Kurust - Does it work? And how does it work?

[M4cruiser]

Need to do some de-rusting on my shed. Years ago I used Kurust with mixed results.

I wonder who here has had success with it?


I know a little chemistry, and I guess it's a chemical reaction to turn iron oxide Fe2O3 into something else - but what?
I wonder what chemical Kurust actually is?

[DWDarkWheels]

I've used it recently for the first time. Sorry, can't really vouch for its long-term success. It's cheap enough so I thought it wortha try rather thann applying paint straight to a flake-free rusty surface. I've been using it on suspension parts of a cheap car project and it does appear to seal the surface before painting.Time will tell.

What sort of mixed results did you have before?

[Belle427]

Take a look at the offerings from bilt hamber, far superior products.

[V8covin]

I've had a look at a few rust convertors recently.
Most only work on rust and won't adhere to clean rust free metal so bear that in mind.
I went for Bilt Hamber hydrate 80 in the end.
It seems to have more build to it than the ones you buy in Halfords like Kurust,Jenolite etc

[Red9zero]

I've always found Kurust to be pretty good. Don't get it on your skin though, as it's a bugger to get off.

[Chris32345]

I used 60% phosphoric acid and a van chassis seems to key to seal the rust of okay to paint over

[M4cruiser]

DWDarkWheels said:

What sort of mixed results did you have before?

^^ Sometimes it lasts a long time, but on others I've had spots of rust appearing again after 3 months.
I think (guessing) it depends on what surface it's put on, and what you cover it with.
It seems to like rust, not bare metal. i.e. It's not a primer.
The covering coat needs to be thick, so it doesn't work on bodywork that shows, because you cover that in thin coloured paint.
That's about my (limited) experience anyway.

[105.4]

M4cruiser said:

^^ Sometimes it lasts a long time, but on others I've had spots of rust appearing again after 3 months.
I think (guessing) it depends on what surface it's put on, and what you cover it with.
It seems to like rust, not bare metal. i.e. It's not a primer.
The covering coat needs to be thick, so it doesn't work on bodywork that shows, because you cover that in thin coloured paint.
That's about my (limited) experience anyway.

I used Karust in abundance on my old Land Rover when I did the light resto.

I’ve always found the best results are achieved by applying two coats of Karust, then grinding 99% of it off again, followed by 2-3 coats of slightly thinned down zinc-rich primer, then a couple of coats of etching primer, then four coats of ever so slightly thinned down Hammorite, (on items such as chassis, inner wings, boot floors etc).

I’ve used it dozens of times and I’ve always been happy with the results, even after a few years.

[How u doing]

105.4 said:

I used Karust in abundance on my old Land Rover when I did the light resto.

I’ve always found the best results are achieved by applying two coats of Karust, then grinding 99% of it off again, followed by 2-3 coats of slightly thinned down zinc-rich primer, then a couple of coats of etching primer, then four coats of ever so slightly thinned down Hammorite, (on items such as chassis, inner wings, boot floors etc).

I’ve used it dozens of times and I’ve always been happy with the results, even after a few years.

And there's me thinking it was the easy option.

[V8covin]

Industrial options like Fertan might be a better option on a shed

[105.4]

How u doing said:

And there's me thinking it was the easy option.

I like to do a job once in order to make sure I don’t need to do it again for several more years.

Rust was a ‘no-cost option’ automatically selected on many Land Rovers and TVRs.

[V8covin]

105.4 said:

I used Karust in abundance on my old Land Rover when I did the light resto.

I’ve always found the best results are achieved by applying two coats of Karust, then grinding 99% of it off again, followed by 2-3 coats of slightly thinned down zinc-rich primer, then a couple of coats of etching primer, then four coats of ever so slightly thinned down Hammorite, (on items such as chassis, inner wings, boot floors etc).

I’ve used it dozens of times and I’ve always been happy with the results, even after a few years.

Etch primer is meant to go over bare metal not another primer.
Hammerite is utter ste.
If cutting out the rust and welding in new metal is not practical or sandblasting not an option either then an application of a rust treatment followed by epoxy primer and then a top coat like epoxy mastic is the way to go

[DVandrews]

I’ve used Trustan 23 in the past with excellent results. It contains Tannic acid and converts the rust to Iron Tannate. You can paint over it and it works well. I don't know if it is still available but there may be similar products around.

Dave

[donkmeister]

As above it's going to be an acid to convert the rust and passivate the surface.

However... out of interest I googled the Kurust material safety sheet and it also contains 1-methoxy-2-propanol... As a non chemical engineer the only use I can think of for an organic solvent in such a product is to dissolve any paint lingering in the nooks and crannies, so make sure you don't spill it on anything else if you use it!

https://www.hammerite.co.uk/files/2017/02/HM_GB_EN...

[M4cruiser]

105.4 said:

I’ve always found the best results are achieved by applying two coats of Karust, then grinding 99% of it off again, followed by 2-3 coats of slightly thinned down zinc-rich primer, then a couple of coats of etching primer, then four coats of ever so slightly thinned down Hammorite, (on items such as chassis, inner wings, boot floors etc).

Well, thank you for that. I guess you are doing a proper job!
Mine's only a shed, so I did a quick job. With luck it will get through the next MoT without the dreaded rust advisory. We shall see what this looks like in 6 months time!

[Piersman2]

I've used Kurust for a while usually to treat surface corrsosion on unpainted areas. For example, the shock bodies of an old Boxster were functionally sound, but the surface corrossion all over was looking awful with lumps flaking away. Quick scrub down to get the big lumps off, liberal application of a couple of coates of Kurust and everything has turned black with a glass like finish, almost enamel like.

And today I've been treating the rust at the rear of the sills of the Range Rover (they all go there!). So rather than allow the rust to eat through I stripped back the trim(s) , gave the paint/rust a quick scrub back with a wire wheel on the drill and coated with Kurust followed by some black Hammerite to give a glossy black finiish. I don't expect it to last forever but it should delay the rust for a few years.

I'm sure the alternatives all do the same thing, but a little 200ml tub of kurst goes a long way, it brushes on easy and is runny enough to get into all the nooks and crannies. I rate the stuff, you can see the rust turning to 'glass' in front of eyes, only takes 20 minutes or so to do it's job and leave a nice , non rusty finish, that seems to last pretty well from what I've seen.