angstqueen Posted January 30, 2023 Report Share Posted January 30, 2023 Hey there--brand new to the forum, so I hope I'm posting this in the right place. For months now I've been looking for a kiln that won't bankrupt me, and a while back I found an old EconoKiln for sale in my city. It was an old model (maybe the j18x, if I remember right), but beautiful inside, looked almost new. However, I've been very cautious about the potential presence of lead in older kilns, so I brought a lead test kit and the brick of this kiln tested positive right away. I passed on it very reluctantly, but I'm wondering if I was just being paranoid? I see people snapping up ancient kilns all the time, and I have to assume that many of them were used to fire lead glazes. Is the lead thing just not that big of a deal, or are my fellow hobby potters unaware that it's an issue? I'm probably just going to bite the bullet and buy a new Skutt so I can stop agonizing over every manual kiln that crops up on FB marketplace, but I wanted to see what y'all thought about the lead issue first. Quote Link to comment Share on other sites More sharing options...
Bill Kielb Posted January 30, 2023 Report Share Posted January 30, 2023 (edited) The lead issue is big for me. The story of Thomas Midgley Jr. is an interesting one. Lead contaminates everything! Good story on contaminating the planet - here https://youtu.be/IV3dnLzthDA IMO good you did not buy it. Edited January 30, 2023 by Bill Kielb Piedmont Pottery, angstqueen and Callie Beller Diesel 3 Quote Link to comment Share on other sites More sharing options...
oompafoxfernpeas Posted January 30, 2023 Report Share Posted January 30, 2023 The presence of lead in an older kiln is definitely an issue, as it can be dangerous to your health if you are exposed to it for an extended period of time. Lead is a heavy metal, and it can accumulate in the body over time, leading to serious health issues. It is also toxic to the environment, so it should be handled with care. For this reason, it is important to ensure that any kiln you are considering purchasing is tested for lead before you purchase it. If the kiln tests positive for lead, it is best to avoid it and look for a different kiln. It is also a good idea to make sure that any kiln you use is properly ventilated to reduce your exposure to lead and other toxins. angstqueen, Roberta12, Callie Beller Diesel and 1 other 4 Quote Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted February 1, 2023 Report Share Posted February 1, 2023 I have a friend that had to go through medically supervised, in-hospital lead chelation treatment because her employer was using a lead based clear lowfire glaze in an insufficiently ventilated kiln, circa 2001. Negative stars, do not recommend. It was a paint your own pottery place, my friend only worked there for a handful of months, and we had just been through years of school that made it clear lead was not to be used in pottery practice if you enjoy your health. Her employer was “old school” though, and thought the “college kids” were just being “paranoid.” It’s only paranoia if nothing’s out to get you. Given that kilns can last decades with relatively simple repairs and the owner went out of business, it’s reasonable to think that this kiln was sold and might still be out there. Circumstances don’t even have to involve deliberate deception. Lots of folks also have no idea what’s in their glazes and don’t realize that it can be hidden in colourants or frits. I don’t think you need to avoid all manual kilns, but testing them for lead is just sensible good practice, like getting a home or a car inspection. You passing on a kiln that tested positive for lead is a cause for celebration, rather than FOMO. There will always be more used kilns that come along. angstqueen and Pres 2 Quote Link to comment Share on other sites More sharing options...
angstqueen Posted February 2, 2023 Author Report Share Posted February 2, 2023 Thank you, everyone! I was beginning to feel pretty nuts for passing on these old kilns. I would ask the seller if the kiln had been tested for lead, and the answer was always no, and then someone else would buy it within the week. Two sellers allowed me to test for lead, and both times were positive, which makes me think it's probably a pretty common problem in older kilns. It really makes me wonder how many people are selling work, often labeled as food-safe, that's been fired in a contaminated kiln. That's probably not as detrimental to your health as being around the firing fumes, but still... Quote Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted February 3, 2023 Report Share Posted February 3, 2023 On 2/2/2023 at 9:28 AM, angstqueen said: It really makes me wonder how many people are selling work, often labeled as food-safe, that's been fired in a contaminated kiln. I went looking to see if I could find some current information on lead contamination in used pottery kilns and if it was possible to remediate. I couldn’t find a lot of information around lead in hobby pottery in general that was less than 10 years old. (If someone else has better search results than I do, please chime in!) I found one mention in a 20 year old Clayart thread that said you could fire the kiln with a bowl of neph sye in it to absorb lead fumes and you’d be fine, but there was no logic presented, or info on how much lead could be removed by this method. The only reason I mention it at all is because both Roy and Hesselbreth commented in that thread, and neither refuted the statement. But again, I have to stress it was written before 2013, when the FDA decided that no levels of lead are safe. There’s a number of sources though that state lead contamination from a kiln is indeed a possibility, although most references were to folk pottery, or ware produced in countries where lead use still exists. Lead on your pots would be fairly easy to check for, if anyone is reading this and is suddenly concerned about their Craigslist kiln. Many readily available lead tests are designed for things like dishes. Roberta12 1 Quote Link to comment Share on other sites More sharing options...
Roberta12 Posted February 4, 2023 Report Share Posted February 4, 2023 Hmmm good thread. I did not realize there were lead tests kits out there. I have purchased and been gifted pottery from other countries. But they are simply decorative for me, I am concerned about lead. HOwever, I do use some of my grandmother's random bowls, mostly as prep bowls. Rather than have them sitting on a shelf. I will get a lead testing kit. If a person is testing a kiln for lead, do you swab the bricks? Roberta Quote Link to comment Share on other sites More sharing options...
Bill Kielb Posted February 4, 2023 Report Share Posted February 4, 2023 (edited) @Roberta12 As they say, check anywhere lead can be so walls, blinds, surfaces kids can get their mouth on. For me it’s inside lid and sidewalls. 3m instant test instructions here https://multimedia.3m.com/mws/media/815979O/3mtm-leadchecktm-tri-fold-brochure-08-28-2012.pdf Edited February 4, 2023 by Bill Kielb Roberta12 1 Quote Link to comment Share on other sites More sharing options...
DirtRoads Posted February 16, 2023 Report Share Posted February 16, 2023 Can you even buy glaze now days that has lead in it? Quote Link to comment Share on other sites More sharing options...
High Bridge Pottery Posted February 16, 2023 Report Share Posted February 16, 2023 Very easy to buy leaded glaze and lead bisilicate frit in the UK, harder to find litharge from ceramics suppliers but it is still available through other sources. Quote Link to comment Share on other sites More sharing options...
neilestrick Posted February 16, 2023 Report Share Posted February 16, 2023 13 hours ago, DirtRoads said: Can you even buy glaze now days that has lead in it? If I remember correctly, Amaco used to have some glazes that had fritted lead in them but I don't know if they're still on the market or not. Quote Link to comment Share on other sites More sharing options...
Min Posted February 16, 2023 Report Share Posted February 16, 2023 US Pigments products for sale re lead: Red Lead https://uspigment.com/product/lead-red/ White Lead https://uspigment.com/product/lead-white/ Lead Bisilicate (aka fritted lead) https://uspigment.com/product/lead-bisilicate/ Lead Chromate https://uspigment.com/product/lead-chromate/ So if someone wanted to make lead bearing glazes in the US or anywhere US Pigments ships to it wouldn't be hard to do so. I haven't seen commercial glazes containing lead for quite a few years in Canada. Quote Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted February 17, 2023 Report Share Posted February 17, 2023 It’s possible to obtain lead as a flux, but you have to go about it on purpose. I don’t know about other brands, but Mason says on their website they don’t use lead in their pigments, so it’s not sneaking in there. Quote Link to comment Share on other sites More sharing options...
DirtRoads Posted February 20, 2023 Report Share Posted February 20, 2023 This topic reinforces my decision to only buy NEW kilns. Pyewackette 1 Quote Link to comment Share on other sites More sharing options...
Stephen Posted March 29, 2023 Report Share Posted March 29, 2023 You can do cone 8 firing schedule with Nepheline Syenite to absorb then retest. I’m hesitant to declare everyone’s old kiln dangerous. Quote Link to comment Share on other sites More sharing options...
Bill Kielb Posted March 29, 2023 Report Share Posted March 29, 2023 (edited) 2 hours ago, Stephen said: You can do cone 8 firing schedule with Nepheline Syenite to absorb then retest. Definitely retest. I am very familiar with removing lead fouling from bores but do not have any idea why the Neph. Sy solution would work. Have heard it before, are you aware of an any citation explaining why / how this works? There are clay and glazes made with Neph. Sy btw. Edited March 29, 2023 by Bill Kielb Quote Link to comment Share on other sites More sharing options...
Min Posted March 29, 2023 Report Share Posted March 29, 2023 @Bill Kielb, I'm curious about the idea of nepheline syenite absorbing lead from a lead contaminated kiln too. I did a quick Google search and came across an article from Clay Times 1995. Link to it here, third subject down from the top. Basically it says make a container to the inside measurements of the kiln, fill it with nepsy then fire at 270F / hr to 2000F then hold there for 2 hours then dispose of the nepsy appropriately. Not guaranteed to be 100% effective and a caveat to test wares with a lead kit. Would be good to see some specific data on this. Callie Beller Diesel, PeterH and Bill Kielb 3 Quote Link to comment Share on other sites More sharing options...
Hulk Posted March 29, 2023 Report Share Posted March 29, 2023 No amount of lead is safe, so says the WHO, CDC, State agencies, etc. Roberta12 and Bill Kielb 2 Quote Link to comment Share on other sites More sharing options...
High Bridge Pottery Posted March 29, 2023 Report Share Posted March 29, 2023 How much lead do these tests pick up? I thought most ceramic materials are contaminated with trace lead, sure I remember Neil talking about an old job where he would test (maybe zinc or tin oxide) for lead contamination. Quote Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted March 30, 2023 Report Share Posted March 30, 2023 @High Bridge Potterymostly they’re meant for things like antique/vintage housewares and detecting lead paint. They measure anything you can dissolve with the reagent supplied. So if there’s some lead there but it doesn’t dissolve, or if it’s below a certain amount, you could get a false negative from the home kits. They’re only meant for a quick yes/ no answer. High Bridge Pottery 1 Quote Link to comment Share on other sites More sharing options...
Bill Kielb Posted March 30, 2023 Report Share Posted March 30, 2023 (edited) 20 hours ago, High Bridge Pottery said: How much lead do these tests pick up? I thought most ceramic materials are contaminated with trace lead, sure I remember Neil talking about an old job where he would test (maybe zinc or tin oxide) for lead contamination. I think in the states 1mg per cm2 for surface transfer limits so test kits are likely to detect in this range. Correlating surface transfer to absorption likely extremely difficult though. I am not aware of any amount of lead though that folks would say is fine after polluting the whole planet with low levels of the stuff. The argument at that time for a time evolved to is it is such a “tiny amount” …… See link above for an interesting accounting IMO Edited March 30, 2023 by Bill Kielb High Bridge Pottery 1 Quote Link to comment Share on other sites More sharing options...
Stephen Posted March 30, 2023 Report Share Posted March 30, 2023 Ya know I have no direct experience but thought that the NS soak was the accepted remedial thing to do . Dunno, there are a LOT of old 70-90's kilns that are in use that very likely are affected, some really large and expensive. I am assuming some are in schools and community programs and badly needed to continue to exist. I have not heard of any big effort to test and get rid of all the ones that have ever glaze fired any pots with lead no matter how trace the lead is detected. I do agree we all want to be safe just hate to see people start throwing out well ruining and perfectly safe old kilns on a mistaken, well intentioned warning that's not valid. Many of these old kilns provide a way for financially strapped people to enjoy pottery even though they are struggling to make ends meet in other areas. Again though if they are truly unsafe they should not be used. Quote Link to comment Share on other sites More sharing options...
High Bridge Pottery Posted March 30, 2023 Report Share Posted March 30, 2023 I was just pondering if you could still get a positive test without actually firing any lead based glazes in the kiln due to trace amounts in other materials. Would be interesting to see if you could get a positive test on a kiln you know hasn't had any lead in. Quote Link to comment Share on other sites More sharing options...
Bill Kielb Posted March 31, 2023 Report Share Posted March 31, 2023 On 3/30/2023 at 1:27 PM, High Bridge Pottery said: I was just pondering if you could still get a positive test without actually firing any lead based glazes in the kiln due to trace amounts in other materials. Would be interesting to see if you could get a positive test on a kiln you know hasn't had any lead in. From what I can see, these tests appear to not report false positive below 1mg / cm2 with 95% confidence. I guess we need to define “trace” amounts that would constitute not having lead. Some info from the EPA https://www.epa.gov/lead/hazard-standards-and-clearance-levels-lead-paint-dust-and-soil-tsca-sections-402-and-403 Allowable levels of dust are fairly low with an emphasis to not aerosolize lead by heating, scraping etc….. High Bridge Pottery 1 Quote Link to comment Share on other sites More sharing options...
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