Element Type pros/cons

[GordonS]

Hi,

A question mostly for Lee, but I though the answer might interest others, so I'm posting rather than mailing him direct.

I was wondering about two types (I think) of elements I see in Kilncare kilns.

It appears the Hobbyfuser/Eurofuser use quartz tubes and the FK series use "Kantal A1 ... wound on the outside..."

I'm not sure that these elements are actually different, maybe it's just the wording, but if they are different, I'd be interested in the pros and cons of the two arrangements.

Thanks,
            Gordon.

[Charli]

Kanthal is the type of wire

Elements referred to as quartz tubes still have kanthal elements, only the metal wire is inside a quartz tube. This means you can't accidentely poke the wire with a mandrel and elecricute yourself!

It has also been said that the kanthal inside the quartz wire doesn't last as long, because the heat is trapped inside so the wire itself gets hotter and wears out quicker. I've no idea if this is actually true, I have elements of both type, but neither one has worn out yet!

[GordonS]

Hi Charli,

I'm sure there's no shock risk in this particular case as I know Kilncare take that issue very seriously indeed, which is partly why I'm puzzled by their wording. That said, there is a power cuttoff and the FKs are not really sensible bead-door kilns, so maybe the cutout is the appropriate and only protection. Which is partly the reason for the question .. if I don't understand, therell almost certainly be someone else out there who doesn't.

Gordon.

[Charli]

The cut-off is a British/European thing, I don't think that legislation exists in the US. But yes, here all the kilns should have to have cut-offs so when the door is opened, there is no electricity going to the elements!

There's some good info on element types and ways to connect them on the joppa glassworks site: http://www.joppaglass.com/construction%20papers/Construction%20papers.html

I don't have a hobbyfuser kiln or anything, I'm just building my own.

[Lee - Kilncare]

Hi Gordon, sorry about the lateness in my reply, I've been running my legs off just lately. O.K do a brew, put yer slippers on and here we go.

OK then, the elements are indeed both the same Kanthal wire wound in the same way. The Quartz elements are quartz tubes with the Kanthal wire element inside it. The other way, the FK way is the same style of element with a ceramic tube passed through the middle of the element.

The longer lifed element is the FK style with the tube through the middle for two reasons. a) the heat of the element is dissipated immediately into the surrounding atmosphere so the element is running as cool as is possible, b) the ceramic tube means the element is hanging, having its own weight supported from the inside.
The element in the quartz tube system is encased and so it runs hotter, hence the much earlier infra red glow at as low as 300c compared to the infra red glow of the FK style which can be 500 plus, but yes, both styles give infra red heating despite claims that the quartz system is infra red as if it is something new, it isn't..
That said, the Kanthal wire we use is 1400c grade, yet glass temperatures of 800-900 are well within the capability's of the wire meaning that, in reality, the quartz tube system will still give a rediculas life span. In the 5 or so years life of the Hobbyfuser we are still to replace a single elements for anything other than accidental breakage and that Is the honest truth and we have an awful lot of Hobbyfusers out there.

Our Eurofuser, a kiln similar to the FK5 uses quartz tubes but we have gone that way purely due to market forces. The trend at the minute is for quartz tube elements and it is seen as something new and technologically superior.
The jury is out on whether the system is better for the glass or not.
It cannot be argued against that the element is protected from the kiln atmosphere and the glass below is protected from any droppage from the tube or element. Valid points.
However, our Kanthal A1 wire coats itself as it is fired and does not drop flakes and our ceramic tubes are of the top grade and so have no powdery content. Can you imagine how many hundreds of FK kilns we have made yet not once have we had any feedback of the elements or the tubes dropping any particles, well, other that the kiln that was built with bricks accidentally salt damaged but that is another story ;p. It can be counter argued that in sealing the element from the kiln atmosphere it is also being shielded from oxygen, an essential component in element protection as element wire is designed in such a way that the oxidisation that occurs at its surface is actually the protective coating for the wire beneath it.

With regards to the Hobbyfuser, the way that the lid is constructed means that the tubes needs to pass right through the lid and become part of the fibre anchor system, this means that the element HAS to pass through the tube. Early Hobbyfusers used ceramic tubes with the element inside but the Quartz system is far superior to ceramic if the element is inside the tube.

To sum it up, there really is little difference, one way or the other. There are pros and cons with both systems. Both work just fine, both last an awful long time if they are designed correctly, both are strong and with regards to the safety issue, we fit UK relevant switch gear to both types of system, unlike most other European makers who feel that no door switch on quartz tube systems is fine.

The original design claims and sales bumf with regards to the quartz system can be summed up in a couple of sentences.
They are cheaper to buy than ceramic rods, they are lighter than ceramic rods and it means that many kiln makers are choosing not to worry about a lot of the expensive door switching issues as the elements are enclosed.

So as you see mate, swings and roundabouts. One thing is for sure, both systems are VASTLY superior to any kiln with the elements embedded in grooves in the kiln lid.....now that's another story all together.

[GordonS]

Hi Lee,

Thanks for that.

Charli's link told me enough about elements in grooves to see that they're not a good idea.


My understanding from your well detailed mail and my other research:

Quartz tubes are perhaps more fashion than function, they're cheaper, may be a little easier to replace, but don't go quite so hot (ref ...fuser's 950C limit rather than the FKs' 1050C limit).

The Kantal elements on ceramic are exposed, but that's not an issue in a larger kiln as they're guaranteed OFF when the kiln is open (which is much more than my kitchen toaster promisses). Exposed would be a very different issue in a bead-door kiln, of course!

It sounds like quartz have not yet been in use long enough for you to have formed a really good view their of  longevity relative to the ceramics, but it presently sounds like a very minor concern.

Thanks again,
                   Gordon.

[Billie]

Hello GordonS    Welcome to Frit-Happens!  Are you a lampworker, fuser, glassblower, or something completely different..?  Would be nice to hear a bit more about you on the Welcomes board  

http://www.frit-happens.co.uk/forum/index.php?board=22.0