Glass blowing
Stained Glass Windows: Managing Environmental Deterioration, published by Historic England in 2020, suggests that glass blowing is a: ‘Glass-forming technique, probably developed in Babylonia and the Middle East by the 1st century BC. Molten glass is gathered into a ball on the end of a hollow pipe, and rolled on an iron former to roughly shape it and to slightly cool the surface. Then the pipe is used to blow air into the glass and form it into a bubble. By repeated blowing, shaping and reheating, the glass can be formed in many ways.’
Archaeological Evidence for Glassworking, Guidelines for Recovering, Analysing and Interpreting Evidence, published by Historic England in 2018, defines a blowing iron as: ‘A long iron tube that was dipped into the molten glass to collect a gather for subsequent inflating and shaping.’
It defines optic blowing as a process in which: 'A gather of glass is blown into a mould with a pattern on the inner surface, which transfers to the glass. Continued free blowing results in movement and distortion of the pattern.'
And overblow as: 'A by-product of mould blowing, referring to the glass that remains outside the mould, which is removed and recycled.'
It defines paraison as: 'The partially inflated gather of glass at the end of the blowing iron.'
And paraison end as: 'A marble-shaped blob of glass pinched from the end of the gather during the blowing of particular forms, such as the bowls of goblets.'
[edit] Related articles on Designing Buildings Wiki
Featured articles and news
We're expanding our collaborative mission by launching DB Intelligence, an exclusive market research advisory panel. Built environment professionals can now get paid to share their expertise on industry trends, products and services.
Panel members receive direct financial incentives for participating in research projects like short surveys, 1-2-1 interviews and focus groups. Register today to shape the future of the construction sector.
Planning condition discharge in England and Wales
A brief exoplanation from a building compliance expert, with further links.
Overheating guidance and tools for building designers
Guidance for dealing with element of building fabric control that have increasing importance.
Shading for housing, a design guide
From the Good Homes Alliance and British Blind and Shutter Association.
UK Standard Skills Classification (SSC)
A shared framework for describing skills needs.
Social media ban consultation comes to close
CIOB urges UK Government to consider social media’s role in careers guidance in ban debate.
The latest of eight Skills England apprenticeship units
The addition of battery manufacturing welcomed by ECA with a warning about the risks of fast-tracked apprenticeship units.
Building Control Independent Panel final report
A precis of a key report led by Dame Hackitt with full recommendations and link to the government response.
Building Safety recap April, 2026
A short and longer run-through of the month, with links to further information and sources.
CIAT May 2026 briefing.
From medieval scribes to modern word art.
ECA welcomes crackdown on late payment and push for clean energy, whilst CIOB seek fixed cladding removal timeframes.
Cyber Security in the Built Environment
Protecting projects, data, and digital assets: A CIOB Academy TIS.
Managing competence in the built environment
ITFG publishes new industry guide on how to meet the ICC principles.
The UK's campaign to reduce noise pollution: Mythbusting, articles and topic guides.