Monday, June 22, 2015

Problems with Highwater clays!!??

I have been told that a bunch of potters are having trouble with Highwater Clay (Phoenix and Orangestone) dunting after firing. (Cynthia Bringle and the Penland class, Jon Ellenbogen, Leah Leitson, etc).

Just wondering if anyone else is experiencing problems.

I assume it is related to Custer Feldspar loosing 2.5% potassium (went from about 10% - about 7.5%) but unsure if it is because it is in both the clay and the glaze or just a clay body problem?

Let me know so I can see if there have been any solutions found.  

Here is an article on the subject if you are interested:

http://www.ronroy.net/analyses/custer-article-.pdf

42 comments:

joshua floyd said...

Any word from Laguna if they are having issues?

John Britt said...

I haven't heard anyone complaining. That is why I am asking because perhaps people aren't talking and if we knew the extent of the problem it may shed some light.

youngscovepottery said...

I am having blistering and duntimg with refired pots. Aurora clay. I have been having weird pinholes also in celadon glazes.

Joey Sheehan said...

Yo Britt! You know about the massive problems I was having with moon white. Using StarWorks now with all the same glazes and haven't had a single problem yet. Just had to adjust glaze thickness and bisque temperature a little bit.

John Britt said...

Jon A. are you getting dunting after they are out or because you aren't slowing at quartz inversion on the refire?

John Britt said...

Joey, What clay are you using now?

Jennifer Siegel said...

I've been having issues with Orangestone, Phoenix, and Trina Buff since last September. Ridiculous spiral cracking, handbuilt pieces just web crack all over, infuriating! Entire semester's worth of student work ruined, not to mention the dedicated community clay work! The shivering and black coring I was experiencing was inexplicable. Been speaking with Highwater since early November, lots of denial at first on their end, speaking with me as if I don't know what I'm doing, but after my relentless troubleshooting... my first instinct was correct - it's gotta be the clay body. 70+ gas reduction firings by my hands in the last 3 years using only (7) HW Clays with the same 25 glaze options available ~ feels great to finally see communication happening regarding this issue ~ thought I was going crazy!
J.Siegel
NC State Crafts Center

Camren Gober said...

They completely ruined the P10 porcelain. I have had the same issues with dunting after firing and it looks dull with a celadon. It used to be a beautiful clay. Three different orders over the course of a year were so dry I had to completely wet and rework the clay. Highwater has completely lost me as a customer. I have switched to Standard 257 Grolleg Porcelain. Great Clay!!! Sad to loose such a great company. I have also heard that Rebecca Wood recently had a order that was poorly mixed. Something about it basically crumbling when rolled through a slab roller. My grandmother could make better clay!!! #TakeHighwaterBackFromTheMonkeys

Terri Friday said...

Hi John. I was having problems with Phoenix dunting for a couple of years. I spoke with Johnathan and Jennifer at Highwater Clays about it over a year ago now. At the time they claimed that no one else had reported to them about having trouble and that there were numerous potteries using the same clay at a much larger volume with out any trouble. I was able to decrease the number of pots that I was loosing to dunting by opening more of my peep holes and increasing the oxygen flow during the firing between 1300F and 1700F when sulfer and carbon are being released. What has always puzzled me is that my pots are all bisque fired prior to being salt fired so...I don't know. I also stopped using Amber celadon as a liner glaze, because I heard that might be contributing to the dunting. At long last I change my clay body to Aurora and so far I have had no trouble. I don't know if this helps, but I do know that a number of people at Odyssey have been seeing dunting problems with Phoenix too.

John Britt said...

I talked to Jennifer at Highwater and we were trying to determine if the changes in Custer were the problem or something else. I don't know the answer. It could be caused by the reduction in potassium in the Custer coupled with the glaze fit. So if pots were fire to cone 9/10 and the glaze had Custer and was low enough exp/cont and the reduction in flux caused tension and cracking. Not sure because everyone uses different liners and glaze thickness and everyone fires to different cones (9-14) with these clays. I will try to find out what other say and get back. Jennifer encourages people to contact her at Highwater.

Patrick Houston said...

Late to read this post, but I had some dunting with Aurora coming out of Shane's anagama. They were not fired to death, and had been cooled slowly. First I had had in a long while.
The clay at Highwater has has issues since they moved to the new place. All it takes is supervision and attention to detail, not that hard of a thing to do.

Marissa said...

Yup - Problems with dunting in Phoenix over the course of a year and half or so. During multiple different firings. I finally switched to porcelain, especially for mugs to avoid that problem. It's too discouraging to lose so many pots after all the work that goes into them.

John Britt said...

Don't know what to say about all this except that Highwater is not sure why this is happening. Jennifer will correct me if that is wrong.

It could be related to the Custer changing and since that whole situation is in flux it may take a while to shake out. That is because Pacer is only selling 325 mesh Custer in the future and that means that it may not be used in clay bodies anymore (too fine).

But not sure.

Clearly some glazes have been effected and will be in the future but we can use Custer 325 in glazes. And if a clay body has insufficient flux and the glaze is also under fluxed it can cause cracking. the Custer has less potassium and using the new custer can cause the COE/CTE to change.

So I am trying some STARWORKS clay and people may just have to switch to Laguna or Standard or Starworks to fix the problems. (I haven't heard of any problems with their clays)

Anonymous said...

I use highwater clay pheonix and loafers and have had no problems with s cracks or dunting. I dont use custer feldspar, I use nc4. I dont know if this helps alot or not.

Lori Buff said...

I use Phoenix and Orangestone with no problem at cone 6 or 7 but last summer I put some in a wood kiln. It was a disaster, all but 1 piece of mine was lost. Another potter in the same kiln lost a lot more work, he was using Aurora. I wrote about it here:

http://futurerelicsstudio.blogspot.com/2014/06/the-good-and-bad-of-wood-firing.html

At the time of writing we didn’t know what was causing it but had a lot of discussion trying to figure it out.

I was also the studio assistant for Cynthia Bringle this spring where we saw the same issue. The most disturbing part was how the pieces might not break until a few days later even when sitting undisturbed on a shelf.

I’m testing some clay from Stone Mountain Clay right now to see if it suites my needs.

Camren Gober said...

The most reliable clay for woodfire is Laguna "Woodfire" B-mix(Cone 13 rated). I have seen 1000+ pieces fired without a single issue in a 4 day firing we hold at 2150+ for most of that time. In that same kiln Stone Mountain 290 has dunting issues. Standard 257 Grolleg seems to do well, but warps if it gets too hot.

Anonymous said...

I used to use Highwater Orangestone and Phoenix. The biggest problem I had before I switched clay was the mix is overly-dry. When they stopped sealing the bags with tape years ago, it allowed it to dry out too much. I often had to re-work entire boxes of it. I started gong to the warehouse and getting the most recent dated boxes and that helped. Their pug mill with the overly-dry mix caused tremendous friction! The outer inch and a half is damaged by the extruding process and the clay platelets are strangely aligned. If not carefully wedged, I ended up often with long, spiral cracks. it is much more evident on large pieces. A good experiment to see this effect is to allow a bag of it to freeze in winter. It becomes very evident how the outer particles behave and then spiral in toward the center. I mostly dig my own clay now but gave up on Highwater and their inconsistencies.

Anonymous said...

I called to complain years ago when Highwater stopped closing their clay bags with rubber bands. I definitely noticed that clay was losing moisture within a few months of sitting around. The explanation I was given by Highwater for the change is that they felt the physical act of securing the bags with rubber bands was causing (get ready....) carpal tunnel with their workers. Seriously??? That response has always shaded my perception of Highwater's attitude towards their customers.

Glenn Woods - Pottery Boys Clay Studios said...

We use Highwater clay exclusively and fire to cone 6 and 10 on Little Loafers, Loafers Glory, Helios, and Half and Half. So far we have no issues with the Little Loafers and our cone 6 range of glazes but we have been working with Highwater since last June regarding Loafers Glory - we use crystalline glazes and the pieces suddenly started dunting and glazes with a Iron 6% or greater started shivering. We started using a blend of Loafers and Helios (50/50) and found that our problems were resolved - not very scientific but it did take care of the problem and they now create this blend on a regular basis. This is now our standard clay in our studio and I would recommend it to anyone firing to cone 10.
It is my understanding that all clay manufacturers are having the same growing pains as they transition to using a different feldspar in their formulas.
The people at highwater were very helpful in trying to fix the problem.

Janet said...

We have had so many problems since the clay change last fall. One of the clays we were using was the high fire loafers. We do cone 10/11 crystalline so dunting is a problem that we have always dealt with on a small scale. About a year ago we noticed that some of the pieces were leaking, although we could not see the cracks. Apparently we had purchased a ton of clay without being notified of the feldspar change. Jennifer at Highwater was active in trying to help us, but our loss had become overwhelming. They developed a custom clay based on some testing we did. We ordered another ton and things seemed to be OK. We still had some dunting, but far less. We then ordered another ton based on our experience being better. We have now lost nearly 60% of what we have produced in the past 6 months. It is maddening!!!!! She said the formula did not change, but that could not be true. Tim has lost two large pots that would have sold for hundreds of dollars. The only things that seem to not crack are the flat pieces. We are in the process of making some glaze changes. I was actually going to communicate with you (John Britt) about that. Jennifer said to decrease the silica in the glaze. On the regular loafers it seems that the crazing has gotten worse. She said to increase the silica. We are working on both of these little by little. I'm not sure where we are going next. Maybe trying some StarWorks clay. We do this for a living and we can not afford this type of loss. Tim uses a custom clay blend using High fire Loafers and a Ben Owen clay. We have also had dunting with this, but not to the same extent.

John Britt said...

Janet,

Don't make glaze changes! IT is the CLAY and they should take it back or I would just throw it way. The time and money spent to fix the problem is outrageous and simply getting a product that works is what you paid for. Get the clay from someone else and pay the shipping! It will cost less than have uncertainty and breakage and lies and you will go out of business. Are you on Facebook? I want to post your letter so other can see what is happening. Otherwise Highwater says that it is isolated when we can see that it is not!

dave said...

I mix my own clays and started having dunting issues, something that I never had happen in 30 years. I cut virtually all of the silica out of my recipe and upped the spar. It was somewhat effective. I also suspected perhaps the fire clay, I was using Hawthorn. I am now using half and half Lincoln and hawthorne and also adding a bit of Pyrophyllite and it has seemed to stop the issue. It was a confounding problem and I had a bunch of ideas as to the cause but I was not aware of the custer issue.

rikki said...

In my previous life I mixed my own clay and was exhausted but pleased with the results. Even then things began to change and we were late in identifying the root causes. Usually because the supplier was unsure of the changes taking place all along. Now as one who has hAd the luxury of experiencing all of the troublesome issues, I realize the science of the clay is beyond what I can control. The mine, the storage, the bagging, the labeling, the formula, the measuring, the mixing and the mill I cannot control. We trust the people who supply our materials to stay ahead of the issues. Because we are paying for a pre mixed product we expect to not have to worry. Most issues are identified by the end user the potter. We are most sensitive to the losses and usually unable to wade through all the variables toward a quick fix. It is now a part of our production to be wary of the next issue, because it will come. We were encouraged to experiment early In our paths. Eagerly we fearlessly played, and learned and maybe wrote things down. Once set with satisfying results, we were on our way. With little preemptive experimentations to follow. A good start would be our suppliers to acknowledge issues with out stonewalling. The schools most of us have learned enough to get started would educate on the science and geology of clays. And to share information. We are all in this together.

Glenn at Callanwolde said...

When High-water was first offered by one of our Atlanta suppliers, I was thrilled! Based on their reputation for quality clays, I jumped on the chance to offer them in our studios. Got bags of clay almost ready to bisque they were so hard, quarter-inch iron craters in the Phoenix, etc. Finally just gave up. My take is that since Brian left, the quality has not lived up to the reputation.

Denise Joyal said...

I'm still using Phoenix I've had for a while. Can anyone narrow the dates of the possible changes?

sue said...

I haven't heard anybody mention Highwater's Speckled Brownstone/Brownstone. Have observed pieces break after fired to maturity while being washed in a sink. Also a piece broke in the microware after being washed. Seems like it is absorbing water with a claimed 1% absorbtion rate. Any experiences, thoughts about this?

Hamilton Williams said...

Clearly I am late to the party on this discussion, but I have been having serious problems with dunting and shivering for the last 18-24 months using Highwater clay. There are times that I have opened my kiln and found multiple pieces not only cracked but completely in pieces laying on the kiln shelf. Some pots have remained intact only to crack a week later while sitting on the inventory shelf. Like many of you have experienced, I was told by the folks at Highwater Clay that no one else had reported any problems.

I have been using Aurora from Highwater for the past several years, Trina Buff for years before that. I make primarily functional pieces and fire to Cone 10 in a new 52 cubic foot natural gas-fired car kiln. My pots are bisqued to 07. The glaze firing cycle is 8 hours. Before building this kiln a few months ago, I was firing in a similar kiln fired with propane in a 12-14 hour firing cycle. I've had the same problem with both kilns and firing cycles.

The loss of pots, work, and sales certainly stings, but I also worry about the longer term problem of a ruined reputation if customers get hold of pots that break spontaneously under normal use. That's the kind of thing that puts companies out of business.

If this is a custer felspar issue, then it is likely industry-wide. I imagine the larger companies are better able to address the issue with modified clay formulations so I'll be looking into getting supplied by Laguna, Standard, etc.

Camren Gober said...

I wrote in here a while back. I certainly had my issues with highwater clays, specifically P10 porcelain. I switched to Standard 257 Grolleg Porcelain with great success. I recently made a new liner glaze, tested it on some pots, everything looked great and I started glazing pots in mass quantities. Days after unloading multiple kilns I discovered that all these pots literally explode when you pour boiling water into them. I downloaded the digitalfire insight software (which is now free!) and ran the glazes through it. The thermal expansion of my regular successful liner glaze is 6.98. The new "pot buster" glaze has a thermal expansion of 6.66. Just for reference my Copper red glazes that craze tend to run around 8.00. Long story short the pots were shrinking around the liner glaze and the liner glaze was not shrinking. Hence BOOM! I would be curious to see the thermal expansion of some of the liner glazes from all these exploding pots. Keep in mind that clays have different thermal expansions meaning that some clays will shrink more, some less. The issue may be at least partially related to glaze fit issues... Digitalfire Insight is now free, so please download and report back!!!

John Britt said...

Camren, Sorry about your problems. Yes the fit of the clay and glaze matters.

This is the problem with deciding what the cause is. Some people use a huge variety of glazes and don't really know what they are doing while others have been using the same glazes and clay for over 40 years.

When I talked to those people (40 years in business!) and they had problems and Highwater was discounting their accounts of problems with clay - then it is clear that there is a problem and Highwater doesn't want to talk about it.

Don't you think it is strange the Highwater won't come on this blog and address the problems? They say nothing!

So, yes a difference in the CTE of a liner and the outside glaze may make a difference, as will the thickness of a pot.So thin pots will definitely have this issue because of no structure to support the pot while thick pots won't show the problem.

But the problem with Highwater clays isn't a glaze issue it is a clay issue.

Camren Gober said...

John,
Thanks for writing in! I would still be see curious to see the thermal expansion of some of theses glazes. As materials change it is likely causing the thermal expansion of both the glazes and clay to change. Julie at Standard says that the thermal expansion for 257 grolleg is 5.72. However a glaze with a thermal expansion of 6.66 is destroying thin pots. (Applied thin at a specific gravity of 143) Julie sent me a recipe that was formulated and tested for 257 grolleg 5 years ago that has a thermal expansion of 6.63 and based purely on the numbers would be likely to break pots. I have not tested her recipe, but would all of this this mean that the thermal expansion of the clay is more likely to actually be in the range of 6.5-7?
Running with my speculative theory of higher thermal expansion in clay bodies, could this be a contributing issue at the root of your example of 40 year glazes and new clay problems?
Don't get me wrong, highwater clays certainly have major x10 issues that they are not addresing. So many issues that I switched clay companies!

John Britt said...

I know I use pinnell celadon with a CTE of 6.6 and it doesn't craze on Helios (grolleg porcelain). I just know many bodies have custer in them and if they don't account for the change in the flux the bodies won't mature. I don't think I have had problems because I fire hotter then 10. I fire to at least 11, but many potters fire to cone 9 plus so I am thinking that those are the people who are on the edge and that is why they are having problems. If you just put a pinnell celadon on the inside of a pot and the same outside I doubt if you would have problems. Only if you put a different glaze outside would the problem manifest. Not sure where this leaves us ?? but How has Julie at standard corrected the problem? They posted their bodies with custer.

Camren Gober said...

John,
I have glazed the pots entirely with this glaze without issues. It is when I use the CTE of 6.66 glaze as a liner and a copper red that crazes on the outside that I am having my issues. I have fired the same glaze combination to cone 10 in both oxidation electric and gas reduction kilns with equally bad results.
When I switched from p10 to 257 Grolleg I had to reduce the specific gravity of my some of my glazes. The 257 matures at a much lower temperature and my copper red glaze was melting off the pots. I have fired the 257 to cone 12 without issues. Just keep it on a flat surface and don't use wads because the pots deform over the wads and warp if placed over the edge of the shelf as low as 10.
The solution to my broken pots with Julie is simply to keep all liner glazes at CTE of 7 or above. I am really curious if part of the issue may be that the CTE of the clay is closer to the 6.5-7 range instead of the published 5.72 for 257 Grolleg. What do you think?

Anonymous said...

I use both Hestia and Phoenix and haven't had any issues. I still use my original glaze formulas also. One thing I know is that for a while they were using G200 EU instead of Custer in their mix. Watch how fast you fire through Quartz inversion.

Kyle

Schnee said...

I recently soda fired some phoenix (Manufactured Feb or March 2015) pots along with some made with phoenix manufactured in 2014. The 2014 phoenix clay pots had no issues. The few I fired that were with the 2015 clay all cracked in some manner. One shallow bowl cracked clear across, one mug cracked down from the rim shortly after unloading, one pitcher cracked below the handle attachment, and one bowl has a small hairline crack midway down running horizontally that also appeared after unloading. They were all fired to cone 10, not higher, in a soda atmosphere. Only the mug had been glazed on both the inside and outside surface where the crack appeared. The other were glazed on the interior and were unglazed on the outside where the crack appeared. All other clay bodies in the firing appeared normal.

I do know of someone with one particular standard clay body that had similar issues only with that particular number clay. I believe it was 378....she had all the pieces dunt from that batch of 378 following woodfiring to cone 10. And in confirming that number on Standard's website, I see they have issued a statement regarding some of their clay bodies and the change in the feldspar. They are suggesting folks glaze test before using those bodies.

John Britt said...

I wish Highwater would publish a list. They seem to blame each potter and try to isolate the problem. But with this many people speaking out it seems to be a recurrent problem. I just learned of a person who used 100,000 pounds a year having similar problems. They quit Highwater too!

Camren Gober said...

I recently posted on here about my pots blowing up due to a glaze fit issue with Standard 257 porcelain. I was wrong. Tried my old and reliable glazes with a higher thermal expansion(6.98) and the pots continued to break when tested with boiling water. After speaking with several potters including Steve Davis the technical person for Aardvark clay, I have concluded that It is a cristobalite issue and not a glaze issue. I am currently testing Coleman porcelain from Aardvark and will report back with my results. Aardvark used g200 feldspar, g200hp for a month, and is currently starting production with g200EU. Standard has always used Custer feldspar. They had it tested and their sample did not agree with the Ron Roy custer article. (http://www.ronroy.net/analyses/custer-article-.pdf#original) Assuming the article is right Standard is adding too little feldspar to the clay. Too little feldspar, too much free silica and a cristobalite disaster! I am going to fire a standard 257 pot unglazed and test it with boiling water. When it shatters that should confirm the overall cristobalite theory...
I will no longer be buying clay from companies that uses Custer feldspar. Custer is an unreliable product that wildly varies in composition. It is not completely the fault of the clay companies that they are having issues, yet they still choose to use Custer. Actually I take that back, it's their fault for continuing to use Custer!
I really "liked" Highwater and used to exclusively use their clays. I am afraid that this is going to put them out of business.
Just looking at clay options here... (please feel free to add to this list!)
-Reliable companies using some form of g200-
Aardvark
Laguna
-Companies using custer-
Highwater
Standard

John Britt said...

Great Post Camren!

Glad you are figuring our your problems. I agree it is their fault for using Custer and not fixing the issues. That is their job...when you make clay ...that is your job. Denying the problem doesn't allow them to fix it, since there is no problem. What they need to either get a technical/ceramic engineer to help reformulate the body with custer or use G-200 EU . It may cost more but then you just charge more. If the clay works we will buy it.

We are all in the same boat and want to just make stuff that doesn't break! I loved Highwater too as does everyone but if they deny, blame and hide then they will never fix their problems. And they will not regain the old customers because of the way that they treated them!! A clearly stupid approach to customer service.

Thanks again for your reply.!

Denise Joyal said...

John,

Another factor to consider may also be the mesh size of the feldspar they are using. Standard clay has posted information regarding their clay bodies and the new shrinkage/absorption they are noting as a result: http://www.standardceramic.com/CusterChanges.html

Denise

John Britt said...

Highwater posted something in their newsletter this month. Everyone will be using 325 M Custer or G-200 EU or Minspar. The thing about Highwater remains they way they treated people during this incident. It is hard to trust them.

Camren Gober said...

I wrote in a while back about all of my Standard 257 porcelain pieces shattering often days or weeks after they were unloaded. I just fired 25 mugs of Coleman Porcelain as a test. Just for the heck of it I pulled one mug out so hot that it was burning me through my cheap leather gloves(well above cristobalite inversion). Brought it inside, ran it under cold water to cool it off. It was steaming... Once it was cold I filled it with boiling water, cooled the mug with cold water again, boiling water again... I can't break this clay. I really tried. This mug was thrown ridiculously thin. My fingertips feel burnt....

I glazed some of the Coleman Porcelain mugs with a liner glaze that I had previously believed was breaking Standard 257 mugs due to its low thermal expansion of 6.66. These pieces also survived boiling water and being promptly dunked in cold water.

My personal recommendation would be to find out what feldspar your clay company uses and avoid any company that uses Custer Feldspar. At least until they switch to g200/HP/EU or Minspar. The composition of custer varies too much to be reliable in a clay body.(http://www.ronroy.net/analyses/custer-article-.pdf#original)

Cathy Kiffney Studio said...

I use Highwater red earthenware, both earthen red and Stan's Red. My work is mostly slab work, wall plaques and platters, etc. i've been having trouble with cracking from the glaze firing. I fire very slow on the way up and down. It is infuriating! I spend Hours, sometimes weeks on a piece and cracks halfway through or all the way! I've had a few crack days later crack right off the wall! I'm doing some large commissions and cannot afford this! They were no help when I called about it. I've been doing this work for 25 years and NEVER had these problems and I've changed Nothing about my process other than being even more careful! I did a search to see if I could find out if others had this problem and I came across this thread. Need to find another clay ASAP. Help!

John Britt said...

Cathy - contact me. johnbrittpottery@gmail.com