Glass Fusing




Introduction: Glass Fusing

About: Interesso-me por ciencias exatas de um modo geral Deste foguetes ate astronomia Desde construcao de telescopios ate polimento de espelhos amadores. Desde eletronica ate.Home science -- I like exact sciences in…

In this tutorial I would like to show an easy way to create some interesting glass objects using a technique called glass fusing.

Basically you melt together two or more pieces of glass to obtain your final piece.
Between the two glasses you add pieces of color glass and/or special high temperature pigments.

Step 1: Cutting the Glass

Here I show the method I used to obtain my glass pieces.

I am using a diamond coated circular saw and a drilling machine to cut some glass disks.
It is a bit tricky to cut the disks and there are some risks of shattering too therefore safety tools (googles and gloves) are a must.
I added a bit of water on top of the glass to act as a cooling agent.

The glas used here is just regular plain transparent glass just like the ones used in windows. I did not measure it but aprox two to three millimeters thick. Many times I just collect them from the streets.

Each piece will require two of these glass disks. Here I used a 25 mm circular cutter giving me aprox 2.1 cm disks
Larger disks can be made but they are easier to break during the cooling phase.

In between these two pieces we will used bits of color glasses to create our art

Step 2: Here I Am Preparing the Pieces

One of the transparents glass disks is used as a base and on top of it I place bits of color glasses.

The color glasses I am just obtaining from the streets. Basically broken pieces of some brands of beer and wine

I managed to obtain a very nice blue color that is used in one local brand of beer

The dark brown color is very easily obtained from the regular large bottle of beer

Green is also easy.

Just today I found out a beer that use a red glass. I will yet test to see if it is real red or just painted. Red glass is usually very hard to obtain and also very expensive therefore I suppose the glass I found today is just painted to look like red glass.
This is easily found out cause if the glass is painted the color will vanish in the burning step

The glass pieces are broken into smaller bits using a hammer. Involve the glass pieces in newspaper and use googles and gloves in this step since you do not want to risk injuring yourself.

You place your color bits on top of the transparent glass disk used as a base and than on top of this you place the second transparent glass disk

In the next step you will fuse these pieces together. That gives the name of the technique
Glass fusing

Step 3: Burning Step

Glass needs a pretty high temperature to begin to melt.

A regular butane or propane torch normally is not powerful enought.

Therefore here I am using a MAPP torch normally used as a tool by the people who fixes and repair refrigerators.
It's normal use there is to melt copper to join together two pipes.

You can see in the pictures I built a small kiln or furnace using special refractary tiles.(bricks)
To help keep the heat in I am using as heat insulator a ceramic wool that can withstand very strong heat. It is relatively cheap and I purchased mine online.
The ceramic wool also help prevent the molten glass to stick to the bricks walls otherwise the sticked glass once it cools down cannot be "unglued" from the brick without breaking the piece.

DO NOT use regular bricks as they have humidity and can explode while being heated.

There are other methods of heating such as a special kiln that goes inside a regular home microwave or an electric kiln.

The MAPP torch method happens to be very cheap. The torch costed me aprox Us 40.00 and the MAPP cilinder costed around us 12.00

Basically lights the torch and point it to the kiln interior. You want to start some 30 cm far from the glasses and SLOWLY places the torch closer and closer to the glass disks until after
some 2 minutes they are hot enought to withstand direct heat from the torch.

Glass is hard to melt down even with the direct heat from this MAPP torch (1.850 C) they will very slowly start to melt down with a consistency of very very very tick syrup.
The heated glass shows an yelowish light when close to melting point.

After you see the two glass disks merged together into an unique piece you can consider the job done.

AGAIN you DO NOT want just to turn off the torch because the sudden change in heat will cause the glass to break due to thermal stress
Therefore slowly places to torch more and more appart from the glass and after some 60 seconds of slowly moving appart you can turn off the torch and as soon as possible cover the kiln with ceramic wool leaving no area uncovered. The kiln will very slowly cool down. Even after one hour it is still too hot to be touched by the bare hands.

MAPP torch reaches up to 1.850 degrees celsium. Remember that and use the googles and gloves.

After this one hour of cooling down you can carefully uncover the kiln and go look you fused glass.
Some of my pieces even with this slow cooling still break appart due to the glass thermal stress during cooling down phase.
An electrical oven in this respect is much better since you can program a very slow cool down phase.

In the photo nr 1 here you clearly see the glass disks as two separate pieces with very sharp edges. On photo 3 the sharp edges are gone and the pieces are fused together into one only unit.

It is not a good idea to use this torch inside a room in a non very well ventilated area because there are emissions of carbon monoxide that are toxic

Step 4: Final Results and Some Comments

In these photos you can see a close up of the final results I obtained. One of the pieces show lines where the piece broke down due to thermal stress. I just glue them together with two parts epoxy resin. Hopefully I will eventually buy an electrical oven to acquire better control of the cooling phase reducing the thermal stress and avoiding these problems.

Besides the color glass bits I use there are also several special pigments that can withstand the very high temperatures and show some colors into the final piece.
Forget about any ink or so because it will burn out during the heating phase

A very nice blue color can be achieved using cobalt carbonate (available on specialized stores for pottery and glass artwork)

Other pigments will impart green or yellow or other colors to your work

RED (transparent red) however is VERY hard to obtain and the normal pigment that allows this color used gold and is very expensive
However non transparent red involves a
lithium pigment that is not that expensive
I am using it on the piece shown on photo 1

Some pigments create air bubbles inside your piece which sometimes gives a nice look
to the piece. As an example
Strontium carbonate

I found in eBay (Tchecoslovaquia) bits of uranium glass (very light transparent yellow) that have the peculiar property of shine almost
like fluorescent green color if iluminated
by UV light - my UV source was just two UV leds and a battery from a watch

The special kiln that can be used inside the microwave is relatively cheap and I used one with good results too.

Step 5: Other Possibilites

Here you see my other attempts

Photos 1 and 2 shows a homemade microwave Kiln. I only managed to built it after seying
Robert Murray's YouTube tutorial on how to make the special ink that coats the interior of the microwave kiln

Photo 3 shows my attempt to build an electrical kiln. It is not finished yet
If I manage to finish this kiln it will certainly be the best option since I can than have total control on temperature and set up slow cooling procedures

Photos 4, 5 and 6 shows another version of microwave kiln

Photos 7, 8 shows other attempts using a butane torch

Photo 9 shows a finished piece made with the microwave kiln shown in photo 4

A final advice this adventure is very nice but there are risks that you must handle not to burn yourself. Please be cautious and always use the safety tools - googles gloves and fire extinguisher

Have fun

Be the First to Share


    • Game Design: Student Design Challenge

      Game Design: Student Design Challenge
    • For the Home Contest

      For the Home Contest
    • Big and Small Contest

      Big and Small Contest



    6 years ago

    I suppose adding metals won't work because the different contraction rate will crack the glass upon cooling


    Reply 6 years ago

    I've seen copper wire work well. gold and silver foils will work, but make sure you don't get anodized aluminum that's just gold or silver color


    Reply 6 years ago

    I liked the uranium glass which glows under UV light. I bought on e-mail 100 small bits for just us 7.00
    I did use copper sulphate but I forgot which color it gave to the glass.
    Real metal I never tried inside my glass.
    I suppose this would help me create a support so the glass could be used as a jewelry or as a pendant. I tried to glue a support on mine glasses but they looked too ugly to be soldable.


    6 years ago

    Even different tipes of glass have different contraction rates and can cause cracks


    Reply 6 years ago

    i've had good luck with bottle glass and bits of marbles. reds tend to burn away


    Reply 6 years ago

    I bought some special pigment for glass fusing and they were interesting to play around.
    Ex cobalt carbonate gives the glass a very nice deep blue color.
    Strontium carbonate creates a non transparent white color with lots of small bubbles inside the molten glass (that stays there after cooling)
    Other pigments were mixtures and I do not know what is inside.
    One of these gives a nice vivid red color (but opaque non transparent)


    6 years ago

    However trying wouldn't hurt provided I buy the silver


    Reply 6 years ago

    The nitric acid to dissolve the silver is the difficult part to get.


    Reply 6 years ago

    Silver nitrate can be purchased straight
    I saw it but it is rather expensive.
    I manage to buy nitric acid 70% and with it I made some silver nitrate by dissolving some 5 grams of pure silver into it.
    However when I did all this I was not melting glass yet so I never tried silver nitrate into my glasses.
    I am currently fighting to build an electric kiln/furnace to melt my glasses.


    6 years ago

    Also silver nitrate might work it would certainly gives a color to the glass but I still do not know which color


    6 years ago

    I tried add gold chloride (to obtain transparent rad) but it didn't work


    6 years ago

    Very cool! I like the idea, and being able to use common, easy to find material makes this a plus. I can see incorporating this into jewelry projects. Have you tried adding small pics of silver in your "glass sandwiches" to see if they will melt and merge with the colors glass? This is somthing I would like to try. Thanks for the ideas, and the great ible!