Lead in Glass

[Zulekah]

Hi,

I am just wondering why lead in glass does not seem to be a concern, whereas lead in other things (like paint) is. I am interested in trying out Satake lead glass.

Does anybody know anything about this? Thanks in advance!

[Heidi von Frozenfyre]

The higher the c.o.e the higher the lead content. The brighter the colors the most likely the higher of c.o.e. and lead :)

The makers of the glass do not need to say the % of lead content if it's under 39%

If it doesn't have lead it's pyrex.

Lead makes the glass flow.

[evilglass]

Plus, the issue with paint and toys and stuff is kids eating it-pulling the paint off the wall and eating the flakes, or eating a toy with lead, thus causing a large amount of lead to get into their system and poisoning them. It's rare, but it happens.

Put a huge disclaimer on your work that it is NOT to be ingested, and I think you'll be safe :)

[Zulekah]

The higher the c.o.e the higher the lead content. The brighter the colors the most likely the higher of c.o.e. and lead :)

The makers of the glass do not need to say the % of lead content if it's under 39%

If it doesn't have lead it's pyrex.

Lead makes the glass flow.

OK, thanks! I'm a bit confused because Satake comes in either soda or lead, but it sounds like even the soda Satake must have lead in it.

Anyway, now I see that I've been using lead all along even with Moretti, so as far as safety, I guess all is well...

[RyanTheNumberImp]

There may be concerns with boiling the glass and having the lead vaporise, as well as using objects made with exposed lead glass to eat.

Then again, we are already using a torch, lots of metals in the glass, lots of metals in foil or leaf form, fuming...

I know that pottery glazes can leach lead out into its contents, but I can't see it being a big problem.

[Cherine Perrin]

Put a huge disclaimer on your work that it is NOT to be ingested, and I think you'll be safe :)

Just thought this was funny!

[JetAge Studio]

Not sure that you have anything to worry about...since Lead Crystal has been around for decades. but...
The concern about lead crystal glass is that certain foods, over a given amount of time and stored in crystal containers (like decanters) can leach the lead out quicker over time. Foods especially acidic, like wine, vinegar, tomato, citrus, etc. leach lead more redily than other "foods". Lead glass is categorized by having a larger amount of lead in it's composition, typically above 25%.
I don't know the percentage of Satake's lead content, but it could be looked into. At any rate, everyday soft glasses the lampworkers, or fusers use is going to be below the 25% range, unless specified. That being said, the glass industry readily uses lead as a flux, so chances are at some point, you're going to be using a glass that has SOME lead in it anyway.

For what it's worth, here's an exerpt from WIKIPEDIA:

"The addition of lead oxide to potash glass also reduces its viscosity, rendering it more fluid than ordinary soda glass above softening temperature (about 600 °C), with a working point of 800 °C. The viscosity of glass varies radically with temperature, but that of lead glass is roughly 100 times less than that of ordinary soda glasses across working temperature ranges (up to 1100 °C). From the glassmaker’s perspective, this results in two practical developments. First, lead glass may be worked at a lower temperature, leading to its use in enamelling, and second, clear vessels may be made free from trapped air bubbles with considerably less difficulty than with ordinary glasses, allowing the manufacture of perfectly clear, flawless objects. When tapped, lead crystal rings, unlike ordinary glasses. Consumers still rely on this property to distinguish it from cheaper glasses. Since the potash ions are bound more tightly in a lead-silica matrix than in a soda-lime glass, the glass when struck absorbs less energy. This causes the glass to oscillate, thereby producing its characteristic sound.[1] Lead also increases the solubility of tin, copper, and antimony, leading to its use in coloured enamels and glazes."

Renee
JetAge Studio

[JetAge Studio]

The higher the c.o.e the higher the lead content. The brighter the colors the most likely the higher of c.o.e. and lead :)

The makers of the glass do not need to say the % of lead content if it's under 39%

If it doesn't have lead it's pyrex.

Lead makes the glass flow.

Um, ok...


There's some pretty sound information on the glass alchemy website:
www.glassalchemyarts.com

Here's a handy number (quote) "If you are working with lead-containing glasses for food or beverage applications, the International Crystal Federation (phone 202-342-8400) can be a valuable source of information and guidelines."

[prairieson]

The higher the c.o.e the higher the lead content. The brighter the colors the most likely the higher of c.o.e. and lead :)

The makers of the glass do not need to say the % of lead content if it's under 39%

If it doesn't have lead it's pyrex.

Lead makes the glass flow.

Hiya toots!

A bit of clarification. More appropriately, the higher the lead content, the higher the coe. While it's true that boro doesn't have lead, neither do many soft glasses. It's the boron that makes it hard glass and soda-lime that makes it soft glass.

To the original question... Renee's post is spot-on, acids can over time cause lead to leach from the glass. But it takes time, it should be fine to drink from lead-crystal but probably not such a good idea to store acidic liquids in it.

While flameworking a bit of lead will gas-off as the glass is melting, but if you've got adequate ventilation and don't "hunker-down" over the torch it shouldn't be a problem. The lead content of the soft-glasses we typically work with is fairly low. As Heidi said, the lead is used to help the glass flow and "fit" with other glasses more readily.

But once our work is ready to be worn or fondled, the lead is safely locked into the glass matrix. There used to be a myth that glass armonica players would die from lead poisoning from constant contact with the lead-crystal bowls in the instrument, but that myth's been since put to rest.

I did see someone working with some neon tubing once, which I suspect had a significantly higher lead content than the soft-glass we use in flameworking, and as the tube was heating about 3 inches of tube on either side of the flame was fumed in silver color... I'm assuming it was lead... yikes!

[chrissy]

Hi all,

The percentage of lead in Satake is 0.1 % for the lead glass rods. I do think there will be some lead in the Soda glass rods as wel but i aspect this to be much lower in percentage.

I have been working with Satake in the past and did not have any problems. accept for once when my ventilation wasn't working properly. I got an headache after about 2-3 hours. So i just stopped for the day.

Chrissy

[JetAge Studio]

I don't use Satake, but I've used Arrow Springs before, love them, and noticed they're a distibutor of Satake. Perhaps they can shed some light. Their website seems to have some good info on the glass. I'm sure if you called them, they might have some additional information about the glass....just a suggestion. :)

Satake, as explained by Arrow Springs has a COE of 120 (!), and says the leaded colors are not compatable with the soda-lime colors. (Satake...or "other" Soda-lime?!!! Hmmm...)
They do not carry the soda-lime colors (Satake brand) anyway.

Humph...I dunno! :doubt:

Good Luck
Renee

[Peach Blossom Beads]

OK, thanks! I'm a bit confused because Satake comes in either soda or lead, but it sounds like even the soda Satake must have lead in it.

Anyway, now I see that I've been using lead all along even with Moretti, so as far as safety, I guess all is well...

Actually, I'm pretty sure that Moretti doesn't have lead in any of it. Bullseye, OTOH, has quite a few colors that are leaded - surprised me how many.

(The Moretti info came from Mike A).

[LyndaJ]

Also to keep in mind, is that some of the other metals in the glass are at LEAST as toxic as lead if you breathe them in. cadmium, arsenic, silver and gold (to name a few) all toxic and all used in glass colorants, and/or fuming processes. More reason to have excellent ventilation.

[RSimmons]

The higher the c.o.e the higher the lead content. The brighter the colors the most likely the higher of c.o.e. and lead :)

The makers of the glass do not need to say the % of lead content if it's under 39%

If it doesn't have lead it's pyrex.

Lead makes the glass flow.


Pyrex (and other borosilicate glasses) use boron compounds as part of the flux. There are lots of glasses that don't contain lead or boron that aren't Pyrex.

A lot of soft glasses, including Moretti/Effetre, have lead in them. EDP and striking red both contain lead, to name a couple. Many of the metallic reduction effects that are created on glass surfaces are metallic lead that reduces out of the glass (from lead oxide).

Robert

[Zulekah]

I don't use Satake, but I've used Arrow Springs before, love them, and noticed they're a distibutor of Satake. Perhaps they can shed some light. Their website seems to have some good info on the glass. I'm sure if you called them, they might have some additional information about the glass....just a suggestion. :)

Satake, as explained by Arrow Springs has a COE of 120 (!), and says the leaded colors are not compatable with the soda-lime colors. (Satake...or "other" Soda-lime?!!! Hmmm...)
They do not carry the soda-lime colors (Satake brand) anyway.

Humph...I dunno! :doubt:

Good Luck
Renee

Thanks for the info! I saw that Arrow Springs only sells the leaded, and I think I will send them an email asking about it.

[Zulekah]

Hey everybody, thanks for all the info!!! I now feel that lead poisoning is not in my future, which is comforting, after reading what it can do to you.

Cheers:waving:

[Peach Blossom Beads]

Ok. This is where I asked about the lead. I posted a thread in the Safety section a few months ago - http://www.lampworketc.com/forums/showthread.php?t=49098

I just now realized that I misunderstood Mike's answer. He did NOT say that there wasn't lead in Moretti (I don't think - I didn't re-read it all). What he said was that it probably wouldn't pose a problem.

So, forget my post. I completely screwed up the info I had. And honestly, all this time I was wondering how it was possible that Moretti couldn't have lead in it. I'm such an idiot!

[Just Nancy]

I'm thinking idiot is a harsh word. ;) Good info in the thread.

[Zulekah]

I'm thinking idiot is a harsh word. ;) Good info in the thread.

My thoughts exactly!

[JetAge Studio]

My thoughts exactly!
Me too! You're too hard on yourself! Aww, everybody makes mistakes, but a REAL idiot is someone who doesn't admit to making a mistake. :) Thanks for your input!! This is a great subject.
Renee

[Peach Blossom Beads]

Thanks all! I really don't understand how I read it wrong, but I did. I really am a very intelligent person but lately I just can't think. I suffer from CRS, I drop things, spill things, I have NO vocabulary left what-so-ever, I write things down and then forget I did it.... I know what I want to say and either forget in that split second or just can't "find the words" to say it so it never comes out.... I use to be very organized and observant. I'd always "get it" and very very quickly - I pick up EXTREMELY fast. Not anymore! I really do feel like a big huge idiot!

Sorry if I offended anyone with my choice of adjective but lately it totally fits.

And I am enjoying this thread. Anyone else got anymore input??

Thanks again guys! I appreciate it!

[JetAge Studio]

One more thing; If you're in doubt about the lead in your piece, weather it be a food bearing object, or a jewelry intended piece, there are lead testing swabs you can purchase. I personally have not used them, and am not sure how effective they are (manufacturers should disclose a number for the consumer), or under what circumstances lead can be leached from everyday use by wearing leaded glass beads in jewelry, but here's just one option...
http://www.leadtestkits.com/kits4.html

But, again, jewelry made from lead glass, PROBABLY won't effect people adversely....however I do know a few people who's bodily chemistry is quite acidic :). Who knows, I don't have the answer to this, but atleast one can test!

Good luck!!
Renee
JetAge Studio

[Emiko]

The percentage of lead in Satake is 0.1 % for the lead glass rods.
I don't know where you got "0.1%" but I'm told by a reliable source that it is around 33%.

[CO_Phantom]

I don't know much about the lead content with Satake, but I do know that if you heat it too much, you can boil it, and it will release probably more toxic fumes than if you were to just melt it.

The Japanese torches don't burn as hot as our torches (they are propane/air rather than propane/oxygen) so the risk of boiling them is much lower using one of these torches. Also, people use it on a HH all the time, and I haven't heard of much problem with that. I know with a MiniCC it's very difficult to keep from boiling the lead glass of Satake.

Very very small amounts of Satake soda lime will work with their leaded glass. For instance, we used soda lime yellow for our stamen cane, with all the rest lead colors for the lily murrini we made in the Akihiro class at the Glasshive. I guess that's similar to using a little bit of Reichenbach (96) with Moretti (104). It will work, you just have to watch proportions. Also, if you look at the Tonbodama book, they use soda lime glasses with lead glasses, I'm guessing in keeping with the theory that a little bit will work, a lot...well....not so much.

I feel like I'm just babbling now, so I'll shut up and go to bed. =)

-Amy

[Kevan]

Don't most people drink wine from lead crystal and isn't wine high in acid?

[prairieson]

Don't most people drink wine from lead crystal and isn't wine high in acid?

Drinking wine from lead crystal is OK, storing it isn't. It's a matter of length of contact.

[RSimmons]

The lead in 'lead crystal' won't leach out in the time it takes to consume a glass of wine. Leaving wine, or more likely a fortified wine like port or sherry, stored for a longer period of time in a decanter or other lead crystal container will leach lead from the glass into the beverage. It's not likely to cause an immediate or severe lead poisoning, but it will increase your intake of the element. Short term use is OK, storage is not a good idea.

Robert

[Dennis Brady]

Because the lead in glass makes in cleaner (free of bubbles) and allows full melt at lower temperatures, many prefer high lead content glass like Gaffer for casting. If I want to pour cast Spectrum or Bullseye, I have to melt to 1800F or higher and accept that it's relatively thick and won't cast into fine detail. If I use Gaffer, I can pour it at 1600F and it'll pick up hair thick detail. It's also near perfect clarity - free of bubbles. Gaffer is COE 96. Although it's the same COE as Spectrum, the difference in clarity is instantly recognizable. The difference in performance is even more dramatic. Spectrum pours like thick syrup - Gaffer like light oil.

[JetAge Studio]

HMMM, bringing back this thread makes me want to re-evaluate my custom blended vinegar stored in "artisan" bottles...ha ha ha!

[Steph'sBeadCorner]

when my sister took her son for his yearly checkup, the lead test questionnaire specifically asked about hobbies related to glass. The physician asked her if my nephew was exposed to lampworking. So, I decided to check it out.

Gaffer (furnace frit) conducted a study to determine the level of lead emissions. In order to give worst case results the lead monitoring was carried out in the studio of local artist melting 2 x 25kgs of casting crystal at 870oC (1600oF) in a deliberately unventilated room. All doors and windows were shut. The results from this study showed that the lead levels were 5x below OSA guidelines and 3x below US OSHA guidelines.

Here's the link to the entire article, (just scroll down to find it) it's titled Casting Crystal Lead Emissions.

http://www.gafferglass.com/technical/casting.htm

If you're worried about exposure, you can also perform a lead-wipe test..I completed a lead wipe test in my studio (directly on the desk in front of my torch and then on the floor area right behind my torch) and the results came back way below the lead level standards.

I do use some Satake and I don't have any paperwork, but I understand it's low in lead. And not a health risk.

Goodluck!

[JetAge Studio]

That is really interesting Steph!! Thanks so much for your input!! Very cool to hear the medical world asks questions related to glasswork!! I'm surprised! (guess they're paying attention..) Good Doctor!! Thanks so much for your comment, it gives a lot of perspective!!\\:D/ (but now I wonder what the doc knows about lampwork!! :) )
Renee Wiggins

[Dennis Brady]

That is really interesting Steph!! Thanks so much for your input!! Very cool to hear the medical world asks questions related to glasswork!! I'm surprised! (guess they're paying attention..) Good Doctor!! Thanks so much for your comment, it gives a lot of perspective!!\\:D/ (but now I wonder what the doc knows about lampwork!! :) )
Renee Wiggins

Suggests that the concern about lead poisoning from torching glass is about the same as the concern about it from using it for stained glass.

If you don't eat it you'll be fine.
If you're fool enough to eat it, lead poisioning is the least of your problems.

[ewdb]

when i told my dr i work with hot glass, he added a lead test to my annual physical.

does anyone else do this?

[Steph'sBeadCorner]

when i told my dr i work with hot glass, he added a lead test to my annual physical.

does anyone else do this?

Well... I think it's safe to say that if you're using basic glass that most lampworkers use... a yearly test isn't really necessary.

Of course, if you're more comfortable with a test, then go for it!

I would ask myself, do I want to pay for a test I didn't really need? I see you live in Canada, so that may not even by an issue.

And 2ndly, do I have adequate ventilation?? Since most of the problems with emissions are resolved by installing proper ventilation.

[Dennis Brady]

Well... I think it's safe to say that if you're using basic glass that most lampworkers use... a yearly test isn't really necessary.

Of course, if you're more comfortable with a test, then go for it!

I would ask myself, do I want to pay for a test I didn't really need? I see you live in Canada, so that may not even by an issue.

And 2ndly, do I have adequate ventilation?? Since most of the problems with emissions are resolved by installing proper ventilation.

In Canada, the blood test is free but bloods test are notoriously inaccurate. To actually measure lead contamination requires a hair analysis test. That isn't normally free but if you tell your doctor you regulary work with lead, he can prescribe a free test. I started getting tested more then 20 years ago and stopped after about 10 years. Although I was steadily increasing the amount and frequency of lead I worked with, my lead levels were steadily decreasing. One possible explanation was simple. I had moved from a city to a small rural island where I wasn't inhaling the usual variety of vehicle and industry generated fumes. The other possible explanation was I had done nothing that would cause me to ingest lead. I don't know what lead tastes like and have no desire to find out.

[castaway]

Boy, there is a lot of miss-information out there isn't there, Lead is in glass to obtain certain colors, the lead increases the amount of the colorant( metal) that can be absorbed. Cadmium-sulphide reds do not contain lead, they contain Zinc
gold colors do contain lead as do the very dark copper greens. Lead will volatilize out of the glass at 999°C well below the temperature of your flame, the Gaffer test you will notice kept below this temperature. The difference between hard glass and soft glass is it's melting temperature or viscosity which controls the coe and thus annealing temperatures, Soda Lime glass is window glass and container glass it is not the glass that you are working with, you would not be able to work with soda lime glass it is very stiff and devitrifies easily, Boro also contains some soda( 4.5%). the colors in glass cannot be obtained in soda glass you need potash as the major alkali to produce most of the colors that you use, Nickle for example gives the lovely violet colors in potash glass but only a dirty brown in soda glass, the same for manganese, purple in potash and brown in soda. I think Emiko is correct here about the lead in Satake it is well over 30% by weight and is in the glass both to obtain the colors and to make it melt more easily and will come out of the glass into the atmosphere of your studio.
cheers, Bernard

[squid]

Boy, there is a lot of miss-information out there isn't there, Lead is in glass to obtain certain colors, the lead increases the amount of the colorant( metal) that can be absorbed. Cadmium-sulphide reds do not contain lead, they contain Zinc
gold colors do contain lead as do the very dark copper greens. Lead will volatilize out of the glass at 999°C well below the temperature of your flame, the Gaffer test you will notice kept below this temperature. The difference between hard glass and soft glass is it's melting temperature or viscosity which controls the coe and thus annealing temperatures, Soda Lime glass is window glass and container glass it is not the glass that you are working with, you would not be able to work with soda lime glass it is very stiff and devitrifies easily, Boro also contains some soda( 4.5%). the colors in glass cannot be obtained in soda glass you need potash as the major alkali to produce most of the colors that you use, Nickle for example gives the lovely violet colors in potash glass but only a dirty brown in soda glass, the same for manganese, purple in potash and brown in soda. I think Emiko is correct here about the lead in Satake it is well over 30% by weight and is in the glass both to obtain the colors and to make it melt more easily and will come out of the glass into the atmosphere of your studio.
cheers, Bernard

I don't understand the part that I bolded above. We ARE working with soda lime glass.

[castaway]

not so dear you are working with a potash- lime glass, there will also be a small percentage of soda in the glass but the main alkali will be potash

[squid]

According to everything I have been able to find Potash-lime glass is Bohemian glass, container glass. Venetian glass is soda lime.

[LyndaJ]

So, potassium instead of sodium as the metal?

[squid]

Chemistry textbook

http://books.google.com/books?id=gu7X8tt01TgC&pg=PA298&lpg=PA298&dq=%22potash-lime+glass%22&source=web&ots=AX83PdZk8J&sig=Ag2IzVRnAQW-2Sm16qbrykvq0d8&hl=en&sa=X&oi=book_result&resnum=10&ct=result

Says that potash-lime glass fuses at a very high temperature and that soda lime is readily fusible.

[castaway]

Well, for a start glass is not "fused" to make it but disolved, a glass recipe for 'soft glass' would contain silica as the main glass former, and then an alkali, iether sodium or potassium or both, then stabalisers, usualy calcium, magnesium and other RO elements, modifiers, boron, barium, zinc, lead to name a few.
when glass "batch" is loaded into a furnace the lower melting materials begin to melt, things like sodium carbonate, potassium carbonate , the nitrates and borax all start to melt early, these in turn help to dissolve the RO compounds the resultant soup of "fluxes" dissolves the Silica Dioxide ( sand) Most glass of the "soft type is batched at between 1200°C and 1300°C regardless of their composition, the extra heat to make potash glass in not an issue for studio glass
as it is only a couple of hundred degrees( silica needs 2000°C to "fuse")
You will find very little on the composition of 'colored' glass, almost all the information you will find will refer to the "base glass" which is the clear glass which makes up the body of the piece. Almost all colors used in the glass blowing industry are lead colours, lead glass uses Potash as its flux although Kugler is now making a lead free range of glass colors using things like Barium and Lithium.
the ancient glass of northern Europe was "forrest glass' or "potash glass" they had no trouble making it in wood fired furnaces, and it was only when the forrests were gone that soda became an important glass flux.
it is true that 95% of all glass made is "soda lime glass" it is however window and container glass, art glass colors are not mentioned in many publications.
cheers, Bernard
It is still not possible to obtain the colors we are all using in "soda lime glass"

[JetAge Studio]

not so dear you are working with a potash- lime glass, there will also be a small percentage of soda in the glass but the main alkali will be potash

I'm not quite clear about this statement either. I too am of the understanding that the glass we (soft glass) lampworkers use is Soda Lime Glass... Soda is a flux as well as potash, and a bit more of an efficient flux as I understand, therefore is used more readily (I'm guessing here) I think it's just generally understood that "soft glass" is Soda Lime Silica glass. Perhaps it's a "generalized" term. I'm no chemist, but I do have a passion for glass, so I'm naturally curious about this.

Here's what I know from my library;

I understand the definition of Soda Lime Silica glass as this:
the glass "former" is SiO2 (silica), with "modifiers" of;
(Soda) Na2O (from soda ash and/or nitrate) is the most important alkali for glass making.

(Lime) CaO (from Limestone). The most important alkaline earth for glass making.

Approx. 22% Na2O, 5% CaO, 73% SiO2 by weight IS Soda Lime Silica Glass according to my reference.

A host of other modifiers are secondary;
Potassia, K2O (from potash and/or potassium nitrate) "has a larger ionic size, and is less mobile, and therefore better for electrical insulation properties, but not quite as good a flux as soda." is one.

You're not possibly referring to "Lead Silicate" glass, which has a higher potash content as well as lead content (flint glass)? Which is also used as "container" glass? Just throwing that out there.

I'm also not quite understanding what you mean in this quote; "it is true that 95% of all glass made is "soda lime glass" it is however window and container glass, art glass colors are not mentioned in many publications.
It is still not possible to obtain the colors we are all using in "soda lime glass"

This could also be a very interesting discussion, but I'm not sure what you're referring to when you mention color...care to elaborate?

Very interesting. I'm just a little confused by some of your reference, or perhaps wording, but I'm in no way claiming I know better!
Thanks for the input!

Renee Wiggins

[castaway]

OK I will have a go Renee. I am not an industrial chemist, I am a glass maker of 30 years experience, glass chemistry was my area of study during my glass course. I have taught glass chemistry to art students at University( a very basic course, you can imagine)
Tere are three basic groups of chemicals in glass making,

glass formers: silica and boron are the major ones

fluxes: Na2O and K2O are the major ones

stabilisers: CaO and MgO are the most important

these are the glass formers

the other group of chemicals in glass are the modifiers, these modify the characteristics of the glass( melting temp, working time hardness etc.)
these are things like lead( which can also be a glass former( tricky isn't it)
barium, zinc,arsenic, antimony and lithium are some of them

the glass that you quoted:
73% SiO2 , 22%Na2O, 5%CaO is indeed a basic soda lime glass, however it would be very difficult to work with such a glass, believe me.

the "95% of all glass made is soda lime glass" is a reference to the much quoted figure used to show why most glass is 'soda lime glass' this is true but it does not refer to the glass that we use in lampworking, this is for the most part 'colored glass' the recipes for producing colored glass are nothing like the "soda lime glass" formula you have quoted.
the colorants in glass are for the most part metals, iether as atomic metal or as oxides or sulphides, these metals give different colors depending on the composition of the base glass, a real give away is a violet glass, this will be Nickle and must be in a potash glass to produce this color, in a soda glass it will be brown, there is no other way to produce a violet glass
there are many different "base glasses" used to produce the range of colors we use in lampworking, to simply call them "soda lime glass" is wrong and missleading a more corect term is of course "soft glass"
It is difficult to get information on the recipes for glass as each maker keeps them secret, the Italians are no different and to ask them what is in their glass is useless as they will tell you what they think you want to hear, or just limply say"Oh it's soda lime glass" and perhaps some of the glass they make is, but not the colored glass that we use.
cheers, Bernard

[RSimmons]

If you look at the X-ray spectra generated by many Effetre and other Italian glasses you'll see the markers for 'soda lime' flux agents along with a number of metals used for color generation.

Robert

[PittsGlass]

If you look at the X-ray spectra generated by many Effete and other Italian glasses you'll see the markers for 'soda lime' flux agents along with a number of metals used for color generation.

Robert

Where can one see this?

This whole thread is just fascinating. I am anxiously awaiting more discussion. Thank you all for sharing your knowledge!

[RSimmons]

I'll post some data on this tomorrow.

R

[RSimmons]

I reviewed the X-ray data on a couple of the Italian 104 glasses (Vetrofond, Effetre). These include: EDP, a light ivory, an opaque yellow, a medium blue, a pink, white, a transparent green and an alabastro. Soda-lime is made up of calcium hydroxide, sodium hydroxide and potassium hydroxide, plus water in the raw form. The spectra from all of these glasses indicate the presence of all three elements in varying proportions. There are other metals that are commonly used as colorants for glass, but I don’t want to get into trying to publish formulas. I think that, based on the presence known flux agents, these can be considered soda-lime glasses.

Robert

[Lisi]

Oops, posted in wrong thread, but I'm glad I brought it up again! I had posted in the Bathroom about a potential customer that had asked me if there is lead in my beads.