Brodie Helmet "Restoration"

[Flying10uk]

I was intending to restore this Brodie helmet to a chief air raid warden's helmet, painted white with a black W on it front and back. I chose to restore this particular helmet because it had already been striped of it's original paint years ago and repainted.

There were several small areas of rust under the paint and, therefore, I stripped off the paint completely and prepped it for chemical rust removal.

I normally use a phosphoric acid based rust remover which is available on the UK market via a chain of tool shops. I placed the helmet in a tank of the rust remover.

2 days later the helmet had partially dissolved. I knew that something was wrong when I went to remove the helmet from the tank as it was significantly lighter than when it went in.

I know that it may appear like an obvious mistake to make and that, with hindsight, I should have checked it earlier but I have used this rust remover for years without any problems.

What I don't know is if the special alloy that these front line Brodie helmets are made from is more reactive to phosphoric acid based rust removers than mild steel.

Information

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[browningautorifle]

I find them made from Manganese, or Hadfield steel...originally but obviously yours wasn't. I found a site that might speak to you, considering you have the helmet in hand. Maybe you'll find a clue here...
https://academic-accelerator.com/enc.../brodie-helmet

In the UK you can probably find many types that we generally don't get to here, considering the wide use over there during and after WW2.

[Daan Kemp]

Interesting lampshade you have there.

[Aragorn243]

That's a holy crap moment. I only use electrolysis.

[browningautorifle]

Only thing I could throw you here is Phosphoric acid is used in Parkerizing solution and we knew there were certain things you didn't put in the solution or they would dissolve. This process cannot be used on non-ferrous materials such as aluminum, copper, brass, stainless steel or any steel surface with large amounts of nickel. Aluminum was one, I wonder after reading that link of variations if this helmet has some type in it? Stainless simply had no reaction and required Oxynate 84.

[Flying10uk]

crap moment

Words to that effect when I first saw it but not as polite.

I did try the magnet test on it and it's non magnetic as I thought it would be and indicating a manganese steel helmet. I wouldn't have thought that it was just manganese that was mixed with the steel to produce the alloy and would have expected other metals like chrome to have also gone into the mix to give hardness.

The helmet shell was a 1939 dated example by BMB and so it's a shame to lose an early WW2 example. I do have another helmet shell in stock by the same maker and dated 1940 which I'll use as a replacement. I'll just be a bit more careful about how long I leave it in the acid bath.

---------- Post added at 02:37 AM ---------- Previous post was at 02:33 AM ----------

Interesting lampshade you have there.

Perhaps I can sell it as a piece of "Modern Art"?

[browningautorifle]

would have expected other metals like chrome to have also gone into the mix to give hardness.

The link I sent showed some helmets produced were specifically NOT hard at all because they were for civilians and made on the cheap.

[Flying10uk]

The link I sent showed some helmets produced were specifically NOT hard at all because they were for civilians and made on the cheap.

I was referring to front line ballistic helmets such as the example I have in post 1 and which I identified by testing with a magnet. The point that I was trying to make is that I do not believe it was just an alloy of steel and manganese that was used in the ballistic Brodie helmets. I would have expected to see other metals also added and an obvious one would be Chrome for it's hardness and wear resistance properties.

The officially produced "not for frontline" use Brodie helmets are normally identified by between one and four holes on the rim. I do have an example in my home front helmet collection. It's an original First Aid Party helmet in original condition.

[browningautorifle]

I do not believe it was just an alloy of steel and manganese that was used in the ballistic Brodie helmets.

I don't know, I suppose. The link describes them but they escape me.

"not for frontline" use Brodie helmets are normally identified by between one and four holes on the rim

Right...

[Flying10uk]

The helmet shell was marked with BMB (Birmingham Motor Bodies) and dated 1939 before I put it in the acid but I think the markings have been lost now.