Glass Blowing


We are excited to share this guest blog from our client Mandy Patchin from Glass House Xperience on the techniques of glass blowing!

The Glass House’s touring glass blowing experience was created by Mandy Patchin and Kai George Scholefield in 2015. They developed this type of studio to grow awareness of this ancient art, grow the glass blowing community, gain meaningful connections among different communities, and share their creative ideas.


I was introduced to glass blowing in 2011.  I started by enrolling in a weekend “introduction to glass blowing” course.  I will never forget the moment I stood in front of the glory hole (the name the instructor gave for the reheating).  I was taken by the heat, the fire and the excitement immediately.

As I watched the instructor I was enchanted and captivated with the whole process. I was in awe. Barry told me the first day that I was a natural and that has stuck with me.  I had so many questions I just ate up the answers.  Let me answer some of those questions here!

What is glass blowing?

Glass Blowing is a technique, dating back to the first century, using a metal blowing tube, molten glass, sometimes forms to create unique glassware such as cups, vases and more.  The metal blow hole allows the gaffer (glassblower) to add air and inflate the molten glass “blob” to form the desired shape (cup, vase, etc.).

For me, glass blowing is a dance with fire.  I really enjoy the fluidity of the molten glass and the endless possibilities to create something new and unique every time I work with a “blob” of glass.

As previously mentioned, glass blowing has been around since the 1st century and the tool and equipment have not evolved much. The main tools used by a glass blowers are the Jacks, tweezers, Soffietta and Shears.

How is blown glass made?

Blown glass is made by introducing a bubble into the interior of the molten hot glass. The glass itself is made using various techniques and when introducing color and pattern to blown glass they can vary in complexity, but all blown glass is made on a hollow pipe using your air to inflate.

Clear Glass is made using the three following ingredients: silica (sand), soda lime and pot ash. When mixed and heated to 2150F it becomes molten. To make glass color we add different metals and elements.

Glass is usually made using a team of glassworkers to make the process more efficient. The main glass blower is known as the “Gaffer” and the assistants help the gaffer to complete the task at hand by bringing punties to transfer the piece or any bit work needed. The gaffer is responsible for the outcome of the piece(s).

This piece has been transferred to a punty so the front of the vessel can be worked on. The punty is only holding the piece with a small bit of glass, it’s meant to break off easily once the piece is completed.

How dangerous is glass blowing?

Glass blowing can be dangerous. Molten glass can be 1400 to 1600 degrees Fahrenheit and the furnace can be over 2,200 degrees. Glass is colored with heavy metals such as cobalt, gold, lead and copper which can be toxic if inhaled.  With proper precautions the risks can be mitigated.

To mitigate the risks of burning your skin you should wear gloves, a long sleeve shirt and jeans to protect your skin from the heat of the furnace and accidentally touching the molten glass. Always wear eye protection!  I would recommend that you wear an N95 mask when dealing with heavy metals and coloring glass.

When working as a glassblower over the long term, it’s important to take precautions.  Colored glass is made with powdered precious metals.  Molten glass is dipped into the power and some of the precious metals are vaporized.  Therefore, proper ventilation is a must and wearing an N95 mask gives you added protection.

The gloryhole gives off UVA/UVB type of light, therefore UV protectant eyewear is a good option.  Don’t look into the gloryhole for too long.  When blowing glass we tend to also use what we call sleeves to shield heat from our arms or even gloves for close up sculpting work.

What do you need for glass blowing?

The three main pieces of equipment needed to make glass are:

  1. The molten glass furnace, melting glass at 2150F. This can be a gas or electric furnace.

2. The gloryhole which is made in a cylinder vessel insulated with fire brick or fire blanket. This equipment is generally gas heat, but can also be electric and is around 2400F.

3. The annealing oven, which is electric. The annealer is used to slowly cool all pieces created to room temperature, which takes 12+ hours. Glass has to slowly cool or it will go through thermal shock and crack.

Every glass blowing studio will need the following items:

  • a furnace to melt the glass
  • a gloryhole for reheating the glass
  • a work bench
  • blowpipe
  • punty (an iron rod used to hold and shape the glass)
  • jacks
  • paddles
  • tweezers
  • a variety of shears
  • a block (wet newspaper at minimum) to shape the glass.
  • glass color
  • annealing oven (to allow the completed glass to cool without breaking)

Each studio will have all of these items along with many other tools to allow you to manipulate the glass to “sculpt” the shape you want.

This is an electric furnace at full temperature, the glass sit in a ceramic bowl known as a crucible, it’s basically a pool of molten glass at the base of the furnace.

From left to Right, Gloryhole, Furnace, Annealing oven.

How to blow glass?

To blow glass, you first dip a 4-ft long hollow pipe (blowpipe) into a pot of molten glass using a circular motion to gather the glass on the end of this pipe. Next, you blow into the blowpipe to create a bubble in the molten glass. You can then shape the glass by continuously rotating the blowpipe, adding more air (blowing) and then shaping with tools.

Once you have gathered molten glass on the end of your blowpipe you can add color using precious metal power or just start blowing for a clear vessel. 

The first bubble is an important step and can be tricky.  You first get a bubble into the glass by blowing down the hollow pipe until a bubble appears where the molten glass is attached to the blowpipe.  You will want your bubble to be big enough, straight and symmetric and close to the end of the pipe.

You can get more gathers of clear glass if you are making a larger vessel, otherwise you just continue to blow shaping it by using tools and heating certain spots of the glass. The hotter spots will inflate more when you blow or use gravity to shape.

When you are done shaping you transfer the vessel onto a solid pipe and work on the opening with is what is attached to the blow pipe. Generally speaking most of the work is done on the blow pipe and once it’s transferred you just open it up to finish.  From here the vessel you make needs to cool slowly overnight in an annealing oven. It’s important that the glass cools evenly and slowly otherwise it will break.

The Following is 5 steps to making drinkware in glass

STEP: 1 Gather glass on 4ft hollow blow pipe

STEP: 2 Blow Initial Bubble

STEP: 3 Blowout Bubble and form

STEP: 4 Transfer Vessel to open the top

STEP: 5 Open to compete form

Glass Blowing Classes

Some of my favorite classes are for kids.  I also have an adult team-building class where employees or teams can make some glassware together.  It’s an experience you won’t soon forget.

I absolutely love teaching glass blowing classes.  Watching the participants expressions, the first time they experience the fluidly of glass is priceless. Glass blowing is surprisingly easy to do. 

With most introductory classes, the instructor will do the hard work to make sure the beginner will leave with their own unique finished piece of glass.

The fun part is using the tools which is what student’s usually do with guidance. Most beginner classes you will make a flower, cup, paperweight, ornament or small vase. Come try glass blowing with Glass House and experience the magic of glass.

For more information on Glass House Xperience or what they offer, please visit them here.

Thank you!

The Costen Insurance Team