Classic cars forum & vehicle restoration.

[baconsdozen]

I have some surface (but pitted) rust on the front sub frame of my P5b. Difficult to get at and its spread under the sealer. Has anyone ever used Jenolite or Kurust on already rusted metal and ho did it fare?. In the past I've used Eureka Fluid film with sucess but I think it would wash off quite quickly on the sub frame,grinding the rust down to a shiny surface isn't a real possibility so it will have to go on sound but rusted steel..
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Thirty years selling imperial hand tools for old machinery(Now happily retired).

[ukdave2002]

Jenolite is basically phosphoric acid;phosphoric acid reacts with iron oxide (rust) to produce ferric phosphate (which is the black stuff) any loose ferric phosphate needs to be removed prior to painting to ensure good adhesion.

Ferric phosphate does offer some corrosion protection, but only short term. Phosphoric acid can be purchased for a fraction of the cost of proprietary rust converters, I think I pay about £20 for 5 litres.

Cheers

Dave

[baconsdozen]

Thanks Dave I used phosphoric acid on guns to replicate the blacking. I've not used it on bits under a car but I suppose it must help delay things if nothing else.
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Thirty years selling imperial hand tools for old machinery(Now happily retired).

[stevel98]

http://www.bilthamber.com/corrosion-protection-and-rust-treatments

[ospringi]

I udet T40 rust protection inhibitor every year...

[Penguin45]

Er, you weren't paying attention, were you Ospringi?

P45.
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'67 Wolseley MkI 18/85, '70 Austin MkII 1800 The Landcrab Forum.

[baconsdozen]

I tried some of the Kurust. It says it turns rust black so it neutralises it and protects the metal. Thats as maybe but where I spilt it on the concrete drive thats gone black and so has one of my finger tips. I wasn't aware that either were rusty but presumably they were and are now both well protected.
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Thirty years selling imperial hand tools for old machinery(Now happily retired).

[MikeEdwards]

The trouble with rust convertors is it's hard to know how much of the rust has been converted. If it's only touching the surface of the rust, that's great if it's only a very thin layer, not so good if the rust is 3mm thick.

[Penguin45]

I've used rust convertors as a secondary treatment - derusting the surface first using a wire wheel and the angle grinder gets rid of the loose, but won't deal with pitting. That's what convertors are best at.

P45.
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'67 Wolseley MkI 18/85, '70 Austin MkII 1800 The Landcrab Forum.

[ukdave2002]

Rust converters are a chemical reaction, they will only convert the areas seen ; normally surface rust, anything more than surface corrosion must be physically removed before the converter is applied, and then the surface needs protection with paint or other seal.

There are some products that effectively encapsulate the rust (normally 2 pack epoxy products) they stop air and water getting to steel, but are only effective if the part is completely sealed.

Dave

[Ray White]

When I tackled the rust on my Stewart Warner vacuum tank I used Fertan as it was recommended to be used in conjunction with Tapox ethanol proof tank sealant. Fertan is in fact tannic acid (Fe2 03) a water based, non toxic product that works in a similar way to phosphoric acid in that it converts rust into a stable compound. It is otherwise marketed as Hammerite kur rust.

Seemed to work O.K.

For bigger items I would just leave soak in molasses. Much cheaper!

[baconsdozen]

Apparently the molasses treatment is used a lot in countries with a warmer climate,I suppose like most chemical reactions the heat speeds it up. Since my initial posting I've had to do some repairs on a part I treated with fluid film some years back,scraping off the coating showed that the clean metal underneath had survived well and the original corrosion had pretty much halted.
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Thirty years selling imperial hand tools for old machinery(Now happily retired).

[ukdave2002]