Stained Glass Painting with Oil

Essential Tips: Part 1

I’m now spending a few days in charge here while Stephen gets on with some particularly difficult painting plus puts the finishing touches to a documentary we’ve made.

Anyway, yesterday I spent a morning painting with oil. And what a calm and happy time it’s been. Not that it isn’t when I’m working with water. It’s just that, with oil, you can pretty much start and stop whenever you want.

And – rather than having a fixed idea of the effect you definitely want to achieve (as is the case with water) – you have the time to push the oil paint here and there, and reflect on what looks best, changing it as you see fit.

So here are some key points about working with oil on top of unfired water-based paint.

If you’re already a “convert”, these tips will come as a handy reminder.

And if you’re new to oil, they’ll show you its amazing potential.

So I’ll start off with 5 tips today, then we’ll continue the series the day-after-tomorrow (Wednesday) and see how we get on.

Two drawbacks of water

First – what’s wrong with water?

Nothing, so far as it goes.

But even the approach we encourage you to learn – painting layer upon layer of water-based paint and just one firing in the kiln – well, even this approach has its limits.

  1. There comes a point when, even though you’d like to paint some more, you know it would harm the unfired paint beneath.
  2. Or it’d just be too plain risky …

And that’s where oil comes in:

  1. See, oil allows you to carry on adding more layers and lines.
  2. And as I mentioned a moment ago, it also allows you to work at your own pace.
  3. Plus you get to create the most amazing shadows.
  4. Finally, you can nearly always make corrections in a way that water just won’t let you.

Now in case you haven’t watched it yet, take 10 minutes to see what I mean:

Let’s get going from when you’ve done as much water-based glass painting as you can.

Instead of firing your glass, carry on working – using oil.

Oil-based paint is an absolutely wonderful way of adding beauty to your work. Yet strange to say it’s rarely used these days. So seize the opportunity and find out how it’s done.

First, just refresh your memory with this short video demonstration. Even if you’ve watched it before, there’s always something new to see:

And now let’s get going with the tips.

I’ll give you three guesses – no, just one guess what my first tip is!

Here’s a clue:

Stained glass painting with oil - start with a lump

Tip #1 – start with a lump

Tip #1 – Start with a lump

Just as with water-based glass painting, when you make yourself a good-sized lump of paint to start with, you save yourself a considerable amount of time.

More importantly, you also give yourself the means to quickly create whatever consistency of paint you need:

You simply use the palette knife to cut away a slice of the lump, then dilute the slice as required with your chosen oil.

From bottom-left you see my small round-headed badger blender (I’ve a few different sizes), my tracing brush (again, I use different sizes for lines vs. shadows), the “applicator” which I use to apply the initial wash, my palette knife, my lump of oil-based paint, and, last of all the jar I keep the paint in when it’s not in use:

It lasts for months and even years like this.

So economical …

And its effects are so beautiful.

Tip #2 – Don’t trace or shade directly on top of water-based paint

If you try to apply oil traced lines and shadows directly on top of water-based paint, your brush will stick and drag.

So don’t do it.

Instead, first lubricate the entire surface of the glass with a very light wash of oil-based paint, which saturates the water-based paint beneath so that it won’t be able to absorb anything else.

Then, when you come to trace and shade, your oil-based marks will hold their own (and not be swallowed up).

To do this, you need a good applicator brush like this one here:

Use a brush like this to lubricate the entire surface of the glass

Use a brush like this to lubricate and saturate the entire surface of the glass

Tip #3 – How to be sure you’ve covered the whole surface

Turn off your light box when you apply the oil.

Turn off your light box when you apply the oil

Turn off your light box when you apply the oil

Like this, you can inspect your glass in natural light. The oiled glass will glisten and gleam; any bits you’ve missed will be dry. Just be sure to touch up those missing bits.

You absolutely need to do this otherwise your blending will scratch and stick.


Yes, I’ll come to that in my next post.

Tip #4 – How to avoid over-oiling your glass

Yes, you need to apply enough of a light oil-based wash to saturate the underlying water-based paint.

But if you apply too much, your oil-based lines and shadows will bleed badly.

Here’s what you do.

Take a sheet of paper kitchen towel. Scrunch it up in your hand. Then gently dab it down over the whole surface of the glass.

Remove the excess oil like this

Here’s how to remove the excess oil

Don’t worry about leaving marks – you’ll solve that problem with the next tip …

Tip #5 – How to create an excellent surface for tracing and shading

Now just take a small round-headed badger and blend away.

Blend the oil wash until it's smooth

You can be quite vigorous here. Providing you’ve enough gum Arabic in the underlying water-based paint, the existing lines and shadows will be fine.

And even if they dissolve a little, you can always re-instate them later.

Until the next time!

And that, Ladies and Gentlemen, is all for today:

  1. Start with a lump of oil-based paint – it keeps for ages
  2. Don’t trace or shade directly onto unfired water-based paint – first apply a wash
  3. Turn off the light box to make sure you cover the entire surface of the glass
  4. Dab off excess oil
  5. Blend away slight blemishes until the oil wash is smooth

I’ll give you more the day-after-tomorrow.

Right now I’m off to “badger” Stephen and see how he’s getting on with that tricky painting he’s got on his light-box.

David Williams, designer and painter of stained glass


P.S. The technical term for dabbing paper onto wet surfaces (tip #4) is “tonking”. Nice, eh?

P.P.S. Part 2 is now here.