Pink salmon primer on F4U-1?

[Eli Raphael]

Gents,

Were the primed surfaces visible in this color or were they covered with finished paint?

Thanks

[thierry laurent]

Hi Eli,

 

some internal areas that could be visible when bays or doors were opened stayed salmon pink without being overpainted on some batches of birdcage Corsairs. One airframe retrieved from water some years ago clearly showed it in the landing gear bays. Try getting the booklets written by Dana Bell. They give a lot of small details about the production of early Corsairs. I don't think you can get better sources.

 

HTH

 

Thierry 

[Eli Raphael]

8 hours ago, thierry laurent said:

Hi Eli,

 

some internal areas that could be visible when bays or doors were opened stayed salmon pink without being overpainted on some batches of birdcage Corsairs. One airframe retrieved from water some years ago clearly showed it in the landing gear bays. Try getting the booklets written by Dana Bell. They give a lot of small details about the production of early Corsairs. I don't think you can get better sources.

 

HTH

 

Thierry 

Thanks Thierry.

Any idea where to get those booklets?

[thierry laurent]

Hi Eli,

 

Here's one example:

 

https://www.ebay.com/itm/385502132966

 

But you can find them easily elsewhere (Amazon and most major model resellers).

 

HTH

 

Thierry 

[TAG]

Hey, Eli

 

Here's the full 411 from @Dana Bell:

 

"The following notes apply to Birdcage Corsairs only - there were additional variations on later models.

The aircraft was expected to have two coats of primer over most assemblies.  The first coat was untinted (yellow) zinc chromate; the second coat was to be tinted to ensure that there were no 'holiday' areas that received only one coat.  As such, there should be salmon nearly everywhere.

The cockpit also needed a coat of darker paint to reduce reflections on instrument faces and windows.  Early on this was Dull Dark Green.

The inside of the engine cowl also needed an additional finish coat to reduce the possibilities of flash fires.  This was usually the same Light Gray camouflage lacquer used on Corsair undersurfaces.

When BuAer decided to step away from salmon and Dull Dark Green, Vought got a special waiver on the two coats of primer.  The first coat was still untinted (yellow) zinc chromate.  If the underlying metal was Alclad (aluminum alloy coated with pure aluminum) no second coat was needed.  If the underlying metal was aluminum alloy, the first coat of untinted zinc chromate was stamped "1st COAT" in black ink; a second coat of untinted zinc chromate was then applied.  Since the primer was translucent, the black stamped notice would appear green under the second coat.

With the Navy dropping Dull Dark Green, the cockpit still needed to be darker.  BuAer recommended Interior Green, but another waiver allowed Vought to used that bright aluminized zinc chromate.  Note that some sub-assemblies were delivered in Dull Dark Green before being introduced to the bright green cockpit.

 

Instrument panels and side consoles were Instrument Black, a satin finish.

Wheel wells were nearly always painted in the underside camouflage color, thought there were a handful of exceptions.

There was still plenty of Light Gray in stock, so that paint was still used inside cowlings into production of the -1As.

 

Remember that US Corsairs used dope on fabric (all the way to the wing tip edges on wings) and lacquer on aluminum.  The two paints were spec'd to the same color charts, but the paints rarely matched when fresh, and certainly never matched as they weathered.

 

A final note on wear over the wing roots - the Birdcage Corsair leading edges were smoothed, just like we expect on P-51 Mustangs.  This was then overpainted with two coats of primer (see above) and two coats of camouflage lacquer.  As boots wore though the camouflage, the primer came off too - you would see the white putty rather than the primer of unpainted aluminum.

 

Dana Bell"

 

Here's some photos of the Birdcage that was fished out of Lake Michigan back in 2010:

 

Salmon pink tail wheel bay.

 

You can see some traces of YZC under the salmon.

 

No interior green here.

 

 

Main gear bays and struts are Light Gray (same as underside) over pink primer.

 

Is this the white putty on the leading edge that Dana referred to, or just plain old YZC?

 

You can find more pics of this airplane at this link.

 

Espero que te ayuden las fotos!

 

Saludos,

- Thomaz

 

[Oldbaldguy]

As tedious as the Corsair must have been to build, I cannot imagine the time (and overspray) required to paint all its many parts several times in so many different colors!

[TAG]

You're spot on there, OBG. Here's a deeper dive into that painting procedure from the Birdcage Erection & Maintenance Manual that I copied many moons ago, all credit to the author William Reece.

 

"There has been a lot of discussion about the use of Salmon colored primer on the F4U-1 Corsair since I posted several messages to the newsgroup rec.models.scale in mid-1996. There was mention of it made at the 1997 IPMS National Convention and Dana Bell mentioned its use in his article in FineScale Modeler. This is an attempt to further clarify and identify the use of Salmon primer on these aircraft.

 

Mr. Larry Webster who is associated with the New England Air Museum has kindly provided me with copies of the original Chance Vought Erection and Maintenance Instructions for the F4U-1 Corsair. This document lists all of the materials and procedures needed to build an F4U-1 Corsair.

 

First in the materials list of finishes for the F4U-1 is Lacquer-Dull Dark Green for use on the cockpit interior, USN Spec. AN-TT-L-51, quantity 1 1/2 gals., supplied by Du Pont.

Next is listed Zinc Chromate Primer USN Specification AN-TT-P-656 supplied by Du Pont, quantity 15 gals. This would be the familiar yellow zinc chromate primer similar to FS 33481 or Testors small bottle Zinc Chromate.

 

Also included in this listing is the requirement for 1 1/2 lbs. of Indian Red Paste, Tinting Medium USN Spec. TT-I-511 supplied by Valentine of New York. Indian Red is a dark red-brown color and is widely available as an artist oil paint sold in art supply stores and full line hobby shops.

 

The Indian Red was to be prepared as follows: 2 oz. of Indian Red mixed in 2 gals of toluol or equivalent (AN-T-8b toluol substitute, similar to lacquer thinner) solvent. This mixture was to be used to reduce 1 gal. of zinc chromate package material (un-reduced zinc chromate primer). This mixture was known as TINTED PRIMER (my caps). This comes from pages 1106 and 1110 of the F4U-1 Corsair Erection and Maintenance Instructions.

 

In section 7.2 of the E&M Instructions the raw aluminum for the construction of the Corsair was treated with a primer coat of zinc chromate. This coat known as the Shop Primer Coat was to serve as a first coat for the finishes to follow.

 

In section 7.31 of section 7.3 Detail Protective Schedules: Class AA for Special Conditions or Material: magnesium alloy parts were to receive two coats of zinc chromate primer followed by two coats of TINTED PRIMER.

 

In section 7.321 under section 7.32 Class A or 3 Coat Protection; the exterior metal surfaces were to receive one coat of primer and one or two coats of lacquer finish color depending on the metal used.

 

Section 7.331 under section 7.33 Class B or Two Coat Protection: states that the Interior of the cockpit from Station 129 to Station 186 and all parts contained therein except the instrument and control panels, control handles, etc. shall be one coat of primer on details or sub-assemblies followed by one coat of cockpit green lacquer after assembly.

 

The interior surfaces of fuselage (except cockpit), wings, flaps, ailerons, tail surfaces and all parts contained within shall receive one coat primer on details or sub-assemblies followed by one coat TINTED PRIMER on assembly; light non-specular gray shall be the top coat on the wheel wells.

 

The engine mount, front face of the firewall and all parts forward thereof shall receive one coat of primer and one coat of TINTED PRIMER except the interior of the engine and accessory compartment cowling and such areas which may be exposed to view. The second coat on the interior of the engine and accessory compartment cowling shall be light non-specular gray; areas exposed to view shall match the surrounding exterior color.

 

Section 14 describes the color system to be used on the Corsair. Section 14.1 deals with the exterior of the aircraft and section 14.4 states that the color of the cockpit shall be finished in cockpit green lacquer as noted in #7.331. The interior of the windshield frame shall be non-specular black.

Sections 14.6 and 14.7 state that the cargo, baggage, fuselage fuel compartment and structural spaces be painted in TINTED ZINC CHROMATE PRIMER as stated in #7.331.

Finally pages 1120 and 1126 of the E & M Instructions describe the use and preparation of tinted zinc chromate primer USN Spec. AN-TT-P-656. Local Process Specification Nos. 21-24-26-28-30-32 Application of Top Coats gives specific instructions on the preparation and application of the various paint coats used on the Corsair.

 

Two methods are given for tinted zinc chromate. Method (a) involves the use of 2 oz. of aluminum paste per gallon of zinc chromate package material thinned 1 part primer to 1 1/2 parts thinner. Method (b) uses 2 oz.. Indian Red Paste per package gallon of zinc chromate primer and thinned 1 part primer to 2 parts thinner.

 

What is the bottom line of all of this? Well, for one F4U-1 Birdcage Corsairs had their interior areas except the wheel bays, engine cowling and accessory cowlings painted in a dull orange-brown tinted zinc chromate primer know as Salmon. The closest paint that I have found to the samples in my possession is PollyScale Railroad, Southern Pacific Daylight Orange.

 

The wheel bays, engine cowling and accessory cowlings were painted in Non-Specular Light Gray to match the underside of the aircraft. The cockpit was painted Du Pont Dull Dark Green. Photos of F4U-1s taken at the time show the cockpits as being a very dark color.

 

Articles recovered from various F4U-1 crash sites confirm these instructions. Artifacts removed from F4U-1, BuNo 02368 which crashed near Exeter, Rhode Island on September 12,1944 show good evidence of the use of Salmon primer on the structural spaces. Other parts recovered from other crash sites show evidence of Salmon on interior spaces and inside the wheel bays and tailwheel bay. Others show Salmon underneath Non-Specular Light Gray in the wheel bay tops.

 

Many thanks to Larry Webster for his time finding the documentation on this subject. Any errors or omissions are the sole responsibility of the author. Copyright 1998.

 

William Reece,
Fly Navy!"

 

Here's a couple of photos that show just how many layers of paint and putty ended up on a section of F4U wing from the bird that was pulled from Lake Michigan.

 

The salmon primer on the internal side of this part shows both the stained and darkened primer after 70+ years underwater as well as the lighter-colored section which was sanded to reveal the original color of the salmon.

 

The reverse, external side shows most of the colors on that Birdcage: Yellow Zinc Chromate, salmon-tinted primer, non-specular Light Gray, non-specular Blue-Gray, Sea Blue, the gray filler used on the leading edge of the wing (similar to that on the P-51), as well as the flush rivet holding these two aluminum plates together.

 

Here's a couple of color period photos from the factory floor for extra credit.

 

Things certainly got messy at the spray booth, note all the runs and splatters in the finish and how our man here has his protective mask around his neck. Not much use there, is it? OHSA would be having a field day if this happened nowadays...

 

They didn't just spray stuff, they also dipped parts into big vats of primer (whilst not wearing gloves). Looks pretty gross but remember, the priority back then was speed and getting as many planes as quickly as possible into action, not cleanliness and most certainly not the health of workers. Total war, I believe is how historians define it today.

 

- Thomaz

[Eli Raphael]

On 7/21/2023 at 12:27 PM, TAG said:

Hey, Eli

 

Here's the full 411 from @Dana Bell:

 

"The following notes apply to Birdcage Corsairs only - there were additional variations on later models.

The aircraft was expected to have two coats of primer over most assemblies.  The first coat was untinted (yellow) zinc chromate; the second coat was to be tinted to ensure that there were no 'holiday' areas that received only one coat.  As such, there should be salmon nearly everywhere.

The cockpit also needed a coat of darker paint to reduce reflections on instrument faces and windows.  Early on this was Dull Dark Green.

The inside of the engine cowl also needed an additional finish coat to reduce the possibilities of flash fires.  This was usually the same Light Gray camouflage lacquer used on Corsair undersurfaces.

When BuAer decided to step away from salmon and Dull Dark Green, Vought got a special waiver on the two coats of primer.  The first coat was still untinted (yellow) zinc chromate.  If the underlying metal was Alclad (aluminum alloy coated with pure aluminum) no second coat was needed.  If the underlying metal was aluminum alloy, the first coat of untinted zinc chromate was stamped "1st COAT" in black ink; a second coat of untinted zinc chromate was then applied.  Since the primer was translucent, the black stamped notice would appear green under the second coat.

With the Navy dropping Dull Dark Green, the cockpit still needed to be darker.  BuAer recommended Interior Green, but another waiver allowed Vought to used that bright aluminized zinc chromate.  Note that some sub-assemblies were delivered in Dull Dark Green before being introduced to the bright green cockpit.

 

Instrument panels and side consoles were Instrument Black, a satin finish.

Wheel wells were nearly always painted in the underside camouflage color, thought there were a handful of exceptions.

There was still plenty of Light Gray in stock, so that paint was still used inside cowlings into production of the -1As.

 

Remember that US Corsairs used dope on fabric (all the way to the wing tip edges on wings) and lacquer on aluminum.  The two paints were spec'd to the same color charts, but the paints rarely matched when fresh, and certainly never matched as they weathered.

 

A final note on wear over the wing roots - the Birdcage Corsair leading edges were smoothed, just like we expect on P-51 Mustangs.  This was then overpainted with two coats of primer (see above) and two coats of camouflage lacquer.  As boots wore though the camouflage, the primer came off too - you would see the white putty rather than the primer of unpainted aluminum.

 

Dana Bell"

 

Here's some photos of the Birdcage that was fished out of Lake Michigan back in 2010:

 

Salmon pink tail wheel bay.

 

You can see some traces of YZC under the salmon.

 

No interior green here.

 

 

Main gear bays and struts are Light Gray (same as underside) over pink primer.

 

Is this the white putty on the leading edge that Dana referred to, or just plain old YZC?

 

You can find more pics of this airplane at this link.

 

Espero que te ayuden las fotos!

 

Saludos,

- Thomaz

 

Thanking you Tomás!!