Glass Tube: Drawn by Two Glassmakers Walking Apart (Pellatt, 1849)

How glass tube was made by hand: a blown gather of glass is welded at one end to a second rod, and two workers walk away from each other while turning, stretching the hot glass into a tube up to 60 or 70 feet long. Because the whole bubble stretches evenly, the bore and the wall stay in the same proportion all along the tube. Result: long glass tube of nearly even bore, cut into lengths when cold. Solid cane is made the same way without blowing. Source: Apsley Pellatt, Curiosities of Glass Making (1849), pp. 106-108. Unknown: the glass batch and the gather's size. Picture: the book's figures.

خبير

Unknown

التعليمات

Gather and blow the ball

Gather a solid ball of flint glass on the end of the blowing iron and blow it out a little, so it is hollow. When it has partly cooled, use it as a core for one or more further gatherings until there is enough glass. For flat-bore thermometer tube, flatten the first ball on the marver with an iron or wooden battledore before the later gatherings. Ours: lead crystal. Not given: the amount of glass.

المواد لهذه الخطوة:

كريستال الرصاص1 flint glass

الأدوات المطلوبة:

فرن زجاج قادر على بلوغ ١١٠٠ درجة مئوية

قصبة نفخ الزجاج

مارفر (لوح دحرجة الزجاج)

Swing it long and fix the post

Lengthen the ball by swinging it, and chill its far end by dipping it in cold water. A second worker makes a disc of hot glass on a rod, the 'post', and holds it upright near the ground. The chief worker climbs onto a chair and drops the hot ball onto the post, where it welds on.

الأدوات المطلوبة:

ماء

قضيب البنتيل

Walk apart and draw

The chief worker steps down and the two walk away from each other, both turning their rods all the time. At first the hot glass sags between them in a curve; fan the parts that are thicker to cool them, so it stretches evenly. Draw it to the length wanted, up to 60 or 70 feet; as it cools it stops turning and pulls nearly straight. Except at the ends, it has nearly one bore, diameter and wall thickness. Ours: a wooden paddle for fanning (Pellatt: a boy's hat).

الأدوات المطلوبة:

قصبة نفخ الزجاج

قضيب البنتيل