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Old 05-28-2012, 07:32 PM
Tim Elias Tim Elias is offline
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Quality and lifetime of wire elements

We use a home built wire melter which uses elements from Aims 1715C for a 80 pound crucible. We're using a Watlow controller: DIN-A-MITE (Solid state power controller) with 2 elements running plus a back-up one.
It ran 2170 for 5 weeks, it went on back-up, then ran for 1-1/2 weeks. Both old elements are now blown.
Can any of you recommend longer lasting system? Different elements (cheaper...) ???

Waiting to hear with appreciation, M-Chantal, Blown Away (haha) Glass
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Old 05-28-2012, 11:35 PM
Mike Hanson Mike Hanson is offline
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You could use this supplier:

http://www.duralite.com/store/script...?idproduct=108

If you are running two elements with a backup use DURA 005680

If you are running three use DURA 005679

make sure to order a spare or two, they are less likely to burn out that way...

Last edited by Mike Hanson; 05-28-2012 at 11:37 PM.
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Old 05-29-2012, 12:11 AM
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Richard Huntrods Richard Huntrods is offline
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What is the watt loading for your furnace? If it's under-powered (wattage wise) then you will be hurting any element you install trying to keep things hot.

There are lots of other threads discussing stretch, installation, keeping elements away from glass fumes etc.

Also, how fast you ramp up, what you melt... wheter cullet or batch and what type of cullet. How hot you melt and for how long... it all factors into the element life equations. That and the color of your tie on tuesdays after a full moon, among many other mystic factors.

Cheers,

-R
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Old 05-29-2012, 05:54 AM
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Pete VanderLaan Pete VanderLaan is offline
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It seems to me that holding at 2170 is a lot of stress in itself. That would be really hot glass to work with.

Did you check your connections after you first fired up? Connections get loose when they are turned on, then, unchecked, they arc. Did they fail near the split bolt or was it inside the kiln?

Most of the wire in this country comes from Kanthal. There is a French source which ostensibly is excellent stuff. Kanthal has been known to have bad batches on fairly rare occasions but I think the operator application is the more likely source of the problem here. Both Mike and Richard are right respectively. Duralite is a good source for both elements and wire and how you hook up the kiln is actually critical to success. I think you need to ask and answer some questions about your process but I doubt that the element itself is the problem unless you used something totally inappropriate to your kiln's needs. You don't even say what gauge wire you used.
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Old 05-29-2012, 08:33 AM
Tom Fuhrman Tom Fuhrman is offline
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For an 80lb. unit which is what I run as well, I use 3 elements and never go beyond 2150 and most of the time I melt cullet and melt it at 2110 or below and get good glass heating over an evening. I also think you may need more insulation in your unit. I get 9+ months from a set of elements from AIM and sometimes longer.
Melting for long periods at 2170 seems very high even if you are melting SP batch. I think you are probably underpowered with only 2 elements. I've been going since Nov. with the new French wire and so far it has maintained heating quality very well.
Most Wire melters just aren't designed to maintain temps above 2150 for any duration. That's like trying to run a VW engine at 140 mph for weeks at a time. It can be done if it is geared properly and the wire melter can be the same way if you run it properly and have the right type of controls.
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Old 05-29-2012, 05:30 PM
Tim Elias Tim Elias is offline
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Going from a Stadelman type furnace for plus 13 years to the wire melter is proving to be huge learning curve as we also now use Spectrum pellets (instead of Spruce Pine). All your info is amazingly helpful and will investigate some different avenues as in:- 3 elements on instead of 2
-french wire? where to get them seems a bit of a concern...
-love the part about insulating more
-getting used to working with a lower temp. glass than previous (2170+) seems doable
-the elements are closed off pot but gassing off damages anyway???
.... many considerations and thank you for info. Will be back once furnace opens (tomorrow) and brain annealed after technical overload...
MChantal
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Old 05-29-2012, 09:01 AM
Dave Bross Dave Bross is offline
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Some Past Posts

Somewhere here there's a link to Jordan's element calculator, or he may pop up and post it.
The only link I found in a quick search was dead. I'm pretty sure there's a live one here.

I selected these from a search here on "watt loading" which is critical to understand for wire melters. I couldn't find the actual math for calculating watt loading but it's here somewhere. Easier to just use someones calculator for that anyway:

http://talk.craftweb.com/showpost.ph...7&postcount=10

http://talk.craftweb.com/showpost.ph...15&postcount=5

http://talk.craftweb.com/showpost.ph...24&postcount=7

There's lots more info to be had here via search.

I won't rehash using variacs for temp control because you're using the digital equivalent.

I do wonder if the dropped voltage from using a variac is helping with the extended element life. It's well proven that incandescent 120v bulbs run at 110 volts or less will last almost forever as opposed to the 120v. Who remembers the little wafer resistors they sold in the 60s/70s to put in the sockets under the bulb?
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Last edited by Dave Bross; 05-29-2012 at 09:12 AM.
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Old 05-29-2012, 03:08 PM
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Scott Novota Scott Novota is offline
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Tim,


You are closing off the elements from the pot right? If I remember correctly 5 to 6 weeks would be about the life span of elements if exposed to the glass gassing off and getting to the elements.


I only ask because I did not see you state that in the post.
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