Antique Bottle mysteries

Ink Bottle
Medicine Bottle
Fire Grenade
Ink Well
23 May

An Old Demijohn Container with bottle mysteries!

I have gotten another old wooden molded demijohn in my collection. As an OLD bottle it is a carrier of many bottle mysteries. They include the following points and if anyone has any clues that will help describe the functions and characteristics that caused these markings, I will appreciate hearing from you. If nothing else it shows good reason to remove the old shipping wicker covering from an old bottle, sometimes.

One main mystery, is the pinch of glass on the neck at the top of the shoulder. It is obvious that it was done after the bottle parison was blown in the mold. So it must have been done to straighten the neck to a more vertical stance. The pinch tool that the glassmakers in Germany used for pinched alcohol bottles, could have been used to create this web of glass.

Demijohn Neck

Demijohn Neck

As you can see the straight tapered applied finish was sloppy, but the neck was still a bit crooked.

The next thing to point out that this pinch of glass is about ¼” thick and a good three inches long. It is not in line with the seams of the two part mold segments, so it was not glass pinched in the closure of the mold segments.

This picture is looking down toward the finish of the bottle. Note the top view of the pinch is at about 7: o’clock.

Demijohn Top View

Demijohn Top View

To continue with the mysteries: it is quite obvious to me that it was formed in wooden molds, made evident by the brushed out charred wooden surfaces on each side of the shoulder molded seams, with one side being higher than the other and the burn off of the match edges at the mold seams.

Demijohn Side Demijohn Side

Proceeding down the bottle there are two distinct areas of brushed out charred wood. One is near the bottom on the left in this picture. You can see how much was removed by looking at the bottom contour on the right side of the base of the demijohn.

Demijohn Side Wall

Demijohn Side Wall

The next mystery is that there are two pieces of tramp glass adhered to the side walls of the bottle. One is about ¼” wide and two inches long and the other is a little wider and two and ¼” long. One of these is shown horizontally in the picture above this.

The second one is near the bottom of the other side in this picture. These seem to be tramped glass in the glass wall of the demijohn. Where they even came from is a mystery.

Demijohn Base

Demijohn Base

The last and strangest mystery of all is the fact that the area where one would expect to find a pontil mark is actually a Y shaped marking about 5 and ¼” long. A really very strange marking and I have no clue of the tool used to make this type of mark, or for that mater if it was indeed an empontilling holding device for holding the glass formation for the work on the neck.

The glass is all bubbly and hints of inclusions exist through-out the glass formation. This is visible in some of the above pictures, as well as this one.

Inclusions

Base Inclusions

It is very evident to me that this bottle, was not made by an expert bottle maker; but it obviously was used to carry a liquid product. I have seen other similar bottom marks. I have seen demijohns similar to this with the mold seam going all the way across the bottom and up the sides to the neck. Any bits and pieces of comment will be appreciated.

contact empontilled

contact empontilled

This is a picture sent to me by an friend in the Netherlands that shows a demijohn with a long contact empontilled device being off from the mold parting line on the bottom.  He has no clue to the age but feels it is a very early formed bottle.  This is added to just show another example of this type of bottle mystery. Thanks to Willem van Traa.

– Red Matthews

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31 Aug

Cold Mold Ripple in Glass Bottles

Cold Mold Ripple Sample

Cold Mold Ripple Sample

It has always seemed strange to me that people started calling a *Cold Mold Ripple* something different than what it really is. Bottle collectors and sellers use the terms *Whittled *and *Hammered* to define what they see in the glass bottle. I haven’t found it referred to as this in the older books, but maybe they didn’t pay that much attention to it earlier. It seemed to come up in the newer books written after about 1927. I think the condition started when they changed from wood and brass to using cast iron for the bottle molds. This appearance is really the difference in the glass wall thickness. One also might explain it as an attempt to make people think the bottle they were selling came from a wooden mold. Thinking that the mold had been whittled with a sharp knife. I think it is time to start rethinking these terms.

Earlier American Historical Flasks didn’t have Cold Mold Ripple, until they departed from the cast brass shell molds that were used to make them in. When they started making them in cast iron molds, they started having the variable thickness in the glass.

These early molds were made in regular cast iron. These molds were also made with greater wall thickness than the early brass shell type molds. The characteristic of forming a bottle by blowing it in the mold; requires that the bottle maker has to create a required shape and size of the first stage of the bottle (the parison shape). This form was critical to having the bottle being blown, to produce a proper distribution of glass wall thickness in the walls of the blown bottle.

This savvy of parison design, size and shape was a bottle maker’s secret knowledge. When I went into the glass industry in the 1950s, this savvy could help a mold engineer direct changes needed to correct the distribution of glass in the bottle being made. If he had that knowledge he could almost select the numbers in his paycheck. Today the whole concept of this problem has been taken over by computerized parison shape design.

* * *

Now then back to the condition of *Cold Mold Ripple.* The early cast iron molds were cast against the sand in a casting flask box. There was a wooden pattern used to create the cavity part of the mold and a wooden pattern to create the outside form of the mold casting. These molds were basically had Grade “A” type of graphite in the iron. I touched on this in my blog, regarding Chilled Cast Iron Mold Cavities. The difference here is that the earlier cast iron molds were not used repeatedly in a fast enough cycle to build up enough operating heat in the molds. A higher temperature was needed to help the glass blow tight and evenly in thickness in the mold cavity. When the parison glass was blown against iron that was too cold, it didn’t let the glass flatten against the mold face, thus the bottle wall had a variation in thickness. This is what makes the glass have a difference in light translucence and what makes it look wavey or rippled like the surface of water when a pebble is thrown into it. If one measured the thickness variations in a broken shard of glass wall material, you would find this difference in thickness.

The whole process of making a bottle free-formed (F-F) by hand, or blown-in-a-mold (BIM), or made on an automatic bottle machine (ABM); each method has a major reliance on controlled heat loss in each phase of the glass forming. The starting temperature of the molten metal (glass) and the temperature needed for each effort to do anything with the forming of the glass, is temperature sensitive. The magic touch of the earlier bottle-maker’s work, thrills me when I get to study an old bottle and marvel at the products they made. Bottle designs were always changed as they had problems where their ingenuity could not correct the condition they were fighting when the bottle was blown. Venting, straps on flasks, champhered corners, scalloped corners and many other concepts were used to solve these problems. Heal tap in the bases of early square medicine bottles was one problem they had a hard time to overcome. Sometimes the shoulder blow-up in the mold was a big problem. Almost every hand made bottle fascinates me.

* * *

Now back to the term *Whittled,* I have tried to point out that this wasn’t even done in the wooden mold. It didn’t even exist in the early brass shell molds – so why do we use it?

First of all, I happen to have three bottles that I am confident were made in wooden molds. One is a demijohn made in a two-part mold that came about half way up the shoulder. At the start of the shoulder curve there were three large vent holes in each half of the mold. One of the holes must have become plugged when this bottle was blown, so there is dimple in the glass almost three inches in diameter and three eighths of an inch in depth, where the glass didn’t blow up against the mold surface. I am confident that this wooden mold was machined to its original shape, but the mold seams only come up about three inches on the shoulder and the rest of the shoulder is free formed with the neck. The cavity walls have areas where loosened carbon fines were cleaned off , that give the body neat characteristic patches of diameter change. It should also be noted that the two main mold seams are raised more than they would be in an iron mold – again suggesting wooden mold burn-off.

This bottle has a nice large blowpipe tubular pontil on it with one side about a half inch long. There was a wooden bottom plate that the mold halves closed around. The bottom seam is set in about an eighth of an inch from the mold diameter at the base and it provided the basic push-up with a contact radius ring around the bottle base where it rests on a surface.

The entire bottle has a mottled surface that makes me think they used a coating on the charred wood surface to protect the wood. It could have been any number of materials, but it was no doubt bee’s wax with sulfur powder in it. What ever caused the mottle, it is not Cold Mold Ripple.

My other two wooden mold bottles were early medicines and the differences in the shoulder height of the upper corners from burn-out is obvious when you compare them. Their surfaces hinted of a coating and there was no Cold Mold Ripple condition, but actually the bottles are probably too small to have it.

In the 3-part molds the dip cast iron part of the mold often had a base ring on the base of the casting and boss iron protrusions on it to hold the vertical hinge pin for side swinging shoulder sections. The base of section of these bottles is usually full of cold mold ripple in the glass while the shoulder-molded section of the bottle is often free of the ripple effect. The shoulder sections had less iron mass and therefore ran hotter than the dip mold base,

Since retirement I have spent a lot of time studying SARATOGA Mineral Water Bottles and I knew that they had changed to chilled cast iron in the time zone of 1862 to 1864, because the bottles stopped having as much Cold Mold Ripple in them.

Another interesting thing is that the Cold Mold Ripple is normally horizontal in the glass. On three occasions I have found it to be vertical and one of those was only vertical on two vertical panels that were on each side of a flask type bottle.

* * *

Now to get back to the *Hammered *description; it just isn’t done in a mold unless it is required to crate a rough cavity or a stippled cavity for the glass to look frosted or have a special surface. Therefore I can’t see how it applies.

Then to be equally ridiculous, no one hammers in a bottle mold unless your want to obliterate an area of lettering that is no longer wanted. Even then it is best done with a riffle file or a round steel cutter burr. Any thing you do in the cavity of the mold will make a mark on the glass. I have some examples of early mold repair done in the 1850 to 1900s where they milled out a section of iron and filled it in with weld. That is a subject that I will be covering in a blog, on the repair of bottle molds. My problem is that there wasn’t much written on this subject either.

When I came into the industry to work, I had to question the: who, why and when; they started chilling the cavities of cast iron bottle molds. I was also at a time, when they put the mold equipment on flame tables to pre-heat it before it went on the glass machine. If the equipment lay on that table of flame too long, they cooked the hell out-of-it and caused a lot of fire cracking in the cavity iron. These marks can be found on early ABM bottles, but I have never found them on hand blown bottles. The machine production speed and the table preheats was just too much for the iron. We made molds out of many different metals to study the effects of different alloyed metals for their resistance to this damage and to evaluate the glass surface qualities produced when it was blown against the different metals. That too is a different subject to cover.

Red Matthews

PATENT: Improvement In Glass Molds

Click here for the Patent PDF
52338_IMPROVEMENT_IN_GLASS_MOLDS-2

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14 Aug

Chilling the Cavity of Cast Iron Bottle Molds

Who, Why, and When

I got a job at the Thatcher Glass Co. in Elmira N.Y. to work in their Central Mold Division as an Applications Engineer and management assistant. After being there for about a year, I was invited to attend a meeting of Glass Plant Managers and Production Engineering people. After the meeting, the V.P. of Manufacturing asked if anyone had any questions. So I asked what I thought was a legitimate question, “Who, Why and When, did they start chilling the cavity of the cast iron bottle molds?” No one could answer the question. It sort of caused a few dead moments, then this V.P. informed me that I had been hired to help with improvements in manufacturing the molds and didn’t need to know the history of things. His reaction made my boss expect that he would be told to fire me. It didn’t happen, and in fact a few weeks later Mr. Burd, came to me and told me that his engineering notes from his former job with Dominion Glass in Canada, which was similar to what he felt my job here should be, were in a trunk over the bottle sample crib and that I was welcome to read and study them, but he didn’t know the answer to my question.

Anyway, I had asked enough questions and put together my own understanding of; “Why” the iron was chilled. I had a friend at the Overmeyer Mold Shop in Muncie, Indiana; that helped me a lot in learning about the castings of mold equipment. Chilling the mold iron was done to create a closer grain in the iron that the glass contacted. This meant a better polish could be obtained in the finished mold cavity.

I also found out that the carbon grain structure of chilled iron was dendritic, and these dendrites were aligned in rows of carbon that ran in a straight line out through the cast iron. This metal form (illustrated below) ran away from that chilled surface for about a ¾” length. This structure of iron has a slower thermal conductivity than regular “A” type graphite in the normal cast iron. This slower conductivity of temperature caused the cavity contact metal to run hotter than the old plain iron molds.

The results were a smoother surface on the glass and a more even blowout of the glass against the mold surface, reducing the effect of the wavy glass that bottle collectors call a Whittled or Hammered look in a bottle. I prefer to call it “Cold Mold Ripple” because it looks to me, like the ripple on water when a pebble is tossed in. This Cold Mold Ripple is usually seen in the lower dip mold section of an old bottle, because that iron did not get hot enough to let the glass blow out flat against the mold cavity surface.

The real truth of the “Who and When” didn’t come to me until a little over 50 years later, when I found the answers in the book: “EARLY AMERICAN GLASS” by Rhea Mansfield Knittle. First published in 1927, two years before I was born.

This lady put together my second favorite book on this Important and First American Industry. The book is a review of Colonial Glassmakers and Glass Houses with a lot of information. Including the, Who, Why and When that I asked for so many years before.

The process of chilling the mold iron cavity metal was developed and patented by Mr. Michael Sweeney. He was involved with several different glass house operations in the area of Wheeling, West Virginia and across the river at Martins Ferry, Ohio.

This is a review of where I found this basic information in the book.

Mrs. Knittle covered some of the problems of mold seam marks and decoration sharpness on decorated glassware being made for the tableware being made in the glass industry. She pointed out that sometimes the glass had to be placed near the furnace hole to reduce the roughness of the mold seam, a troublesome fire polish effort. They placed the mold seams where the decoration would hide the seams, but the sharpness still couldn’t approach the sleek surfaces of cut glass. She pointed out how they tried to cool the molds with metal air tubes between the glass piece cycles and that on occasion their problem was having the glass stick to the mold surface.

In the book on page28, in the first paragraph, she wrote: “The process invented by Michael Sweeney for chilling the inner surface of the mold, explained in another part of this volume, eradicated much of this trouble.”

I had to read on and in chapter XLVII “THE WHEELING-MARTINS FERRY GROUP” is discussed. In the first paragraph of page 394 reads: “Michael and H.R. Sweeney, who later became leading figures in the mid-Western glass industry, established their first house in the northern part of Wheeling in 1835.”

The story continues and at the bottom of page 397: “Just before the Civil War broke out, the house (of Wallace, Giger & Ensell) was on the verge of failure, when Michael Sweeney of Wheeling and James Phillips took over, establishing the well known firm of Sweeney & Co.”

This company grew and added other glass men and developed, including the addition of glass presses, discussed in the Knittle book. In the third paragraph of that page she wrote: “Michael Sweeney has obtained a permanent place in the history of glass-making as the inventor of an improvement whereby the inner surface of the mold is chilled to proper temperature, rendering the metal susceptible of the smoothest polish and giving the product a sharpness of outline almost equal to that of cut ware – a condition never before obtained.”

I had known that this patent must have been obtained around 1862 or 1863. In my quest for and in my studying of bottles of the SARATOGA Mineral Water era, I had decided that this chilling of mold cavities must have developed in the SARATOGA glass production around 1864. It was obvious because of the change in the surface sheen and condition of the bottles. The concept of chilling mold cavity cast iron must have taken off through out the industry.

I have not been able to get a copy of this patent from the U S Patent searches. Apparently some of the patent records were destroyed. If anyone knows of other book reference material on this subject, please advise me.

The following sketch is to illustrate the cross section of a mold and to show the dendritic carbon characteristic and tight iron matrix of the iron next to the bottle mold cavity:
Types of carbon graphite structure in a chilled mold cross-section.

The chilling of cast iron mold cavities was accomplished by placing a cold cast iron form of the objective cavity on top of the drag of the sand casting flask set-up. This iron chill had to be placed so that it lined up with the mold cavity pattern, which was formed in the sand pack of the cope section of the flask set-up. This is best pictured by another sketch in my opinion. After the molten cast iron is poured into the feeder sprue to the cavity in the sand of the cope, the flask assembly has to be knocked down and the old cold cast iron chill piece has to be knocked out of the mold casting half, before it is seized by the shrinking mold casting. This same procedure is done for the other half of the two-piece mold equipment.

Position of the mold in a foundry flask assembly.

The pattern for the chill has to be smaller than the final cavity size of the bottle. The pattern makers have to allow for about 1/8” of the surface metal in the cavity to be machined off when making the final mold cavity. The pattern for the chill has to also be sized to compensate for the shrink of the chill iron casting. There is also about 1/4 th of an inch of iron to be machined off the face of the mold casting.

All of this is simplified considerably from the standpoint of working the casting into the final mold assembly. There are parts to the pattern making that will provide a chill print in the drag for the setting of the iron chill in the green sand of the lower flask. There are special lugs that have to be on the end of the casting to allow for holding the castings while the parting faces are machined. These lugs are also involved when the two mold halves are turned and machined on the outside diameter, (an operation called banding). After the face milling and banding, the mold halves have to be machined on the ends and the initial machining of the cavity will take place in this operation. After that the mold cavity has to be machined to the sized specifications. This is different for all of the different kinds of molds that have ever been made. I put in this basic cycle of mold making because I was involved in the whole sequence of mold making operations. Anyone that is interested and wanting more information, ask me your questions.

Red Matthews

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04 Aug

Key Lock on a Shoulder Seam Bottle Mark Mystery

A while back I tried to buy a bottle that had a mold mark on it that I didn’t recognize. The mark was on the shoulder mold seam line, 90 degrees from the shoulder mold parting line seams. So it became a bottle mystery. Unfortunately or untimely I found the solution before I got this one written up. This was an early utility bottle that sold on eBay. I didn’t win the sale, also unfortunately. Now that’s three un-‘s.

Here is a picture of the mold mark that puzzled me.
keyed lock system (top right), which was called a Full-height Three Part Dip Mold

I was studying in my #3 Favorite Book “The Illustrated Guide to Collecting Bottles” by Cecil Munsey, and found the answer on page 39. There was mention of keys being used to hold mold shoulder sections on molds as far back as 24 AD and before the hinged shoulder sections. Now that perked my interest. I read on and found that early dip molds for bottles were set up with vertical lifting shoulder sections. Some hinged on two sides of the dip mold for lifting up and out to release the blown bottle for lifting it out vertically. These were often keyed in lock-up to the top of the dip mold by key slot in the side of the dip mold at the top seam match and a key on the shoulder section that locked into the dip mold keyway, producing a positive location of the shoulder sections on the dip mold. Some molds were set up with a vertical hinge pin on the side of the dip mold and side swinging shoulder sections that could be opened and closed by a mold attendant to permit opening and lifting the formed bottle out of the dip mold for empontilling and finishing the top of the bottle to the desired finish. Full-height three-part mold.On page 43 there is a picture of this first keyed lock system, which was called a Full-height Three Part Dip Mold. On that same page the next picture shows the side swinging shoulder mold system, which was also called a Full-height Three Part Dip Mold. Both pictures were from Dr. Julian Talouse’s work.

I am quite sure my mystery bottle was done on the first type of mold pointed out here, although the picture does not appear to have a lock key system. Earlier dip molds had individual shoulder sections that had to be manually placed on the top of the dip mold after the parison was inserted for the blow. The method was too slow for the bottle makers and didn’t have much favor. They preferred to work with the free formed shoulder method.


Now you know, if you see this key mark on a shoulder match seam that, this was how it got there. Find one and you’ll have an old bottle.

Red Matthews

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01 Aug

Snuff Bottle Dot Marks Mystery

Through the years of bottle collecting I have never bought a snuff bottle. I have looked at them, fondled them, but never got the bug to buy one. Now I have done it.

I have heard and read in eBay listings that the dots on the bottom of these jars, were an indication of the strength of the snuff. I have been studying vent dots on old bottles for about 15 years and I have a good explanation for them. But I haven’t read in any of my reference books about the dots, being an indication of the content’s strength.

Snuff Bottle Snuff Bottle Base

This first snuff bottle has six dots on the bottom. For the size of the bottle, I am sure that two would have been enough to let the air out of the mold below the parison expansion in the final blow of the jar.

So I am looking for your help…

Red Matthews

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18 Jul

Hand Blown Bottles

The history of glass making is covered in lots of books. This is not to try to rewrite history. My object is to help the bottle enthusiast understand some of the skills that Early Bottle Makers have had to develop to create the beautiful bottles that they made. My main interest is in the American bottle industry, but with its acquired skills that go back over 3500 years. The early bottle makers went through a lot of learning to get these skills developed.

I once found a writing of a Master Bottle Makers work stages to making a bottle. Now I can’t find it. These men had to know glass making from start to finish. The art of making a Hand Blown Bottle takes in all of the technology of the batch, the process of proper melting and blending of the glass batch in the furnace. The objective form of the container he needs to make. The physical concept of gathering a proper amount of glass and forming it into a parison shape that will blow out to the container he is making. Hand blown Bottles may be free blown or blown in a mold. This later forming has the hidden concept of shaping the parison properly to obtain good glass distribution of glass wall thickness when it is blown in the mold. He also has to understand controlled heat loss, because each stage of his forming has to hold its shape and be moveable in each stage of the forming process. It is a mystery to me how they developed these skills and I have collected pieces that I wouldn’t part with, because they represent the unbelievable skill shown in their forming.

The Master Bottle Maker worked with a group of associates; their efforts being done as a group at the SHOP by their glass furnace. The teamwork depended on each person’s skill and the team accomplishment of making a good bottle depended upon each of their own participation. The team consisted of a gaffer, the bottle maker, two attendants, and a carrier.

The team worked around a Bottle Makers Chair. The tools they used were very much the same as tools used for seven centuries, in many parts of the world. They included iron or steel blowpipes, punty rods, scissors, pucellas or tongs, shears and shaping tools, marver plates of either stone or cast metal that was flattened to allow the glass to be formed on them. The wooden tools were: the battledore (a paddle type of tool for flattening the sides or bottom of a parison), a wooden ladle, shovel, forming blocks, etc. These wooden tools were kept in water or kept wetted, to prevent them from excessive charring when used to form the hot glass. The carrier had a fork type of tool for carrying the finished product to the annealing furnace. Some times the carrier used a set of tongs that had wooden gripping pieces to hold and not mark the glass.

The gaffer would have preheated tools available. When the glass metal (the molten and blended glass material in the crucible) had been in process for the proper amount of time, the team would be ready to make glass products. He would insert a blowpipe in the glass metal and gather a gob of glass on the pipe. Passing this to the Bottle Maker – he would puff some air into the blowpipe and then seal his mouth end of the blowpipe with his tongue or thumb. The hot glass would expand the air that was in the hollowed gob of glass and the bottle maker would then be on his way to making a product. Often he would have to swing the blowpipe to stretch the neck glass to the desired length. The process of reducing the glass diameter at the neck was done by this stretching and twisting to take it to a smaller diameter. It often left marks and bubbles in the bottles neck.

The Bottle Maker would add more air and begin the process of making the parison shape for the bottle they wanted to make. During many of his stages of shaping the glass he would have to roll his blowpipe on the side rails of his chair to keep the molten glass concentric. Due to the glass temperature at this point the glass would settle if it wasn’t rolled until the glass skin temperature was cooled enough to make it hold. He would also have to shape it using his tools as necessary.

The blowing of a glass bottle requires a series of functions, on the part of the Bottle Maker that involve controlled heat loss. The melted glass starts out at over 2000 degrees F. and the parison shape has to be stable for inserting in a mold for the final blowing. If the bottle is being Free Formed, the key thing is still the distribution of the glass in the completed bottle form, as this is responsible for the containers strength.

If the parison shape is to be BIM (ie. Blown-In-Mold), the distribution of the glass in that mold is entirely dependent on what the Bottle Maker created in the parison glass shape. In my collection of old bottles I have some unbelievable examples of perfection that are hard to think they could have been achieved. Improper shaped parison form can cause heal tapped thinness in at the bottom of a bottle. It can cause unfilled shoulders near the top of a bottle. The formed parison that he has made, is the secret of having a good distribution of glass in the product, when the bottle is blown.

When this bottle is blown, it has to be removed from the blowpipe and the subsequent completion of the bottle involves the shaping and forming of the bottles finish (top) specification as needed. To accomplish this, the normal earliest method was to use a previous blowpipe with the neck glass of the previous bottle still on it. The gatherer would have reheated this glass on the previous blowpipe and he would assist the Bottle Maker by attaching it to the bottom of the newly formed bottle. This process is the empontilling operation. The Bottle Maker would then chill the bottle’s neck for cracking it off or shearing off the blowpipe. The gatherer would reheat the new bottle neck glass in the window of the furnace and give it back to the Bottle Maker. Depending upon the finish specification, the gatherer would pick up some glass from the crucible and prepare a ribbon of glass to be applied around the neck of the new bottle. The Bottle Maker would then be responsible for tooling or forming the hot glass to the desired finish specification.

Later the blown bottles were put in a sabot, snap case, or a shoulder holding device for the Bottle Maker to apply glass and tool it to the specified finish requirement.

After the bottle is made, a carrier has to take it from the Attendant or the Bottle Maker and place it in the annealing furnace. It might be of interest here to mention that glass is always a liquid even when its viscosity is near 0. As glass is formed and moved in the process of forming an object from the hot molten glass metal, the material is stressed much like moving a metal sheet in a punch press die. This stress can be seen under special lighting, and is relieved by the annealing process, after the bottle has been formed. If the glass were to be set aside without annealing the stress would eventually cause it to explode and break.

Early American Bottles were made from glass raw materials found near their glass factory. The furnaces were wood fired and the glass batch was melted in ceramic crucibles. The making of crucibles was a localized responsibility which needed a good clay source. Some early crucibles were imported to the Americas for glass melting. It was of course a very expensive source.

The early glass was a soda ash type of glass. The silica sand at each glass house was a little different in iron content and the soda ash was normally the wood ashes from the furnace. These glass products had inclusions of the unburned carbon and impurities that caused a lot of bubbles in the glass. This early glass is often referred to as “Mountain Glass”. The location of a successful glass house depended on a good supply of wood as a fuel. The clay and limestone plus transportation were all considerations for where a glass house might survive.

This early drawing illustrates a lot of the operations that I have covered above and is a good illustration of the 1800’s glass house. Click the image for an enlargement.

Early Glass Manufactory

Early Glass Manufactory

Red Matthews

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