Manufacturing
The earliest floats, including most Japanese glass fishing floats, were hand made by a glassblower. Recycled glass, especially old sake bottles, was typically used and air bubbles in the glass are a result of the rapid recycling process. After being blown, floats were removed from the blowpipe and sealed with a 'button' of melted glass before being placed in a cooling oven. (This sealing button is sometimes mistakenly identified as a pontil mark. However, no pontil (or punty) was used in the process of blowing glass floats.) While floats were still hot and soft, marks were often embossed on or near the sealing button to identify the float for trademark. These marks sometimes included kanji symbols.
A later manufacturing method used wooden molds to speed up the float-making process. Glass floats were blown into a mold to more easily achieve a uniform size and shape. Seams on the outside of floats are a result of this process. Sometimes knife markings where the wooden molds were carved are also visible on the surface of the glass.
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