Swede
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Anyone good at glass work?
I have always been fascinated by the skill of the glass apparatus artists who can start with raw glass tubing and stock, and turn them into unique lab
objects of functionality and beauty. I realize this is not a trivial thing, and takes years to master. Is there anyone here who can perhaps point to
online resources that he finds particularly valuable? Any tips to get started? I appreciate any thoughts.
Thanks!
Swede
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Phosphor-ing
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East Carolina University has a glassblowing website that is pretty good for the basics.
http://www.ecu.edu/glassblowing/gb.htm
"The nine most terrifying words in the English language are: 'I'm from the government and I'm here to help.'" -Ronald Reagan
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JohnWW
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I have a couple of ebooks on laboratory glass-blowing, downloaded some time ago; one of which is by the late Robert Barbour, who was the Head
Technician of Victoria University's Chemistry Department in Wellington, N.Z., and later the same at Waikato University, Hamilton, N.Z. I worked with
him in the late 1960s, and he was quite a famous glassblower. I will see if I can find those ebooks on one of my hard drives, or the URLs from which I
downloaded them
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watson.fawkes
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A small treatise on eye protection
I'm in the process of setting up a small facility for working glass. Of all the things I researched, the most problematic one to get information on
was eye protection. Largely, this is because scientific glass has become such a specialty over the last generation, that there's not all that much new
publication about it, and all the old methods of eye protection were inadequate. Here the upshot, though. Buy Phillips ACE 202 for working
borosilicate.
Adequate eye protection must simultaneously accomplish four different goals:Ultraviolet. The lens must suppress UV radiation
to avoid immediate damage to the retina.
Visible. The lens must provide adequate total shading so that you can stand to look at the work. If your iris is as closed as it gets, you
probably don't have enough total shading.
Infrared. The lens should suppress infrared to avoid cataract formation.
Contrast. The lens should suppress the sodium emission line ("sodium flare") so that you see what you're working on. Sodium flare can make it
difficult to put heat right where you want it. As you might imagine, getting all those at once is a bit of a technological feat. You want a
transmission spectrum that looks like a mesa, cutting out high and low, with a spike down at the sodium line. The ACE 202 material is a glass
specially made for Phillips by Schott. I had a spectrum for it sent to me by a fellow at Schott technical support that I spoke with. (I'd post it, but
it's stranded right now from a disk crash.) That spectrum looks just like you'd want it to. It's available shaped into lenses with frames and also as
plate material.
All the other single-composition glasses I've seen are insufficient (with one exception below). Didymium, the old standby, has insufficient infrared
suppression, but suppresses sodium flare well. It's been implicated statistically for cataracts in glass workers. It's OK for soda-lime working, where
temperatures are lower, and thus also are total IR loads. Cobalt blue (originally borrowed from the steel trade) has decent total shading, but doesn't
protect against UV well. There's a guy out there selling laminated didymium-plus-something lenses. It seems like they'd work, but I believe the ACE
202 material is cheaper. The one exception I know of is the TM 2000 glass by TM technologies. From looking at its transmission spectrum, it looks fine, although it may be too dark for borosilicate but
should be good for silica. I can never remember where to find more than the product page on their site, but there are somewhere some pretty amazing
pictures of what it will do for flare reduction. This material suppresses not only the sodium line, but those of a bunch of the other alkali metals as
well.
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Swede
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Wow, thanks for the fast replies. I would never have guessed that working with glass presented a significant eye hazard beyond the standard -
fragments and shattering.
I will look into the resources mentioned, and JohnW, if you happen to find a link to those books, a PM would be greatly appreciated. If not, no big
deal. Thanks again.
My goal is to be able to construct very basic apparati (apparatuses?) A simple condenser, small funnels, RB flasks, ampoules, typical entry-level
organic chem stuff.
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watson.fawkes
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Quote: Originally posted by Swede  | | Wow, thanks for the fast replies. I would never have guessed that working with glass presented a significant eye hazard beyond the standard -
fragments and shattering. |
Yep, it's not obvious and the information out there is hard to find, so it was the
most important thing to get out first.
For a good starting read, Creative Glass Blowing by Hammesfahr and Stong is my recommendation for a fairly-easily available book on the
subject. Don't be misled by the title; the last chapter is on scientific glassware. It teaches basics like pulling points and the ring seal. One of
its advantages is that it does talk about art glass and has little projects for it. Even if your interest is in scientific ware, I can recommend these
as practice exercises for getting a feel for how glass behaves as a material. In addition, the materials here are soda-lime glasses, which work at
lower temperatures and are generally friendlier. It's difficult to practice scientific ware in flint glass, which is hardly available any more in
standard tubing. I did a bit of this as a kid, when it was much more common and included in chemistry sets. That last chapter, though, describes
non-trivial project like a McLeod vacuum gauge, a Graham condenser, and Housekeeper seals.
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watson.fawkes
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Here's the link for the ACE 202 glasses: Glass-Working Safety Glasses.
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densest
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"Glassblowing An Introduction to Artistic and Scientific Flameworking", Edward Carberry, ISBN 1-888833-09-2 (other ISBNS are -08-4, -04-1, and -10-6,
all the same text, different bindings, b/w instead of color). A good primer to intermediate text with good sequences of pictures and sequential
lessons. "Flameworking" is the name for assembling pieces from tubing and rod. It blurs into "glassblowing" which is construction from blobs of molten
glass, but what you are talking about is flameworking. Some of the suppliers mentioned below sell DVDs/videotapes which are really helpful to
supplement the texts.
Borosilicate (pyrex) is the standard scientific glass. Flint (soda-lime) glass is easier to work but much harder to anneal correctly and much easier
to break.
For working borosilicate you MUST wear high quality eye protection. Didymium glass is not enough. 202 or 286 glass is the minimum.
Shade 3 or 5 welding filters OVER the 202 glass is necessary for working colored borosilicate or for working clear at high
temperatures for long periods. Without this protection it is very likely you will get cataracts or have retina damage. This cannot be overemphasized.
The damage is painless and cumulative and never heals.
You will need an oxygen/propane or oxygen/natural gas torch. Trivial pieces can be done in a MAPP gas torch, a Meker burner, etc. If you want to make
pieces which last, they must be annealed in a kiln or lehr. A ceramic kiln equipped with a ramp-hold temperature controller is what most amateur
workers use. Trivial pieces can be flame-annealed and cooled under ceramic paper or in vermiculite, but they are likely to crack at the worst possible
moment. You must have an exhaust fan - any flame which will melt borosilicate produces substantial amounts of nitrogen oxides - enough to smell 100
feet away.
Lastly, you will need patience to practice a lot. I've been working borosilicate for about 7 years and my pieces are far lumpier than I'd like.
Admittedly, I've not practiced nearly enough due to way too many other things to do.
http://www.waleapparatus.com, http://www.generationsglass.com, http://www.winshipdesigns.com, http://www.macbicnj.com, etc. are suppliers I've used. It's an expensive hobby (so's chemistry...) and a rewarding one.
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bquirky
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Off topic.. But
I saw a dude the other day down at the local flea market who had a stall and a work bench setup making the most amazing glass stuff by hand small
animals, swans etc. im sure it was all soda lime glass but still there are people out there that can do it well.
off topic again.
But the other day i succeeded in making a copper-powder/carbon electrode using Bitumen Tar and a cheap soda lime glass test tube.. it was glowing a
dull red so i guess that makes it about 600 deg C makes me wonder if soda lime glass is more useful than we give it credit for.
regards.
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Swede
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Great stuff, thanks! It's obvious that the masters have decades of experience, but it would be nice to do some basic stuff like tapping the neck of a
RB flask to add a nipple, or turning a small erlenmeyer into a vacuum filtration rig. Stuff like that. 
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quicksilver
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Blowing glass for different items demands certain glass types. The glass tubes one may find in chemistry supply store / web sites is VERY easy to use
and the only issue is LOTS of practice & technique. Practice does not make perfect IF you are practicing the wrong technique.
However, the common recycled glass in beer bottles is a mix of many different type and is NOT easy to use without extensive practice. There are
several different types of glass with unique properties of their own....but mixed together in a recycling and processed through an automated process
& you may be frustrated more than you would IF you know the exact properties of the glass sold for specific purposes.
One technique that seems to be mandatory is to KEEP the whole of the piece hot: do NOT let areas cool off - no matter the type of glass used - very
few will maintain their heat and cracking or lunmping will frustrate even really well practiced professionals.
One thing that has helped is to set up a charcoal stove out doors and a single torch with a large supply of medium temp gas flame like propane.
However, a cooler surface can be used for many useful techniques IF the concept is to flatten on area but the "cooler" area must still be hot by most
human standards; about 80-100C. The actual blowing must be very consistent WITH the heat or you will have a sphere or other shape with a very thin
wall on one side or more.
The torch allows a "seal" to be set but what you are dealing with will seem like "taffy or gum" & it can get very fluid, very quickly. It's a lot
of fun but I have been enormously impressed with some of the objects I've seen from "Journeymen" glass-blowers.
There are some excellent books available but the only sure fire method is to practice and practice
[Edited on 11-1-2010 by quicksilver]
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The_Davster
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Thread Moved
11-1-2010 at 10:48 |
JohnWW
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| Quote: Originally posted by JohnWW | | I have a couple of ebooks on laboratory glass-blowing, downloaded some time ago; one of which is by the late Robert Barbour, who was the Head
Technician of Victoria University's Chemistry Department in Wellington, N.Z., and later the same at Waikato University, Hamilton, N.Z. I worked with
him in the late 1960s, and he was quite a famous glassblower. I will see if I can find those ebooks on one of my hard drives, or the URLs from which I
downloaded them |
Here it is:
http://rapidshare.com/files/3511434/glassblowing_for_laborat... 2.31 MB
Other glassblowing ebooks are on:
http://www.masro3.com/medical-tests/7198-glassblowing-labora...
Links for the Glassblowing Bible are given on this page:
http://kimth2.softarchive.net/glass_blowing_bible_discover_e...
Also: (I downloaded them in 2007)
"Lab Glassware":
http://208.72.236.210/pdfs/5701235.pdf
"Glassworking Manual":
http://icase.unl.edu/guidoks/chemistry/chemglas.pdf
Addendum: Some more pages with glassblowing info and ebooks:
http://linux.wareseeker.com/free-glass-blowing-school/
http://ww.ebookee.com/Glass-Construction-Manual_223707.html
http://www.ebooksx.com/Glass-Mechanics-and-Technology_29165....
http://asoriaz.tripod.com/glass-blowing-salso.com.html
http://hackaday.com/2008/01/07/how-to-make-a-vacuum-tube/ - has:
http://rapidshare.com/files/82175021/How_to_make_a_vacuum_tu...
[Edited on 12-1-10 by JohnWW]
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densest
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Very important to remember: do not mix glass types with different coefficients of expansion (COE)!! It -will- crack. Absolutely guaranteed. Soft
(flint) glass is about COE 93 (93 x 10-7 parts per degree C). Borosilicate is about 32-33. Differences of more than about 3 or 4 will cause cracking.
Put glass you've worked on between crossed polarizers after annealing to check for excess strain. Bright or colored areas show strain which may
(will!) cause cracking later.
Working soft glass is somewhat different from working hard (borosilicate) glass. Soft glass remains soft over a wide temperature range. Hard glass has
a narrow range between hard, soft, and boiling. This affects how you work it by changing timing a lot.
@watson.fawkes - borosilicate glass should be available almost anywhere. It comes under a lot of trade names besides Pyrex (Duran from
Schott, Kimax or KG-33 from Kimble, 7740 or 774 from Corning, Simax from Kavalier, etc. I don't know the Chinese trade names) and is made in Europe,
the US, and China in large quantities, so it should be more-or-less "local" even Down Under, or at least shipping shouldn't be too
outrageous. If not, sorry, and I'm a bit amazed.
@bquirky - Flint glass sometimes can be used at higher temperatures - once! It softens enough that (for instance) a test tube might stay together, a
flask would deform, and something more complex would fall apart. If used above its strain point (473C) and cooled quickly, it becomes strained and
will shatter.
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DJF90
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http://www.teralab.co.uk/Glass_Blowing/Glass_Blowing_Menu.ht...
This guy has done some pretty amazing stuff, although its all made out of soda glass. Similar principles of course apply to borosilicate working. A
few things I disagree with him on is on the "Cutting tubes" and "Joining and annealing tubes" pages; firstly he breaks the glass towards
himself, and secondly, he holds the tube(s) wrong when i) flame polishing the broken edge and ii) heating the tubes ready for joining. Whilst
these are likely habitual to each individual, it is a bad way of working and can lead to burns if you aren't careful where you put your hands.
Phosphor-ing's link explains why...
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watson.fawkes
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Oh, that's not the problem. I had been
looking for a source of flint glass tubing; that's what's not very available any more. The only thing I had found at the time (a year and a half ago,
or so), were bundles of mixed sizes, most horribly overpriced (like around $30/lb), the rest in rather large quantities. So while writing this message
I searched again to verify this, and lo-and-behold, there are a number of sources for sized tubing in one pound quantities at reasonable prices. I can
only guess that something in the supply chain changed in the interim.
The flint glass, incidentally, was for teaching kids some basic chemistry stuff; think _Golden Book of Chemistry Experiments_. You can do simple bends
and nozzles with an alcohol burner. Since it works at lower temperatures, there's much less need for specialized equipment. I still think it's a good
entry material for getting a feel for molten glass as a material, even for folks who want to work borosilicate.
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ninefingers
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| Quote: | | Flint (soda-lime) glass is |
Soda lime glass isn't Flint. Flint is Lead glass--most glass you see commonly has lead. It is also in lead "crystal". The lead makes it sparkle. A
lack of oxygen/air in your flame "devirtifies" it and it turns black from the lead being reduced.
I'm trying to repair some Pyrex stuff right now but my flames aren't hot enough. I tried Oxygen; it only goes POWW!!! on a glass fire. Need a regular
Oxy-Acetylene torch that I will use propane in, I guess.
Used to have a friend with a glass lathe (this was in CA); never got to use it.
My 1919 Victor Xray tube just rolled out of an holder and broke. The glass was paper- thin in the middle--it would flex by hand. Incredible piece of
glass working.
I believe Amateur Scientist had some glass working. They are online or on a disk. One was all on Pyrex, and annealing with cotton balls/fiberglass
and a smoky flame.
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watson.fawkes
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The flint glass
used in optics, where you have the flint glass / crown glass pairing, may well have lead in it, as did the original flint glasses. The flint glass
used in scientific glassblowing, though, typically does not have lead. The flint itself refers to the mineral source of silica in the glass, not to
the fluxing agent used to make it workable.
The problem with POW! in a glass fire (for everyone else, "glass fire" is the term of art for a particular class of burner nozzles common in the neon
sign trade) sounds like a pressure regulation problem.
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ninefingers
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Wikipedia; Flint Glass: | Quote: | | With respect to glass, the term flint derives from the flint nodules found in the chalk deposits of southeast England that were used as a source of
high purity silica by George Ravenscroft, circa 1662, to produce a potash lead glass that was the predecessor to English lead crystal.Traditionally,
flint glasses were lead glasses containing around 4–60% lead oxide; however, the manufacture and disposal of these glasses are sources of pollution.
In many modern flint glasses, the lead can be replaced with other additives such as titanium dioxide and zirconium dioxide without significantly
altering the optical properties of the glass. |
It says :"in many modern..."; not All. Lead adds "sparkle". It does not aid its melting, working or preclude/ prevent oxidation (definition of
"flux") while being worked. Original glass was sand and soda lime; which "alloyed" with the sand and lowered its its melting point. Soda/lime
glass, which I used in a science class in the seventh grade; works much easier than lead/borosilicate glass; and is far more forgiving. Lead is Not
added for workability. In Neon tubing; it is used to made the only glass tubing not requiring annealing--a near impossibility once a sign is bent.:
Unless you only use soda lime or absolutely brand new glass that has no lead in it--i,e.; "Green"--you will run into lead. I have many shapes, like
lantern chimneys, etc, that still have lead in them. Joining them to other glasses may prove impossible, but I'll see. I expect lead; I always adjust
for a slight oxidizing flame to prevent devitrification/unworkability ("blackening")
My regulator is just fine. I can adjust the oxygen to a tee. It's just my glass fires are for natural gas/propane and compressed air. The mixer and
burner on an Oxy-Propane or Oxy-Acetylene are different.
Oh, well, I just need to do some Neon right now, and won't need Oxygen.(I hope-!)
[Edited on 3-15--10 by ninefingers]
[Edited on 3-15--10 by ninefingers]
[Edited on 3-15--10 by ninefingers]
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densest
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@ninefingers - The National brand torches sold by flameworking shops cost about $100. Dunno if that would be too expensive. They were (are?) the
standard inexpensive torch for glass work. They can be clamped or handheld.
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12AX7
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Eh, "flux" is Latin for "to flow". A flux makes things flow. A flux lowers the melting point of a glass mixture, or of a slag, or makes a metal flow
better onto a surface, etc. So it does aid its melting or working (lead silicate has a fairly low melting point, if not necessarily lower than soda
or potash in terms of relative workability -- I'd need a reference for that), and has nothing to do with prevention of oxidation (indeed, a lead-rich
slag applied to molten brass, for instance, will result in oxidation of zinc, replacing it with lead, and as noted, lead can be reduced easily).
Tim
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