Some Mistakes I Made: Maybe You’ll Find Them Useful

Sometimes things succeed; and sometimes they don't

So I’ve been working through the new designs David prepared for our workshop at Bryn Athyn this coming June.

My George III is coming on just fine for now …

First test

Stained glass George iii

Fine so far …

The techniques so far:

Undercoat, copy-trace, wash & soften, strengthen, flood, highlight & soften.

Next stop:

Glycol for further shadows.

Everything worked out fine and just as I expected here.

But not so for my Piper.


This is one topic people really write to me a lot about. Yes, blistering, fritting, bubbling in the kiln.

Thankfully, long gone are the days when everyone assumed it was always caused by painting over unfired paint.

Our own times are more enlightened. Now it’s widely accepted that you can paint many layers, and sometimes also thickly, and fire your glass just once – with scarcely a care in the world.

Three things in particular help successful flooding:

  1. Well-mixed glass paint, which you re-mix each time you load your brush
  2. Spread your paint quickly, spread your paint thinly, move on and never ever go back
  3. Fire slowly

But now look at this, which didn’t work:

Problems with stained glass painting

Blistering at the edges

I’m glad to show this to you because I’m perfectly relaxed about confessing my mistakes.

And I certainly went wrong here.


Two mistakes.

First mistake

One, I did something which subsequently caused blistering. (Careless me.) Namely: I defined the area-for-flooding with lines which were much too thick.

My ‘wall’, my ‘boundary’ was far too substantial.

You see blistering is also caused when areas of paint don’t join well with one another.

Then in the kiln they fight it out – and one side or the other must back off.

Which happened here.

You have been warned.

Second mistake

Two, my second mistake: I was too much on auto-pilot.

Think for a moment about my lines which marked off the area I planned to flood.

The point is, there’s nothing wrong with them. (Look at the same lines around the horn: they’re lovely, though I do say so myself.)

Also, there’s nothing wrong with my flooding.

But … put the two together, and no matter how perfect your technique, things go wrong.

So my second mistake was …


With glass painting, when you trace a line, you need always to consider what you intend to do afterwards.

The line is good or bad to the extent that it supports your aim for it.

Yes. Fit for purpose. Whatever the purpose is.

You see, a mistake which beginners always make is to look at their lines and curse.

A proficient, confident glass painter on the other hand may certainly damn a line. But then it’s not because of what they see. It’s because they know it won’t let them do what they want to do.

My mistake was: I built up all my lines to the same depth, regardless of what was going on right next to them.

So I copy-traced the main lines. Then I strengthened them exactly. And then I thickened them.

Yes, I thickened all of them.

If I hadn’t flooded, everything would have been just fine.

But I did flood and of course things blistered.

Nothing wrong with my trace lines in themselves. It’s just I shouldn’t have done what I did around those areas where I later chose to flood.


But am I down-hearted?

Not a bit.

This was a test piece after all.

And your attitude to a test piece must be: if it succeeds or fails, it succeeds.

Because you learn something.

Because a bigger error never sees the light of day.

Here, not just me giving a demonstration at Bryn Athyn, but maybe also you’ve seen something useful here:

Is this trace line good / bad (in itself)?


Will this line let me do what I want to do?

Essential point about your test piece

Now you’ve read this far so I’m going to give you a really valuable piece of advice.

Before I start a piece, I practise the key elements.

Like with this lion here (who’ll also come to Bryn Athyn with us):

Stained glass griffin

Test piece – OK so far

As you see …

Design for winged lion in stained glass

Design for winged lion in stained glass

… my test piece is just part of the image.

So like I said I take a small piece of glass and practise the key elements. The tricky ones. The eyes. The mouth. The hair.

But here’s the point.

Don’t assume it’s easy to identify the key elements.

Because it isn’t.

That’s what the Piper shows me.

I thought:

Outlining is easy, flooding is easy …

Big mistake.

So it’s just as well my test piece for the Piper in fact contained the outlining and flooding together – not just the eyes and mouth and nose (the ‘tricky’ bits).

So now I’m off to do a second test piece for my winged lion.

A test piece which combines all the key elements – not just the ones I naively think will prove most difficult.

Stephen Byrne of Williams & Byrne the glass painters

16 thoughts on “Some Mistakes I Made: Maybe You’ll Find Them Useful

  1. I live in southeast Washington state USA and am having a problem finding good brushes: any help and or advice would be more than welcome. My best to you and yours – enjoy your summer.

    Thanks again,

    • Jack, Thanks for your good wishes (- we can’t wait to get over to your fine country in June!). As for brushes, we mainly use exactly the same brushes as water-color painters use. So, even if there aren’t so many glass painters in the US, there still must be many watercolorists: maybe see if you can find an online art catalogue?

      Also, here’s a link to the ones we use. And PELI Glass will also ship brushes to you. Here’s a link.


      • Last year I switched from my Windsor Newton sables to DaVinci #35 full body rounds. You won’t have to go over your trace lines as these brushes carry a large, even amount of paint. In the past I discovered if you use too much gum or haven’t really mixed it so there are no little bits of gum unmixed, you can end up with the burn off or flakes.

        I tend to tell my students if your trace lines are seemingly too light they will deepen as you add your Matt.

        I still prefer English distilled turps for my wash. Keep up the good work.

        Have a blessed Holy Week and a wonderful Easter.
        Sister Marie

        • Thanks, Sister Marie, for your good wishes and also for your tip about the Da Vinci #35: what size do you use for tracing?

          P.S. Just heard back via e-mail – da Vinci maestro long tapered kolinski #35 size 7 most often for detailed work (sizes 9 or 10 for long broad lines).

  2. Thank you Stephen. I greatly appreciate your honesty and helpful hints. Flooding has given me ‘fits’ in the past and now I have more wonderful information with which to proceed. My heart is still sore that I am not going to be able to meet you and David this year. Tears have stopped but moans and whines continue.

  3. To Jack re: brushes.

    As mentioned by Stephen and David, Peli Glass is an excellent place to deal with. I ordered brushes from them about a year ago and they arrived within 2 weeks in perfect condition. Although a little pricey, I found that their badger brushes are cheaper than what you can get in North America … (I live in Canada).


    • Yes, exchange rates can sometimes make items pricey, but with Peli Glass you are sure to get really good products and also excellent service. (Thanks for your recommendation, John.)

      N.B. we don’t get a commission from Peli Glass for mentioning them.

  4. Dear Stephen,
    Don’t be too hard on yourself. I can only see beautiful designs that remain beautiful even after having to rework two, three or more times to get them married to the glass the way you like it.

    • I imagine we all have our dark moods, Herman, when all our work seems pitiful! All the same I do believe that, like I said, a well-conducted test is never a failure ‘even if’ it tells you something we hoped it wouldn’t.


    • Joe, I think too much gum Arabic is one factor amongst several. But I believe that a slower firing schedule can go a long way to preventing those blisters which would otherwise occur with a fast schedule: you see, me and David regularly use a lot of gum, but rarely get blistered paint (sure: exception given above) because we fire so very slowly.

  5. Dear Stephen,

    I notice some of my lines are raised higher then others and higher than the matting after firing. They don’t look fried. Is this a malfunction?

    I haven’t tried flooding.

    The best,

    • Hi John,

      If the line hasn’t fritted and you like the effect, I don’t see anything wrong.

      All I’d say is that those lines might prove too high if you were to flood around them in a single firing – just as happened with my Piper.


  6. Hi Stephen, I am wondering how I would go about painting only a small portion of a glass piece. For example, I fused a butterfly out of fused glass onto another piece of fused glass but I want to paint in his antenna. Can I just paint these lines and refire the piece? Will the paint run or stay right where I put it? How about letters? Say I want to write a saying along the edge of a piece of fused glass? Do these pieces need the undercoat step since the whole piece isn’t being painted.

    Thanks so much for your great website and terrific tips to help us out!

    • Julie, hi! First up, the undercoat isn’t necessary: just use one if it’ll help you.

      Second, if you do use one, you don’t have to keep it: you can always clean it carefully off from around your lines, then fire your glass afterwards.

      Third, for sure it’s fine just to paint a small portion of the glass – in the example you give: just the antennae.

      ‘Will they run?’ – I imagine you mean: ‘Will they run in the kiln if there are just those two lines?’ And no: they won’t run. Once they’ve dried, they’ll stay where you put them (provided that you handle the glass carefully till the paint is fired).

      Best thing: some small tests – feel your way step-by-step.

      And of course ask more questions as they occur to you.

      All the best,

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