What do you put your glass on when you fire it?

"When you put your glass in the kiln to be fired, what do you put on your shelf so the glass does not stick to the shelf?" (Mary McE., Washington, US)

We use trays made from 1/8 inch gauge mild steel which are ½ inch deep. We fill the trays with whiting (calcium carbonate) or Plaster of Paris. We take a sheet of toughened glass and press down the powder so that it is perfectly smooth on top. This is the surface on which we fire our glass. The glass doesn't stick (not even when it's been painted on both sides). When the compacted powder get dirty, we take a spoon and lift away the dirty bits, then add more powder and press it all down again.

Do you anneal glass when you silver stain it?

"I wanted to ask you about firing silver stain. We're experimenting to get the right temperature in our kiln, but I wondered if it is still necessary to come back down slowly through the annealing range if we have only fired to approximately 570 Celsius / 1070 Fahrenheit?" (Kathryn W., Salisbury, England)

We don't anneal (or even soak) silver-stained glass for two reasons:

1. We don't think the glass has got hot enough for the heat to stress it significantly.
2. Silver stain is very temperature-sensitive. This means it can "metal" and discolor if it gets too hot or even if it stays hot for too long.

How to design painted stained glass #1

"What's the most common design 'mistake' you see amongst people who are learning to paint stained glass?" (Peter D., Kentucky, US)

A mistake we often see is when people leave too little room between a tracing line and the edge of the lead which surrounds it. This makes the design look cramped. It makes the lead look like a boa-constrictor snake, squeezing the life from the painted image.

For example, the next time you see a picture of a painted stained glass head, observe the actual structure of the design. We don't intend to be flippant here, but it could almost look as if the head were encased within a transparent space helmet! - That's how much room is left between the painted head and the lead border which surrounds it.

You'll also often see that this outside area has been blocked in with flooded paint. This is such an effective technique for opening up a design. It's actually one big reason why we introduced flooding and silhouettes in Part 2 of our book, Glass Painting Techniques & Secrets from an English Stained Glass Studio.

Always consider how much space you need to leave around a traced line in order to make sure that your design looks open. Our suggestion to you is that, when you draw and design the cut-line for a stained glass pattern, take care that the lead doesn't encircle the image so tightly that the painting appears cramped.

Have a look at how we've designed these dog roses: look at the amount of space between the edge of the leaves, for example, and the lead around them. You see, if we had drawn the leaves right up against the border, they would have looked squashed.

Also look at the space around the flowers. The lead doesn't strangle or suffocate the design: the lead supports the design and permits the design to breathe.

How was this done? - #1

How do you believe this effect was achieved? (Rebecca H-B., Tennessee, US)

This looks very much like frit, that is, fine grains of glass and enamel which were sprinkled onto the glass in a particular shape, then fired at a particular temperature: a decorative embellishment on the painted glass.

How long can you keep glass paint after a first mixing?

I ask this question because it often happens that I only need to paint a small surface with a particular paint, and then I don't need to use it anymore for several months" (Ivo de C., Antwerp, Belgium)

Our lumps of glass paint last for many, many months. Even when they dry out, it's possible to re-constitute them so that they are excellent for painting with. The main thing is to cover the lumps when you aren't using them.

Painting with a lump is excellent when you have a complete set of painting operations to do: an undercoat, copy-tracing and strengthening, softening and shading, half-tones, flooding and so forth. You just dilute a little of the lump to make glass paint that is exactly the consistency you need for each different kind of painting that you are doing.

Even if you're only going to do some tracing for a couple of hours just once a week, we think it's still worth painting with a lump: a lump gives you such control over your paint that it's really a false economy to mix up a tiny quantity.

On the other hand, when we are using enamels or silver stain, it's true we sometimes also just mix a small amount. Here it will also depend on the media that we're using. For example, silver stain mixed with water is very brittle when it dries out, and difficult to reconstitute. So, if we were using water-based silver stain, we too would only mix a small amount.

Doing things differently

"You often say that there are many different ways in which glass painting can be done. So, for example, do you always soften your tracing lines? Do you always do all your painting in a single firing?" (Helena B., California, US)

One point we find especially silly is the idea that tracing lines must be fired before you shade. So that's one reason why, in our book, we prove that this is utter nonsense: we show you how to shade before you trace, then how to paint with oil on top of unfired shading and tracing, then fire your glass just once.

But, as you rightly say we say: there are many different ways in which glass painting can be done. Indeed, it's fine to fire your tracing lines before you shade ... if that's what the design requires.

So, to answer your question directly: we don't always soften our tracing lines, and sometimes we also fire out glass several times.

Here's the exciting idea: the techniques you discover in Glass Painting Techniques & Secrets from an English Stained Glass Studio can all be combined in many different ways.

How was this done? #2

"What techniques would you use to paint a copy of this piece of glass?" (Fabio de M., São Paulo, Brazil)

As part of our stained glass techniques, when we make a copy, we always do a test. We'd then observe the result and change the sequence as necessary.

This is the first sequence that we would follow for our test.

1. Paint a light dry-colored undercoat with water-based paint.
2. Copy-trace the lines.
3. Thicken and/or strengthen these lines as needed.
4. Add highlights.
5. Paint a light oil wash over the entire surface of the glass.
6. Add darker oil paint to the areas where there aren't any highlights.
7. Blend and soften the oil.
8. Allow it to dry, then re-establish some highlights.
9. Fire the glass.

Gum Arabic powder

"I see you prefer liquid gum Arabic, but I only have powdered gum Arabic: how do I use it?" (Clare B., Dursley, England)

Yes, we do prefer gum Arabic in liquid form, and the third edition of our Glass Painting Techniques & Secrets from an English Stained Glass Studio explains how to use both liquid and powder. Anyone who bought the early edition is welcome to a free guide to using gum Arabic powder: please write and tell us.

Size

"What is the size of your glass palette when compared with the size of your paint lump?" (Drew McE., Tyne and Wear, England)

Our glass palettes are about the size of a standard piece of writing paper (8 inches by 11).

We use between 2 and 4 ounces (50g - 100g) of glass paint to make a basic lump: you'll find full details in Part 1 of our e-book, which shows you exactly what to do to mix perfect glass paint. The lump is between 2 and 3 inches across as you can see here.

Lavender oil

"When you paint with Lavender oil, do you use Spike Lavender essential oil or "ordinary" Lavender essential oil?" (Maria C., Yonghe City, China)

We use both types of Lavender oil. We haven't noticed a difference. We also use many other types of oil. But always ask advice before you use anything other than water for your glass paint.

How much ventilation do I need for firing?

"I would like to install a kiln in my basement, but installing ventilation would be difficult since the walls are all cement. I can of course open the door when firing. Do you think this is enough when firing glass paints? Based on your experience and knowledge, are the gases coming from firing glass pretty toxic or are they relatively harmless? (Stephanie L., Oregon, US)

Different brands of glass paints have different ingredients, so it's important to check with the manufacturer. But it's probably the case that, for most paints, the most "hazardous" time is not when you fire the glass but either when you mix it or when you scratch out highlights. These are the occasions when there is the greatest potential for you to breath in dust from the glass paint, which is never a good thing.

But you asked specifically about firing. With a gas kiln, ventilation is essential, because the gas requires oxygen to burn. Also, you would need to take advice from the manufacturer about whether or not a gas kiln can ever be used in a basement (since gas might sink and gather on the floor).

With an electrical kiln, the need for ventilation is probably determined by the media you use.

Here's an extreme example: we sometimes mix our glass paint with a particular kind of oil whose fumes, according to the supplier, are dangerous to inhale. These fumes must be vented from the kiln as the kiln gets hotter (otherwise they might combust or might affect the quality of the paint) so, first of all, we open the kiln's bung holes. Now that we've stopped the kiln from exploding, we must allow the fumes to escape from the studio, so we always open all our doors and windows (even in winter).

But this is an extreme case. When we paint with water as a medium, we wouldn't generally ventilate the studio, apart from the fact that, during summer, with the kiln on, the studio can get hot.

You can always buy a small, table-top extractor fan with replaceable charcoal filters: this is a piece of equipment that copper foil hobbyists often use. We often place ours near the top bung hole of our kiln as the kiln heats up. This is just an extra precaution in case there are particles which are rising up on the hot air into the studio.

We always take precautions, because we love life. At the same time, it's important to measure risks fairly and accurately: just breathing city air, for example, can be harmful. And glass painting is a real pleasure.

Glass painting techniques and secrets

Nothing's a secret with us: what's the point? When you order Glass Painting Techniques & Secrets from an English Stained Glass Studio, you are welcome to ask us questions, and we will answer you to the best of our ability.

Our stained glass courses are easy to obtain. To order your copy of Glass Painting Techniques & Secrets from an English Stained Glass Studio, just click right here.