Jump to content
Bill Kielb

Bonded Nitride shelves for soda firing

Recommended Posts

Soda firing and shelves

We have been searching for a solution to the foaming issues with our old silicon carbide shelves boiling away each soda firing. My question is does anyone have real experience with the knock off bonded nitride shelves and or the super cool advancer types. All manufactures and sales folks tend to not guarantee yet are anxious to sell their shelves as the answer. At this point anyone with actual experience in the use of the knock offs would probably carry more weight than the respective sales mumbo jumbo I get.

Edited by Bill Kielb

Share this post


Link to post
Share on other sites

It's been a while since I've salt/soda/wood fired, but every brand of silicon carbide shelf I've ever used or seen used does some foaming, including advancers. Some are worse than others. We had a set in grad school that would drip big blue globs if you fired too long. If I remember right, Advancers aren't all that bad. The really cheap fake Advancers don't hold up all that well in any type of firing- they warp. I have not seen or heard about the high end Advancer-type that are from Germany(?) being used in salt/soda, but I would expect them to behave similarly to Advancers.

Share this post


Link to post
Share on other sites

Advancer shelves are wonderful when it comes to glaze runs/atmospheric drips (fly ash, soda deposits, etc) because of their virtually 0% porosity. Not only does the extremely small amount of porosity make them superior to other types of kiln shelves, including traditional silicon carbide, but it also has a thin glassy layer which has developed during the nitriding process.

Now, I can speak to glaze runs with first hand experience. They do primarily come off quite easy with a steel putty knife, however I got a carbide tipped paint scraper, which makes getting off more stubborn bits much easier. Even having to put in a little elbow grease (1-2 mins per shelf at most), it is heads and tails better than any other shelf Ive used.

In regards to salt/soda deposits; I personally havent fired my advancers in a salt/soda kiln, however I did speak at length with the technician at Smithe Sharp (his name is Marshall, wonderfully knowledgeable guy) who did tell me that using them in my soda kiln (planned for near'ish future) will be just fine. Definitely DO NOT spray the shelves with your water mix if doing soda mixed with water, and avoid dumping salt directly onto shelves. However, the "tears" or deposits which build up, will be easily scraped off with a putty knife, and according to them, the shelves will be fine to take back to your IFB stoneware kiln and no fears of vapors.

I have not used the knock off advancer shelves myself. From what I hear, they perform just about as well as the advancers in regards to their flatness, lightweight, and durability. However, I do not think that the knockoffs are nitride bonded, just slip cast, fine grained silicon carbide. Thus I believe they have a higher porosity rate, and would likely perform worse when it comes to drips/deposits. I could be totally wrong on this, but this was my impression. There are a number of "knock offs" of the advancers out there, and I am seeing more and more retailers carrying their own brand (wont name names). In my opinion though, there are the imported versions which are thicker (about 3/8-1/2") and have the "relief cuts" in the corners of the shelves, then there are the same thickness 5/16" shelves which are better, but still not as good as the advancers; again, they could be just as good, and we're only talking branding here, but from what Ive gleaned, this is the case.

Talking with the tech at SSFB he said that the advancers undergo two seperate firings to make the shelves; one to something like cone 16-18 to harden the shelf, and a second, much longer (like 30 hours or something) firing where the nitriding is done and the glassy layer is developed. I dont understand the chemistry in relation to the two firings, but thats what he told me occurs.

I have talked to folks who did use the advancers in their wood kiln; worked wonderfully! They did not use them directly behind firebox though;too uneven temps in initial stages, and would break the shelves. Anything after first stack behind firebox is fine though.

It would be nice for someone to do an in depth comparison of these shelves since they are coming down in price (ever so little, and slowly) and becoming more prevalent. Also, if you havent seen, SSFBS makes a whole slew of kiln furniture from the advancer material; beams, plate sitters, posts, etc. The beams are awesome! Posts in all 4 corners, beam on top to span as many shelves as you want. On a 3,4,5 shelf deep kiln, this now means that every shelf on that layer is perfectly in line with its neighbor, and any platters/work which spans a seam, will be perfectly flat too. Seen some photos of very long cars (30-40') using all advancer beams and shelves/plate sitters...makes me drool.

Edited by hitchmss

Share this post


Link to post
Share on other sites

I bought a few of the cheap import shelves with the relief cuts about 10 years ago. They started warping when I was using them for cone 10 reduction, and continued to warp when I switched to cone 6 electric. They warped along the full length, and aa little bit at the relief cuts. I still have 3 of them that I only use as cover shelves. I don't know if their quality has improved over the last 10 years, but I'm not willing to buy more to find out.

Share this post


Link to post
Share on other sites

I have16 knock offs.

Bought them after visiting the folks at Axner and even went to see a potter in Orlando that used them in reduction.  For the 1/5 cost they have been great in the reduction kiln  (Fulfilled the studio budget restrictions at the time) and are by no means as cool as the advancers but extremely functional. Glaze  does not stick and  they can be easily replaced several times over for the cost of the premium stuff.

My hope was to find someone with experience using them in soda firing. Soda firing is so harsh on equipment that if these performed reasonably they would be a much better choice than $3000.00 for the high end stuff which likely would never be used for anything else again and quite frankly would be the best shelves of all our shelves.

All information is helpful  so thanks for the feedback!

Share this post


Link to post
Share on other sites

maybe the manufacturer/retailer of the shelves you are interested in, can put you in touch with someone they know uses their shelves in salt/soda? Ill let you know how mine do in the soda kiln, but thats gonna be a couple of years.

Share this post


Link to post
Share on other sites

Bill 

My shelves kicking around are all  mostly 12x24-here a loose idea of what I have and am using

65 advancers-use them in reduction high fire

4-5 china knock offs-some with cut out some without-they warp easy at cone 11 so mostly set aduidse these days

2-4 the newer Bailey Germany made advancers-these are pretty new a year or two now-I reviewed these here last year-use them every fire reduction

40-45  1 inch thick dry pressed high alumina English shelves-used to use these in reduction -replaced with advancers-now use in salt kiln only

tons of old silicon carbide and a bunch of cordalights-never use them

In my salt kiln I have had the best results with the dry pressed high aluminia

one word of note I spray my salt into it in hot water in water solution so shelves like advancers do not like that temp shock

Advancers do clean up easier as nothing sticks and I assume the goobers would knock right off.

I have used the china shelves and they goober up good and warp as you would expect.The advancers I have not tried but will now try one (where the spray does not get) that I have so many(bought 10 recently for a deal-only 170$ each )

I like to  not to have to scrape heavy deposits  off sheves and anything with silicon carbide will attract salt/soda more than lower silica/carbide containing materials.

The German shelves and the advancers are about the same price these days and I consider them both equals.

The china shelves soak up the goo and warp so easy they are a poor choice.

I love the dry pressed high alumina shelves from England (I got mine thru Tacoma Art center in 10 lots) back in the day-80-s and early 90's.

the biggest drawback is they weigh 33# each

Hopes this helps Bill

 

Share this post


Link to post
Share on other sites
3 hours ago, Mark C. said:

2-4 the newer Bailey Germany made advancers

I was hoping someone would chime in on this specific knockoff of advancers. @Mark C. how do you find these compare to the true advancers in cone 10-12 ox/redux? I have 21 advancers and love them; not a single complaint. I see the bailey version are about $20-30 per shelf cheaper and wondered if they were worth the little cost savings?

$170 a shelf for used advancers is a good deal.....want to share?! Honestly, 65 advancers is just too many for one potter to have....let me help you by taking some of those off your hands :lol:

Share this post


Link to post
Share on other sites

None for sale yet my friend.

I found a guy who bought a kiln at a high school that came with new advancers. He sold kiln as he live on an island and has a smaller kiln that these shelves did not fit. He had 12 of them and cut 2 down -that was NO small task so he put the other 10 on crags list and I saw them .He sold them to me and delivered them as well. He bought the smaller advancers with my money for his kiln. Since I was on zero rush he did this in a few months when he and his wife where on vacation. people like to visit our area as its got some great features-super ocean huge trees great rivers and few people. Really nice folks who are new to pottery and doing it with gas as they only have power they generate on island so no electric kilns to speak only propane that they boat over. They plan on starting a school of sorts there. They have to boat it all over-its on an area called the delta in central Cal.

I have stayed in touch and they visited me the next year at my UC Davis show in May.

I have not yet used these latest 10 shelves.I'm Hording them -sorry

As to the Bailey German ones I did full review of them and they are everything an advancer is with a more rounded corners. Same exact size. Maybe even a glasser surface .
i say buy the cheaper ones-shipping is high on either brand -it used to be a deal if you bought in groups of 10 from Smith -Sharp I would inquire from each seller about a discount in larger groups

Share this post


Link to post
Share on other sites

@Mark C. I was more joking about taking them off your hands.....there are few things that will have to pried from my cold dead hands....my kiln shelves are one of those.

However, if you do ever go to sell them, Id happily buy any you'd be wanting to get rid of.

Glad to hear about the bailey version being good. Agreed about shipping; when I go to Minneapolis this year for a show Im going to buy a number of advancers from the factory....no shipping costs!

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×

Important Information

By using this site, you agree to our Terms of Use.