Large shell, how to clean it?

[Canny Steve]

Hi all

Found this almost right next to where Malins filmed the Hawthorne mine explode. Had to leave it in April where it had been ploughed up but "discovered" it again lost in some long grass the following month, so this time decided to bring up the car, as it is very very heavy.

So can anyone recommend the best way to clean it up to identify it? It is hollow inside after digging out most of the mud.

[auchonvillerssomme]

The thin driving bands would identify it as German cant see properly but looks like 150mm?

[Canny Steve]

It does appear to have a thin driving band toward what is now the top of it. Trouble is all the mud, pressure washer maybe, would it stand up to that sort of punishment?

[auchonvillerssomme]

I would leave it in a bucket of soapy water for a few hours and gently clean with a nylon brush.

[Old Tom]

A measure of diameter seems the best bet. I have no experience of trying to clean such items, but would suggest it is too deeply corroded for much to be gained. Soak in a bath of paraffin might be a start.

Old Tom

[auchonvillerssomme]

This one was in the same condition. Scrubbed then lacquered.

[Canny Steve]

So none of this brick acid malarky and all the rest i've seen online. Right marigolds and stiff brush it is then!

[auchonvillerssomme]

The problem with stuff like brick acid on metals in this state is that they soak in and are a pain to neutralise completely and if you don't, after a year you have pile of flaky rust.

Mick

[ServiceRumDiluted]

Soak in warm water to soften the mud, remove this manually with a brass brush, then paint the driving bands with alloy wheel cleaner for a short time, 5 minutes or so. Then get a brass brush for your drill and scrub up then paint with kurust.

Or, if it's a one off consider looking at local body shops, fabricators or engineers to get it bead sand or grit blasted.

[KevinBattle]

Hit it enough times with a sledge hammer and then someone else can clean it (and you) away!

[Canny Steve]

So now I need to add sledge hammer to the list?

[Beerhunter]

I'm intrigued. How do you check for a live fuse, remove the filling etc. Or do you get an ATO to do it?

[Torrey McLean]

Hello - It's a German 90mm (I think that's the size, but it might be 150mm) shrapnel shell that successfully detonated as designed. The fuse is gone and it is harmless. The best way to clean it is by electrolysis (after cleaning all the mud out), but this is an intensive process. Regards, Torrey

[pylon1357]

I'm intrigued. How do you check for a live fuse, remove the filling etc. Or do you get an ATO to do it?

This is where the use of a good sledge hammer comes in, as mentioned above.

[Canny Steve]

Thanks for the replies everyone. I should probably clarify as the picture isn't clear but the shell was 3/4 full of mud when it was found. I'm pretty sure without a fuse and something inside it to actually explode the chance of it exploding to me is quite minimal. If I has even the slightest doubt in my mind that it could be live I would have left it where it was as I have countless others.

The purpose of the thread was identification and an attempt to start cleaning up numerous finds and we all have to start somewhere so asking here seemed as good an idea as any.

[Doug504]

Method I've used in the past is to power wash / jet wash to remove all mud and dirt. You'll probably have to wire brush the outside and use a long scraper to remove encrusted mud etc. from insides. Then leave to dry thoroughly, I'm talking a couple of weeks here. You'll find rusted iron flaking off at this point and you'll be able to chip any loose flakes off, I've used a bricklayers chisel for this, (wear eye protection). It's worth leaving another week or so, in a dry atmosphere to see if there is any further flaking off. As "ServiceRumDiluted" states the next step is to paint with Kurust and polish the driving bands if they are still attached. Finally when all dry, give a coat of lacquer / varnish. A bit long winded I know, but otherwise you will be picking up those loose rust flakes every time you move it, and this doesn't go down well with long suffering partners.

Doug.

[Canny Steve]

Thanks for that. I had a bit of a practise on some other bits of shell earlier and found the brass wire brush tough going. I have a pedestal grinder with brass brush wheel so shall give that a go might make for easier work on the big one.

[ServiceRumDiluted]

The pedestal brass brush option is a good one, these are not delicate fragile things! Eye protection is a must as the wire bristles often fly off and respiratory protection is a good idea also. The only problem might be the weight of the thing. In terms of identifying it I'm pretty sure its a harmless body of a German shrapnel shell of either 130 or 150mm calibre. To complete it you'd need the nose assembly which usually blew off intact, they are not too difficult to come by. The correct fuse (I think) would be a dopp z92 and this is usually still attached to the nose. I can post a picture with dimensions if required.

[Canny Steve]

A picture would be great, thank you. After posting I did think to myself, how the hell would I lift it long enough to clean it! Think i might buy a brass brush attachment for the drill, quicker than the hand brush, and use the pedestal for lighter things. Back to the local diy shed.

[ServiceRumDiluted]

Here you go;

The Ogive has a vertical height of 8cm, the fuse is a Dopp Z92 and makes the whole nose 14cm high. Thread depth (included in the above measurements) is 1.3cm.

External diameter is 14.4cm, internal diameter is 13cm (all approximately!)

I hope this is useful.

I also forgot to add that if you soak anything in water it is well worth adding a corrosion inhibitor. I work for a lubricant and chemical company so can get this easily, but the most accessible way is to get radiator fluid corrosion inhibitor from a plumbers merchant. This will stop any further rusting from the water, though it is not a long term preventative.

Diluted.

[centurion]

Rather than sand or grit blasting which might be unduly abrasive if some one does blasting with grain (bran to be precise) that will clean the mud and crud away without doing damage to the metal. Don't know if such techniques are still available but I got some one to do this for some old pre WW1 motor cycle parts about 15 years ago and they came up a treat.

[Beerhunter]

I'm pretty sure without a fuse and something inside it to actually explode the chance of it exploding to me is quite minimal.

As an ex-TA Sapper, "pretty sure" isn't sure enough for me.

[peregrinvs]

I restored an inert Stokes mortar bomb that was in not dissimilar condition. To get the rust off I first gave it a wash to get the mud and loose rust off and then applied some 'percussive maintainance' to chip off some more flakes of rust. Then I gave it a long soak in concentrated Fernox DS 40 central heating cleaner and with periodic scrubs with a wire brush I gradually stripped it back to bare metal. After that it depends whether you want to try and restore it to its original appearance by filling in the pitting and repainting it.

I've also had good results with Bilthamber Deox-C rust remover. I'm currently working on de-rusting inert examples of a 13pdr shrapnel shell and a Mills No.36 drill grenade prior to restoring them.

[johnreed]

Take it to a company that does Sandblasting/shotblasting I had two dugup rifles done by this method then painted with Kurust.

John

[ServiceRumDiluted]

My pet engineering company told me that for things like this you need to be a little careful with the media used for blasting. Shot blasting relies on impact and can be very destructive and would possibly damage lettering or thin metal. Not a problem for a dirty great shell but could mess up a brass fuse. Glass bead blasting is much kinder but takes more time, I've experimented with this and the results are very good, a German 77mm shell taken back to shiny metal with the lathe turning marks still visible. I'll be trying grit blasting soon, this relies on a cutting rather than impact action and I'm told gives quicker results and is non damaging. I was strongly advised not to shot blast anything delicate.