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Glass Discussion & Research. No ID requests here please. => British & Irish Glass => Topic started by: Anne on January 16, 2010, 11:21:10 PM

Title: Apsley Pellatt, the Falcon Glass Works, London
Post by: Anne on January 16, 2010, 11:21:10 PM
The Falcon Glass Works, in London, or 'APSLEY PELLATT'S WORKS' are described in a long, florid and prosy article on Lee Jackson's fascinating Victorian London website. The piece is from The Busy Hives Around Us, dated 1861, and describes the glass works and the glass workers and what they do. It covers recipes for glass, the furnace, blowing and cutting, and interestingly (as a subject we've discussed on the board before) the cause of sweating in glass, and more besides. It's quite a long piece but well worth reading: http://www.victorianlondon.org/professions/glass.htm
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: KevinH on January 17, 2010, 12:11:55 AM
Fascinating  :)

I wonder what the research source was for:
Quote
The sand is brought from Aylesbury in Buckinghamshire, and Alum Bay in the Isle of Wight.
Maybe that's true, but Apsley Pellatt himself, on page 35 of his own book, says:
Quote
Formerly, flints were calcined and ground, ... but for many years past, Isle of Wight, Lynn, or Reigate sands have been substituted; ...
No mention of Aylesbury as a famed source of sand suitable for glass making!
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: Anne on January 17, 2010, 12:15:18 AM
Aylesbury isn't on the coast methinks Kev... how curious! The Internet Archive has the full text of the original book here: http://www.archive.org/details/busyhivesaroundu00londiala which includes illustrations to accompany the article.
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: KevinH on January 17, 2010, 01:16:36 AM
In fact, Aylesbury is barely three miles (5 km) from Halton Woods, near Wendover, one point in which, is the furthest place in England from any coastline. However, Reigate is not coastal either, but presumably had sufficient quantities of good quality sand in its locality.
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: Anne on January 17, 2010, 02:05:07 AM
Ooohhh I hadn't realised about Reigate... I wonder where I was thinking of on the coast  then...?  My brain is a bit scrambled this week as I've had a lot of sleepless nights with the pooch who is suffering from canine dementia and tends to "sing" at night when we're trying to sleep! ::)
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David E on January 17, 2010, 11:01:37 AM
A little background on the Falcon Glassworks, courtesy Old English Glasshouses, Francis Buckley* and A History of Glassmaking in London, David C. Watts', the latter of which has many illustrations and far more background detail.

Was thought to be founded in 1693 as the Falcon (Faulcon) bottle house, and underwent several name changes from c.1752 until c.1802. The site was not always fixed either as the works moved to Holland St in 1814 (by Green & Pellatt) and the Old Kent Road (passing 'Go') in 1877 and then to Stourbridge in 1895. Pellatt's involvement appears to date from 1803.

According to Watts, "From the same account[1] we learn that sand for the batch came from Aylesbury in Buckinghamshire and Alum Bay in the Isle of Wight.". David may very well be able to expand further on the source of sand. I know that sand mines were not necessarily coastally-based but, of course, land does not remain static and marine skeletons can be found halfway up mountains! :)

*An excellent historical book, published and reprinted by the Society of Glass Technology (http://www.sgt.org), but seriously marred by the lack of an index!

1. Ref. The Busy Hives Around Us, 1861, James Hogg & Sons
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David E on February 03, 2010, 12:09:12 AM
Just a little update on this, but according to J F Chance's book, A History of the Firm of Chance Brothers & Co. Glass and Alkali Manufacturers, 1919, Chance Bros. was also using sand from Leighton Buzzard - this is from my own scribblings:

Quote
The sand Chance Bros. used for making glass was, until 1835, being transported from the Isle of Wight and proved to be an expensive commodity when using sea, road and canal to reach its destination. A new supply was found much closer to home near Leighton Buzzard in Bedfordshire and proved a worthy replacement. The land was finally bought in 1842 and the first sand mine created at an area called Heath and Reach.

I'm not sure if this is relevant, but Leighton Buzzard is not far from Wendover. I wonder if there is a tenuous link between the two companies?
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: KevinH on February 03, 2010, 12:47:07 AM
There are still gravel and sand workings around the Leighton Buzzard area and possibly also at Heath & Reach (I've not been there for many years).

My earlier Wendover reference was for furthest point in England from the sea, but yes, Aylesbury, Leighton Buzzard and Wendover are ptretty much in the same general region. But Wendover is on the edge of Aylesbury Vale / Chiltern Escarpment (chalk) and may not have the same ground structure as the other towns. However, I really have no idea what I am talking about now, so I will stop before I dig myself into a pit of some type. ;D
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David E on February 03, 2010, 12:08:10 PM
Thanks Kev. I was wondering if Apsley Pellatt was purchasing sand from Chance Bros. due to the latter's ownership of the mine from 1842?
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David W on February 03, 2010, 04:35:55 PM
Many thanks to David E for his comment. My book also quotes The Busy Hives Around us. It is dated 1861, just after Pellatt (1859) so the sources of sand should not be written in tablets of stone (Ha! Ha!). I was more worried about the suggestion that the best crystal was made from batch materials without the addition of cullet. This seems to me to be highly doubtful although the sort of thing the firm might say to impress an inquisitive visitor. Remember that story of the glasshouse owner throwing a sovereign into a pot to colour gold ruby glass? It was quoted for years. Secrecy and putting competitors off the scent were all part of the activities of the time.

Pellatt is interesting in that we tend to take his account as totally accurate in all its detail. The Busy Hives may have a sting in its tale!
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David E on February 04, 2010, 02:57:41 PM
I've always wondered about cullet and the advantages of using it, but as glass that has been previously mixed, it should have good properties. But Ray Drury (former Chance chief engineer) was quite adamant that Chance's glass was far superior to Pilkington's because it used cullet. Strangely enough, Pilks in-house magazine, c.1960s, was called Cullet News!

So was this seen as a way to save money, or improve the quality of glass? I'll ask Ray. Of course, the differences between rolled-plate and fine lead crystal is poles apart!

But in a visit to the works at St Helens in 2007, it was evident that Pilks used cullet, with huge quantities of it being shoveled into the hopper, mixing with the sand and chemicals, prior to entering the tank furnace.
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David W on February 04, 2010, 05:26:36 PM
Glass Circle News has been running a series on the importance of cullet in founding glass. The forthcoming (March issue) includes an article by a recently retired professional expert on the subject. Its particular purpose is to reduce the melting time and temperature and so prolong the life of the pot/tank. All glasshouses generate a certain amount of cullet from their own furnaces which would have been available for making the best new glass. Cullet collected from other sources would probably have been used for a lower quality glass.
The article is about non lead glass and the author says a minimum of 10% is desirable.  For modern large scale melts it is crucial properly to clean it up first. It's worth a read (when it comes out next month) for those interested in the subject.
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David W on February 04, 2010, 05:57:25 PM
Cullet -historical thoughts.

In my Glassmaking in London, p. 142, is reproduced a section of Rocque's 1746 map showing the Salt Petre Bank glasshouse near the Tower of London. Next to the glasshouse is shown what is clearly a huge pile of cullet labelled on the map as "Glass House Hill".

During WW2 I used to ride on my bike past the Glasshouse of Davey and Moore (Brimsdown, Enfield). I was always impressed by a colossal pile, some 8 or 9 feet high, of broken glass nearby sparkling in the sun. I was too young at the time to know why it was there but now I realise that it must have been cullet. There is more on this firm in www.glassmaking-in-london.co.uk.

When Pilks still had their own museum (some time in the 1970s?) I was shown round the float glass plant. The broken glass in large heap of batch being fed into the oven was clearly visible. When you see the glass coming out it makes you realise just how much batch has continuously to be fed in.

A glasshouse I visited in Damascus and another at Hebron, near Jerusalem, before the present troubles, both appeared to make their glass entirely of broken bottles in pretty crude oil-fired furnaces which is why I think it tends to come out with so many bubbles in it. Blue glass was made by stirring in a paste of copper salts (sulphate or nitrate I would guess.)
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David E on February 04, 2010, 10:30:10 PM
Fascinating stuff - it's always with regret when we took things for granted in childhood, something which is now long gone :-\ Interesting that you were at Pilks when Ray was at Chance Bros, which meant regular trips for him up there. He was quite amazed when we were there in 2007, to see that Pilks was still using some of his installations on the rolled-plate plant. He left in 1976! I was also very impressed by how much was being fed into the furnace in the rolled-plate plant - a very impressive sight.

I see that map in your book is dated 1746 - quite amazing.

I got a speedy reply from Ray, which is most interesting:

Quote
We used a lot of cullet because it was much easier to melt and refine than frit.Pilks also used cullet but I don't know in what proportion. I used to know the proportion but not now but it must have been in excess of  80%, except when we were making coloured when a large proportion was frit to get the colour right. The cost was the main reason but cullet did improve the quality as the glass had already been refined. Quality control of the cullet was paramount. Ferrous was easily removed but a single aluminium bottle top could cost us a fortune in production.

I'll ask Ray to qualify the 80% figure - sounds like they were recycling more glass than they made!

Ivo might be able to expand on Middle-east glass production.
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David W on February 04, 2010, 10:53:19 PM

Yep! what Ray says fits exactly with my understanding of the situation.

However, I was thinking that increasing the proportion of cullet decreases the amount of frothing you would otherwise get from a raw batch. But Ray talks about adding frit which has already been cooked to remove the gases from the carbonates etc. Hence using cullet not only helps the melting it also saves on the preliminary cooking that would otherwise be required  for the batch.

I call that a win-win situation!!!

The article coming up in Glass Circle News talks about the rubbish that has to be removed from the recycle bin ranging from a banana skin to a handbag complete with contents.

Incidently, the batch for lead glass generates very little froth as most of the carbonate is replaced by lead oxide. So in that case the cullet could be added directly to the batch.

Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David E on February 05, 2010, 09:02:27 AM
Hard to appreciate molten glass actually frothing! :o But this could introduce tiny bubbles, which affects the clarity I suppose.

One glass technologist on this forum who has proved most helpful to us in the past is Adam Dodds (me in particular, my book, p.32), who might like to offer something about the industrialisation side of glassmaking. I'll give Adam a nudge.

Always fascinates me how the small addition of a chemical can drastically alter the mix and colour - although the story of throwing in the gold sovereign probably has some basis of truth, with a manager doing it to impress some clients, Ray's thought that a single aluminium bottle-top could have a really diverse effect is quite amazing, considering the massive bulk of glass in these tank furnaces.
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David W on February 05, 2010, 02:01:03 PM

Its not the molten glass that froths, it is the carbon dioxide released in the earlier stages of the melting process. In one studio glass experiment I saw described at an Association for the History of Glass meeting, quite spectacular pictures indicated that perhaps half the batch could be thrown out of the pot by frothing when the batch is added to an already hot pot. Fritting causes a controlled release of the carbon dioxide so that this does not happen.

As you suggest the residual bubbles do cause problems with fining which is why Bohemian crystal is often plagued with a myriad if tiny seed bubbles. This makes most early Bohemian crystal instantly recognisable. Masking this problem may be why much quality continental glass is so heavily engraved.

Full lead crystal glass does not suffer from this problem.
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: Adam on February 05, 2010, 02:34:56 PM
Thanks for the nudge, David E.  I would have missed this due to the well-known fact that very long threads do sometimes find the subject matter changing part way through.  One or two points I might make.

First, briefly a word of warning about the word "frit" when coupled with reference to Pilkingtons.  For some reason, Pilks used the word to mean the same as what all the rest of the industry called "batch", i.e. mixed raw materials which were not, so far as I know, "fritted" in the heat-processed sense used by most people.

David E., I think I can understand why people find the concept of glass "frothing" hard to visualise.  Remember we would be talking about glass at the temperature at which it is melted, which is a lot hotter than its working temperature which is how most people see it.  Think of warm or even hot golden syrup (and no, I haven't seen that froth!).  About five years ago, buried deep in a thread called "Glass Moulds" I said, following talk about stirring glass, I think, I said:-

"This sort of treatment was highly respectable and was (is?) used all over the world.  It was also called blocking, but we peasants always called it tatying.  It could be used for at least two different reasons.  The first was to use the large bubbles of steam produced to sweep away any fine bubbles (seed) remaining from the melting process.   The second reason, and the one for which I tatied most frequently, was to mix the melt thoroughly, usually if I was changing colours.  Anything which produces huge glugs of gas and generally stirs up the melt can be used.  The textbooks talked about wet banana stalks and the Germans reputedly used lump vitreous arsenic (arsenious oxide) which was very dense and therefore could be just chucked into the pot.  Big wads of wet newspaper have been talked about, but I'm not sure how that was used.  We used big potatoes, one at a time, cutting a hole in so that the sharpened end of the heavy rod (maybe 3/4" dia at least) could be forced in.   After maybe a minute of glugging, thumping and minor earthquakes the remains of the spud would break free and bob quickly to the top.  Molten glass does not wet carbon, so  the black thing was easily fished out.  Visitors were always surprised that the bit of spud left in the middle was still raw.  We would only need a second go if the spud came off the rod prematurely.  

  I vividly remember being called in once during the night because a pot of cadmium yellow (still a bit experimental) was refusing to clear of seed.  It must have somehow (I haven't a clue how) become  supersaturated with gas because when we tatyed it half the pot contents came out on to the floor looking like a cross between candy floss and something out of Quatermass!  That was the exception - tatying was normally a benign if spectacular process."

With hindsight, the excess gas might have had something to do with lack of cullet.  Any new composition obviously couldn't use cullet to start with because there wasn't any!  I cannot remember whether this was a first attept (zero cullet) or just early production (very little cullet).

Re cullet in general, I have made glass with cullet content varying from zero to 90% or higher.  At the extreme ends odd things might happen as described, but in general the amount used depended on what was available on the day.  I have little or no experience with bottle or flat glass production where "foreign" (i.e. not produced in-house) cullet is used and where tight economics may dictate a close watch on the effect of cullet ratio on melting rate.

Re sovereigns thrown in the pot I too have heard this one from trusted sources within the factories concerned.  I'm still not convinced and it was much too expensive to have a go myself!

Since typing the above, I have seen David W.'s posting, which also covers frothing.  Re fritting, David, was this actually done in the non-Pilkington sense of the word?

Adam D.
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David E on February 05, 2010, 06:31:22 PM
Thanks for that Adam. I'll have to ask Ray Drury about his definition of frit. He was at Chance Bros. so there might have been some common usage of the term between the two.

I love the description of 'tatying'! ;D

Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David W on February 05, 2010, 10:51:45 PM

Many thanks to  Adam for his comments although tatying is not quite what I am talking about.
To really answer this problem of foaming we need to get just a bit technical although I was always bottom of the class at physical chemistry. So I hope I have got the maths right!
Let us just consider the contribution of calcium carbonate the molecular mass of which in round figures is 100 g -1.

Now consider a batch with 10%  or 100 g of calcium carbonate in a batch weight of one kilogram.
By definition one gram  mole of calcium carbonate contains one gram mole of carbon dioxide which, also by definition,  would occupy, as a gas, 22.4 litres under standard conditions.

The combined gas law tells us that p1 x V1/T1  =  p2 x V2/T2 where p = pressure, V = volume and T = temperature under the initial (1) and final (2) conditions. However, p1 and p2 remain unchanged and so can be ignored.
The final carbon dioxide volume, V2, then becomes V1 x T2/T1
If we assume starting and final temperatures of 20 and 800 degrees C. This becomes 22.4 x 800/20 or that the gas has expanded 40 times. In terms of common units this is from about 5 gallons to about  200 gallons or, more realistically, about half that amount since the temperature rise is not instant. Even so, by any standards this is a big volume. And this comes from only 1000 grams of batch.
It is this massive release of gas during the early stages of founding that causes foaming and which the slower rise in temperature in fritting avoids. I think fritting normally stops at about 500 degrees C.

Adam’s tatying is not caused to any extent by this process but, as Adam correctly explains, by the water in the potato, wet paper etc. being turned to steam – albeit superheated steam. The potato itself only chars because to burn it requires oxygen and there in not much oxygen in a glass melt.

I take Adam’s point about Pilks frit. It raises the interesting question of how the gas volume change is managed in a float tank furnace. One solution would be to substitute calcium oxide for calcium carbonate. Or it might be controlled by the speed of batch addition at the cooler end of the tank which is a quite massive affair. Are their any of Pilk’s experts around to explain this?

Re sovereigns: I understand that these were thrown in the pot but that they definitely did not colour the glass ruby.
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David E on February 05, 2010, 11:01:47 PM
Re sovereigns: I understand that these were thrown in the pot but that they definitely did not colour the glass ruby.
Just a quickie to say that I always thought this story was linked to Bristol Blue?
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David W on February 06, 2010, 12:25:49 PM

In my post  (#9 Feb. 3rd) on the source of glass sand used by the Pellatt works I gave the date of Apsley’s book as 1859. It should, of course, have been 1849 so that there was a twelve year gap between it and the 1861 Busy Hives Around Us article.

By 1861 Apsley had long been involved in parliamentary affairs and his younger brother, Frederick had been running the factory for some nine years.  This time gap may explain the different sources of sand stated to have been used by the two authors. The different sands said to have been used shows that the Busy Hives article was not just a rehash of Ashley’s book.

As with any historical detective work the time scale of the sources of information must always be considered. One frame does not always give the complete picture.

My apologies for the date error.


PS. Sorry David E, I do not understand how Bristol Blue (glass coloured by cobalt in the form of smalt) has any connection with gold ruby.
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David E on February 06, 2010, 01:10:23 PM
Quote
PS. Sorry David E, I do not understand how Bristol Blue (glass coloured by cobalt in the form of smalt) has any connection with gold ruby.
Not a problem: I would never purport to be a technologist, but it was just that I remembered a topic on this forum some time ago where I thought it was stated that gold chloride was used in true Bristol Blue (not the modern cobalt variant), hence the gold sovereign fable, but perhaps I got it wrong :-X
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: KevinH on February 06, 2010, 07:22:59 PM
For clarification (or not?) David's reference to gold chloride and 'true Bristol blue' appears in two earlier topics in the Board:

Identifying Blue glass..........Bristol, Cobalt, Irish? (http://www.glassmessages.com/index.php/topic,6818.msg58109.html#msg58109)
What's "Bristol glass"? (http://www.glassmessages.com/index.php/topic,19949.msg114407.html#msg114407)




Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David E on February 06, 2010, 07:30:14 PM
Thanks, but I may have been listening to my own rumours!  ;D
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: Adam on February 06, 2010, 09:58:59 PM
David W. - While accepting your sums (without checking them myself - I trust you!!) I don't quite understand the point about frothing (forget tatying).  In normal melting, pot or tank, using sodium and calcium carbonates in the normal way, I have never had any frothing problem nor have I heard of it happening to anyone else.  Of course frothing occurs, but not sufficiently to be a nuisance.  Having said that, we always filled our pots twice, the second time after the first fill had died down.  I suppose if we had stuffed as much batch as possible into an empty pot we might have had a problem, but why do that?  Am I missing a point somewhere, not having read every word of the thread?

Adam D.
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David W on February 07, 2010, 01:00:23 PM
Adam:-Your points are well made.      So the question is why, accepting the evolution of a large amount of CO2 and that the traditional way of overcoming this problem was a preliminary fritting (it is documented as the way used in 16th century Venetian glassmaking, for example*), do you not find it necessary?

The maths point up the huge gas expansion associated with temperature rise and my guess (no better than that) is a combination of modern furnace control and the speed of addition of the batch to a (relatively small?) pot. I guessed that Pilks use of raw batch in their float line might be controlled in this way.

I have never seen a pot being charged but I have watched a parison being rolled over a thin layer of sodium bicarb.in order to fill it full of decorative bubbles. So the effect is there, it must be a question of control.

 I wonder about the temperature of your pot at the time of charging and what you mean by “allowing it to settle” before the second addition and for how long? At a conference in Dublin some while ago we were taken to see some studio glass blowing but it turned out that the pot had only been charged for an hour or two and the glass, although fluid, was still too viscous to work. How long does it take for a batch to get to the point of use in a modern furnace?

Pellatt describes the length of time it took to found a pot of glass and how even this depended on whether or not the wind was in the right direction. The tradition of the glassworkers living on site and a bell being rung when the “crisis” (as it was called) was reached and the glass ready to work, were all part of this problem.

From what you say it does seem to me that modern technology has made it possible to eliminate the fritting process, an improvement I have not seen described before. What do you think?

*Moretti, C. And Toninato T, (2001) Ricette vetrarie del Rescinamento (Glass recipies of the Renaissance), Marsillo pub. The fritted product was described as “breads” (i.e. lumps the size of a bread roll and was stored as such for future use.) The Venetian texts never mention the use of cullet and I wonder how the batch to cullet ratio would also affect this problem.
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David W on February 07, 2010, 01:20:04 PM
Adam, I owe you an apology.
I have just quoted you as writing "allowing it to settle" when you actually wrote "allowing it to die down".
I have not yet discovered how to see your text and write a reply at the same time. Can anyone help on that?
So although I hope my quote means the same my apologies again for getting it wrong.
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David E on February 07, 2010, 01:34:29 PM
Quote
how to see your text and write a reply at the same time

Just scroll down - the full textual content is there when you reply to a topic.
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: Adam on February 07, 2010, 08:21:16 PM
Both Davids - Many thanks for asking and answering the question about seeing what one is replying to.  After all these years I hadn't noticed that I can scroll down just like answering an email!!.

David W. - You have mentioned 16th century glassmaking.  Now my glass technology is years out of date by most standards (I quit the industry 38 years ago and didn't have much to do with the melting side for ten years before that) but relative to the 16th century I must be fairly modern!!  If, as you suggest, fritting was used back then (and I wouldn't know) then "modern" practice has certainly eliminated any need for it.  Copious amounts of carbon dioxide, water vapour and (sometimes) nitrogen oxides are given off and for the last hundred years at the very least (and even I can't go back much further!) they have not represented the slightest problem. 

Batch when heated starts to bubble up as the components start to decompose and, if filled on top of existing glass (always in a tank furnace: usually in a pot) it will remain floating on top.  I suppose you could call it frothing, but that is a dangerous word in this thread!  Eventually it will settle down to something like glass but full of bubbles.

Re pots, David, ours held about a ton.  In our 12-pot furnace we would work six pots every other day, so the total time between first filling and working would be under 40 hours, but in many cases the time could be cut if it fit the shift working.  The second would usualy be five or six hours after the first, in some cases followed by a third at the furnaceman's discretion.  Nothing to do with frothing - simply the wish to achieve a brim full pot of good glass.  Present-day single pot furnaces could be much quicker than that depending on available temperature, open or closed pots etc. etc.

Re continuous tanks, the principles are much the same whether small 10 ton ones like ours or 1000 ton plus jobs as used in the bottle and flat glass industries.  In all cases the batch is fed in one end at a rate compatible with how much is being pulled out the other end.  In all cases some means is provided (often a solid barrier with a submerged hole or "throat") to hold back floating, partially melted batch in the "melting end" and to allow a drop in temperature in the "working end".

Small studio glassmaking his mushroomed enormously since "my" time.  The small quantities involved must mean that in many cases they would prefer to buy in batch from outside.  I know nothing about this (Adam A.?) but at the risk of opening another can of worms I would not be surprised if some form of fritting took place simply to make handling less dusty.

Adam D.
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David E on February 07, 2010, 10:25:02 PM
With regard to frit and the terminology (mentioned earlier in this topic), I had a reply from Ray Drury:

Quote
Yes I mean that 80% was cullet and 20% frit. [I queried the ratio - DE] There was not a lot of frit in evidence in the chutes down to the batch feeder which continuously fed the Rolled Plate furnaces but when it came to other glasses, possibly pot melted the proportion of frit could be almost anything. When we were making coloured rolled plate much more frit was used to get the colour.

So it would seem that both Chance and Pilkington used the term 'frit' to mean the sand mix.
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David W on February 19, 2010, 06:39:23 PM
Adam,
Many thanks for your explanation. I am sure it is not the first time that practice has not behaved according to theory. I was moved to look up another glassmaker , Harry J. Powell,  Glassmaking in England. He, page 13, quotes another ancient , Theophilus (c. 1140), as follows:-
“A mixture of the extracted alkali with sand and a small proportion of lime was heated in the calcar (a type of reverberatory furnace) until partly fused. When cool the fused mass, called “frit”, was broken into fragments and shovelled into crucibles standing in the melting furnace. In the crucibles the frit melted, became fluid and threw to the surface a scum of impurities. After the scum had been removed by skimming the remaining glass was ladled into pans of water. The water was drained off and the glass, when dry, was replaced in the crucible for final melting.”

Unfortunately,  according to this translation, Theophilus does not explain the workings of the fritting process although it becomes clear that the batch ingredients leave much to be desired.  I don’t suppose that you were troubled with scum, ladling into water etc.

It is always dangerous to try looking up the original text and when I turn to the translation of Theophilus by Hawthorne & Smith (Dover Books, 1979) I read :-
Chapter 4. The Mixture of Ashes and Sand.
“When you have arranged all this (i.e. built the furnace), take beechwood logs completely dried out in smoke, and light large fires in both sides of the bigger furnace. Then take two parts of the ashes of which we have spoken before, and a third part of sand collected out of water, and carefully cleaned of earth and stones. Mix them in a clean place, and when they have been long and well mixed together lift them up with the long handled iron ladle and put them on the upper hearth in the smaller section of the furnace so that they may be fritted. When they begin to get hot, stir at once with the same ladle to prevent them from melting from the heat of the fire and agglomerating. Continue doing this for a night and a day.”

That’s it. There is no account of what to do next as the Powell version suggests. And there is no mention of frothing.
How one equates these two quite different accounts is a problem. It has been suggested that Theophilus got his account from an even earlier one by Binguccio. Perhaps Powell was quoting the wrong author!
What is annoying though, is that although Powell explains all this historical stuff he does not say what they actually did at the Whitefriars works.

There is no need to reply that you did none of the above.
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David W on February 26, 2010, 05:55:31 PM
Adam, Re the term "frit"

I have just by chance come across a published Royal Institution lecture of December 8, 1933 by a Major R.M. Weeks, a director of Pilkington Bros.
In this lecture entitled "The Making of a Sheet of Glass" he first describes the batch components in some detail; he then says " Having mixed the raw materials, or frit as it is called, the next step is to melt it...."
So this fully supports the accuracy of your definition. Incidentally, there is no mention of any frothing, either when filling a pot by hand or mechanically for a tank furnace.

I also tried the GMB search facility for the word "frit" and was rewarded with a long list, some with a somewhat muddled understanding of the meaning of the word, such as picking up fragments of broken glass on the marver with a hot paraison. So it does seem that this is a word that needs to be defined for the context in which it is used.

One contribution that I had not previously noticed is that Pellatt records that he fritted (baked) his batch before use. Another suggested that the composition of fritted batch was not changed by the subsequent melting. I think this might on occasions be true but on most occasions some further change must have occurred as part of the founding process if the fritting, which should fall short of actual melting, was properly carried out.
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: flying free on January 26, 2017, 09:38:21 PM
Picture here of the Falcon Glassworks in 1827
http://alondoninheritance.com/wp-content/uploads/2015/07/Founders-10.jpg

and link to the article
http://alondoninheritance.com/tag/falcon-glass-works/

and quote from the article

'The Falcon name has other associations with the area.

Between the end of Holland / Hopton Streets and the Hopton Almshouses was the Falcon Glass Works. Built in the late 18th century by the firm of Pellatt & Green, partly on the site of a Millpond (the millpond can be seen on John Rocques map above. Look slightly below the red dot and to the left and a small shaded area adjacent to the road is the original millpond. The curve of the current road still maintains the outline of the millpond)

Writing of the Glass Works in 1843 in his History of Surrey, Brayley states that Their present importance and excellence are mainly due to the taste and exertions of the present proprietor and the employment of skilful hands on materials that science and experience approve. By these means the most elegant productions of the Continent are advantageously rivalled, and in some respects surpassed.

Falcon Glass Works as they appeared in 1827: see picture linked above

As can be seen, they were located at the point where Hopton / Holland Streets loop round, back to Southwark Street and Sumner Street. The same location now with the curve of the road (due to the original millpond) still very obvious:'

and an engraving of the interior in 1842 here
http://glassian.org/Making/falcon_glass_houset.jpg

http://glassian.org/Making/falcon_glass_house.html

m
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: David E on January 26, 2017, 10:42:20 PM
Thanks for that, M, but sadly I have to report that David C Watts, author of The History of Glassmaking in London, died December 2015. I have placed the notice here.

LINK: http://www.glassmessages.com/index.php/topic,64260.0.html
LINK: http://www.glassmessages.com/index.php/topic,64261.0.html

MODS: Remove whichever is inappropriate.

It is ironic that I only learned about this today, and you posted this topic soon after.

Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: flying free on January 26, 2017, 10:53:45 PM
oh my ... I've been looking at the site all evening - a great site, which I've used often and read extensively.
I'm very sorry to hear that.

m
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: Anne on January 27, 2017, 12:38:25 AM
David, thank you. I've removed the Cafe one and left the other in News, along with our other obits/notices.
Title: Re: Apsley Pellatt, the Falcon Glass Works, London
Post by: flying free on October 29, 2017, 11:54:57 AM
an 1850 engraving of the inside of the Falcon Glass House, Holland Street, Blackfriars.

https://collection.sciencemuseum.org.uk/objects/co66217/falcon-glass-house-holland-street-blackfriars-print