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LOOKING BACK THROUGH a few recent Gazettes, ruling bow pens seem to be making a comeback. In my opinion they are highly underrated tools for the modeller. With a bit of practice, they can work wonders.

Screen printed plastic windows: we have all seen them and probably made good use of those plastic windows provided in most card building kits including Superquick, AlphaGraphics, and Metcalfe Models. They work well enough (from a distance) and are a quick and easy no-fuss solution for the smaller scales.

Seeing how they did it in the smaller scales got me thinking some time ago when I upgraded to 7mm. I wondered if the white printed window framing method would work in the larger scale? Sure, I’ve built a few AlphaGraphix O scale shop fronts and used the supplied printed frames, but could I produce a reasonable facsimile on my own? Would they work, look and feel right, and more importantly would I be happy with the outcome? My intention was to produce my own windows for my upcoming scratch-built GWR signal box, engine shed and accompanying goods building, without having to spend hours cutting and gluing tiny pieces of plastic strip on to glazed surfaces. Yep, some will say ‘Lazy cop-out Dave.’ But you know, it’s about choices and the playtime one has left on the board.

No argument, scale windows well-constructed and accurately representing the prototype will obviously win awards. But I’m not one to spend valuable time looking at windows, or for that matter looking out of them and dreaming what could be.

There are truckloads of timber window frame data out there. Even if some of the individual frame parts are called different names in different countries, one can generally fudge it; a word I use often! I’m no builder, but a little bit of real-world knowledge wouldn’t hurt on this project. You’re probably gazing out of one now. Have a look at the frame illustration and you’ll get the picture. Here’s how I do it …

TYPICAL WINDOW PARTS (wooden joinery - not to scale)

STEP 1. Draw the windows Working from a drawing or model, I accurately measure and draw up the selected window’s frame opening on paper. I sometimes use pre-printed A4 grid paper but in this exercise, I just used plain paper. Remember to number which is which. As a guide, I usually draw in the sashes and mullions in thick (or thin lines), or sometimes in a different colour.

STEP 2. Prepare the clear plastic glazing For the glazing, I often use clear plastic packaging (shirt boxes etc.) I have used clear plastic A4 presentation cover material but prefer a thicker material and not quite so perfect; a few surface ripples and milky films actually add to the reality of a ‘dirty’ window look. Cut the plastic film larger than the area you will finally require. Place the clear plastic over each window drawing and tape down.

If there is one, put the dull side down and the shiny side up. Then I like to lightly sand around the outer window frame perimeter, using 800 wet or dry. This provides a key for the paint to adhere. If you hold the plastic up to the light you will see the very fine scratches. I don’t sand hard or for very long, just enough to dull and key the surface. That’s the front side to be painted.

Try not to scratch the actual exposed viewable glazed areas, leave them as glossy as possible to reflect light. You can always weather them later.

STEP 3. Paint and the ruling bow pen I’ve used all manner of paint options, from basic house paint, enamel and acrylic, to cheap artists’ oils, and I still find good ol’ Humbrol satin or matt enamel, oil-based, works best for me. Slower drying with more control is my preferred method. Mix to whatever frame colour and sheen level you want, although I prefer matt.

Rather than use paint straight from the tin, I decant a little onto a plastic or metal lid. Mixing in a small drop of thinners will give you the control you will need. It is really important to get the consistency right. Too thin and the paint will run out of the bow pen and you will get blobs, too thick and the paint won’t flow at all, giving you interrupted broken lines. Practice your technique.

I have used neat Humbrol, but it must be thoroughly stirred and mixed. I still decant into a separate mixing tray. Yes, we are talking about mixing the paint first with a brush and then transferring it to the bow pen a little at a time. Don’t attempt to mix the paint and thinners in the drawing pen nib itself. And definitely do not plunge the pen straight into the paint bottle.

I can usually get one small window out of one fill. As they say, practice makes perfect. So, test the paint consistency and your technique before moving to the final finished window frames.

Test various nib gaps. I have several bow pens in various nib sizes and swear by the method of dragging various weights of thin paper through the nib point, opening or closing down the adjustment screw to allow the paper to slide through the gap without catching. 80g/m2 typing paper is a good starting point.

I have experimented with filing away the factory nib point on an oil-stone to gain more line width control for my various other ruling projects such as model boat decking planks and large artworks for interior décor commissions. Even stropping the fine nib point a couple of times across very fine wet or dry paper can make huge improvement to the line quality.

STEP 4. Painting the frame/mullions Now following your drawn window frame and using a straight-edge or beveled set-square or ruler, paint over the frame’s horizontal lines first. Now rotate the work and working horizontally again, paint in the remaining lines. Simply put: work in one direction only, never go back, otherwise you may mark or drag the wet paint to where it is not wanted. Work smoothly and confidently. Practice will tell you how much pressure to exert, the desirable speed and when a blob is about to happen.

STEP 5. Fill in the outside frame Once the fine frame lines are drawn, you will need to widen the window frame’s outside width. I use the same mixed paint, brushed right up to and over top of the existing paint fine line. I usually lay the paint on fairly thick which gives the impression of the frame’s thickness. I like to do this before the fine lines dry, that way the wet thin lines have time to merge with the brushed areas, making a smooth transition of paint colour.

STEP 6. Build up paint thickness I find that as the paint dries it flattens out and shrinks a fraction and can be a little bit transparent in places. So, I wait until the paint is dry (overnight) and go over this outside extended frame area with a couple of thicker coats. This helps to give the window frame an almost scale thickness.

For example, see the engine shed office window that I prepared earlier.

STEP 7. Sash/casing surround I like to mimic the outer sash/casing frame in card. I cut out an opening 2-3mm or so wider than the painted window frame. This gives the window a reasonable representation of frame depth. One can better see this in the example photograph. Put glazing aside for a few days to let the enamel paint really harden.

STEP 8. Installation Carefully test fit and trim the finished windows to size, referring to your pre-numbered frames. On most of my buildings I have allowed for a very small rebate in the window wall openings. This allows me to use a few drops of canopy glue around the edge and fix each window in place. Job done. I have used doubled-sided tape, but I always follow up with a dab of ‘belts-n-braces’ glue.

The windows used in this demonstration have now been installed on the freelance GWR signal box and engine shed currently on my workbench (AKA the dining table).

Should the Editor approve, I have taken several work-inprogress construction photographs of the signal box and shed for a building report update later. Let there be light.