Advice on the best way to clean this Dornier 17 part

If your item is going into a fairly dry environment you could just spray it with WD40;

There are a multitude of products that are superior to WD40. LPS3 is one:
https://www.youtube.com/watch?v=DeaKjU0nac8

LPS1 also works to a lesser extent. Another option would be gun blueing.

Ok.
For comparison purposes here are some old tools that I found in my shed that I have stopped using due to rust.
My Deox C arrived today and I have placed the tools in a bowl of hot water from the tap. I added four tablespoons of Deox C.
I will leave them to soak overnight and see what happens in the morning.
Gerry

For the plastic handles I find a wipe down with lacquer thinner followed by a polish with Pledge does wonders. I have 25yo ChannelLocks that look new.

Hi all,
My old rusty tools have been cleaned up considerably using the DEOX C solution.

I have also managed to get hold of a Junghans cockpit clock for the gear.
Cheers once again
Gerry[ATTACH=CONFIG]244788[/ATTACH]

You’re a lucky man…..I’ve been after a nice piece of a Bramo-Fafnir 232 for years!

Any more where yours came from? 🙂

Hi
Those pictures are great.
My piece is definately the part marked number 12.
Thanks for posting these.
Gerry

there is no correct answer, it all depends on the specimen examined.

Agreed, the RAE report references a number of other Bramo-Fafnir strip down reports by a number of UK companies, the RAE engine was a 323 P/1 Werk No 7257.
Here are a couple of the Figure pages from the report that might be helpful.[ATTACH=CONFIG]244765[/ATTACH]
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The wartime RAE report I have access to gives the steel specification as 0.2%C, 1.1%Cr, 0.3%Ni, 0.2%Mo Carburised

I’ve got a book that gives the chemical analysis of the steel as follows:

0.17% C, 2.10% Cr, 1.93% Ni, 0.30 Mo, 0.16 V

Assuming I’ve correctly identified this as the Driving Gear from the reduction gearing of a Bramo-Fafnir 323P.

Of course, there is no correct answer, it all depends on the specimen examined. The example that gave the analysis above was from a Dornier 17Z shot-down some time before the end of 1941. My guess is that this represents a steel that would only have been produced pre-war?

Ok.
For comparison purposes here are some old tools that I found in my shed that I have stopped using due to rust.
My Deox C arrived today and I have placed the tools in a bowl of hot water from the tap. I added four tablespoons of Deox C.
I will leave them to soak overnight and see what happens in the morning.
Gerry

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Hi
Here is a photograph of the cog following the second period of electrolysis and prior to the bead blasting.
The electrolysis process cleaned the gear of all of the rust but left the cog a matt black colour.
The white mark that you can see is calcium carbonate from the hard water in our area. (If I had used distilled water this would not have happened).
Thanks also to aeronut for the breakdown of the steel compound.
Cheers
Gerry

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The wartime RAE report I have access to gives the steel specification as 0.2%C, 1.1%Cr, 0.3%Ni, 0.2%Mo Carburised

I had thought that this was made of steel but I think it is cast iron.

No, it will be steel. I will try and find you an exact specification.

Your part looks very similar to the Farman type reduction gears of Bristol aero-engines (Mercury, Pegasus, Hercules) although the gear teeth themselves look a little delicate?

I have to say I was astonished at the finish that you’d achieved, it looks just like it has been glass-bead-blasted…

…then I read your earlier post! Do you have a photograph of the finish before bead-blasting?

If your item is going into a fairly dry environment you could just spray it with WD40; you may get very light rust reappearing if it gets too damp (stored in a garage for example) and it makes the silvery finish go a duller grey but I think it gives the most ‘authentic’ feel if you just want to protect the blasted finish. Alternatively you could opt for a good wire-brushing (on a wheel preferably) to lose the ‘frosted’ finish and to restore some of the shine. On a gear I would probably go for wire-brushing (if you can get into all the nooks)!

Cheers Brian,
I will put a clear varnish on it.
Cheers
Gerry

Gerry kurust will leave it blue/black.

If you want the natural look – just treat it currently with oil or a thin coat of clear varnish. You just need a thin coat to keep water from re-rusting the surface.

Brian
One more question.
Will kurust leave the gear stained in any way?
I want the part to look like it does now.
I cant get abyone to quote for chroming which was the finish I originally wanted.
Gerry

Interesting thread this. I did something similar a number of years ago with Phosphoric acid as the electrolyte. It was fascinating watching the scale fall off as it fizzed and the end result was a clean non-rusting finish and then an electro-platted copper finish after I reversed the polarity and eroded the bare copper cable I was using as an electrode. It was only a small experiment as the phosphoric acid wasn’t cheap so I may have to have another go with these cheaper electrolytes.

trying to make a piece of steel rusty

The local council makes my car go rusty by just using vast quantities of common salt 😡

Hi Brian
Would it have been easier to have used it as a sacrificial anode to attract the rust from another piece of rusty metal?
The rebar that I used became covered in rust from the propeller gear.
Hark at me giving scrap metal man advice!!
Seriously though, thanks for the advice re this.
I really enjoyed the process and am pleased with the outcome.
Gerry

Looks Nice Gerry. Good luck with the clock.

I have the opposite problem at the moment trying to make a piece of steel rusty for a client who wants a reproduction ARP sign. I scarified the metal and repeatedly dipped it in a vinegar/peroxide/salt solution. Then sat it outside for a month.

If you want to return your Do17 part to original you can consider the above.

Looks good. Whatever you cover it with do it quickly. Now naked, any moisture in the air will already be making its mark. One of the advantages of DeoxC is that it leaves a (grey) protective film, easily removed with a quick wire brushing, so the object doesn’t need to have an instant protective coating applied.
Just out of interest, below are ‘before and after’ DeoxC treatment pictures of a section of heavily rusted Hurricane tubing. I wasn’t expecting to find that much surviving paint! (The brown stain on the ‘after’ is the remains of the jointing compound.)

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Hi all,
I am really pleased with the finished result.
I had thought that this was made of steel but I think it is cast iron.
Anyhow, it has come up really well and I may just treat it with Kurust and leave it as it is.
I had wanted to get it chromed.
Now the search for a Dornier clock to go in it!!
Thank you to everyone that posted advice.
Cheers
Gerry
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