Question about a statement regarding APM elements

[not a bot]

Hi,

 Thank you for letting me join the forum. I am shopping for a kiln for my wife and was trying to learn more about real life experiences with APM elements.

I stumbled upon a Google link to an old thread found here at this forum. An excerpt from that discussion caught my attention and I would like to better understand the context etc.

Here is the old thread: 

 

Here is the statement that caught my attention:

@neilestrick Posted April 7, 2016

"APM elements aren't as durable when you get crud on them. A glaze glob can fry one out, and the savings is gone."

The statement seems easy to understand, but I am wondering how one might manage to get a glob of glaze on an element. Is this something that would only occur if you were hastily loading a kiln with freshly glazed objects that still had a wet coating, or is it possible for a dry coating of glaze to melt and somehow launch off an object and land on an element? Is it possible to avoid getting the elements corrupted with contaminants with careful handling or is this a routine concern that will occur from time to time despite making simple efforts to prevent the issue?

Thank you very much for any helpful info you can share.

Thank you!

 

Edited June 23, 2022 by not a bot

[Jeff Longtin]

Welcome to the Forum NotaBot.

There are several reasons why a glaze might "pop". Not so much the glaze itself but something "other" thats gotten into the glaze. Perhaps while you were glazing you set the unglazed pot on a dirty shelf such that something then got into your glaze when you dipped the pot? Perhaps there is a contaminate in your clay that exploded when it was heated? Perhaps you applied several coats of glaze and they had an unexpected reaction to each other? 

I've been making cone 6 porcelain pots for 30 years and rarely had this happen. (Mostly single dip.) These last few years I've been working in a pottery shop where we use cone 6 stoneware glazed with multiple layers of glaze. We loose elements regularly due to glazes popping. 

 

[oldlady]

sorry i am not one of our mechanical geniuses.   i have no idea what an APM element is without the name, not an acronym.  and maybe not then,  but i do know how glaze can get into an element slot.   some inexperienced potters do not dry the items they want o glaze fire and they blow up, sending bits of glaze and partly fired clay all over the kiln.  that is only one way and would likely only affect a few of us who single fire from greenware to glaze finish.

yes, careful handling will help a lot.   i have only done this once in 50 years. 

 

 

Edited June 23, 2022 by oldlady

[Mark C.]

glaze on elements-heres a few options on how glaze can get onto elements

wrong clay used and melts and blobs of glaze and pot drips onto elements-seen this happen

pots blow up-usually greenware in a glaze fire and stuff is all over the place -seen that happen

kiln overfires and glaze runs off pots all over the place -seen that happen

glaze pops off like others have said 0seen that happen

I do not even glaze fire in an electric and have seen all this in other kilns

In ceramics stuff happens-it just does-one accepts it and moves on hopefully with lesson learned

amp elements in my view are only worth it if you fire all the time (for example a professional pottery using the kilns daily)

[neilestrick]

I think everyone else addressed the issue with elements getting messy. APM elements are only recommended if you're primarily firing to cone 10, like if you're doing crystalline glazes. There's not a lot of other good reasons to be firing an electric kiln to cone 10.

[PeterH]

6 hours ago, neilestrick said:

I think everyone else addressed the issue with elements getting messy. APM elements are only recommended if you're primarily firing to cone 10, like if you're doing crystalline glazes. There's not a lot of other good reasons to be firing an electric kiln to cone 10.

Not knowing what APM elements were I found a couple of references, which seem to emphasise Neil's point that they are intended for a rather specialised market.
https://www.theceramicshop.com/content/1269/APM-Elements/
https://bigceramicstore.com/pages/info-ceramics-tips-tip85_kiln_elements_1

[not a bot]

Thank you everyone.

The way I see it, the Advanced Powder-Metallurgical alloy is simply a better material, made available through not so new and improved processing. That is why I was, and am interested in it. I can not see how employing it for cone 6 firings has any downside other than cost. It seems that if the elements did not suffer some type of damage the use of these elements would prolong a sort of consistent performance  over their lifespan. It seems difficult not to appreciate how the alloy can provide an all around benefit. I imagine that if it cost no more than the standard issue material everyone would happily employ it.

https://www.kanthal.com/en/products/material-datasheets/strip/kanthal-apm/

As a hobbyist merely seeking the pleasure of working in a home studio, not a single cent can be calculated in terms of cost effectiveness. I was enthusiastic that the improved product might enhance my wife's enjoyment, and was not especially worried about cost. I also wanted to minimize any practical restrictions for experiencing and learning about high firing processes.

Having said that, learning how easily an element can  become damaged and require replacement has diminished the hope of realizing any possible benefit, so I think we will  settle for standard elements and be aware that replacement may be required at any time.

Thank you!

 

 

Edited June 24, 2022 by not a bot

[Bill Kielb]

1 hour ago, not a bot said:

hope of realizing any possible benefit, so I think we will  settle for standard elements and be aware that replacement may be required at any time.

just thinking about this-
I think a wise choice as for normal firings they may have diminished benefit and still wear as a standard element or nearly so just because they tolerate high temperatures better is not necessarily an indication that you will exponentially increase your midfire longevity.  My thought is that’s likely not the case for their current price point. With respect to consistency,  a controller will adapt for the most part until it can’t. With respect to immediacy element wear is pretty noticeable as firing times begin to creep up and at about 10% higher resistance many kilns run out of sufficient power to finish a firing at reasonable speed. One can always measure where they are at periodically if needed.

For kilns that were critical we just created a baseline measurement of a new element taken inside the kiln at the available extremes so retaking and verifying the drift was fairly easy (relatively accurate and repeatable) without opening a bunch of panels. Of course making sure power was disconnected was extremely important for folks that might be less familiar with kiln service before even contemplating doing this.

Edited June 24, 2022 by Bill Kielb

[neilestrick]

2 hours ago, not a bot said:

As a hobbyist merely seeking the pleasure of working in a home studio, not a single cent can be calculated in terms of cost effectiveness. I was enthusiastic that the improved product might enhance my wife's enjoyment, and was not especially worried about cost. I also wanted to minimize any practical restrictions for experiencing and learning about high firing processes.

There isn't any benefit to the APM elements other than longer life with high temp firings. There won't be any difference in the success of the work being fired, better firings, etc. Like Bill said, at cone 6 the benefits will likely be decreased, and at 4 times the cost it's just a waste of money. The good news is that the regular elements will handle cone 10 firings just fine (if your kiln is rated for cone 10) for a few dozen firings, and then if your wife decides she wants to do a lot more cone 10 crystalline work, you can put the APM elements in later. From an 'enjoyment of the hobby' standpoint, your money is better spent on a touchscreen controller, lightweight shelves, and a good venting system.

[Babs]

Just saying to OP.

General care such as carefully vacuuming kiln and elements between firing as glaze isn't the only reason for elements to fry.

Top loader, crud can slide off into element grooves.

[oldlady]

absolutely get advancer shelves instead of the elements.  they have never been within my budget but i sure wish they were.