Glassblowing and old newspaper
Posted by Phillip on Wed 12 Sep 2012Categories: Uncategorized | [7] Comments
A Dartington glassblower uses a newspaper paddle to shape a piece of blown glass
A letter in the Financial Times about a month ago piqued my interest. It stated that the characteristic salmon pink pages of the FT play a unique role in producing hand-made crystal glass at Dartington crystal. Since I was about to go on holiday to Devon, and had planned a trip to the Dartington factory anyway, I decided to do a bit of investigating myself.
In the FT letter, the correspondent says that the reason for using the pink pages of the FT is so that no trace elements are transferred to the crystal ‘when the protective newsprint is peeled away’, as they might be with other, bleached, newspaper.
This sounded a little implausible to the chemist in me. If the newspaper was only being used for protection, surely any interaction with the crystal glass would be confined to the ink, or any contaminants left from the paper processing, rubbing off on the surface? The possibility of significant chemical reaction between the glass and the newsprint at room temperature seemed remote at best.
A tour of the factory quickly confirmed my hunch. The role of the newspaper is much more than simply protective, but perhaps quite surprising. It is an integral tool in shaping blown glass. The yellow-handled paddle in the picture is actually made up of a wad of newspaper.
This yellow handled paddle is actually a stack of newspapers
As the glassblower blows and shapes a globule of molten glass into a tumbler (in this case) or any other object, part of the process involves dipping that paddle into a bucket of water and holding it up to the red hot glass. At the same time he rolls the blowpipe backwards and forwards to ensure the glass is the right shape and consistent thickness.
Newspaper is absorbent and cheap to replace, making it ideal for making these paddles. However, being in contact with glass at several hundred degrees means the paper does burn away slowly, so it’s important it doesn’t transfer contaminants to the glass in its semi-molten state, which could then create imperfections in the final product.
So that begs the question, what is it about the FT that makes it the preferred choice of glassblowers? Is it something to do with the chemical processing of the paper? Is the paper bleached less ferociously than its white cousins? Or does the dyeing process mean any residues from the bleaching are washed out more thoroughly? Or is it simply tradition with little scientific backing? Speaking to some of the Dartington staff I got some vague answers about the ‘quality of the paper’, but it would be interesting to know if any of our readers have more insight.
If you have never watched a glassblower at work, it is quite an amazing experience. The apparently effortless skill of a master glassblower is breathtaking. No wonder it takes around 10 years to reach that level. But, as with glassblowing for chemistry equipment, it is a skill that is slowly dying out – Dartington is one of the last commercial-scale producers of hand-blown glass in the UK.
Phillip Broadwith
Thu 13 Sep 2012 at 2:52 am
Hi Phillip,
It is the quality of the paper.
In the USA we use the New York Times and the Wall Street Journal for the same reasons.
I personally use UNPRINTED newsprint paper, just to avoid any possible chemicals in the inks, especially colored inks.
Tony Patti
http://www.glassblower.info
gaffer@glassblower.info
Thu 13 Sep 2012 at 6:46 am
[...] Glassblowing and old newspaper In the FT letter, the correspondent states that the sense for using the pink pages of the FT is so that no hint elements are transferred to the crystal 'when the protective newsprint is peeled absent', as they may be with other, bleached, newspaper … Read more on Chemistry World (blog) [...]
Thu 13 Sep 2012 at 12:08 pm
Hi Tony,
Thanks for stopping by. I had wondered whether unprinted paper would be preferable, but assumed that the temperature of the glass would simply carbonise any organics in the inks.
Can you clarify what you mean by the ‘quality’ of the paper? Is it to do with weight (thickness/density), or some aspect of the chemical composition or the way it’s treated?
Thanks,
Phillip
Thu 13 Sep 2012 at 3:12 pm
Hi Phillip,
In terms of quality of paper, it has to do with it “staying together” after soaking in water, not just for hours, but possibly days.
Inferior paper will “disintegrate” more quickly.
What you don’t want is a hole or thin spot, which allows the heat/steam through to the hand.
Do you have a higher-resolution photo of that yellow-handled tool you could email me? I suspect it is a “footing tool” but have not previously seen any using wet newspaper.
We mostly just use wet newspaper free-hand.
My chemistry question for you: might colored inks have chemicals in them which would be potentially dangerous to breath when raised to perhaps 1500 F temperature? When glassblowers use newspapers, they generally avoid the colored pages, which is why I found the selection of the salmon-colored FT particularly unexpected choice.
- Tony
Thu 13 Sep 2012 at 7:28 pm
We here at Solinglass in Brattleboro Vermont used the FT paper recycled from a friend who got it for her business. We used it for about a year then we figured the ink changed so we swithed to the Wall Wstreet Journal then various others,including the Brattleboro Reformer! We figured soy inks and paper quality definitely plays a factor in the glass hot shop! Great article! Thanks
Marie
Tue 18 Sep 2012 at 9:56 am
Hi Tony,
Thanks for the clarification.
Unfortunately, that’s the best picture I have of the paddle. It was described to me as a compressed wad of newspaper, and the glassblowers would dip it into the bucket of water before using it to shape the glass. There was a similar wooden, cup-shaped tool in use for the same kind of task.
As far as the chemistry of the inks goes, I would imagine that 1500F would be hot enough to burn up, or at least vaporise most organic (in the carbon-based sense) ink components.
However, I’m not sure if there are metals etc used in the coloured inks used for printing photographs, which might explain why they are avoided. There is also a lot more ink there in total, so it may just be about concentrations. My guess would be that the salmon dye used in the FT pages is organic-based, and used at a very low concentration (to keep costs down) and hence burns up with the paper to CO2 and water, or other volatiles that escape with the steam rather than contaminating the glass.
Sat 22 Sep 2012 at 1:58 am
Hi Phillip,
Thanks for the additional information.
While I worry a little about possible contamination of the glass from colored newspaper, it is the breathing of those vapors you mention which are my primary concern.
We are in very close proximity to the newspaper when we are using it, and there is lots of steam and smoke, especially when the papers are being used for the first time (at the beginning of the use of a new pad of wet newspaper).
- Tony