Wobbly Glass

[Flyfisher]

We have a number of original windows that are glazed with wobbly glass and it's . . . er . . . wobbly, ie it gently distorts the entering light as one moves one's view through it. It's not easy to describe the exact effect though it is quite a 'gentle' form of distortion. I'm sure many people here will know exactly what I mean, probably through having similar glass in their own homes.

The reason for mentioning this is that I was recently at Hampton Court Palace and noticed some 'wobbly glass' that looked very different to anything I've seen before. The glass was certainly not clear but had very defined lines of distortion such that the overall effect was very different to the 'wobbly glass' I've seen before, especially when close to the window. I hope the attached photos convey what I'm trying to explain.

Does anyone know how this sort of glass was manufactured? Is it a modern approximation of the more gentle 'wobbly glass'? Any other thoughts?

 

[MikeG]

I believe it is blown glass, which is cut and opened out from the bottle-shape to the flat just before it cools.

 

[Kearn]

Maybe the person blowing it was a little short of breath, rather than giving big smooth lungfulls..

 

[88v8]

Yes, as Mike says, it could be cylinder glass.

Good descriptive site here albeit no pics
http://londoncrownglass.com/About.html

Tatra can supply
http://tatra-glass.co.uk/cylinder_glass.php

Did you also notice the sashes hung on chains?

Ivor

 

[livias]

Early is spun glass so curved lines in it
Later is rolled glass as ohers have said
Now is float glass. To get the old effect on the cheap you can use greenhouse quality glass which may have bubbles etc and is thin

 

[JanJonWestWales]

thought it was called "float glass"
According to Wikipedia........
Until the 16th century, window glass or flat glass was generally cut from large discs (or rondels) of crown glass. Larger sheets of glass were made by blowing large cylinders which were cut open and flattened, then cut into panes. Most window glass in the early 19th century was made using the cylinder method. The 'cylinders' were 6 to 8 feet (180 to 240 cm) long and 10 to 14 inches (25 to 36 cm) in diameter, limiting the width that panes of glass could be cut, and resulting in windows divided by transoms into rectangular panels.

The first advances in automating glass manufacturing were patented in 1848 by Henry Bessemer, an English engineer.[4] His system produced a continuous ribbon of flat glass by forming the ribbon between rollers. This was an expensive process, as the surfaces of the glass needed polishing. If the glass could be set on a perfectly smooth, flat body, like the surface of an open pan of calm liquid, this would reduce costs considerably. Attempts were made to form flat glass on a bath of molten tin—one of the few liquids denser than glass that would be calm at the high temperatures needed to make glass—most notably in the US. Several patents were granted,[5] but this process was unworkable at the time.

Before the development of float glass, larger sheets of plate glass were made by casting a large puddle of glass on an iron surface, and then polishing both sides, a costly process. From the early 1920s, a continuous ribbon of plate glass was passed through a lengthy series of inline grinders and polishers, reducing glass losses and cost.

Glass of lower quality, drawn glass, was made by drawing upwards from a pool of molten glass a thin sheet, held at the edges by rollers. As it cooled the rising sheet stiffened and could then be cut. The two surfaces were of lower quality i.e. not as smooth or uniform as those of float glass. This process continued in use for many years after the development of float glass.

 

[wobs]

As an aside, I have recently ordered some more wobbly glass, to replace some I broke some time ago.

Our normal glass supplier who does stained glass etc, usually has a stock of horticultural glass in stock, which is slightly wobbly, but a modern approximation. Unfortunately, he says that horticultural glass is now made to a higher standard, and just as flat as float glass.

Fortunately, he has a bit of old wobbly glass in stock that someone had given him, so I am sorted, when its ready.

As for the pics in the OP, is it possible it was made the same way as our normal wobbly glass (blown, and rolled out), but done before the technique was perfected?

 

[noj]

That looks like some sort of machine made, textured glass to me (but can't find an obvious maker) - bet the pattern repeats.

Anybody seen this stuff - http://www.herefordglass.co.uk/restoration-glass/ - it's a float, can be toughened, but no idea what it costs?

 

[Flyfisher]

As for the pics in the OP, is it possible it was made the same way as our normal wobbly glass (blown, and rolled out), but done before the technique was perfected?

Who knows? I understand the technique of blowing and then rolling out glass to make it flat but I can't really imagine how such a process would result in the many straight lines shown in the photo. It wasn't so much wobbly glass as obscured glass.

Noj's comment about it being machine made is understandable from looking at it but surely not in the context of it being in such a fine building as Hampton Court Palace. I'm assuming it's either original or has been replaced with something akin to the original for glass of that period, but it is only an assumption.

Whatever the actual history, such glass would have been fine for admitting light but almost useless for viewing any outside detail.

 

[Me!]

Looking here at how Reamy Glass is made - https://www.lamberts.de/nc/products/reamy-glass/, perhaps it is something similar?

 

[Penners]

If you want the effect of medieval glass, but can't find/afford anything that looks truly wobbly, the best solution is to use ordinary modern glass and then to knock back a few gins before you look through it.