Industrial microwave for fusing boro?

[Riley]

Many of us have probably seen the microwave kilns (ceramic dome and plate) they sell for fusing glass in a microwave at home, but has anyone tried or considered this on a larger scale using an industrial microwave ?


Considering power consumption on current crucible furnaces, I'd like to discuss the possibilities of quicker high voltage slumping and fusing of boro. Ideally an industrial microwave (used) that runs 220v and a basic recipe of the ceramic used currently, would be all that was needed.


Anyway, just a long running idea I thought we could collectively ponder. Or mainly just Doug giving it a thumbs up or down.

[Wilbur]

i believe someone did a class at EGS on this awhile back.. i want to say mike shelbo? the guy who does the GA color chart goblins... not concrete on the instuctor....

[Aymie]

The microwave kiln can only go so big before it stops being even heat.

I have a whole thread all about it.

[jesse dog]

And is there anyone out there fusing boro products that customers are buying?

[Aymie]

Yes. Lots. Once again, find the threads about it. You can do all kinds of prep in there as well.

[Riley]

Aymie, I do recall this thread but after searching I can't find any info on it other than you selling them:
http://www.talkglass.com/forum/showthread.php?34430-large-microwave-kilns&highlight=Microwave+kiln

I started this thread to talk about industrial microwaves. As in ones not necessarily even for cooking. If you can melt boro in a 1000watt residential microwave then could it be possible to scale that up? Specific frequencies and techniques would invariably have to be used, but being an electronic layman, I'd hoped for more off a discussion then "it doesn't work, look up the threads".


The threads here say nothing of industrial microwaves. Let's start from there.

[Aymie]

The problem is scaling up the size of the microwave kiln. That's what I was trying to say. I went with the medium rather than the large, because the largest they currently make has issues with heating evenly.

[Riley]

High frequency glass microwave:
http://www.gyrotrontech.com/images/article.pdf

and a Portland based company that might be cool to visit:
http://www.aeginaglassworks.com/ourvision.html

[jesse dog]

The team members at Aegina are butt kickers! Definitely worth a visit.
and a Portland based company that might be cool to visit:
http://www.aeginaglassworks.com/ourvision.html[/QUOTE]

[brian falls]

High frequency glass microwave:
http://www.gyrotrontech.com/images/article.pdf

and a Portland based company that might be cool to visit:
http://www.aeginaglassworks.com/ourvision.html

Interesting stuff

[Greymatter Glass]

Get signed up for "Ceramic Industry" a trade magazine from BNP publications.

There are suppliers of microwave furnaces for high tech and industrial scale glass furnaces. They're not cheap, but they advertise them as a long term cost effective solution to regular replacement of Moly-D elements....

[byron3]

http://www.imp.mtu.edu/microwave/microwave.htm

[somewhere]

Get signed up for "Ceramic Industry" a trade magazine from BNP publications.

There are suppliers of microwave furnaces for high tech and industrial scale glass furnaces. They're not cheap, but they advertise them as a long term cost effective solution to regular replacement of Moly-D elements....

moly disilicide elements at glass temps will last forever if not disturbed. The main caveat is they are extremely fragile.

I know your just quoting what they wrote but still wanted to clarify.

[somewhere]

I think the problem with microwave fusers are the fact they don't heat the glass but heat the metallic slurry painted on the inside of the fuser itself. After the glass becomes mten it will start a melt down with little to no control. This causes extreme heat in concentrated areas. No one has figured out a way to control this which is why there has been little evolution in this direction. I don't think it matters how big or powerful the microwave is it has set limitations on the way the heat is distributed.

I have seen the microwave furnaces and they can only produce readily boiled seedy glass at best.

[Riley]

Seems like technology with room for growth. The companies touting it are very convincing as far as energy usage, speed, and efficiency. Before I posted this I hadn't looked at microwave furnaces specifically. I can't afford beam microwave tech but I thought it would be cool to at least slightly further current microwave understanding.

That said, it will be a cool technology to watch advance.

[jesse dog]

I think the problem with microwave fusers are the fact they don't heat the glass but heat the metallic slurry painted on the inside of the fuser itself. After the glass becomes mten it will start a melt down with little to no control. This causes extreme heat in concentrated areas. No one has figured out a way to control this which is why there has been little evolution in this direction. .

Interesting. Traditional glass tanks utilize convection to circulate and stir the batch in a measured and predictable way, so perhaps someone can figure this one out.

[dustyg]

To clarify what somewhere was saying, glass is conductive when molten, and not when cool, so once it starts melting it just melts down.


http://youtu.be/cskB5c0mJ58&t=1m50s

[Riley]

In a thread I posted a while back I postulated creating an induction heating glory hole. The idea being glass was heated to the temperature of conduction in a kiln (what is the specific temp of conduction?) then placed within a coil to charge the temp up. I don't know if it's possible to wind the coil wide enough to have the space of a small glory hole but I thought it was a decent idea.


Now as far as microwaving glass, I'm imagining a similar process whereby the glass is heated in a crucible in a kiln (to conductive temp), then placed into a microwave furnace, thus creating greater uniformity of temp. I'm wondering if a microwave furnace could be built more like a boro crucible furnace so it could withstand greater temps?


i love science and glass, so these kinds of ideas are some of my favorite. I gain an understanding of what is and isn't possible, and the science behind it that makes it so.

[byron3]

Interesting. Traditional glass tanks utilize convection to circulate and stir the batch in a measured and predictable way, so perhaps someone can figure this one out.

My thoughts here would be that in convection the heat can be applied where needed(ie: you have a tank that is bottom heated on the left side, convection will make the liquid rise, and will pull in cooler liquid from the bottom right side) thus the flow would be predictable. With a microwave beam you are heating a whole batch................... my thought would be why not just use good ole air, forced through high temp nozzles??