to lower my top working temperature because of the slower ramps.

Would a slower approach to 1650-ish temps allow more time for the glass to melt, and therefore, puddle?

Again, I'm completely inexperienced with other types of glasses other than Bullseye, so take my questions for what they're worth, but would a slower approach be worth a try? Maybe try a ramp up of 200-300 deg./hour, thereby doubling the heat-work achieved by the kiln, and measure the resulting changes to the end state of the glass and/or devitrification?

Just my two cents, because that's about all the sense I have to spare...

warm regards,

Eric

The reason to fire fast is because there is no harm in thermal shocking the glass, so there is no reason to go slowly. You do have to get the heat work done though, so there is a point at which you want to stop and hold until your task is accomplished. You want to balance temperature and time to a point at which you are getting success. Firing too hot, too fast, can cause problems, as can firing too low and too slow.

Scotty: All bottles that look alike are not made out of the same furnace. However you can check on the bottom or bottom sides of the bottle and match the numbers you see there an you will have glass made in the same furnace. There is a catch and a big one: The glass plant is always adding cullet (broken recycled bottles) and other ingredients to the furnace and this will change the COE. Your safest bet is to find projects that only reqquire one bottle. Georgia

Georgia Novak wrote:Scotty: All bottles that look alike are not made out of the same furnace. However you can check on the bottom or bottom sides of the bottle and match the numbers you see there an you will have glass made in the same furnace. There is a catch and a big one: The glass plant is always adding cullet (broken recycled bottles) and other ingredients to the furnace and this will change the COE. Your safest bet is to find projects that only reqquire one bottle. Georgia

Georgia's last statement is a very good one. Remember that glass made in a furnace in the morning may well not be compatible with that same color of glass made in that same furnace in the afternoon. Holding the glass at a high temp for a period of time is enough of a factor to throw compatibility off.

That said, in general, the bigger the glass furnace, the more consistent is the glass that it puts out. Bottles are generally made in large scale plants. The recycling process mixes broken bottles with batch in preplanned percentages.

thank you all again. my mind tends to go in one direction but with your thoughts, suggestions and skills my brain starts to flow in a lot of directions. don't know what i would do without you all. scott.

bottle 'incompatibility'..... i wonder how many folks that talk about that actually work with bottle glass on a daily basis. i may jinx myself saying this but i just do not find it to be an issue. rosanna