Monday 12 April 2010

Kiln Disaster & Melted a Days Work :(

I bought this Prometheus Pro 1 kiln at the Enamellers Guild Conference. I was quite excited about it (I'd been looking for a more transportable kiln and without vat this was a bargain!)
Above you can see the picture of it's first firing ~ with an empty chamber, just in case!. As some of you know I normally fire at 950 degrees, for 1 to 2 hours. This has worked fine in my Paragon SC2 ever since I got it (a number of years ago).....A jeweller friend of mine was round (we were doing some tube setting together) but as it was a brand new kiln I still checked the piece after about 20 minutes. At this point, looking through the little view hole, it was fine & pristine..... Another 20 minutes later and the piece was the puddle of molten fine silver you can see above.
We left the door open as the metal was literally hissing and bubbling...This picture was taken after the shock & "Oh my Gods" had died down and after I went and got my camera (and it's STILL molten).
Once it had cooled you can see why we were so worried - the metal had been melting it's way through the tile!!!

The supplier said that I should only fire at 800 and he wasn't suprised it melted. When I pointed out fine silvers melting point was higher than 950, the return answer was that was didn't matter as the instructions say to fire Art Clay at 800........but,
needless to say I'll now be firing at 899oC in my "big boy" and a little less in the Prometheus
Nic xx
P.S> If anyone knows how to get a lump of tile off a very melted 4 1/2 hours work please let me know....(and if you like the "Break The Rules" art then visit http://www.fredbabb.com/)

8 comments:

  1. Hi Nic, I would fire at 890c as I think the variables on the kilns thermostat settings kiln by kiln are too unrealiable to fire nearer to the melting point of silver at 961c.

    Fantastic conference weekend and you have soooo many likes in commom with me it was a bit spookey!!! :-)

    Really enjoyed your company and love your work.

    Joy x

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  2. Thanks Joy
    I've never had a controller kiln with such a petite firing chamber & it seems to make a big difference. When we opened the door on the first "Oh my God" we switched the switch over to display & that said 1000 (though only for a second so goodness knows what was happening).
    My Paragon now has kisses on the door and a promise not to stray again....lol

    It was wonderful to meet you too and I definitely agree on the likes (even down to the moderate drinkies rofl!)
    Congratulations on the Honourable Mention, very well deserved as your work is fantastic!
    Nic xx

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  3. Oh dear!
    The cheek of the man! I only really use the low fire ACS so only go to 650, I like that it can be fired at such a low temp. I hope you manage to salvage the silver!
    L xx

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  4. I have a small kiln too Nic, and they do get hotter, so I never go above the 900 recommended by PMC, leave a latitude +/- 20 degree, so 950 getting too close to melting point for my liking anyway...do try again, great for travel kilns. guess chip the board off? soak in something??? would be interesting to see what you can do :( xx Em

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  5. Thanks Emma!
    An idea of the temperature variance for these mini kilns is so useful :)
    It's a shame they don't give some indication in the instructions, causing me to lose 25g of clay and a kiln shelf to finding out. :(
    Think the "scrap" will be left for another day
    too many other projects and now one more to catch up with, lol
    Nic x

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  6. OOh Nic, what a pain!!!!!!!

    My minikiln gets very hot too, I think it is due to the much faster ramp than the SC2 and the much much smaller chamber.

    They occasionally overshoot as they heat up so fast, so if a piece is very temperature critical, I guard it and open the door - OR, set a slower ramp speed, which you should have instructions for?

    However, I'd never fire silver to more than 900 in it. I usually fire at 800 or 850 in the mini kiln and it works great.

    You poor thing!!

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  7. Very, very useful advice :)
    Thanks Petra!
    As a very talented enameller said a few days ago....it's only metal.
    If I say that lots of times I'll believe it eventually, lol
    Nic xx

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  8. Hi Nic! Thanks for the Etsy welcome. I'm sure I have so much to learn but it's been a fun adventure and exciting! I have not played with metal clay in a very long time but still love looking at all your post. Happy Spring! Valentine says hi :)

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