Fertan?

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chinita

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Time to de-rust the wrought iron floors again.

Have tried all the usual rust converters but pretty useless. Only one remaining is Fertan - which seems to have a different composition.

Anybody any experience with it?
 
We use "Fertan" in Australia but I don't think it is any better than "Ranex". I think you will find both have Phosphoric acid in them which converts the rust (iron oxide) to ferric phosphate.

Star pickets that I have recycled have been given a coat of Ranex and then painted with Rustguard (or Killrust) epoxy enamel to keep the moisture out. I don't have any problems.
 
I have tried every steel treatment going - inc Fertan - on my mild steel keels over the years.

The only paint ( not rust converter but I am dubious about them ) which stands head and shoulders above the rest by a huge margin is Dulux Metalshield.

It's one part but requires its special one part primer.

Despite the scraping action of the keel in its casing, the plate looks as good when the boat is lifted in autumn as when painted / wiped over in spring, something I can't say for anything else I've tried.
 
chinita said:
Time to de-rust the wrought iron floors again.

Have tried all the usual rust converters but pretty useless. Only one remaining is Fertan - which seems to have a different composition.

Anybody any experience with it?
Click to expand...

I have found Fertan to be an effective rust converter, it is certainly different to rust removers that are solely phosphoric acid, but I have not used it in the marine environment

Loose rust must be removed first and a second application made to any areas of rust remaining after the first application.

Well worth a try I would say. I notice that Jenolite, well known for their ordinary phosphoric acid based rust remover, also do a similar rust converter.

Presumably you paint the floors after rust treatment?
 
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From memory (ages ago when we were restoring an old iron / steel working narrowboat) the primary active ingredient in Fertan is tannic acid rather than phosphoric acid and it converts the rust rather than removing it (phosphoric acid products will, if left too long, eat away the good metal too! Tannic acid won't)

Supplied in industrial quantities (we had a LARGE area to treat!), Fertan proved very effective. The meanies wouldn't give us a heritage project discount though, pointing out that 90% or more of their sales are to heritage projects!

That, by the way, tells you something. It is the rust converter of choice for heritage projects and the only one that the technical types from the Science Museum (who were partially funding the restoration) approved the use of
 
Bru

I agree with you that Fertan is based on Tannic acid and is a rust converter. Phosphoric acid is also a converter converting the rust to iron phosphate: it does not remove the rust.

View attachment 57392
 
chinita said:
Time to de-rust the wrought iron floors again.

Have tried all the usual rust converters but pretty useless. Only one remaining is Fertan - which seems to have a different composition.

Anybody any experience with it?
Click to expand...

Having a steel boat I an constantly fighting with rust that never sleeps.

I use Hydrochloric acid (brick cleaner) to remove all the rust to an extent that the steel will flash rust in a short time after washing. I then use Phosphoric acid to remove this flash rusting and drys with a protective coating the will stop the further rusting until the steel can be overcoated with paint.

Rust converter does convert the rust it coats but not the underlying rust which is still active and caused the rust to come through again.
 
When I use these products on smaller items, I dry the work before painting, using a hot air gun. Seems to help.
Also, I remove as much rust as possible using abrasives before applying the converter.
 
I've used Fertan on and off for many years, and find it fairly effective.
I would say that if circumstances permit, I would prefer instead to remove all rust and scale etc, with strong acids, blasting, or both, and then epoxy coat from bright metal.
But when that's not feasible or practical, then Fertan certainly gives you an immediately stable surface, and significantly delays further rusting.
 
coopec said:
Bru

I agree with you that Fertan is based on Tannic acid and is a rust converter. Phosphoric acid is also a converter converting the rust to iron phosphate: it does not remove the rust.

View attachment 57392
Click to expand...

OK, to get technical, phosphoric acid converts rust into ferric phosphate and then, unless immediately neutralised, eats away the ferric phosphate back to bare metal (and beyond if left too long). Hence phosphoric acid formulations are normally sold as rust removers

Tannic acid converts the rust to ferric tannate and does not remove any material. Nor, in the strengths used for rust conversion, will it attack the base metal (to any appreciable extent anyway. Being an acid it would eventually if left long enough). Hence it is sold as a rust converter rather than a rust remover

On heritage projects, phosphoric acid does not meet with the approval of the heritage police because it actually removes original material and, worse, if inexpertly applied can readily remove sound metal. Tannic acid meets with their approval because, apart from any loose flakes removed by wire brushing etc., no material is actually lost (they get very hot under the collar about such things)

Both products, if used as instructed, will leave an inert protective layer which helps to prevent further rust however Fertan, amongst others to be fair, also contains a polymer which bonds to the ferric tannate and produces a very stable base for repainting.

Personally, from a fair bit of experience of dealing with rusty old boats and boat bits, I would always choose Fertan. It works, others often don't or don't work that well
 
I don't disagree with Bru, but I've found phosphoric acid stuff such as jenolite to be very worth using when you can't quite get back to shiny metal. I have bits of motorbike I've cleaned as best I can with w&d paper, then used phosphoric on the remaining pits. These have endured much better than when I've skipped the jenolite phase and gone straight to painting.

For the OP's wrought iron floors I would think the problem is getting the water out of the remaining rust and sealing it out, whatever converter product is used.
I assume the floors cannot be removed and galvanised.....
I'm thinking this a piece of work that cannot be got back to 90-odd% shiny metal.
Would a zinc-rich primer help, or is that not going to be compatible with the tannic chemistry?
 
Bru said:
. Hence phosphoric acid formulations are normally sold as rust removers
Click to expand...

I guess it is not important but can you give me the name (s) of those products?

I know a lot of people think it removes rust but even the makers of (say) Ranex don't claim that
 
coopec said:
I guess it is not important but can you give me the name (s) of those products?

I know a lot of people think it removes rust but even the makers of (say) Ranex don't claim that
Click to expand...

https://www.google.co.uk/search?q=p...4caxMh6qpuUEA#q=phosphoric+acid+rust&tbm=shop

How many would you like? :D

Ranex are a bit unclear, frankly, on exactly what their product does. Reading their blurb, they headline rust conversion but then go on to say it removes surface rust. Phosphoric acid will remove the ferric phosphate and it will remove the base metal if it's left long enough.
 
Bru

Yes you are right. I suppose any acid will dissolve iron/steel.

I'm not sure you can buy 85% Phosphoric acid in Australia.

I just checked out eBay, there's one crowd selling 300ml bottles for brewing (they don't say the strength) and only one crowd selling it in 20l containers but I'd have to go to Melbourne to pick it up.

View attachment 57393

There is no way Australia Post would allow an 85% strength acid in the mail.

"Delivery Varies" I wonder what that means?
 
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coopec said:
Bru

Yes you are right. I suppose any acid will dissolve iron/steel.

I'm not sure you can buy 85% Phosphoric acid in Australia.

I just checked out eBay, there's one crowd selling 300ml bottles for brewing (they don't say the strength) and only one crowd selling it in 20l containers but I'd have to go to Melbourne to pick it up.

View attachment 57393

There is no way Australia Post would allow an 85% strength acid in the mail.



"Delivery Varies" I wonder what that means?
Click to expand...

OK Clive try these
http://www.chemlink.com.au/albright.htm
http://aussiehomebrewer.com/topic/29848-where-to-buy-phosphoric-acid/
http://www.woodworkforums.com/f65/strength-phosphoric-acid-144088
http://www.liquideng.com.au/corrodip.html

Local to you.
 
"I really wouldn't be playing around with phosphoric acid, unless you have a fume cupboard and some serious knowledge on the stuff. It's very, VERY deadly."

If that is true I'm not surprised the supply is restricted!

PDF]Common Name: PHOSPHORIC ACID HAZARD SUMMARY ...
nj.gov/health/eoh/rtkweb/documents/fs/1516.pdf
* Phosphoric Acid is on the Hazardous Substance List because it is regulated by OSHA and cited by ACGIH, DOT, NIOSH, IRIS, NFPA and EPA. * This chemical is on the Special Health Hazard Substance List because it is CORROSIVE. * Definitions are provided on page 5.
 
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The recent "good life" farming programme recommended citric acid.

The Ford Transit rescue forums recommend Vactan - rust converter and primer.

The former looked very effective on the TV but seemed to do nothing for my Tranny bits.

The second seemed to do what was expected.
 
Graham_Wright said:
The Ford Transit rescue forums recommend Vactan - rust converter and primer..
Click to expand...

Vactan is pretty much the same as Fertan -- tannic acid and a polymer (I seem to recall there was a legal case years ago where Fertan claimed exclusive rights to the formulation but lost on the grounds that tannic acid is a natural product and can't be patented and the competitors were using a different polymer so weren't breaching any rights held by Fertan)

Both, I expect, do pretty much the same job. I'd go for Fertan myself because I've a fair bit of experience of using the product and it' always worked but if Vactan is significantly cheaper I would give it a try

Never tried citric acid and just had a quick google to find a lot of user feedback suggesting it works best if warmed up rather than at ambient temperature. Bit tricky on a boat keel!
 
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