Preserving rusty artefacts - any tips?

[DuncanBro]

I bought this French fuse today and was wondering if anyone had any tips on preserving it or sealing the metal to stop it disintegrating. 

I have shrapnel from both world wars too, some of which is slowly crumbling away.

I looked on the Internet and there's loads of products out there, all with wildly varying recommendations.

Anyone got any advice please.

[JMB1943]

Put “rust” into the search box.

You will see that this topic has been discussed extensively.

Regards,

JMB

Edit: I have read that the active, red rust can be converted to an inert black form by boiling the artefact in distilled water for a while. I have not tried it, so this is more of an observation than a recommendation.

 

Edited 26 May , 2023 by JMB1943
Add info

[MrEd]

I have a grenade with rust like that, but a bit deeper. I used rust converter liquid which killed the active rust and then I gave it a coat with a microcrystalline wax called ‘renaissance wax’ and that has been stable for many years now. 

[DuncanBro]

Thank you both, that's really helpful.

[battle of loos]

good morning,

For fairly thick objects, I use sandblasting.
then I put WD40.

michel

[AOK4]

To be honest, the value of that thing is extremely low. It is just a part of a French fuze. I would say it isn't worth spending more effort or money on it.

Jan

[Dai Bach y Sowldiwr]

There are several rust converters on the market that you can obtain from your local motor accessories shop.
Basically they convert rust - Iron (3) Oxide (Fe2O3) into Iron (2) Oxide (FeO).

I use a tannin based one called Fertan, which pleasantly smells like old wine barrels. There are also Phosphoric acid based ones available.

If you want to try an eco-friendly method, some farmers immerse their rusted tractor parts in molasses. Rusted engine blocks and the like come out gleaming after submersion for a few weeks. Many farmers use this as a silage treatment/additive. You can probably find small quantities in your local agricultural supplies store.

 

Edited 26 May , 2023 by Dai Bach y Sowldiwr

[MrEd]

Fertan is a good rust converter 

[HenryTheGerman]

Phosphoric acid is a good rust converter. It converts iron oxide to iron phosphate which is water repellant and does not corrode any further. Treatment must occur with phosphoric acid in excess quantities, in order to convert the rust completely. The problem, however, is to remove the excess acid from the object after treatment. Rinsing with and bathing the object in water is helpful. - Rust conversion can be done slowly and carefully with Coca Cola because it contains phosphoric acid but you need some liters for the treatment of such objects like yours. The colour of phosphorus converted rust is dark blue-gray.

Soaking of rusty objects with WD40 will lead to crumbling and disintegration.

Regards

H

[MrEd]

4 hours ago, HenryTheGerman said:

Phosphoric acid is a good rust converter. It converts iron oxide to iron phosphate which is water repellant and does not corrode any further. Treatment must occur with phosphoric acid in excess quantities, in order to convert the rust completely. The problem, however, is to remove the excess acid from the object after treatment. Rinsing with and bathing the object in water is helpful. - Rust conversion can be done slowly and carefully with Coca Cola because it contains phosphoric acid but you need some liters for the treatment of such objects like yours. The colour of phosphorus converted rust is dark blue-gray.

Soaking of rusty objects with WD40 will lead to crumbling and disintegration.

Regards

H

Black treacle works well also, but is very very slow 

[DuncanBro]

21 hours ago, HenryTheGerman said:

Phosphoric acid is a good rust converter. It converts iron oxide to iron phosphate which is water repellant and does not corrode any further. Treatment must occur with phosphoric acid in excess quantities, in order to convert the rust completely. The problem, however, is to remove the excess acid from the object after treatment. Rinsing with and bathing the object in water is helpful. - Rust conversion can be done slowly and carefully with Coca Cola because it contains phosphoric acid but you need some liters for the treatment of such objects like yours. The colour of phosphorus converted rust is dark blue-gray.

Soaking of rusty objects with WD40 will lead to crumbling and disintegration.

Regards

H

Hi, thank you for the information, I'll try that. 

[Chasemuseum]

Be careful what you soak in phosphoric acid. Iron and steel are OK but not brass, copper or zinc. These will react to actively with the acid.

[DuncanBro]

45 minutes ago, Chasemuseum said:

Be careful what you soak in phosphoric acid. Iron and steel are OK but not brass, copper or zinc. These will react to actively with the acid.

Thank you.

[Chasemuseum]

Sorry, I meant "too actively". More specifically, the phosphoric acid is likely to totally dissolve any zinc present. So it will strip the zinc out of the surface of brass and leave the copper behind. This will leave brass looking like copper but with a rough nasty surface texture. 

 

Many, many years ago I used to work at a chemical plant manufacturing phosphoric acid. Compared to sulphuric, hydrochloric and nitric acids it is a very mild product, just expensive. Very expensive. We also made sulphuric. The phosphoric cost 10 times as much. An additional word of warning, some of the commercial rust converters also contain a small amount of sulphuric. This is done to make the product much cheaper. The problem with these products is that any sulphuric acid that is not cleaned away and neutralized after the treatment process will reactivate aggressive corrosion in steel. It may look great for a year or so and then explode into deep pitting rust.

 

I have not seen it sold for many years but "Naval Jelly" was a phosphoric acid based paste that could be painted on surfaces to treat rust.   

[trajan]

IIRC, JMB did a good job about 3-5 years back using molasses on a helmet.

Trajan

[DuncanBro]

Thank you everyone. 

[Flavio]

On 25/05/2023 at 21:24, DuncanBro said:

I bought this French fuse today and was wondering if anyone had any tips on preserving it or sealing the metal to stop it disintegrating. 

I have shrapnel from both world wars too, some of which is slowly crumbling away.

I looked on the Internet and there's loads of products out there, all with wildly varying recommendations.

Anyone got any advice please.

They crumble due to rust that has not yet been treated or due to the fact that some fuzes are made of aluminum or zamak?