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depth charges

Posted: 03 Jul 2016 14:04
by cootafleet
I need to know the colour [color] off WW2 US MK 6 ashcan type depth charges for my USS TENACITY FLOWER CLASS corvette. Black and white photo's vary a lot.

Re: depth charges

Posted: 03 Jul 2016 18:29
by MikeJames
I understand they were normally delivered from the factory to the depot and then on to the ships in the standard USN Haze Grey.

Some smaller ships may have repainted them to match a camouflage scheme, for example in the green scheme used by PT Boats in the South Pacific to blend in with the shorelines of the islands they hid amongst, but for larger vessels such as the Flower Class, it was probably not something they bothered with.

After all they were somewhat obscured behind the Flower's quarterdeck bulwarks and not visible to casual observers.

There may also have been an element of 'why bother' by the corvette crews given they were expended as a round of ammunition. It wasn't as if the crews weren't already busy just trying to maintain the ship's paintwork in the harsh climes of the North Atlantic without worrying about the depth charges as well.


Re: depth charges

Posted: 03 Jul 2016 19:40
by SlatsSSN
A great question. From information I got from the late Hugh "John" Lambert in the UK many years back, depth charges supplied to the British were typically un-painted munitions. The war effort could not spare it, and typically they had a very short life span at the high of the war. That said I'd think there is a fair amount of conjecture, and can't say the same however for US supplied munitions. Plenty of examples show colours painted to suit the camo of the ship that they were on.

Re: depth charges

Posted: 04 Jul 2016 13:30
by cootafleet
Found this on the US HISTORIC NAVAL SHIPS ASSOC. site.
dated Dec. 1943
3. To conserve critical materials galvanized finish of cases has been discontinued.
Cases are now finished as follows.
[a] All surfaces parkerized.
[b] Interior surfaces painted with 1 coat projectile cavity paint.
[c] Exterior surfaces and central tube painted with 1 coat zinc chromate primer.
[d] Exterior surfaces painted with 1 coat dark gray paint.
So prior to 1943 I guess you painted them if you could, some photo's of the era certainly show them as painted. :gu:

Re: depth charges

Posted: 04 Jul 2016 16:29
by alienpew
Wot in crap's name is 'parkerized' ? Is that where they are dragged through a park & covered with grass skid marks ? good camo for Pacific !

I have an interest in B1's question as well, my FRISCO has 2 d/c racks on stern in 42', so I guess they should be galvanised according to
directive 747. A bit more colour to play with.


Re: depth charges

Posted: 04 Jul 2016 17:53
by MikeJames
Allan, the internet is a wonderful thing, perhaps you should use 'the Google'.

Parkerizing, bonderizing, phosphating, or phosphatizing is a method of protecting a steel surface from corrosion and increasing its resistance to wear through the application of a chemical phosphate conversion coating.

Parkerizing is usually considered to be an improved zinc or manganese phosphating process, and not to be an improved iron phosphating process, although some use the term parkerizing as a generic term for applying phosphating (or phosphatizing) coatings that does include the iron phosphating process.

The process involves submerging the metal part into a phosphoric acid solution whose key ingredient is often zinc or manganese, with varying additional amounts of nitrates, chlorates, and copper. In one of the many processes that have been developed, the solution is heated to a temperature of 88–99 °C (190–210 °F) for a period ranging between 5 and 45 minutes. A stream of small bubbles is emitted from the metal part as the process takes place; when the bubbling stops, the process is complete. In addition to this particular processing temperature, there have also been various similar Parkerizing processes developed and patented that permit using either lower temperatures (for energy efficiency) or higher temperatures (for faster processing).

Zinc phosphating results in a non-reflective, light- to medium-gray finish. Manganese phosphating produces a medium- to dark-gray or black finish. Iron phosphating produces a black or dark gray finish similar to manganese phosphating. The grain size of the zinc phosphating is usually the smallest among the three processes, providing a more appealing cosmetic appearance in many applications. Many firearms that are Parkerized turn to a light greenish-gray color within a few years, as the coating ages, with the protective coating remaining intact. Cosmoline, especially, interacting with Parkerizing, can cause the greenish-gray patina to develop on firearms that are stored in armories.

Manganese and iron phosphating coatings are usually the thickest electrochemical conversion coatings, being thicker than electrochemical conversion coatings such as zinc phosphating and bluing.

As for all chemical conversion coatings, the Parkerized surface must be completely covered with a light coating of oil to maximize corrosion and wear resistance, primarily through reducing wetting action and galvanic action. A heavy oil coating is unnecessary and undesirable for achieving a positive grip on Parkerized metal parts.

Alternatively, the Parkerized surface may be painted over with an epoxy or molybdenum finish for added wear resistance and self-lubricating properties.

Re: depth charges

Posted: 05 Jul 2016 08:31
by alienpew
Wots 'the Google' & how should I apply it to model plastic replicas of d/c throwers ? ah well ! perhaps I'll just slap a coat of
basic grey over them & call it 'colourising or improvising' !


Re: depth charges

Posted: 05 Jul 2016 10:31
by cootafleet
:alien: Just do the PROJECTILE CAVITY PAINT on the inside and you can't be wrong :tup:

Re: depth charges

Posted: 14 Jul 2016 10:28
by kimwhite
Hi Allan
Looks like iron based Parkerization or plain old paint would work for you, in a dark grey. No one could query the authenticity of that choice.
Keep building!

Re: depth charges

Posted: 14 Jul 2016 19:37
by MichaelB
Go on Al, use Savage Blue on it.