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Thread: Reduced Glass Surfaces

  1. #1
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    Default Reduced Glass Surfaces

    Here's a link to an article on surface analysis of art glass that's just been published in Microscopy Today. One you get to the home page to to Materials Applications (page 28).

    http://content.yudu.com/A1ot70/MTO18...y-today.com%2F

    Robert
    Robert Simmons
    Director for Bead Donations
    Beads of Courage, Inc.

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    Robert,
    It's a great article, thanks for taking the time to investigate everything and sharing it with us.
    conclusion...have good ventalation!
    Thanks,
    Leslie

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    WOW! I have seen hazardous material information included with enamels and powders but never with glass rods. And now that we are all so excited about the silver rich colors, we are definitely playing with heavy metals. I must admit, I need to re-read the article to get all the information out of it. I know it was not directed to glass workers but it is something we should know about.

    BTW - I have a friend who is a jeweler that gets a heavy metal test on a regular basis - should we be doing that, too?

    Debby

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    Actually the article is somewhat targeted at the glass community. I've had many discussions about this over the last couple of years and what I keep hearing is: "Show me the science." Here's the science, reviewed by scientists who have no serious involvement with glass.

    Remember that reduction surfaces and striking colors are entirely different processes and striking usually doesn't leave a residue or coating on a surface. Metals that are bound in the matrix of the glass don't interact with the exterior environment (either the flame or the skin) in the same way that surface reductions do. I haven't done any fuming studies of the striking silver glasses yet, though, so we don't know for sure what's getting into your torch plume.

    If you do a lot of fuming or surface reduction then a periodic heavy metal check might not be a bad idea, but for general glass work with good ventilation it's not likely to be an issue. Note the 'good ventilation' aspect - this is one of the important points of the article.

    Thanks much,
    Robert
    Robert Simmons
    Director for Bead Donations
    Beads of Courage, Inc.

  5. #5
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    Robert, thank you so much for your research, posting and sharing of your article. It is incredibly interesting. Amazing how there is so much cross-over. Brava and congratulations!

    Anxcious to hear from others as they read the information...

    -Kendra

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    Robert, thank you so much for the link. I've been waiting for this! I'm off to read now.

    Okay, Robert, great article. We greatly need information like this in our art. Thank you.

    Now a couple of questions, if you don't mind.

    So, regardless of the components of the glass, if it is worded in a neutral flame it is not dangerous; is that correct?

    With regard to those reducing/oxydizing colors, the surface, once the metallics are brought to the surface they are dangerous to either the subsequent wearer of the glass beads, and to the glassworker as the zinc/lead/ect. is in the plume behind the bead.

    Did I understand that correctly?
    Last edited by PamDugger; 08-30-2010 at 07:14 PM. Reason: to ask questions.

  7. #7
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    Hey Pam,
    It's been a long time coming, hasn't it? I wanted to run my data past some associates at NIST to be sure that I had it right and they encouraged me to get on with it last year. Then came the review/publication cycle........I'm more than happy to discuss this at length with anyone who is interested. To my mind it is an issue that needs to be brought out front, especially for new folks. I'm planning to continue my work as time and $$ allow.

    There are really a couple of issues to consider. Most of our glasses are colored with metals and those metals remain bound into the matrix of the glass. There is probably some evaporation at the surface with any glass, but for the most part it is negligible and not a problem if you use proper ventilation. Proper ventilation is the key phrase here - an open window and a door somewhere aren't going to cut it (you and many others know this, some still don't get it).

    With any metals on the surface you are going to evaporate at least some material into the torch plume. Metal vapors in the torch plume will spread into the atmosphere of the work area unless there is very good ventilation present. In my mind this presents a clear hazard to anyone in the room. I evaporated lead out of Rubino in a neutral flame -it's hot enough to vaporize the lead in the glass. Metal vapors of any kind are not good for the respiratory system. Metals will also condense out of the atmosphere onto any surfaces in the room if they aren't removed with the torch plume.

    Metal on the surface of a cold bead as a genuine health hazard is an open ended question. In the case of Rubino Oro the layer really isn't thick and the mass of elemental lead is, in reality, quite small - but it is essentially elemental lead. The legal issue of lead in a 'coating' comes into play here. There are XRF (X-ray fluorescence) devices in use today that are battery powered and no larger than your average hair dryer. They can very easily detect lead on the surface of a bead. I discussed this in detail with one of the manufacturers about two weeks ago when I presented a paper on this topic in a forensic microscopy symposium. A quick read on the lead regulations of the CPSIA will make it clear how much of a problem this might become if you are the person who gets checked at a show. Statistically improbable, but possible none the less.

    So, after probably too much discussion, the immediate health hazards come from evaporating metals into the atmosphere around the torch area. Almost any flame hot enough to melt the glass enough to work it will do this. Good ventilation is of primary importance and cannot be stressed enough. It's not a lot of fun and tends to be expensive, but if you are going to work glass, (IMHO) it is just as important as your torch.
    The real health risk from wearing glass with metals on the surface is questionable. It depends on a number of factors, including the type of metal, amount of metal and sensitivity of the individual. The known issue is more legal than medical.

    I hope that this answers at least some of the questions. I'd like to continue the discussion.

    Robert
    Robert Simmons
    Director for Bead Donations
    Beads of Courage, Inc.

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    Thank you, Robert.

    So, assuming that a person has a reasonable ventilation system and they work glass that is not considered "silver" glass, they should probably be fine. However, the danger comes when a person works the - can I call them reactive glasses? Just heating these glasses in the flame to melt is dangerous unless sufficient ventilation is present to evacuate the fumes. And assuming you work in your home with family members present, pets, etc., unless sufficient ventilation is present it could harm those around you.

    Have you tested any of the newer reactive glasses - and I won't ask for names - and have you tested boro glass? Do you have any preliminary info there?

    One more question, since so few members actually people this forum, have you discussed with The Glass Bead writing an article for our magazine so all our members can be apprised of your information?

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    Heh Pam - how funny...I sent an email to Robert this AM about getting a copy of his article for the Glass Bead. Thanks for thinking of it, too. Appreciate it.

    -Kendra

  10. #10
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    Yes, assuming good ventilation the average glass worker isn't really at risk from the torch plume gasses. Even the 'reactive', 'reduction', 'whatever you choose to call them' glasses should be safe to work with assuming good working conditions. It's the folks who work in their kitchens, dens, dining rooms, etc. and don't use active ventilation who put themselves and others at risk. The risk is from the nitric oxides (NOx) formed by combustion in the torch flame as well as heavy metals outgassing from some glass formulations. The NOx will dissipate from the room eventually while any metals will likely condense as they cool and settle out, adding a new component to the dust in the room. The same goes for deliberate fuming - only a small amount of the evaporated metal sticks to the target and the rest goes into the air until it cools. Anyone present will be exposed. Even small amounts in the short term can add up to problems in the long term.

    Artists need to educate themselves about the technical aspects of their chosen media. IMHO art and science are two sides of the same coin - you need a certain grasp of both to be safe and successful in either one. But that's a story for another day.

    The copyright for this article belongs to Microscopy Today and will require their permission for any reproduction. We'll see how that shakes out with them, but I'll sign off on it if they will. Otherwise we'll work something else out.
    Thanks,
    Robert
    Robert Simmons
    Director for Bead Donations
    Beads of Courage, Inc.

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