USN GSB Scheme - use of primer

[Wez]

Were the external surfaces of aircraft like the Corsair, Avenger, Hellcat and Helldiver that were finished in the Gloss Sea Blue (GSB) scheme primed before the application of GSB?

 

If so were they painted with Yellow Zinc Chromate primer?

 

Did it depend upon the manufacturer?

 

Under normal circumstances I'd expect a primer to be applied for environmental protection purposed but as these aircraft weren't expected to have great longevity, would they have gone for the weight saving and quicker build by missing out the external primer stage?

 

What I'm wondering is whether those aircraft that survived the war and went on to other users such as the French in Indochina and had pretty hard use would wear directly down to bare metal or would there be a primer stage beneath the blue first?

[11bravo]

I've got plenty of pictures of Corsairs that show YZC primer showing under worn off blue paint.   I am certain the same would apply to all other aircraft as well.  The Navy was pretty rigid on painting standards. 

[Work In Progress]

Yes, definitely primed

[Wez]

Thanks both, it's what I expected but I did wonder whether under the exigencies of war they did something different - apparently not.

[Troy Smith]

On 19/07/2020 at 15:43, Wez said:

Were the external surfaces of aircraft like the Corsair, Avenger, Hellcat and Helldiver that were finished in the Gloss Sea Blue (GSB) scheme primed before the application of GSB?

 

If so were they painted with Yellow Zinc Chromate primer?

 

Did it depend upon the manufacturer?

 

If anyone knows the full details of this, it will be @Dana Bell

 

There maybe variance between different manufacturers in primers used though.

 

Regarding dropping of painting, the USAAF found it acceptable. the USN did not.     If you search up Corsair KD431,  

 

there is a walkround here, GSB is pretty durable

 

 

Also,  well worth a read

 

Main point,  that  WW2 GSB ANA 623 is NOT FS15042

[Julien]

GSB in itself was a very durable paint, hence its choice, but no paint alone is durable unless they surface is properly prepared and primed. 

[Dana Bell]

Hi Wez,

 

Primers existed for three reasons: to protect the metal from corrosion, to reduce the buildup of static electricity, and to give paint something to adhere to.  By WWII zinc chromate primer had become standard in the US, yellow for the first coat, tinted for subsequent coats.  (The tinting allowed inspectors to ensure that an airframe was completely coated.)

 

The fun is in the details, and new details are found all the time.  Martin had an exclusion for the B-26, arguing that their enamel adhered to the Alclad skin without a primer.  Northrop tried the same thing with their Jet Black paint, which peeled off in sheets - a bad call there.  Vought, Brewster, and Goodyear got an exemption to apply one coat of primer to Alclad sheet, and two coats of yellow zinc chromate primer to all other alloy surfaces.  (After the first coat was applied, the surface was stamped with black ink to identify the first coat; the second coat of yellow (untinted) zinc chromate changed the appearance of the ink.)

 

The Navy was particularly concerned about corrosion, so nearly every aircraft had at least one coat of primer - that salt water environment was murder on aluminum alloys.  Cost and weight considerations meant that a single coat was usually acceptable on exterior surfaces.

 

Cheers,

 

 

Dana

[Wez]

Thanks @Dana Bell

 

I'm aware of the reasons for applying primer (I'm an aircraft engineer), but there are other coatings which could be applied which do much the same job but don't have a tint like YZC does for instance.

 

The point of my question was to ascertain that whether the paint would wear directly to metal or would primer be seen around the periphery of the metal area before the blue starts.  From the answer you've given it would.

 

I wondered whether the USN would give manufacturers a bye during the war on account of aircraft longevity not being what is is in peace time and a weight saving would give a performance benefit.  It would seem the USN were just as concerned about aircraft flaking away before your very eyes on unprotected surfaces.

 

One final question from me at least, what colour primer did Curtiss apply to the SB2C Helldiver?

[Dana Bell]

Hi Wez,

 

I've seen a lot of correspondence on primers and painting, and there doesn't seem to be a common set of rules.  In fact two Wright Field memos actually complained that there were NO common standards and it was becoming difficult to know how to answer manufacturers' questions.  The Army tended to go lax on priming requirements due to factory/production problems - North American and Boeing each had a factory without a decent paint shop, so they were given reduced requirements for interior priming on P-51s, AT-6s, B-25s, and B-17s.  Still, the exteriors were primed before camouflage was applied.

 

I've not seen the Navy give anyone a similar break, though I'd need to go through every contract file to be sure it never happened.  I don't have any good gen on the SB2C, but it may have been primed similarly to the A-25 (which was built in a separate factory).  An original transparency in NASM's Hans Groenhoff Collection shows a primed A-25 on the assembly line; everything is in yellow zinc chromate except the outer wing panels and tail planes, which are green-tinted zinc chromate.  (Because of the artificial lighting, I can't even guess which of the green tints was used.)  If those panels were primed by the same subcontractors who produced parts for the SB2C, this may have been the standard used on the Navy Helldivers.

 

I wish I could pin this down for you, but this is as far as my at-home resources will provide.

 

Cheers,

 

 

Dana

 

EDIT - I don't know how I originally left out the word "NO" at the end of the first line above, but it belongs there and changes the meaning of the snetence in an important way...

Edited July 22, 2020 by Dana Bell

[Seahawk]

6 hours ago, Troy Smith said:

 

 

NB.  for the wider readership, the finish of this aircraft is NOT representative of an aircraft in service, even a well-used one: it's how an aircraft looks after 15+ years' use and abuse as a ground training aid  at Loughborough and Cranfield technical colleges.

Edited July 22, 2020 by Seahawk

[Wez]

58 minutes ago, Seahawk said:

NB.  for the wider readership, the finish of this aircraft is NOT representative of an aircraft in service, even a well-used one: it's how an aircraft looks after 15+ years' use and abuse as a ground training aid  at Loughborough and Cranfield technical colleges.

Generally I would agree with your statement but as always, there are exceptions.

 

I was looking into the French use of Helldivers in Indochina, on the whole they kept their appearance very well except for those areas most used by the crew and particularly the groundcrew, the wingroots in particular were quite worn, similar in fact to those on the forward part of the inner wing in the photo.  As with all things, it's a case of studying your subject and applying your knowledge. 

[Wez]

1 hour ago, Dana Bell said:

Hi Wez,

 

I've seen a lot of correspondence on primers and painting, and there doesn't seem to be a common set of rules.  In fact two Wright Field memos actually complained that there were common standards and it was becoming difficult to know how to answer manufacturers' questions.  The Army tended to go lax on priming requirements due to factory/production problems - North American and Boeing each had a factory without a decent paint shop, so they were given reduced requirements for interior priming on P-51s, AT-6s, B-25s, and B-17s.  Still, the exteriors were primed before camouflage was applied.

 

I've not seen the Navy give anyone a similar break, though I'd need to go through every contract file to be sure it never happened.  I don't have any good gen on the SB2C, but it may have been primed similarly to the A-25 (which was built in a separate factory).  An original transparency in NASM's Hans Groenhoff Collection shows a primed A-25 on the assembly line; everything is in yellow zinc chromate except the outer wing panels and tail planes, which are green-tinted zinc chromate.  (Because of the artificial lighting, I can't even guess which of the green tints was used.)  If those panels were primed by the same subcontractors who produced parts for the SB2C, this may have been the standard used on the Navy Helldivers.

 

I wish I could pin this down for you, but this is as far as my at-home resources will provide.

 

Cheers,

 

 

Dana

Thanks Dana, that's quite helpful actually.

[Julien]

1 hour ago, Wez said:

Generally I would agree with your statement but as always, there are exceptions.

 

I was looking into the French use of Helldivers in Indochina, on the whole they kept their appearance very well except for those areas most used by the crew and particularly the groundcrew, the wingroots in particular were quite worn, similar in fact to those on the forward part of the inner wing in the photo.  As with all things, it's a case of studying your subject and applying your knowledge. 

One thing I was told by an old RAF pilot was when they operated over the jungle they used to wear heavy boots to fly as incase they needed to bail out going through the tree canopy might be easier in decent footwear. The ground crew were not happy with the damage they did clambering in and out tho !

 

Julien

[Blimpyboy]

Just a smidgin of undercoat showing through...

 

 

 

Edited July 23, 2020 by Blimpyboy

[Blimpyboy]

On 7/20/2020 at 12:43 AM, Wez said:

but as these aircraft weren't expected to have great longevity

I see and hear this a lot and it always confuses me, no matter the context.

 

Certainly, it’s foolish to expect no losses in a shootin’ war; however, I can’t think of any operator who would purchase, man and maintain any aircraft on the basis that it won’t last long.

In the same vein, I can’t imagine too many maritime operators - particularly among major powers - that would neglect some form of effective corrosion protection, let alone camouflage, by assuming a major churn of airframes.

 

 It makes ol’ BB scratch his head in confusion.