Glory Hole
A reheating chamber that brings a cooling piece back to working temperature without touching the main furnace.
Shaping / Blowing
| Jaw shape | Curved, matched pair |
|---|---|
| Length | 250 - 400 mm |
| Material | Brass or stainless steel |
| Jaw width | 12 - 25 mm |
| Stage | Shaping, necking and lip opening |
Compatible glass types
Soda-lime
Borosilicate
Lead crystal
Compatibility assumes the tool is rated for the working temperature of that glass family. Check the maker's documentation before use.
Overview
Jacks are the tool that defines the silhouette of a vessel. The curved jaws wrap around the glass and, as the pipe rotates, squeeze it inward to form a neck or outward to open a rim. Because they cool the surface as they shape, jacks also stiffen the area they touch, which is what lets you build a narrow neck on a soft piece.
Safety notes
- Jacks hold heat. Use a heat shield and keep the handles away from your forearm.
- Never squeeze hard on a cold piece. The glass will crack at the jaw line.
Using it well
Practical guidance
- Wet the jaws slightly so they glide rather than grab.
- Neck in several light passes with a reheat between them. One heavy squeeze collapses the wall.
- To open a lip, angle the jaws outward and let the rotation do the work.
What to look for
- Matched curved jaws for even pressure
- Long handles for control at a distance
- Brass option that leaves fewer marks on clear glass
High temperature tool
This tool operates in or near the working range of molten glass. Read the safety notes above before first use, and never work with it without eye protection, heat-resistant gloves and working extraction.
Reference information only. Specifications are published ranges drawn from manufacturer documentation and normalised for comparison. They vary between makers and between individual units. This page does not sell or endorse any product, and does not guarantee any result. Follow the equipment manufacturer's instructions and take hands-on instruction before operating hot glass equipment.
Related
Tools used alongside the jacks
Gathering Pipe
A solid rod used to pick up a gather when you are working solid rather than hollow.
Gathering / Shaping
Heat Shield
A radiant barrier that slides onto the pipe and protects the back of your hand.
Gathering / Shaping
Wooden Block
A soaked fruitwood block used to shape and chill a gather while it is still soft.
Shaping
See the shaping & tools workflow
Read the category overview, or jump into the 3D Studio to see these tools applied to a live piece.