Re-creating a happy accident glaze

[EarthToMatthew]

Hey everybody, so I'm in a really frustrating predicament. I recently mixed a glaze based on a recipe I found on glazy.org and somewhere along the way I made a mistake. Not sure what the mistake was, I may have added the wrong ingredient, may have forgotten one- it could be anything really.  The thing is, I REALLY like this glaze accident. It's not so great on it's own, but when mixed with other glazes it's very interesting and beautiful.  I'm going to be unreasonably devastated if I can't figure out how to recreate this, or at the very least find a recipe that has similar properties.

I'm hoping that if I share a photo of the glaze someone might know a similar recipe.

Another option I'm considering is trying to reverse engineer the glaze, if that's even feasible.  I thought if I sent the remainder of the accident glaze to a lab for testing they may be able to give me enough information to figure out what I did. I'm no glaze chemist but I wonder if an experienced one would have the capacity to reverse engineer a glaze based on the results of the test.  I know this is a bit extreme  but I really want to figure this out.

If anyone has any experience with something like this I would appreciate your advice and opinions. I'll attach a few photos of the glaze for you all to have a look at. The first photo is the glaze on it's own, the second is the glaze applied over John's Noxzema. Thanks in advance!

Edit: I thought I should add the recipe I used to make this glaze. I've tried to make a second batch but it didn't turn out like the first.

RECIPE:

Gerstley Borate - 50.00
Spodumene- 30.00
Wollastonite- 20.00
Bentonite- 2.00
Chrome Oxide - 2.00
Cobalt Carbonate- 1.00


 

Edited July 20, 2023 by EarthToMatthew

[Min]

3 hours ago, EarthToMatthew said:

I've tried to make a second batch but it didn't turn out like the first.

How did it turn out? Picture?

[Babs]

4 hours ago, EarthToMatthew said:

Hey everybody, so I'm in a really frustrating predicament. I recently mixed a glaze based on a recipe I found on glazy.org and somewhere along the way I made a mistake. Not sure what the mistake was, I may have added the wrong ingredient, may have forgotten one- it could be anything really.  The thing is, I REALLY like this glaze accident. It's not so great on it's own, but when mixed with other glazes it's very interesting and beautiful.  I'm going to be unreasonably devastated if I can't figure out how to recreate this, or at the very least find a recipe that has similar properties.

I'm hoping that if I share a photo of the glaze someone might know a similar recipe.

Another option I'm considering is trying to reverse engineer the glaze, if that's even feasible.  I thought if I sent the remainder of the accident glaze to a lab for testing they may be able to give me enough information to figure out what I did. I'm no glaze chemist but I wonder if an experienced one would have the capacity to reverse engineer a glaze based on the results of the test.  I know this is a bit extreme  but I really want to figure this out.

If anyone has any experience with something like this I would appreciate your advice and opinions. I'll attach a few photos of the glaze for you all to have a look at. The first photo is the glaze on it's own, the second is the glaze applied over John's Noxzema. Thanks in advance!

Edit: I thought I should add the recipe I used to make this glaze. I've tried to make a second batch but it didn't turn out like the first.

RECIPE:

Gerstley Borate - 50.00
Spodumene- 30.00
Wollastonite- 20.00
Bentonite- 2.00
Chrome Oxide - 2.00
Cobalt Carbonate- 1.00


 

 

 

Top one, one you like?

Left out the cobalt, ? Prob not as sipmple as that because bottom image is a runnier glaze . Second batch same firing schedule, same Specific Gravity?

[Jeff Longtin]

Having recently worked at a pottery shop, where inexperienced young people mixed 10-20 gallons of glaze a day, I'll offer this: more than likely you carried over one of the percentages.

Rather than use 30% Spodumene you may have used 50%, for instance.

Considering the desired glaze is extremely matte I would suggest you added 20% Bentonite rather than 2%. 

[EarthToMatthew]

4 hours ago, Min said:

How did it turn out? Picture?

I don't have a picture on hand but it turned out glossy and grey/blue.

 

 

3 hours ago, Babs said:

Top one, one you like?

Left out the cobalt, ? Prob not as sipmple as that because bottom image is a runnier glaze . Second batch same firing schedule, same Specific Gravity?

The second image is a glaze combo, it's the accident glaze applied over John's Noxzema.  The second batch was done the same way except for whatever mistake I made the first time around. I know I had the specific gravity consistent both times as well as the firing. 

 

 

2 hours ago, Jeff Longtin said:

Having recently worked at a pottery shop, where inexperienced young people mixed 10-20 gallons of glaze a day, I'll offer this: more than likely you carried over one of the percentages.

Rather than use 30% Spodumene you may have used 50%, for instance.

Considering the desired glaze is extremely matte I would suggest you added 20% Bentonite rather than 2%. 

That could definitely be the case! It wouldn't be the first time I made that mistake.  I'll give the extra bentonite a try and see what happens.


One more thing that I forgot to mention in my initial post, I've kinda wondered if the gerstley borate I used was something else in a wrongly labeled bag. If that's the case I can't even begin to fathom what it was in that bag, I have so many ingredients. 
 


 

[Kelly in AK]

I’m no glaze wizard, but I’ll throw in my impressions (worth 2 cents, not a penny more). It’s such a “fluxy” glaze recipe, I really can’t imagine how it could be so stiff and matt, especially with all that Gerstley borate. I do wonder how it behaves in the bucket, Gerstley being prone to gel and help suspend non plastic ingredients. If the bentonite was so overloaded it seems you would have noticed something funky when you mixed it. I feel like you didn’t miss the spodumene, that’s contributing to the brown-ness.

Edit: After a good night’s sleep I do remember seeing a picture of bentonite fired near maturity on Tony Hansen’s site. Very brown. 

Edited July 21, 2023 by Kelly in AK

[Min]

Just as a side note the original glaze recipe you posted in no way will make a durable glaze.

[Babs]

Wha is the number or name on Glazy, perhaps you adean error copying that. If bentonite aded in any large quantity, i would be so lumpy in the buckrt and hard to sieve

[PeterH]

15 hours ago, EarthToMatthew said:

the second is the glaze applied over John's Noxzema.

There is a John's Noxema 117/5 at https://www.flickr.com/photos/glazes/40006967621
... is this the recipe you use for the bottom glaze?

PS Glazy has a Noxema  https://glazy.org/recipes/6522 and a Noxema Blue https://glazy.org/recipes/2475

[Min]

On 7/20/2023 at 11:12 AM, EarthToMatthew said:

the capacity to reverse engineer a glaze based on the results of the test.

If you did get an analysis of the glaze you would probably get something like what is below which you would then need to work backwards with to make a recipe to supply those oxides. It would likely be very expensive to get testing done.  Take these figures and try to make a glaze with them on Glazy without looking at a recipe and you will get an idea of how to do it.

Edited July 21, 2023 by Min
clarity

[EarthToMatthew]

18 hours ago, Kelly in AK said:

I’m no glaze wizard, but I’ll throw in my impressions (worth 2 cents, not a penny more). It’s such a “fluxy” glaze recipe, I really can’t imagine how it could be so stiff and matt, especially with all that Gerstley borate. I do wonder how it behaves in the bucket, Gerstley being prone to gel and help suspend non plastic ingredients. If the bentonite was so overloaded it seems you would have noticed something funky when you mixed it. I feel like you didn’t miss the spodumene, that’s contributing to the brown-ness.

Edit: After a good night’s sleep I do remember seeing a picture of bentonite fired near maturity on Tony Hansen’s site. Very brown. 

Yeah after doing a little research I feel I've come to a better theory of what may have happened, because I think you're correct about it not looking right for a recipe with so much gerstley borate. I believe I may have had a bag of material wrongly labeled gerstley borate. If this is the case then I have no chance of re-creating this very easily because I have so many raw materials. I may have put too much bentonite but your right about it being fairly noticeable. I don't remember needing to add much extra water or having any problems mixing it. Thanks for your 2 cents! I'll take any I can get haha.
 

 

18 hours ago, Min said:

Just as a side note the original glaze recipe you posted in no way will make a durable glaze.

I figured it probably wasn't  a very strong glaze, I could tell just by the surface. When applied over other glazes it changes  quite a bit,  and becomes more of an effect glaze, I like it for the texture it takes on when coupled with glossy glazes.  I suppose it isn't too ideal for functional pieces but I wanted to experiment with it and see what would happen in other applications. 

 

16 hours ago, Babs said:

Wha is the number or name on Glazy, perhaps you adean error copying that. If bentonite aded in any large quantity, i would be so lumpy in the buckrt and hard to sieve

It was initially an altered version of an Emerald glaze from John Britt's mid range book. I definitely messed up when I copied the recipe, as one ingredient was omitted completely.  I realized that first mistake when it came out brown instead of green and doubled checked the recipe. When I tried to recreate the accident glaze I came to the realization I made and a second mistake that's harder to identify. After a little research I'm starting to think that gerstley borate I used was in a mislabeled bag that contained a mystery ingredient.

 

11 hours ago, PeterH said:

There is a John's Noxema 117/5 at https://www.flickr.com/photos/glazes/40006967621
... is this the recipe you use for the bottom glaze?

PS Glazy has a Noxema  https://glazy.org/recipes/6522 and a Noxema Blue https://glazy.org/recipes/2475

Thanks for the links to those Noxema recipes! However, it's actually the brown in the first photo that I'm looking for, the second photo was just to show how it paired with other glazes. I was worried I might confuse the situation if I posted that haha.

 

 

6 hours ago, Min said:

If you did get an analysis of the glaze you would probably get something like what is below which you would then need to work backwards with to make a recipe to supply those oxides. It would likely be very expensive to get testing done.  Take these figures and try to make a glaze with them on Glazy without looking at a recipe and you will get an idea of how to do it.

Ah yeah I suppose that is probably out of the question then, I would definitely be biting off more than I can chew if I went that route. I'll just have to let this one go I think, maybe eventually I can find a recipe that gives a similar effect. I've been saving a lot of brown recipes I found on glazy, I'm just going to mix a bunch and start testing!

[Babs]

3 hours ago, EarthToMatthew said:

Yeah after doing a little research I feel I've come to a better theory of what may have happened, because I think you're correct about it not looking right for a recipe with so much gerstley borate. I believe I may have had a bag of material wrongly labeled gerstley borate. If this is the case then I have no chance of re-creating this very easily because I have so many raw materials. I may have put too much bentonite but your right about it being fairly noticeable. I don't remember needing to add much extra water or having any problems mixing it. Thanks for your 2 cents! I'll take any I can get haha.
 

 

I figured it probably wasn't  a very strong glaze, I could tell just by the surface. When applied over other glazes it changes  quite a bit,  and becomes more of an effect glaze, I like it for the texture it takes on when coupled with glossy glazes.  I suppose it isn't too ideal for functional pieces but I wanted to experiment with it and see what would happen in other applications. 

 

It was initially an altered version of an Emerald glaze from John Britt's mid range book. I definitely messed up when I copied the recipe, as one ingredient was omitted completely.  I realized that first mistake when it came out brown instead of green and doubled checked the recipe. When I tried to recreate the accident glaze I came to the realization I made and a second mistake that's harder to identify. After a little research I'm starting to think that gerstley borate I used was in a mislabeled bag that contained a mystery ingredient.

 

Thanks for the links to those Noxema recipes! However, it's actually the brown in the first photo that I'm looking for, the second photo was just to show how it paired with other glazes. I was worried I might confuse the situation if I posted that haha.

 

 

Ah yeah I suppose that is probably out of the question then, I would definitely be biting off more than I can chew if I went that route. I'll just have to let this one go I think, maybe eventually I can find a recipe that gives a similar effect. I've been saving a lot of brown recipes I found on glazy, I'm just going to mix a bunch and start testing!

Unlikely you will find one,imo. @Min gave the reason.

Chuck that bag of Gerstley out unless someone has the knowledge to identufy the substance it contains.

Get a check sheet going when you mix glazes, double check yourself...we've all, well I've had similar brain lapses or interruptions in the midst of making batches of glaze.

Tick substance, tick weight, tick into the bucket, that substance off the table.

Edited July 22, 2023 by Babs
Adding info

[Kelly in AK]

Potters have their own kind of white powder problems. 

[Babs]

Perhaps if enougb of us we could get free testing!

[Rae Reich]

I have had buckets of Mistake glazes, also Mystery glazes - bags of unknown origin that fired with desirable effects. Being the kind of potter who wants to make unique and original pieces, I cherish the special qualities and try to use those one-offs creatively while they last. The one-of-a-kind nature of That glaze on That pot can be a selling point.
Some of us older potters have experienced the disappearance of specific glaze materials and we don’t always try to replicate the lost effects, we just find what new stuff we can do with what’s available. There are so many possibilities ….

[EarthToMatthew]

On 7/22/2023 at 9:28 AM, Rae Reich said:

I have had buckets of Mistake glazes, also Mystery glazes - bags of unknown origin that fired with desirable effects. Being the kind of potter who wants to make unique and original pieces, I cherish the special qualities and try to use those one-offs creatively while they last. The one-of-a-kind nature of That glaze on That pot can be a selling point.
Some of us older potters have experienced the disappearance of specific glaze materials and we don’t always try to replicate the lost effects, we just find what new stuff we can do with what’s available. There are so many possibilities ….

Yeah well said Rae, I'm sure this won't be the last mystery glaze I will have to mourn haha. I have just enough left to make a mug so I'll make it a special one and hopefully one of these days I'll find a glaze combo that has the same properties.

[Callie Beller Diesel]

If you know what bag you got your “gerstley borate” out of, there are some things you can do to figure out what it is. Gerstley borate is sort of a taupe colour, and could be confused easily for a ball clay. You can make test balls of the material and see how it melts/behaves in your bisque and glaze firing. That would give you a way of narrowing it down and making an educated guess. 

Melt flow test instructions here.

[Joseph Fireborn]

That glaze does not have any Gerstley Borate. There is no way it would look like that unless you under-fired it. The fact that you can put another glaze on top of it and it is still mostly on the test tile means there is definitely no GB, unless that other glaze on top has absolutely no frit in it?

So if you wanted to replicate that glaze and figure out what it is, I would do this.

1. Since you said you had a few unlabeled bags, I would mix up that exact glaze but missing the 50% GB.

2. Figure out how many cups you want to use, so say its 10 attempts to figure this out. Measure out 100ml of glaze with the mystery recipe but don't include the Gerstley Borate. Instead leave that out. But use the same amount of water you would have used if it was in there.

3. Measure out 10ml with a syringe into each cup, making sure you stir well before each one. I use a milk frother for this...

4. Take your 10 mystery attempt materials that look similar to Gerstley Borate that you might have used instead. Put 50% weight(the missing GB amount) of the mystery chances into each cup. You will have to do the math on this to figure out what this should be, but it isn't difficult at all.

5. Glaze a test tile or a little test dish or whatever you want in the 10 mystery glazes and make sure to record everything.

6. Fire it all on the exact same schedule with the same load mass that you did for the first tile.

7. Pull out the results and keep any of them that look similar to the original tile, go from there.

Edited August 20, 2023 by Joseph Fireborn

[Hulk]

Detailed notes might be helpful, as new accidents may occur (likely), and some o' them happy as well!

I wanted to suggest using cookies, just in case, aka waster slab, a thin slab of clay the glazed ware sits on, which will prevent running glaze from pooling up on the the kiln shelving.

[Min]

On 7/20/2023 at 7:23 PM, EarthToMatthew said:

...I've kinda wondered if the gerstley borate I used was something else in a wrongly labeled bag. If that's the case I can't even begin to fathom what it was in that bag,...

If you do suspect something is mislabelled it would be a good idea to try and figure out what is actually in the bag. David Hewitt and Mike Bailey wrote an article on trying to solve the mystery of what's inside unlabelled bags and buckets, it's a good article, might help. Firing a small amount of the material in either a tiny bowl or a depression in a slab of clay is a good start. Try about a 1/2 tsp from the bag of what you think is Gerstley Borate, see if you get a puddle of melted pale tan coloured crazed "glaze" at bisque temps.

[Joseph Fireborn]

That article is amazing. Book marking that. I don't know if I will ever have to do that, but if I do. Wow.