Gloster Gladiator - aluminium dope vs natural metal

[AdrianMF]

Hi there,

I'm just starting a Gladiator build and would like to know if it should be aluminium dope all over, or with polished natural metal panels at the front? Looking at contemporary pictures on t'interweb leads me to believe it is aluminium dope all over.

Thanks,

Adrian

[Rabbit Leader]

Adrian,

I think you are correct with the overall Aluminium finish.

If you trust the Ducimus series of books which came out when I was still in nappies - there is mention of this being the case. And yes, I think most of this information is very credible.

This book is available to read on the net, and I have provided a relevant link to the exact page.

http://www.boxartden.com/gallery/index.php/Profiles/Camoflage-Markings/05-Gladiator-Gauntlet/Gladiator-Gauntlet-Fury-and-Demon-5-02-960

Clicking the arrows in either direction will allow you to view the complete booklet. Actually the whole series and a lot more is here too.

Cheers.. Dave

Edited August 10, 2014 by Rabbit Leader

[AdrianMF]

Thanks Dave! Overall dope it is, then!

Regards,

Adrian

[Buster213]

Thanks for the link Dave, Gauntlet is fourth on my list to build after Sopwith Baby, Pup and Camel from WW1, Ive book marked the page for future reference.

Buster

[Richard B.]

yes, aluminum dope for the cloth areas, but aluminum paint for the metal parts. not sure of the paint formulation. The two areas will appear slightly different.

[Work In Progress]

Whether it was going on to fabric or metal the aluminium finish was all the same stuff in that era, i.e. cellulose based clear dope with aluminium powder stirred in. There's no difference in shade between the metal and fabric covered surfaces.

[Edgar]

The only possible difference would come from the undercoat; silver over red on fabric, and silver over grey on metal. I don't know enough about paint, but, as the undercoat and finishing coat specifications were 1.25 ounces per square yard each, they sound fairly thin to me.

[Selwyn]

Hi there,

I'm just starting a Gladiator build and would like to know if it should be aluminium dope all over, or with polished natural metal panels at the front? Looking at contemporary pictures on t'interweb leads me to believe it is aluminium dope all over.

Thanks,

Adrian

Go to the Bulldog thread in this forum http://www.britmodeller.com/forums/index.php?/topic/234966351-bristol-bulldog/ and scroll down to post 14 there are pictures of the contrast on the RAFmuseums Bulldog that you may find useful.

Selwyn

[Old Man]

No paint on the Bulldog metal, Sir. The metal was bare, and often polished up to a brilliant shine.

I would not venture a comment on English practice, but I know the U.S. Navy had a very hard time coming up with a dope formula that could be used on both fabric and metal. I believe they wound up using a lacquer for the metal and a dope for the fabric and wood when they went from grey metal and aluminum doped fabric to overall 'silver' in the thirties.

[Nick Millman]

Whether it was going on to fabric or metal the aluminium finish was all the same stuff in that era, i.e. cellulose based clear dope with aluminium powder stirred in.

No it wasn't. Cellulose nitrate or cellulose acetate dope on fabric. Enamel or cellulose lacquer on metal. The habit of referring to all finishes as "dope" in that era confuses the distinction. Dope is a thick, viscous liquid applied to the fabric to tauten, preserve and strengthen it, as well as improve its appearance. There were clear dopes, pigmented dopes and semi-pigmented dopes.

[Nick Millman]

The only possible difference would come from the undercoat; silver over red on fabric, and silver over grey on metal. I don't know enough about paint, but, as the undercoat and finishing coat specifications were 1.25 ounces per square yard each, they sound fairly thin to me.

Depends how many coats were applied. One dope application process from 1939 specifies 9-10 coats, variously clear and pigmented, with a mixture of brushing and spraying.

[Greenshirt]

I've got one reference on USN aircraft (not with me and on other side of the Atlantic) that indicated the basic aluminum color to be the same for both metal and fabric, in the tins, but when applied the metal areas took on a greyer tone whereas the fabric areas remained silvery (described as only slightly for both but just enough for the eye to discern). At some point the Navy found the right formulation, and the metal and fabric areas started to look the same, but within a couple of years they were all repainted light gray as war was looming.

Always my objective is to get that look on the older ones, but I still don't quite have it right.

Tim

[Edgar]

Depends how many coats were applied. One dope application process from 1939 specifies 9-10 coats, variously clear and pigmented, with a mixture of brushing and spraying.

True, and at some stage (don't know when) we went over to "Scheme Z," which was five red coats, two of which were a 50/50 mix of dope/thinners.

[John R]

Would it be helpful to look at pictures of the Shuttleworth and Flying Legends Gladiators? There are plenty available or would these a/c finished differently.

[Dana Bell]

I don't want to hijack the thread, but there have been several notes about US Navy aluminum colors that were correct at certain times. In the 1920s and early '30s, the Navy used only enamels for finish coats. For aluminum finishes, aluminum paste was mixed with spar varnish to create a paint that would cover most of the aircraft. When that enamel wouldn't stick to the metal primers then in use, the Navy refused to switch to a lacquer, changing the color to Aircraft Gray (originally called Navy Gray, then changed to avoid confusion with the ship color). This led to a distinctly different finish on metal and fabric.

In the mid-1930s the Navy learned of the Air Corps' successes with pigmented dopes and lacquers, and also began to use zinc chromate as a metal primer. As these finishes were phased into service, the all-aluminum finish returned, though there were slight (but noticable) differences between fabric and metal areas.

The unpainted metal was rarely used by the Navy - it usually involved Alclad, an aluminum ally sheet coated with nearly pure aluminum in the manufacturing process. Invented by Alcoa in the late 1920s, it would see little use until the md-1930s (and then was often overpainted).

This doesn't answer the original question; since I've no first generation notes on British finishes, I'll leave that subject to Nick and the others who study the subject!

Cheers,

Dana

[Nick Millman]

Just to clarify, the "pre-grey" USN finish Dana mentions was to soak the fabric in fire retardant, then apply two coats of cellulose acetate dope, followed by not less than two or more than four coats of cellulose nitrate dope, then two coats of 'aluminium wing enamel' (which was the pigmented spar varnish). In other words that finish was applied over 4-6 coats of conventional dope. The USN reckoned that this 'enamel' gave better protection than dope and was better suited to fabric repair, but they made exceptions to allow certain manufacturers to use aluminium pigmented dope.

My understanding of the spar varnish finish was that it was also used for glue set fabric over wood components such as rigid wooden hulls and floats. Then (clear) spar varnish was used to seal the aforementioned aluminium enamel finishes. But there were reported problems with the durability of that finish, especially on water contact parts of the airframe.

SR-15a of August 1931 specified aluminium pigmented dope for fabric surfaces and grey enamel for external metal and wood. SR-70 of May 1933 required the use of pigmented dopes as the final coat on fabric surfaces and ruled out the use of clear dope.

[AnonymousLL45]

just used the Alclad semi matt aluminium on the underside of a Hurricane, looks just the job.