Hand-cutting the stencils to apply the various nomenclatures to our 750 Litre Oxygen Cylinders for the Car Door Typhoon. The secret is to cut the the stencils with the work piece resting on a sheet of window or picture frame glass using a Swann-Morton scalpel (or similar.) This system works well and can be done using standard inkjet paper rather than shelling out large sums for one-use commercial stencil medium.
Most people tend to use either a wooden board or a commercial cutting mat, and wonder why it didn’t work or went horribly wrong. The problem with using either of these items is that the two work surfaces tend to gather assorted score marks from previous cuts, and the blade tends to find these score marks and wander off-course. Glass doesn’t have this problem and the cuts usually follow the intended path; (especially when cutting curves). The use of inkjet paper also allows the use of your favourite font.
You could, of course, invest in a commercial laser cutter, or farm the the job out to a specialist firm; but being a non-profit-making Charitable organisation, we have to, by necessity, cut them by hand using the old-school method. Besides which; the original stencils were made in exactly the same way.
Here’s the most complex one…
By: jeepman - 6th March 2020 at 15:04
Those clips almost look like the old style of jubilee clips made of wire with a wing nut instead of slotted head screw to tighten up and with some way of mounting to the frame added.
Would it be possible to reform a larger clip into a figure of eight in some way, perhaps with the aid of some heat, and add a variable size collar from some rolled spring steel (from a old saw perhaps) to go under the wire circles.
By: No.2 A.A.C.U. - 5th March 2020 at 20:54
Excellent work
By: windhover - 5th March 2020 at 09:06
Fun day yesterday… fabricating the first of the two required Oxygen Cylinder cradles.
The scratch-built replica was constructed using only the A.P. illustration and dimensions taken from the 750 Litre Cylinder itself. No other references are available.
The cradle was constructed from 17SWG aluminium strip using period Mushroom-headed rivets to secure the circular body straps; and period 120° Countersunk head rivets with suitable plain washers sandwiching the outer and inner faces of the swivelling head bracket; (which secures the cylinder valve collar); to allow for its arc of travel.
The construction of the valve collar retaining bracket has yet to be figured out; so, much in the way of grey matter acrobatics is next on the agenda.
(And then, we have to do it all again for the other cradle… still, it keeps us off the streets!)
By: windhover - 22nd February 2020 at 20:24
The final effect of the stencilling on the 750 Litre Oxygen cylinders. Slight overspray as would be expected on curved surfaces…but, at least it is authentic. The original period stencil font was cut using the 1940s “Marsh Model R Stencil Cutter Typeface which is no longer available in its original form. The modern Marsh typeface is slightly different, so Stencilla Regular True Type Font which closely resembles the original was used. The font weight (size) is dependent on the specific lettered nomenclature: (eg: OXYGEN, R A F, etc). Stencilla font uses a rather odd-shaped number 6; consequently, a standard Arial number 6 font in equivalent weight to the Stencilla lettering was used on the specific nomenclature, but with a hand-cut separating ground.
The next fun game will be the reproduction of the Cylinder cradles. (P/No: B.99392). The actual metalwork is straightforward ( 1″ wide 17SWG strips); but the Valve collar attached to the front of the cradle is likely to be a tad problematic!
By: cometguymk1 - 18th February 2020 at 07:25
A few interesting tips 🙂 I must admit to hating stencils after working on 146 fire bottles and having to spray the instructions on. Never went smoothly.
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February 17, 2020 at 8:05 pm