The mold repair half leaf mark was used when a nick occurred in the mold cavity by rough handling.  If in handling, a tool was dropped or the bottom plug was dropped into a cavity, such a nick could have occurred.  When the cavity was damaged it would require either throwing the mold away or repairing it.

Anyway, I have been working for about three years looking for the explanations of this mold repair process which seems to date its use between 1820 and 1860.  I have two SARATOGA Mineral Water Bottles with the mark of this “1/2 Leaf Repair” in the cavity.  I am sure that the failure was caused by something being dropped into the mold cavity and nicking the surface to the point where they had to repair the mold to keep it operational for a period of time.

In the case of these half leaf cavity repairs, the mold half was held on an angle plate, bolted to the face of a ball vise – by utilizing a handling hole drilled and tapped in the top of the mold.  The ball vise could then be twisted and locked where an end cutting milling tool could do the machining in the cavity in which ever direction the repair was needed.  I have examined my two bottles very closely and decided that the welded in metal ended up with a change in the carbon distribution.  The cast iron metal used for the earlier molds was a type “A” graphite found in plain gray iron castings. Mold iron suppliers had their own designated mold iron pulled from a certain level in the cupola to make sure it was right for glass forming molds.

This plain gray mold iron was also cast in a small rod form so they could supply the mold manufacturing and repair shops these rods for braze types of torch welding.  In the process of welding the welder would have to puddle the rod iron into a line and then after the mold half was preheated, he would puddle the iron into the machined half leaf cavity.  In this process the graphite in the iron was broken down into small nodules in the puddled material.  These small nodules were washed out of the mold in the area welded in.  Prior to use, the cavity weld metal had to be benched to riffle and smooth the patch material to the inner diameter of the mold cavity.  I have noticed that they did not try to re-cut lettering into this welded metal because of the concern of having the weld being broken out of the mold cavity.  I also doubt if it would chisel very well for re-cut the lettering.

The only exceptions I have found a half of a half leaf on the neck of one of my SARATOGA Mineral Water bottles. This weld repair was done right up at the top edge of the mold in the neck area. It was obvious that some of the mold in that area had been broken out. Further down in the same cavity there is a full half-leaf of weld repair done near the embossed lettering of the front panel. It was done nearly vertical on the left side of a “/ SARATOGA \” arched over a large “/ A \” over the “/ SPRING CO \” horizontal with the “/ N.Y. \” under that. The milled half leaf nearly removed the S of SPRING and the vertical part of the P in the lettering. Here are pictures of this bottle to show the welded patch and the riffling of the welded metal. Another unique thing about this bottle is the dense black color of the glass. There is no light penetration possible, but a lot of light reflection trying to photograph the bottle.

Another SARATOGA Mineral Water bottle I have, has this same type of half-leaf weld vertical and near the bottom of the back panel in that mold half. This is a pint bottle with an embossed front panel for: “/ EXCELSIOR \” arched over “/ SPRING \” horizontal over a lower arched “/ SARATOGA. N.Y. \”. It is also a later bottle than the one above because it has been made in chilled mold iron castings. This is evident because there is no Cold Mold Ripple in the blown out glass in contact with the mold cavity wall. The embossing is a better strike and there are two small mold vents drilled in the start of the mold shoulder of each half. These facts date that bottle after 1850. Evaluating the half leaf surface of this repair, we can see the marks of riffling and the texture of the washed out graphite giving the glass the cloth like texture.

This bottle goes along with the development of chilling the mold cavity metal.  It was  given a date span for the patent obtained by Mr. Michael Sweeney for chilling the inner surface of the molds.  Some where between  [1835 to 1845].  Though his interest in doing this was to help his pressed glass dishes and table ware release the glass with greater ease.  From what I have read he did it because this was done to plow points to help their wear life.  I doubt if they even knew that the thing that helped them was the difference in the iron grain size – to give the mold surface a better polish; and the difference in heat transfer to give them a hotter mold cavity surface.  Heat that helped the glass blow smoother to the mold surfaces.  Part of their objective was to help reduce the appearance of a rough mold seam on the glass.  These conditions were really helped by the improved polish, small grain size and the strength of the mold section match edges.  Prior to this, they had to flash re-fire the product to reduce these seam marks and this was an expensive process for a problem solution.  I have not been able to get a copy of the patent – I guess they were destroyed in the patent records fire.  Michael Sweeney and R. H. Sweeney, were in the glass business in the Wheeling, Martin’s Ferry Ohio and West Virginia.  They were also involved with other men from New England Glass and other operations.  There was a Henry Clay, James F.Barnes and John H. Hobbs and these men were all named in early glass companies in that area.  The news of the process was picked up by mold casting suppliers and spread to most parts of the world in a short time frame.

In my studies of these Half-Leaf Marks, I have had the help of Mr. Tod von Mechow, who is a well known authority of early Soda & Beer Bottles of North America. He sent me several pictures of this Half-Leaf Mold Cavity Welded Repair.

I also have had the pleasure of discussion with Mr. Jim Hagenbuch, the editor of the well followed magazine: ANTIQUE BOTTLE & GLASS COLLECTOR. In the February issue of 2009, he covered this same type of mold repair mark. He also gave me permission to include here, the pictures that were in his article.

In conclusion, I wanted to point out that many have thought these marks were created by a flap of glass being applied to the blown bottle – to cover a hole in the glass. Because of the temperature of the formed glass bottle coming out of a mold and the lack of available flat strips of hot glass for application, these concepts of accomplishment just do not seem possible to me. It just couldn’t be applied this completely in the shaped form or glass contact sealing of the bottle to contain any fluid contents.

– Red Matthews

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