Fertan?

Different people different results. I have had very good results with Fertan on my keel.
When I bought my Westerly 6 years ago it was a project, and the keel was just a mass of rust and pitted. There wasn't much paint on it so stripping was not an effort.
I ground out the really bad bits gave a coat of Fertan, then filled and faired. 4 coats of primacon, and 2 of antifoul.
Six years on, and a week after lift out just a few small spots of rust appear
 
Hydrozoan said:
Interesting rust converter testing article by US National Park Service here: https://www.ncptt.nps.gov/home/sear...3315:is9fzdjxbce&cof=FORID:10&ie=UTF-8&q=rust

Unfortunately, I cannot find any sign of the further study on how rust converters fare in a salt environment, which was to have ended in early 2015.
Click to expand...

I haven't read the report myself. Is it the report you were looking for? (It just says "outdoor" no mention of "salt")

The actual research report:
http://ncptt.nps.gov/wp-content/uploads/metal-paper-88.pdf?1ef327
 
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The Rust-Oleo product appears to have come out top over the other types of acid (which surprises me not). They then say they were going on to test various tannic acid based products including Fertan against each other but I can't find any further info on that study either

It does confirm my empirical opinion that the tannic acid & polymer formulations are the best and the best known such in the UK is ... Fertan :D
 
A vote in favour of Fertan here, I have a wood boat fastened with iron rivets and nails, and Fertan works very well on the rivet ends inside the hull which show rust due to condensation. You could say it's holding the hull together!
 
coopec said:
I haven't read the report myself. Is it the report you were looking for? (It just says "outdoor" no mention of "salt")

The actual research report:
http://ncptt.nps.gov/wp-content/uploads/metal-paper-88.pdf?1ef327
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That's the paper on the first part of the work, linked in the article I linked. However, both the article and the paper referred to further work in saline conditions, IIRC due to be finished in early 2015 and in which Fertan would feature as well as other products including the Rustoleum product which came out best in the first study.

EDIT: Fertan was not included in the first study, IIRC.
 
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coopec said:
The yacht I'm building is f/g so corrosion on steel yachts is academic. Would any of the articles here be relevant? I would think coatings on oil rigs would be "state of the art"

https://www.google.com.au/#q=oil+rig+corrosion+coatings&tbas=0
Click to expand...

Colleagues of mine assessed every rust converter they could get their hands on using scientific methods of preparation and exposure in a salt spray cabinet. This was sponsored by what was then the world's biggest tanker fleet. None of the products was found to be worth using. Instead a paint system was developed that is not far off the one in your link, although as it says times have moved on and the latest zinc rich primers may be better. The system has been adopted word for word by the operators of the same company's offshore production platforms. Surfaces are grit blasted to the best standard, SA 2.5 or needle gunned where this is impractical. All paints are epoxy based and from memory are two coats of zinc-rich primer, five coats of intermediate and one or two of top coat.
 
vyv_cox,

thanks, that confirms every experience I and anyone I know has had with ' rust converters ' on boats, cars and anything else.

Proper preparation and a serious protective coat has to be the way.
 
vyv_cox said:
Colleagues of mine assessed every rust converter they could get their hands on using scientific methods of preparation and exposure in a salt spray cabinet. This was sponsored by what was then the world's biggest tanker fleet.
Click to expand...

What, actually, were they assessing? Because although Fertan and the other polymer containing products will offer some limited protection against the formation of rust post-treatment, nobody in their right mind would expect them to prevent formation of fresh rust in a salt spray environment. That isn't what the products are formulated to do

vyv_cox said:
None of the products was found to be worth using.
Click to expand...

For rust protection or rust conversion?


vyv_cox said:
Instead a paint system was developed that is not far off the one in your link, although as it says times have moved on and the latest zinc rich primers may be better. The system has been adopted word for word by the operators of the same company's offshore production platforms. Surfaces are grit blasted to the best standard, SA 2.5 or needle gunned where this is impractical. All paints are epoxy based and from memory are two coats of zinc-rich primer, five coats of intermediate and one or two of top coat.
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A protective coating over the treated surface is essential regardless of the form of treatment.

In an industrial environment, shot blasting or needle gunning the rust off back to bare metal is an acceptable, and in most cases better, solution than using a rust converter. But shot blasting or needle gunning a historic artefact would cause the heritage police to have kittens. And puppies too!

Fertan does what it says on the tin! It converts rust to an inert tannate which can then be covered by a suitable protective coating. Trust me, it works (although it may need several applications in a severe case - we used gallons of the stuff on the historic narrowboat hull and it didn't come cheap in those quantities
 
vyv_cox said:
Colleagues of mine assessed every rust converter they could get their hands on using scientific methods of preparation and exposure in a salt spray cabinet. This was sponsored by what was then the world's biggest tanker fleet. None of the products was found to be worth using. Instead a paint system was developed that is not far off the one in your link, although as it says times have moved on and the latest zinc rich primers may be better. The system has been adopted word for word by the operators of the same company's offshore production platforms. Surfaces are grit blasted to the best standard, SA 2.5 or needle gunned where this is impractical. All paints are epoxy based and from memory are two coats of zinc-rich primer, five coats of intermediate and one or two of top coat.
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Post 22#

Maybe it's the several coats of Primacon that are doing the trick for me.
 
nigelmercier said:
Now I'm confused, I thought phosphoric acid products were converters?
Click to expand...

Read my earlier posts!

In brief(ish) phosphoric acid does convert rust to ferric phosphate but unless washed off and neutralised pdq it goes on to dissolve the phosphate. So in normal use it effectively removes the rust. Tannic acid converts the rust to ferric tannate but being a much weaker acid it doesn't dissolve much if any of the tannate so it removes very little if any material

Hence, as I posted earlier, phosphoric acid is usually sold as a rust remover whilst tannic acid is usually sold as a rust converter (however, there are some very confusing descriptions in some products blurb)
 
nigelmercier said:
Now I'm confused, I thought phosphoric acid products were converters?
Click to expand...

Yes I thought it was only a converter too but the Ranex (or equivalent) we buy in retail stores in Australia is quite diluted so it doesn't eat away the rust or much of the parent metal.

Maybe this is why they don't air-freight to Australia? (There are similar air freight regulations too)
This is off topic but I wonder whether we will ever find out the truth.

Aviation expert thinks MH370's cargo hold is crucial to figuring out how ...
www.businessinsider.com.au/exploding-batteries-in-mh370-cargo-hold-...
Oct 16, 2015 - "More than a year after Malaysia Airlines Flight 370 went down in a remote part of the Indian Ocean, we're still have no answers about what .. " (WAS IN THE CARGO HOLD)

View attachment 57407
 
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Bru said:
What, actually, were they assessing? Because although Fertan and the other polymer containing products will offer some limited protection against the formation of rust post-treatment, nobody in their right mind would expect them to prevent formation of fresh rust in a salt spray environment. That isn't what the products are formulated to do
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As far as I remember, although I was not doing the work and know the results by discussion, they treated standard panels with many different treatments according to instructions. They then painted them using a standard system, although I do not know what that was. They painted untreated panels using the same system. After exposure in the salt spray cabinet there was no detectable improvement as a result of using the converters or whatever other products.

I emphasise that this work was carried out to the highest scientific standards by professional investigators on behalf of a major user, who also would have had input into the test methods. The problem with any one-off job such as you describe is that it is impossible to know whether the 'converter' has had a beneficial effect, as there is no standard, untreated specimen.
 
vyv_cox said:
As far as I remember, although I was not doing the work and know the results by discussion, they treated standard panels with many different treatments according to instructions. They then painted them using a standard system, although I do not know what that was. They painted untreated panels using the same system. After exposure in the salt spray cabinet there was no detectable improvement as a result of using the converters or whatever other products.

I emphasise that this work was carried out to the highest scientific standards by professional investigators on behalf of a major user, who also would have had input into the test methods. The problem with any one-off job such as you describe is that it is impossible to know whether the 'converter' has had a beneficial effect, as there is no standard, untreated specimen.
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I'm not being picky for the sake of it, I'm genuinely curious ...

Were the panels rusty prior to treatment? And what did they hope to achieve?

If, and from the context I'm guessing this was the intent, they were looking at whether rust converters provided increased long term protection after rust conversion / removal with an otherwise identical paint system the results would not surprise me. Although the polymers added to the likes of Fertan provide some protection against the formation of new rust, the claims of long term protection are and always have been somewhat overblown in my 'umble.

And as I've already said, shot blasting and / or needle gunning to remove all rust prior to painting if feasible is bound to give at least as good, probably better, results than chemical treatments

The question isn't whether Fertan etc provide better long term protection but whether to use mechanical or chemical means of rust removal (or conversion)

If shot blasting or needle gunning to remove all traces of rust and clean back to bare metal is available and feasible, it is likely to be the best option. And on, say, yacht keels it's what I''d go for unless the cost was prohibitive.

Fertan or similar is the option of choice where mechanical methods are not viable or acceptable. E.g. heritage projects or thin (non-structural) panels. From experience, I wouldn't expect it to make any appreciable difference to the long term protection from rust - only a good and well maintained paint system will do that
 
Bru said:
I'm not being picky for the sake of it, I'm genuinely curious ...

Were the panels rusty prior to treatment? And what did they hope to achieve?
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Well in this study on which the results were released last month (actually March 2016)
the panels were rusty.

[PDF]Introduction - NCPTT
https://www.ncptt.nps.gov/wp-content/uploads/metal-paper-88.pdf?...
Mar 21, 2016 - COMPARATIVE STUDY OF RUST CONVERTERS. FOR HISTORIC ... In this laboratory study, NCPTT's research team sought answers to the following questions

View attachment 57416


Sorry if I am being obtuse.........................................
 
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