Geodesic Heart

Representing the network of people who worked together to try to Find Mark.

7½″ x 7½″, 45 pieces. ©2012, JoHN MiLLeR, Portland Oregon.

PolygonFlux had just been published, so I cast the heart as a polygon, symbolically choosing 15 (Why 15??) sides — 7 on one side, 8 on the other. From there, filling the heart with an array of triangles came naturally. I carried each of the polygon's vertices to the frame, radiating from the center area of the heart. Geodesic arcs appeared through and across the Heart, and the design became whole.

The Cartoon

In stained glass artwork, the Cartoon is a Black & White line drawing of the design that shows the pieces of glass to be made. The cartoon only represents the geometry of the design. I wanted the heart to be roughly the size of a human heart.

I used carbon paper to transfer the design onto Fasson Paper, which is a vinyl-like peel-off adhesive product. The red ball-point pen ink on the paper shows that each line was traced. Each piece is numbered in order to keep track of it. The number also indicates the general orientation of the piece. The numbers are also transferred to the Fasson Paper via carbon paper. The Fasson Paper then gets cut up with pattern shears, along the lines. The paper cartoon is preserved, not cut up.

Choosing the glass to use

The assignment of glass stock to the pieces is often the most difficult step of glass artwork. I wanted to use a red glass, but not pure cathedral red glass. I thought the glass might suggest heart muscle. The background color would be flesh tone. In this case, I think I found some red in in my shop, and looking at it actually gave me the idea for texturing the red area. I went shopping for the neutral cream color that would go with the red. One never knows till after it's all made, and you see light come thourgh it for the first time.

Laying out the pattern pieces

At this point, I had to think of how and in what order I would cut/break the glass. You can't just stick the pattern pieces on any old way because you can only break glass in a fairly straight line (shown by bright red below). So, laying the patterns out on the glass is a matter of shape and orientation, not numeric order. In this case, there were ripples in the red glass at this end of the plate, so I used that end to give the heart some texture. The rest of the red glass was basically smooth. (Laying the pattern out on glass can be done safely indoors.)

Here is the red, before breaking. I added red lines to the photo to show my first three breaks.

The next two photos show the pieces successively broken.

Out in the shop ... breaking glass

My first three breaks were to get three glass 'bars' out of the red. First, I scored the lines with the glass cutter.. A long break is done from the end with running pliers. The glass breaks instantly. (The three separate bars aren't shown.) Then I scored and snapped off pairs of pieces, with regular breaking pliers, or with my bare hands.

Next task was to break each of these pairs apart.

Now you can see that I needed to break just a bit off the sides of most pieces. I'd score a line, and then hold the piece with my fingers and use the breaking pliers to snap off a small amount — see piece #23.

Only takes a few minutes to break all this. You scratch it with a glass cutter, then snap to break.

All the pieces broken

The cream-colored glass was broken, and also ready to have its edges ground smooth. That's scrap glass in the middle, left over from trimming pieces. This step is done outside in my Shop because of the glass splinters, etc!

Tools. The glass 'cutter' has a green handle. Breaking and running pliers are shown. The breaking pliers have a red band.

Not shown: Using an electric glass grinder to make the glass match the pattern perfectly. All the edges are straight and dullish after they are ground. The grinder has a rotating head with diamond grits, and a water bath to keep glass bits from flying all over.

Taking ground pieces into lab sink

After grinding, I took the pieces to my lab sink to wash any remaining glass grit off. You can see pieces have been carefully ground to match the templates. My light wasn't good in the shop, so I took some back out for touch up. It's important to get them all ground to fit, otherwise the pieces won't fit together as per the Cartoon.

All the pieces

Back inside now. The adhesive sometimes slips when water from the grinder get under it. I'm showing the pieces that were 'loose', by sliding the pattern off to the side a little. (This is basically irrelevant, because of the next step!)

Next step is to remove the Fasson paper, wipe glass clean and dry, and mark the numbers on the glass itself with a sharpie.

Wrapping pieces with copper foil

This shows the remaining unwrapped pieces, and one being wrapped. You can see the Cartoon in the distance. The copper foil tape is wider than the glass is thick. The tape goes on the side edge, then you have to folded it down onto the face and work the corners. When the foil is on all the edges of the piece, you use the roller to burnish it very flat and tight on the sides and face.

One Single Piece

Shows the copper foil obviously. The foil has not yet been folded over the edges, nor corners 'tucked'.


The white on the right is the used Fasson paper stuck onto vinyl. Supposedly, it can be re-used to make another set of pieces. But it doesn't stick very well because it may have some glass grit gets under it onto the adhesive, etc.

Loosely Fit Together

It's so pretty with the copper, that you hate to solder. Next step is to make a jig to hold the pieces tight and square for fluxing & soldering.

Getting ready to solder the heart

This shows the wooden jig, holding the pieces together. This was done inside the house, setting up to solder.

After it is soldered on the front, you flip it to apply and work the solder on the back. (The jig isn't needed to solder the reverse side.)

Note that the numbering is arbitrary, because each piece is handled individually, in any order. Numbering is just a way of keeping track of each piece — otherwise you'd have a hell of a time figuring out which triangle went where. You can lay the original cartoon down inside the jig as a guide to where the pieces go, or just refer to it.


After both sides are soldered, the numbers can be washed off. Here it is backlit. After this step, I put a dark patina on the solder, using an acid.

Patina and Frame

Next, I cut zinc for the frame. This shows the frame just fit on, before soldering the frame. I also put the dark patina on the frame.

Final Notes

The art uses several chemicals in the process. An acid flux is applied with a brush to all the copper lines - that makes the hot solder flow down in between the pieces, not just on the surface. So the heart is very strong. My teacher told us that a glass piece like this is actually stronger than a single piece of glass the same size. I believe it.

After the soldering was completed, I rinsed and applied a neutralizer to kill the acid of the flux. Finally, a light soapy wash and quick dry.

The patina acid is an optional step — it just accelerates the oxidation that would take place naturally of many years.

Note about care: The foil can't take prolonged soaking in water. This copper foil technique is for indoor art work, not exterior installations.

Special pattern shears are used to cut the lines of the pattern that were traced onto Fasson Paper. The shears are three-bladed scissors! One blade cuts agains two in order to remove a small 'kerf' from the paper so that the pieces are just a bit smaller than the geometry, allowing space for the copper foil and solder.

The process was started on the 14th with the cartoon and Fasson paper, and laying it out on the glass. The glass breaking and grinding was all on the 15th. Final assembly and soldering was on the 16th, at around 10:30 or 11PM, for Mark.