new Globars September 2006

[Paul Hayworth]

http://www.newmaterials.com/news/905.asp
KANTHAL LAUNCHES NEW SILICON CARBIDE HEATING ELEMENT

for batch melting

[Dave Bross]

I don't think they'll ever get around my major objection to silicon carbide, which is that water vapor destroys it quite quickly.

I wet all my batch.

[Michael Mortara]

Having used SiC for seven years I feel qualified to say the water vapor thing is not a factor. We have had a set of thin wall bars in our furnace for three years and have not had a single failure nor seen any significant loss in out put. I pour wet cullet in my furnace (200#) every week.

[Brian Gingras]

michael: what brand are you using?

[Pete VanderLaan]

I know that Sky Cambell had serious problems with moisture on SiC bars about two years ago. I think it really takes operator experience.

[Dave Bross]

I suppose you could design the furnace to isolate the elements from the moisture too.

or...

Sky had a friend who built flues into his SIC melter, which he would open when batching. One in the top and one in the bottom. Theoretically the heat should carry all the problems out the top flue. Elements were also beside the pot in that melter if I remember right.
Sky may remember what the element life was for that setup.
Sky's elements were over the pot.

Michael,

Besides brand/type, what's your location in the furnace for the elements?

[Michael Mortara]

We get our elements from IsqR. They are the straight through type, which are really the only type you should be using in a batch or cullet furnace. There are three bars over the pot and one under the bottom. A major diffrence is the type of bar, thin wall vs. the standard bar. Pay an extra 20% for the thin wall as they last three time longer than the standard.

[Paul Hayworth]

http://www.hubglass.com/furnacecombustion.html
Galss Furnace Combustion Control Systems - HUB Consolidated

Duralite Packages MOLY-D -- STARBARS

[Brian Gingras]

Or....you could contact Steve and get a better electric furnace. Somehow the idea of sticking Moly's in the exact same furnace design that ran on gas just doesn't work for me!

[Pete VanderLaan]

or the added expense of starbars which is considerable. I use the elements Steve brings in from China which are made to the exact same specs for a fraction of the price.

[Brian Gingras]

if you add up the furnace base cost and the price for the durlatie controls they get a bit pricey...$38,000+ for a 500lb unit and it will bleed your wallet with the huge chamber and heavy castables to heat up and lose heat...this is only my opinion of course based on my observations of actual units.

[Pete VanderLaan]

While I haven't seen the furnace from John, if it indeed is simply a conversion of a gas furnace, that has a lot of inherent problems that have to do with oversized combustion chambers that you don't need, thermal mass you don't want and a generally bigger unnecessary box than is called for.

I say that becaue my existing moly meets that description. I built it and would do it completely differently based on my experiences. Mine costs more to run than it should because I think Gas. I have had to change that mindset. I love the moly but converting your gas design is not a good plan.

If indeed the Chiles furnace does that, it would be similar to those kilns from Aim or JenKen which are really bisque pottery kilns put together with a control package that sort of maybe can be seen as a glass furnace if you squint.

While I think John builds a fine, if rather expensive furnace for Gas operation, I would not think that a converted gas unit would really be a good investment. The electric package that comes from Duralite which I believe to be similar to the one once offered thru EZ Therm to be profoundly overpriced. That particular package drove me right into Steve's arms. I was initially quoted 12,000 dollars just for the electric package and I'm not a fool. I bought a plane ticket to Portland instead. Moly calls for a whole different way of thinking. Don't get sucker punched.

[Brian Gingras]

from hubglass.com :


"Electric Furnaces

To better meet our customers’ needs, we have decided to add electric packages as an option for furnace heating. The furnace is our same tried and true free standing crucible design with moly disilicide elements instead of a burner. "


While I agree that the gas furnaces are good furnaces, they are not the most efficient, again in my opinion from being around multiple furnaces from different makers.

[Sky Campbell]

Originally posted by Pete VanderLaan
I know that Sky Cambell had serious problems with moisture on SiC bars about two years ago. I think it really takes operator experience.

Hey folks, let me clarify. I bought 4,000lbs of very wet gaffer batch on a good deal. The bags had seen enough water to be falling apart. I was litteraly shoveling batch and bags in the furnace with out any thought of the water content.

Before element failure we melted our own batch that we watered to keep dust down but nothing as wet as the gaffer. Also melted alot of sp. My elements were 2 years old when they prematurly bit it do to moisture. Kanthol sent the elements to headquarters and told me failure was my fault do to moisture.

You should be able to go 5 years or better from sic even the cheap chinese ones I know of are 3 years strong and the price is cheap!

My opinion is that moisture should not be a deciding factor agaisnt sic.
I wouldn't abandon sic for moly. Easy hot element change. Cheap price. No transformer. For me it's a no brainer.
Sic elements are easy to use cheap to buy and definitly have there place for melting glass. My 2 cents...

[Michael Mortara]

We were melting the gaffer batch for a while, it was decent glass but the melt gasses off some of the strangest stuff I've ever seen, and we had some slag comming off the elements the I directly attribute to the batch. Lost a couple of elements but have not had that problem since switching to the system 96.

[Paul Hayworth]

http://www.kilncare.co.uk/hotglass.htm
KILNCare - The U.K's No.1 Kiln Manufacturer

USE _W_ TYPE MOLY ELEMENTS

[Dave Bross]

Hey Sky!

Thanks for the update on that.

Who has cheap chinese ones? I might be tempted to experiment given a low price and moisture not being the issue I thought.

[Rollin Karg]

Andy Lau is the guy I get my moly's from and I think they do Silicon carbide also. He is a good guy and very dependable.

Here's his e-mail:gaoxiang liu <gaoxiangliu@yahoo.com.cn>

[Paul Hayworth]

http://handmade-glass.com/subscribers/efurnace.html
Handmade-Glass.com - Electric Glass Furnace

[Paul Hayworth]

http://www.zircarceramics.com/pages/elements/specs/molydis.htm
ZIRCAR Ceramics: MOSI2

[Paul Hayworth]

http://handmade-glass.com/cgi-bin/conf.pl?read=24390
Re: wire burner questions

[Paul Hayworth]

http://www.striniartglass.com/images/2%20new%20pots.JPG
2 new pots.JPG (JPEG Image, 1024x768 pixels) - Scaled (79%)http://www.striniartglass.com/images/2%20new%20pots.JPG
2 new pots.JPG (JPEG Image, 1024x768 pixels) - Scaled (79%)

[Brian Gingras]

how about some info with these posts? and that last one shows spiril cut elements, they just love to short out in a glass furnace.

[Pete VanderLaan]

I agree with Brian. Simply posting access sites doesn't really give any qualitative review and in some instances can actually lead someone astray.

[Paul Hayworth]

http://www.mayneislandglass.com/170lbinvestedsicfurnace.htm
Mayne Island Glass Foundry - 170-pound Silicon Carbide Electric Glass Furnace

Sorry but Photos are the Best I can Do

[Brian Gingras]

interestin choice for insulating materials...that looks like Mineral Wool safing insulation if I'm not mistaken...man If I had known that stuff insulated well on a furnace, I wouldn't have tossed a ton of it our last week!

How about some commentary at least with your links, like why your posting it, what's interesting about it. This thread looks more like a directory than a discussion!

[Richard Huntrods]

Brian,

Which picture? You mean the yellow stuff? I believe that's "Roxul" - rock wool insulation. Works perfectly for the outer 2" of these furnaces. I have the same stuff as the last 2" of my 40lb electric.

I saw this furnace when I visited Mark a couple of years ago. Pretty sweet. Very nicely made. As I recall, that furnace takes 80amps to start, but much less at temperature (don't recall the figure).

-R

[Brian Gingras]

yes the yellow stuff. I thought I recognized it, but couldn't be certain. I just threw away about 100 SF of the stuff last week ina trash run...we buy it occasionally for fire blocking in residential homes, I didn't even think of it's application in a studio...ooops.

[Pete VanderLaan]

Brian: My first trailer left Santa Fe this morning. I am driving east with the three dogs and the 16 ft trailer on thursday. I will be in touch if you can still help.

Paul, what Brian is saying is to offer up a reason for posting the links you post. Otherwise, for those on slow modems, going to a link for no good reason is a real time waster.

[Brian Gingras]

Pete, just let me know...I'm teaching this weekend at Snow Farm through next Tuesday, but after that I'm around...The help I have is out constructing a home depot but can be recalled fairly quickly also.

-Brian

[Glenn Randle]

Paul,
Thanks for posting those links. I found them quite useful, and they weren't a problem for my dial up. They probably are too technical for beginners, but they are exactly the type of info that I can use.

peace,
Glenn

[Charles Friedman]

Originally posted by Michael Mortara


I pour wet cullet in my furnace (200#) every week.

Michael,
After 14 years (same furnace) of using sil, carb. elements. Spiral bonnets and solid rod. Putting wet cullet would have been the last thing I would have done.
Popping bits of glass where shorting the life span. I always preheated cullet (when I used it) I would preheat my SP batch if I heard a pop or too many. They lasted much longer that way.
Now I use the same type of elements, thin walled, 4 on each side of a #80 pot. I have heard that any hot glass that gets in contact with the rod, it just drips off. No harm.
I am a bit conservative on the way I charge and have never let any popping going on. I do not want to try it that way.
I am very curious on how your furnace and rods looks on the inside from all that popping from wet cullet?? Or is popping of glass does not happen?? Can you describe or photos?

[Jon Myers]

Originally posted by Michael Mortara
We were melting the gaffer batch for a while, it was decent glass but the melt gasses off some of the strangest stuff I've ever seen, and we had some slag comming off the elements the I directly attribute to the batch. Lost a couple of elements but have not had that problem since switching to the system 96.

We ran a couple of tons of gaffer too and that stuff not only made the elements grow a weird white hard hard hard crystal. (Think the majic growing crystal farm they have for kids) It also ate the shit out of our refractory. More damage done to the furnace in 2 or 3 tons of gaffer than 6 years of spruce. I have a couple of photos of the elements I'll hunt down. The crust on the elements is evidently insulatative as the parts of the elements covered by crust glow darker than the rest of the element. When we were using the gaffer I tried to describe what was happening and no one had any idea. (in fact I was told more than once that gaffer was almost exactly like spruce .... it just had more pure (refined) ingredients)(I hate it when you have a question and the person who knows gives a canned BS answer that not only doesn't answer the question but somehow insuates that you are an idiot for asking it.) Mean as it is, I'm glad you had the same issues, now I know it was the batch not the furnace castable or the salt air (we're by the ocean)(Course the salt air never did anything to the furnace with spruce) or me imagining things . I KNEW it was the batch but I had no backup. (well Jordan saw it but since he was out here the salt air might have grown crystals on his brain too)

[Jordan Kube]

So that's my problem!

[Pete VanderLaan]

I have never said that Gaffer was just like SP87 so I guess you never asked me. . Your experience is consistent with a whole lot of people who have used Gaffer sadly. Nice stuff but hard on furnaces. I think colder melts would help.

[Michael Mortara]

Spectrum 96 has the same furnace eating off gassing, though to a lesser degree than the Gaffer and the CBG. It seems to go after the insulating castable and insulation. I have white powder frosting the face of the furnace around the door. It has eroded the interface of the gathering port and door seal,
I will have to rebuild the port with a dense castable.
Live and learn.
Charles, my wet cullet does not pop all over the place, I am charging at 2140 so the cooler temp may have some thing to do with that, the inside of the furnace is clean and no slag on my bars. No drop in out put from the bars after 18 months. I have about 14 inches to the bottom of the elements above the pot.