British Camo Rubber masks

[Work In Progress]

The rubbing down and gloss coat would sort it out, but at fairly outrageous labour cost. Well, it all makes my skin crawl just to think about it. Makes me want to time-travel back to 1940 with several big rolls of modern fine abrasives, an orbital buffer, some cutting compound and some finishing mops.

Edited July 15, 2013 by Work In Progress

[Test Graham]

If you're going to do that just take some modern paint instead.

[Work In Progress]

Logically, you make perfect sense. Instinctively I suppose I am at heart a fixer-upper, and find myself drawn to improving the dreadful mess they've made of things rather then setting up a paint line of my own!

[Greenshirt]

If I could travel back in time, I'd just take a good camera and leave the negatives with some key people, plus some good descriptions with lots of details. My assumption is that nobody believe me if I produced a bunch of modern digital photos and descriptions after bringing them back. But then again if time travel were possible...

Tim

[Edgar]

The rubbing down and gloss coat would sort it out, but at fairly outrageous labour cost. Well, it all makes my skin crawl just to think about it. Makes me want to time-travel back to 1940 with several big rolls of modern fine abrasives, an orbital buffer, some cutting compound and some finishing mops.

On the Spitfire (without a gloss coat,) the extra time needed for the smooth DTD517 finish (which included filling rivets and panel lines on the wings' leading edges, then sanding down and priming) was estimated at 50 hours (25% skilled,) and was termed "negligible."

A new trade, Aircraft Finisher, was instituted about the same time (1942) as the DTD517 finish, whose job it was to keep the finish as pristine as possible (so, preferably, no black panel lines, and swathes of worn-down bare metal.) I've found a copy of the (just) post-war Aircraft Finisher's handbook, but, at over 110 pages, that's not for here, sorry.

Edgar

[stevehnz]

Thanks for putting those up Edgar, an interesting thread that I've been following for, oooh, just a wee while.

One thing that occurrs to me with this subject of roughness & masking mats, I'd guess that a full size plane would spray one colour then another rather than the modellers way of all over one & then mask off for the pattern in a different colour. Maybe the first colour unmasked but close to pattern & the second masked? Would there be a hard edge to the second colour that needed rubbing down to acheive the target smoothness or would there be sufficient gap under the mask to allow a fraction of overspray to feather the edge? I can't imagine a hard ridge at the edge of the second colour of perhaps 10thou + would be considered desirable or acceptable.

Steve

[Edgar]

Not according to witnesses; it was one all-over coat, then the mats, then the second colour (if you think about it, any "feathered" edge will still be rough, and need sanding smooth before the mats come into play.)

Makes me want to time-travel back to 1940 with several big rolls of modern fine abrasives, an orbital buffer, some cutting compound and some finishing mops

.You're being a little unfair on the ability of the men who were around at that time; mops, rubbers, etc., were standard items for furniture polishers of the day, and many of them were drafted into the forces (Avro, for one, complained they'd been left with not just old, but infirm, staff in their paint shop.) In the Aircraft Finisher's handbook, the art of "pulling over," using a thinner-soaked pad, is explained; this would be second-nature to anyone from the furniture trade.

Edgar

Edited July 16, 2013 by Edgar

[Work In Progress]

I'm not setting out to denigrate the ability of the people - if you look at the list of things I would take back, I was hoping to put some better materials and equipment into their hands - though I accept that if they were mainly inexperienced in the work then poor skills may have been a big part of the problem too. But it's almost always quicker and cheaper to give people adequate training at the outset using sample pieces that don't matter, rather than have to re-work actual production items that have been finished badly, or (even worse) send badly finished work out into service.

Assuming the facts set out in the memo you reproduced are correct, something must have been badly wrong, whether it was paint formulation, equipment or the methods or skills being employed. 1/100" roughness in the paint is appalling considering the aerodynamic penalties, and a big step back from normal civilian production pre-war, if you look at contemporary finishes of aircraft, watercraft and cars (plus, as you mention, furniture).

[Edgar]

When camouflage was introduced, it was solely to hide the aircraft when on the ground, and there was little thought of drag, especially on biplanes, with their built-in headwind. When speed became vitally important, all sorts of things were experimented with, to try for increases, and paint smoothness (while remaining matt) was just one of them.

It was Supermarine's Joe Smith who discovered the smooth synthetic paint, and recommended it to the Air Ministry, who initially (true to form) treated the idea with scepticism, until they actually viewed the results, during a meeting with the company.

Whip aerials, different-shaped r/v mirrors, stone guard removal, ejection chutes cut flush, exhaust stubs reshaped, internal-armoured windscreen (plus others) were all done to increase speed.

It was, largely, I.C.I. who led the way on painting skills, since they introduced courses, in aircraft finishing techniques, around 1942.

Edgar

[Test Graham]

Presumably there is some link across to the PRU, where considerable work was being done on obtaining a smooth finish on aircraft, and also on the use of duck-egg blue for aerial camouflage. It seems very unlikely to be a pure coincidence that the first smooth colour was Sky.

[Edgar]

The first P.R. unit isn't a very good example, since Sky, or Camotint, was Sidney Cotton's invention, and he took out a patent on it (probably why the Air Ministry renamed it Sky, when they turfed him out of the job, and pinched the colour.) Cotton was renowned for doing things his way; not for nothing was his unit known as "Cotton's Air Force."
When the "Western Group Supervisor" J.E.Serby, wrote to Bristol's 20-4-40, he said that, for the Blenheim IV (the P.R. version, as far as I can tell,) they should call for "lacquer to DTD63 with reduced gloss, gloss not to exceed that shown on samples to be obtained from the Bristol Aeroplane Co. Ltd." He also said that all other aircraft will comply with the new Type "S" standard; that "new" seems to imply that type S didn't exist before 1940.

[gingerbob]

None of which seems to run counter to Graham's observation that Cotton's boys might have had something to do with it, though no doubt it was 'regularized' to join the mainstream.

bob

[Test Graham]

I said nothing about specific timescales for the introduction of "Type S". Blenheims (including Mk.IVs) were already being painted with a very similar colour, at least as early as winter 1939/40, as seen in snow scenes in France at this time. It's smoothness is another matter. However, I stand by my comment that the PRU, on Ministry instructions, were undergoing experiments in obtaining the best speed from Blenheims for PR duties. These were Mk.Is by choice, being the lower-drag shape to start with. Cotton was clearly a great inspiration for the early establishment and operation of the PRU, but he wasn't working alone and in isolation. These experiments in drag reduction and smooth finish will have been taken on board by the appropriate staff and the introduction of the Type S finishes was the result of the convergence of a number of approaches.

After all, the value of a smooth finish was known to every aeronautical student or practitioner. Achieving it is more difficult, especially in wartime build and operation.

[Space Ranger]

What happened to the image of the Supermarine Spitfire camouflage drawing with the note about the use of mats? Was it ever re-posted? I'd like to get a copy if possible.

Edited October 3, 2013 by Space Ranger

[AMStreet]

A little late to the party I will admit, but reading through this topic a couple of thoughts occurred to me:

1) The fact that it's pretty obvious from colour photos of that some RAF heavy bombers had the colour demarcations sprayed with a tight spray and then the rest filled in with a wider nozzle, and why was a rubber, or other kind of mask, was not used? Have you thought of how heavy a mask suitable to a Lancaster's mainplane would be? I don't think two men could handle it and keeping in from slipping would be a problem as well.

So, OK for fighters, not so good for larger airframes.

2) The use of "horse hair" as a filler for the mats. As has been said, the use of such a material would probably have meant that there would have been a lot of tailless horses about. I might be wrong but would not coir, the fibrous outer casing of coconuts, be a better material? There were lots of coco palms within Allied held territory and being a vegetable by-product of the coconut industry would surely have meant an adequate supply. Of course my suggestion maybe completely wrong but I do think that a vegetable filler for such mats is more likely than an animal one.

Just my two-penny-worth. I am sure that mats were used but only where such use was an aid to production, which was, after all the whole idea.

[gingerbob]

I don't know anything about the population of horses in wartime Britain, but having been around horses this spring, I bet horsehair (doesn't have to be tail, does it?) would be much easier to come by than coconut husks!

bob

[gruffy]

I don't know anything about the population of horses in wartime Britain, but having been around horses this spring, I bet horsehair (doesn't have to be tail, does it?) would be much easier to come by than coconut husks!

bob

Actually horses hair is used quite a lot in the building industry then and now. It was used in lime mortars to bind everything together. Easy to get hold of in Britain than coconut husks!

[Edgar]

Curry a horse, and hair gets pulled (have a look at the curry comb and brush, after grooming, sometime); there were also many shire horses still in harness in the 1940s, especially with fuel for tractors on ration, and it was common practice to dock tails, since there was far less cleaning needed (think emanations from the orifice below the tail.)

The masks didn't cover the whole surface area in one piece, since the design was largely stripes and triangles, so consisted of several pieces; it was also usual for wings to be held vertically, in jigs, not laid flat, for spraying.

Also, from what I was told by a man who'd used them, they were less than 1/2" thick, so not as heavy as some think.

Edgar

Edited May 8, 2014 by Edgar

[Andrew Jones]

Lots of horses in wartime Britain , used in agriculture , forestry and the haulage industry, in fact many farms only became mechanised with the advent of war , due to lend-lease and the War-Ag commitees. Many horses would be slaughtered at the end of their working lives and probably many more for meat, [ with rationing in force people were not as picky as today ] ,this would give a large supply of horse hair. Much easier to find than coconut fibre I would think.

Andrew

[Edgar]

Before this takes yet another twist, if you look back, I said that the material, described to me by someone who had used the mats, sounded remarkably like the rubber-come-horsehair packing material which I've used, and seen used. I am not saying horsehair was definitely used, because I was not there to see it.

[Work In Progress]

As I knowing nothing much about horses, the phrase "curry a horse" gave me COMPLETELY the wrong idea just now. But I've Googled it. Mind duly unboggled.

[andygif290368]

Mildly spicey served with a corriander naan bread.

I cant believe until I read this thread that spitfires camouflage only came in two patterns.

Now I've checked I see they swapped left to right, but did they also swap green for brown too?

Edited May 9, 2014 by andygif290368

[gingerbob]

Now I've checked I see they swapped left to right, but did they also swap green for brown too?

Normally no.

bob

[Test Graham]

The mirrored patterns were only used early in the war, standardising on one. Exchanged colours were allowed for in the original plans, but are rarely seen on UK Spitfires - although Wing Commander Minden Blake's personal Mk.Vb was an exception. Exchanged colours are however common on Desert Scheme Spitfires, possibly because of misunderstanding where the Dark Earth was supposed to be. It was the lighter colour on the Temperate Scheme but the darker one on the Desert, so there could have been misunderstanding in the paint shops working from b+w drawings.

[PLC1966]

Curried Horse ?

Frikandel mit Curry ketchup anyone....