[Peter]

Hi Everyone,

I had the pleasure of seeing some pieces thrown with Laguna' B-3 clay. It's almost black at ^6 and has a wonderful raw natural look to it unglazed.
My question is has anyone here had experience with it? The fact that it contains Manganese is a little bit of a concern for me. It'll be used for purely
decorative pieces but the handling of it may require extra safety measures.
The MSDS sheet seems to gloss over the 6% Manganese issue.
I'd also be interested in how this clay holds glazes. There seem to be some mixed reviews but the sources are vague.
Any information would be greatly appreciated.

Peter

[lcar]

Hi Peter,

I am curious about the answer to your question as well. The lack of response makes me wonder how many people know for sure? I say follow your instincts and wear gloves if you are throwing with it. IMHO I don't think food safe is a concern if you have a food safe glaze that fits well. I am not even sure leaching would be a problem as long as the clay is mature. Always make sure your kiln is well ventilated as you don't want to be breathing the fumes.

I would be interested to hear if you learn more.

(waves from Prince George)
Leanna

[bciskepottery]

This might be helpful. http://groups.yahoo..../message/235995

[Peter]

lcar, on 03 October 2012 - 08:15 AM, said:

Hi Peter,

I am curious about the answer to your question as well. The lack of response makes me wonder how many people know for sure? I say follow your instincts and wear gloves if you are throwing with it. IMHO I don't think food safe is a concern if you have a food safe glaze that fits well. I am not even sure leaching would be a problem as long as the clay is mature. Always make sure your kiln is well ventilated as you don't want to be breathing the fumes.

I would be interested to hear if you learn more.

(waves from Prince George)
Leanna

Hi Leanna,

I have to agree. It doesn't seem like a popular clay.
It's beautiful at ^6 but apparently shouldn't be used above ^5. Not sure about that because the mugs I saw were all ^6.
I've never thrown with gloves. Are there any that are recommended to withstand throwing clay?

High 5 from Summerland
Peter

[Peter]

bciskepottery, on 03 October 2012 - 02:25 PM, said:

This might be helpful. http://groups.yahoo..../message/235995

Thanks Bc.

My Google hates me..... lol

[bciskepottery]

Peter,

I use Standard 266 -- appears to be a clay body similar in color to Laguna B-3 and also with manganese in it. My kiln fires "hot" and I get some bloating. Studio kilns I've used fire a cooler Cone 6 and did not have that issue. So, Cone 5 is likely a temperature where they get consistent results.

Bruce

[Dinah]

Manganese in body needs to be dealt with in throwing by using gloves, especially if you've an open cut etc. Mask up when turning. Want to point out that Hans Coper's early demise was no doubt hastened by not masking up, and his smoking habit. Manganese is an oxide which needs to be used in studio with some awareness as to its toxic affects. I use a body over here on the top left hand side which I buy from Seattle Pottery Supply called Goldstone and has manganese dioxide flecks. But it disappointingly bloats at anything higher than ^5. Fact. The image in my avatar is Goldstone, belly dusting with a spray of Dinah's Adjusted Ash, clear liner and on glaze transfer. Pot sold.

[Peter]

bciskepottery, on 04 October 2012 - 04:31 AM, said:

Peter,

I use Standard 266 -- appears to be a clay body similar in color to Laguna B-3 and also with manganese in it. My kiln fires "hot" and I get some bloating. Studio kilns I've used fire a cooler Cone 6 and did not have that issue. So, Cone 5 is likely a temperature where they get consistent results.

Bruce

Bruce,

I'll be testing at both ^6 and ^5. My interest in this clay will be mostly for hand building. Gloves and mask will be used to be on the safe side.

Peter

[Peter]

Dinah, on 05 October 2012 - 04:46 PM, said:

Manganese in body needs to be dealt with in throwing by using gloves, especially if you've an open cut etc. Mask up when turning. Want to point out that Hans Coper's early demise was no doubt hastened by not masking up, and his smoking habit. Manganese is an oxide which needs to be used in studio with some awareness as to its toxic affects. I use a body over here on the top left hand side which I buy from Seattle Pottery Supply called Goldstone and has manganese dioxide flecks. But it disappointingly bloats at anything higher than ^5. Fact. The image in my avatar is Goldstone, belly dusting with a spray of Dinah's Adjusted Ash, clear liner and on glaze transfer. Pot sold.

Hi Dinah,

I will be using gloves and a mask. The manganese content is high so I won't be taking any risks. Consensus seems to be that best results are achieved at ^5. I'll do some testing at both 5 and 6.

Thanks,
Peter

[neilestrick]

Although I usually err on the side of caution, I'm going to respectfully disagree with the need for gloves. If the clay body is labeled non-toxic, then it can be safely handled in the form in which is was purchased, i.e. moist clay. Dust and such is another issue, like with any clay, but if it was toxic in the moist form is could not carry the ASTM D-4236 safety label, nor would Laguna take on the liability of selling something that toxic without proper warnings. The risk of exposure from absorption is much less than the risk from inhalation. The guys mixing the clay run a much greater risk than we do.

That 6% listed on the MSDS is also a 'less than' amount, which means it could be 1%, or 5%, etc. 6% may be a threshold amount that they stay under on the MSDS. They don't have to give exact amounts, to prevent giving out proprietary secrets.


I just got off the phone with Standard, and their 266 has 1.5% manganese, 200 mesh. Standard uses the Duke University Department of Occupational Health and Safety to test their materials and issue label information. Duke also runs test for ACMI, the largest art materials safety labeling associtation in the U.S (http://www.acminet.org/Safety.htm). When I worked for A.R.T. clay, I also used Duke for safety testing, so I know how rigorous they are. We used to have to send in our copper for lead testing. Anyway, Duke doesn't find 1.5% manganese to be a problem, so neither do I.

[Peter]

neilestrick, on 09 October 2012 - 12:26 PM, said:

Although I usually err on the side of caution, I'm going to respectfully disagree with the need for gloves. If the clay body is labeled non-toxic, then it can be safely handled in the form in which is was purchased, i.e. moist clay. Dust and such is another issue, like with any clay, but if it was toxic in the moist form is could not carry the ASTM D-4236 safety label, nor would Laguna take on the liability of selling something that toxic without proper warnings. The risk of exposure from absorption is much less than the risk from inhalation. The guys mixing the clay run a much greater risk than we do.

That 6% listed on the MSDS is also a 'less than' amount, which means it could be 1%, or 5%, etc. 6% may be a threshold amount that they stay under on the MSDS. They don't have to give exact amounts, to prevent giving out proprietary secrets.


I just got off the phone with Standard, and their 266 has 1.5% manganese, 200 mesh. Standard uses the Duke University Department of Occupational Health and Safety to test their materials and issue label information. Duke also runs test for ACMI, the largest art materials safety labeling associtation in the U.S (http://www.acminet.org/Safety.htm). When I worked for A.R.T. clay, I also used Duke for safety testing, so I know how rigorous they are. We used to have to send in our copper for lead testing. Anyway, Duke doesn't find 1.5% manganese to be a problem, so neither do I.

Hi Neil,

Thanks for your informative reply. My concern was that information I received from the gal using B-3 that her hands were stained from the clay.
I want to believe that the safety label is reliable and appreciate the fact that Laguna wouldn't risk liability by selling a toxic product without proper warning.
Using gloves is not something I look forward to so I'll experiment with it and take precautions, as always, with the dust.

Thanks again,
Peter

[JBaymore]

Neil is correct on the "wet state is basically OK" comments.

If that clay has up to a 6% manganese dioxide content, then up to 6% of the dust you let accumulate in your studio from that clay is that material. How much of this 6% is in the air suspendible/respirable range is another factor. Likely not all 6%.... most of it will be very large (relatively) particles....probably in the 200 mesh range. So not all of it will get airborne by any means... which is where the real issues with manganese dioxide lie. Inhalation.

Of FAR more concern here are the manganese dioxide FUMES that will come off of the kiln during firings. Most people tend to think "fumes" are gases of some sort... but they actually are sub-micron particulates. THAT stuff stays airborne a LONG time unless the air in the space is changed (turned over). And it is HIGHLY respirable. So your kiln venting is critical to safely firing this stuff. BNecause those fumes settlle out of the air eventually and then comprise a portion of the general "dust" in the studio. That dust is easily gotten back into the air unless wet cleaning catches it (or it never gets there in the first place).

So really attend to the kiln venting. And think about where the venting you use is "disposing" of the effluent outside too. Hopefully not in your kid's play area, your neighbor's windows, or even right back into your make-up air supply (I've seen THAT far too often).

best,

..............john

[neilestrick]

Dinah, on 05 October 2012 - 06:46 PM, said:

Manganese in body needs to be dealt with in throwing by using gloves, especially if you've an open cut etc. Mask up when turning. Want to point out that Hans Coper's early demise was no doubt hastened by not masking up, and his smoking habit. Manganese is an oxide which needs to be used in studio with some awareness as to its toxic affects. I use a body over here on the top left hand side which I buy from Seattle Pottery Supply called Goldstone and has manganese dioxide flecks. But it disappointingly bloats at anything higher than ^5. Fact. The image in my avatar is Goldstone, belly dusting with a spray of Dinah's Adjusted Ash, clear liner and on glaze transfer. Pot sold.

This what I was referring to in regards to the gloves. But, yeah, the stuff is a mess and stains everything it gets near. I really don't think a mask is necessary when trimming, as the clay is still in a wet form when leather hard.

Hans Coper did a lot of finish work on dry clay, and also worked a lot with raw manganese. It's very different than throwing a wet clay that contains only a couple of percent of manganese.

[Peter]

JBaymore, on 11 October 2012 - 07:46 AM, said:

Neil is correct on the "wet state is basically OK" comments.

If that clay has up to a 6% manganese dioxide content, then up to 6% of the dust you let accumulate in your studio from that clay is that material. How much of this 6% is in the air suspendible/respirable range is another factor. Likely not all 6%.... most of it will be very large (relatively) particles....probably in the 200 mesh range. So not all of it will get airborne by any means... which is where the real issues with manganese dioxide lie. Inhalation.

Of FAR more concern here are the manganese dioxide FUMES that will come off of the kiln during firings. Most people tend to think "fumes" are gases of some sort... but they actually are sub-micron particulates. THAT stuff stays airborne a LONG time unless the air in the space is changed (turned over). And it is HIGHLY respirable. So your kiln venting is critical to safely firing this stuff. BNecause those fumes settlle out of the air eventually and then comprise a portion of the general "dust" in the studio. That dust is easily gotten back into the air unless wet cleaning catches it (or it never gets there in the first place).

So really attend to the kiln venting. And think about where the venting you use is "disposing" of the effluent outside too. Hopefully not in your kid's play area, your neighbor's windows, or even right back into your make-up air supply (I've seen THAT far too often).

best,

..............john

Hi John,

I'm a firm believer in proper kiln venting for every firing. My studio's on 8 acres and the vent's not in any area of concern. I've yet to detect any smell while the kiln is firing so I'm confident in it's effectiveness.
The kilns are on a loft level of my studio and I've had issues with heat build up so I've installed a 2600cfm, thermostatically controlled blower with 2, 12" fresh air inlet vents. None are near my kiln vent so there isn't cross contamination. The temp is controlled to 78 degrees max keeping the area comfortable enough to work in.
I wet clean all surfaces so I'm confident that dust is minimal although I do use a proper respirator when necessary and never do any final sanding or cleaning in the studio.

Thanks for your information,
Peter