Printable PDF Tip & Tricks booklet.

Making Glass Core Vessels

Glass core vessels were one of the first glass items ever made, perhaps preceded only by glass beads, small glass sculpture and imitation stones.  Originally, glass core vessels were formed over a mixture of sand and clay that was sometimes supported by a metal mandrel. Today the process is similar, except with today's modern materials available to us we can modernize the technique while still keeping the integrity of the process developed thousands of years ago by glass pioneers. This method can be used to not only make vessels, but also large hollow beads.

Take 00 or 000 steel wool and pull it apart to make thin, narrow, long layers. Wrap it around a stainless steel mandrel. An 1/8" or larger mandrel is better than the smaller sizes, because the larger size mandrel holds the steel wool better and helps prevent it from spinning loose while working the hot glass. Wrap the steel wool tightly at first, so it won't slip, and then a little looser so as to be able to make the wrapping go into the shape you want. The steel wool wrap can be placed near the end of the mandrel to make an item with a hole at each end like a bead, or at the very tip and even past the tip to make a vessel.

When you are satisfied with the shape, use a small brush to cover it with Dip-n-Go Sludge™ mandrel release. Apply several coats, if necessary, allowing them to naturally dry between applications. The final thickness of the coating should be at least 1/16".  Make sure that the mandrel release covers all of the steel wool, not just where the glass will be applied. A full coverage coating adds a lot of strength to the steel wool and helps in keeping the mandrel from spinning free. It also insulates the steel wool from direct contact with the flame which would otherwise easily burn up. You can smooth out the surface with your finger before the mandrel release dries or you can wait until it dries, wet your finger and smooth the surface. The second method gives you more control, because it only affects the surface leaving the under coat to hold the shape.

Once the mandrel release has fully air dried, introduce it to the flame to heat it up similar to when making a regular wound bead, but don't let it get too hot or the extra thick coating of mandrel release may crack and the steel wool will burn up. If a little cracking happens or if a little steel wool burns you should have no problem, but the core will be a little more delicate.

Finally, apply the glass where you want it. Work it as you would if making a regular wound bead or sculptured glass. Be very careful to not pull or push too hard or the core will slip from the mandrel. If you use an opaque glass to cover the mandrel release, any of the coating's surface imperfections will not show from the outside of the glass. You will not have to be so fastidious about cleaning out the inside.

After annealing, remove the steel wool by picking it out. The mandrel release is harder to remove. It can be removed by scraping or you can use a moto tool with a diamond burr.

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