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Skutt Clamshell element management

Posted: Fri Jun 14, 2013 12:31 pm
by Don Burt
In my Skutt Clamshell kiln the elements are suspended on tubes oriented perpendicular to the lid hinges. Over time they creep back toward the rear, and the coils bunch-up and touch. Mine got really bad after about ten years. So I replaced the elements. Now evenivity emanates. But I don't want the elements slipping back into a bunch at the rear of the kiln like they did before. I'm following Doug's advice in not opening the kiln when the elements are hot. But if possible, I'd like to adhere them to the mounting tubes.
I don't see a way I can do that with element pins. But could I do something with a kiln cement in a few spots on the tubes to create ridges or bumps
that would discourage the elements from creeping?

Re: Skutt Clamshell element management

Posted: Fri Jun 14, 2013 12:56 pm
by GuyKass
Don-

If you don't mind me asking, what did the elements cost? Did you do it yourself?

If you come up with a solution, I would love to know what you come up with...

Thanks,

Guy

Re: Skutt Clamshell element management

Posted: Fri Jun 14, 2013 12:59 pm
by Morganica
You mean snake a little wire or something down the tube, covered in kiln cement, and deposit it at judicious intervals inside the tube, creating a barrier too big for the element coil to bypass?

Seems like it might be a tricky business to get the cement firmly seated in the tube, and to hold the element without actually sticking to the element. And if the cement is adhered to the quartz tube...does kiln cement contract at the same rate as quartz? Is there a chance the tube could crack? Or, probably more likely, that the expansion and contraction would dislodge the cement glob so that it wasn't doing the job?

And if it worked, how would you remove the old element to replace it with a new one when the time came?

Dunno, never tried anything like that so I have no idea...but that's what I'd think about anyway...

Re: Skutt Clamshell element management

Posted: Fri Jun 14, 2013 2:09 pm
by Kevin Midgley
When I had one of Brock's Rick LaLonde design kilns the elements were wrapped around mullite rods. Over time, despite being always horizontal they too would bunch up towards the ends. My solution was to jamb bit of a ceramic button between the mullite rod and the roof of the kiln in a few places and it restricted the movement of the coils. Wire as someone suggested might just carry the current better than the element and short it out. :shock: :shock: :shock: If the problem is inside a quartz tube then you won't be able to jamb anything between the coils and the solution lies in replacement of the coils and the careful minimal stretching of the new coils when they are installed. Over stretching of the replacement element coil on the re-install, might just encourage the problem to reoccur sooner rather than later. If you've never stretched elements, it is exceedingly easy to overstretch them and incredibly difficult if at all, to reverse that mistake.
Opening a clamshell while hot, with the elements installed in a pattern that allows shifting downwards by gravity, is obviously problematic as is long term storage of said type of kiln with the lid in an open position.
Perhaps if you bring this problem to the attention of the manufacturer, in their quest for excellence, they may design the lid layout differently in the future.
I suspect Don while doing painting firings will be frequently peeking at his glass and opening the lid while hot for a good view of his paints being fired.

Re: Skutt Clamshell element management

Posted: Fri Jun 14, 2013 3:35 pm
by Don Burt
The elements are wound around mullite rods rather than inside quartz tubes. Hence I thought I could put some bumps between the coils with some refractory cement product or other. I do have the kiln propped up in the back, so the elements are off plumb, hoping maybe that will discourage them from retreating. Levelivity isn't an issue for my work. I've spoken with Perry at Skutt about the design, Kevin. He's sympathetic.

Guy, I bought my elements a couple weeks agon from the Skutt headquarters. They were between thirty and forty bucks apiece. I also got a new thermocouple from them, and paid a bit of a premium for that. Can't remember exactly how much. The elements come nicely packaged, with some instructions and are easy to change.

Re: Skutt Clamshell element management

Posted: Fri Jun 14, 2013 3:56 pm
by Rick Wilton
It sounds like you may be looking for a solution without a problem.

If you can get 10 years out of it without any really serious issues then maybe you don't need to "fix" it. Besides after 10 years maybe a new element isn't such a bad thing anyway. I've had people look at my element configurations and ask how I can use my kiln like that. (as if how I feel about it makes a difference on how it fires) I over stretched my elements a bit when I built it so they have a few "dog legs" to use up some of the extra length. The quartz tubes got broken in a couple places when I installed them, yet it fires just fine.

No it's not pretty but it fires just fine the way it is. I figured I'd need to modify it, or replace them... they work fine as is... so why mess with it.

Re: Skutt Clamshell element management

Posted: Fri Jun 14, 2013 4:51 pm
by Tony Smith
Try stuffing a piece of fiber paper between the element and the rod two or three places along its length... It might give it just enough resistance to keep it from creeping.

Tony

Re: Skutt Clamshell element management

Posted: Fri Jun 14, 2013 5:15 pm
by Rick Wilton
Any of these FIXES are opening the possibility to much bigger problems like stuff falling onto your glass.

If it isn't truly broke don't fix it. (imo)

Re: Skutt Clamshell element management

Posted: Fri Jun 14, 2013 7:20 pm
by Don Burt
Rick Wilton wrote:Any of these FIXES are opening the possibility to much bigger problems like stuff falling onto your glass.

If it isn't truly broke don't fix it. (imo)
Stop being rational and level headed. We're talking about my kiln here Rick.

Re: Skutt Clamshell element management

Posted: Fri Jun 14, 2013 8:57 pm
by Bert Weiss
One more reason I prefer a bell to a clamshell.

If the clams were made with elements embedded in fiber board, this problem would be solved. Paragon has been working with this concept in some of their kilns.

Re: Skutt Clamshell element management

Posted: Sat Jun 15, 2013 8:50 am
by Marty
Don Burt wrote:
Rick Wilton wrote:Any of these FIXES are opening the possibility to much bigger problems like stuff falling onto your glass.

If it isn't truly broke don't fix it. (imo)
Stop being rational and level headed. We're talking about my kiln here Rick.
Don- you need to rotate your lid about 90 degrees so the elements run side to side instead of front to back. snort.

Re: Skutt Clamshell element management

Posted: Sat Jun 15, 2013 9:21 am
by Don Burt
I've considered things like that. Like removing the hinges altogether too and turning it into a bell. Ultimately the Rick Wilton position prevails

Re: Skutt Clamshell element management

Posted: Sat Jun 20, 2015 4:46 pm
by Mark Wright
Has anyone tried heating these coils up with a torch and pushing them back to the front of the kiln? They are very accessible by removing the top cover.

Re: Skutt Clamshell element management

Posted: Sat Jun 20, 2015 5:27 pm
by Don Burt
I did some of the torch thing. Its a two person job and time consuming and unpleasant. You can do it though. I gave up and installed new elements from a skutt kit. I'm practicing creep avoidance technique now and am in remission pretty much