Rust converter?

[firstascent2002]

Trago Mills sells alot of pots that promise to turn rust to somehting better!

Trago mills sells alot of rubbish and the occasional gem

Do rust converter sprays really do anything?

My trailer is rusty!

Jamie

 

[vyv_cox]

This is a subject that attracts polar opposites! Some colleagues of mine tested every one they could find in a salt spray cabinet, subjecting the results to highly scientific analysis. The work was carried out for a marine tanker operator and has since formed the basis of paint specifications for offshore installations. Not a single one of the products was worth buying.

 

[JimC]

I've tried a fair few rust convertors over the years on the keels of a succession of bilge-keelers. None have worked for me except the most recent: Vactan, so far at least - my bilge keels have lasted a season without any rust bleeding through the antifouling - first time ever.

 

[theoldsalt]

I use Hammerite Kurust from Halfords on my keels; then covered with several coats of Hempel underwater primer finishing off with antifouling.

Obviously I don't expect the same result as a shot blast and epoxy coating but my combination works well for me on the small patches that I find after liftout.

 

[Topcat47]

I've used Jenolite in the past. Then an anti-rust primer followed by a couple of topcoats. Hammerite is as good as any. The important thing is to get all the loose stuff off and make sure any that remains is "converted". I'd not use this for something like a keel though if shot blasting and a good epoxy was available.

 

[VicS]

Another vote for Jenolite..
Availability seems a bit variable ?? but there is an alternative called Jenoseel.

Also found Fertan to be effective.

As said be sure to get rid of all the rust. As much as possible by mechanical means then by repeated application of one of the chemical treatments.

I'll use Jenolite when I next tart up my trailer ... I have a large bottle of the stuff, "acquired" many years ago

 

[Zagato]

I have been acid converting rust for years on cars and it can work but ONLY on surface rust. It won't penetrate rusty metal, not even 1mm thick rust, you have to wire brush/blast etc pretty well all of the rust off I'm afraid.

Prepare your metal right back and use it as a kind of rust prevention primer - whack POR-15 paint on top and nothing will get through! Not sure POR-15 paint can be used for marine purposes.

 

[cliff]

Naval Jelly works for me.
Available Here

 

[NB Willawaw]

Vactan is pretty good stuff

 

[wotayottie]

Trago Mills sells alot of pots that promise to turn rust to somehting better!

Trago mills sells alot of rubbish and the occasional gem

Do rust converter sprays really do anything?

My trailer is rusty!

Jamie

Not really. Remember your schoolboy chemistry. All iron needs to rust is water, oxygen and warmth. You cant protect against the latter so to stop rusting you need to eliminate the contact with water and air. Good epoxy based paint films will do that, and you can even apply them over well adhered rust. You dont need to "convert" it.

 

[Cotillion]

Flag

I used Flag Rust Converter and have been impressed. Two coats + two of marine primer and it has kept most of the worst away for the last three years. Not saying I havent had to "retouch" a bit but only a fool would believe this problem could be cured forever, afterall, nature will have her way in the end.

 

[Fosdyke Wash]

POR 15

POR 15 paint is recommended for marine use. Their system involves removing as much rust as possible, cleaning with their product "Marine Clean" (then rinse with water), treat with their "Prep & Ready" for a zinc phosphate surface (then rinse with water). When completely dry, apply 3 coats of POR 15 paint.

I followed the instructions but adhesion to my cast iron lifting keel was poor. After a season some smallish areas peeled off sheets, duly patched. After season two I've had to re-apply to all the top half of the keel.

The manufacturer recommends "Prep & Ready" to prepare bare metal for any paint - instead of a rust converter.

 

[ghostlymoron]

POR 15 paint is recommended for marine use. Their system involves removing as much rust as possible, cleaning with their product "Marine Clean" (then rinse with water), treat with their "Prep & Ready" for a zinc phosphate surface (then rinse with water). When completely dry, apply 3 coats of POR 15 paint.

I followed the instructions but adhesion to my cast iron lifting keel was poor. After a season some smallish areas peeled off sheets, duly patched. After season two I've had to re-apply to all the top half of the keel.

The manufacturer recommends "Prep & Ready" to prepare bare metal for any paint - instead of a rust converter.

Who's it recommended by? The manufacturer? I've tried various things on my cast iron keels; kurust , hammerite primer etc. None was 100%.
I think Vyv's scientific tests tell the story - None of them work . Industry standard is SA 2.5 plus zinc rich primer immediately applied. For most of us, that's not financially viable so mechanical preparation and suitable primer immediately (I found International Primocon good) and same again next year - but hopefully less.
Perhaps a topic for PBO if you're still listening Ben!

 

[Zagato]

With the varying responses I wonder for those where it hasn't worked the metal has not been prepared properly. As said these treatments won't "soak" into metal and treat it, it only treats surface rust. Rust as you know can go deep, it will only treat rust that it is in contact with. You have to use it as part of a correct process. i.e. blasting off the thicker layers of rust.

Professionals if they can will blast rust off first then dip the whole item in acid before galvanising, painting etc. Acid converting treatments such as Ku-rust, Jenolite etc should be used the same way for the DIY man! It's no good getting a rusty lump of iron and wire brushing the loose stuff off, belt it with a hammer or dig a screwdriver into it, you will see how deep the rust is, no converting treatment will resolve that.

I found marine clean to be utterly useless by the way another environmentally friendly but useless product. Whacking an electric current though the rusty item works wonders though in a bucket of the right stuff

 

[Zagato]

This is a subject that attracts polar opposites! Some colleagues of mine tested every one they could find in a salt spray cabinet, subjecting the results to highly scientific analysis. The work was carried out for a marine tanker operator and has since formed the basis of paint specifications for offshore installations. Not a single one of the products was worth buying.

Vyv, not sure what the test was, do you mean they placed metal plates covered in various acid converting brands and sprayed them with salt?

If so they will rust, the treatment is designed to neutralise existing rust not be used as a barrier against attack, once it dries it useless, just acts as a primer. It's not a non-porous, active ingredient. ACF-50 is damn near it though for a while, stays active up to about 1 year - excellent stuff for the right use

 

[vyv_cox]

Vyv, not sure what the test was, do you mean they placed metal plates covered in various acid converting brands and sprayed them with salt?

If so they will rust, the treatment is designed to neutralise existing rust not be used as a barrier against attack, once it dries it useless, just acts as a primer. It's not a non-porous, active ingredient. ACF-50 is damn near it though for a while, stays active up to about 1 year - excellent stuff for the right use

I cannot tell you exactly what was done, only that it was done by research scientists after presenting their proposals to the sponsors of the work, who were at the time the world's largest tanker fleet. I assume the panels wer corroded in controlled conditions, treated, then painted using a system that mirrored that used on ships. A salt spray cabinet is a recognised apparatus for many corrosion simulation tests.

 

[Zagato]

OK

 

[Mistroma]

I used to regularly "convert" rust by painting with phosphoric acid. It reacts with rust to form an inert phosphate layer and this protects against further rust formation. It is quite good if you can leave excess acid in place (e.g. Inside a hollow structure) where the acid won't be a problem. e.g. Inside tubular spaceframe found on old TVRs.

However, the coating is easily damaged and only reforms if excess acid is still present. It is white, powdery and fairly easy to remove. So not much use on its own as a rust proof coating, but OK for treating surface rust. I had gallons at zero cost so used it quite a lot.

However, I wouldn't pay inflated prices for products using phosphoric acid as the active ingredient. I know that there are lots of other products using various other ingredients but it sounds as if there aren't any really good ones (based on Vyv's comments).

 

[Fosdyke Wash]

POR 15

POR 15 was recommended in an e-mail to Yachting Monthly (Sep 08) by Proctor Taylor - he'd treated the keel on his Westerly Tiger:

"Five and a half years later, there's no rust and no bubbling and the keel's as smooth as a baby's bottom. It's been mistaken for brand-new keel when she's out of the water!"

Hasn't been so successful for me...

 

[gasdave]

Two and a half years ago I took my bilge keels back to bright metal with wire brushes and the assistance of an angle grinder. I then treated them all over for good measaure with a couple of coats of Fertan before the appropriate number of coats of Primacon.

So far I have had no further rust problems coming through the antifouling.