Rust Converter

[Keith Partington]

I jet washed my 2007 Land Rover a couple of weeks ago and noticed some rusting around the chassis area. I have been looking online for a rustproofing solution and visited a local DINITROL Treatment centre, after inspecting the vehicle they noted that the small rust patches can be treated with a rust converter called RC 900 is this correct or should you buy new parts? The product he recommended can be viewed here https://www.dinitroldirect.com/product/dinitrol-rc900/

[nickwilliams]

Hi Keith, welcome to the forum. 

It's difficult to give you reliable guidance without more specific information on where the rust is and how bad it is. Can you post some pictures?

Edited September 4, 2017 by nickwilliams
Spilleng urrer

[SteveG]

Hi Keith

RC900 is very similar to a number of converters like Bilt Hamber's Hydrate 80 etc. They all work in the same way, chemically reacting with the rust to seal it in preventing it from increasing. For all of them you have to remove all loose rust etc with wire brush and then clean thoroughly. All of these converters need you to paint on top, or coat with a wax and/or wax underseal or for max protection paint, then wax underseal.Personally, I prefer hydrate 80 as it's brush applied, so you can work it into the crevices etc. However it needs a couple of coats to ensure you get good coverage, and you can't brush inside the chassis, so here rc900 with a spray lance is ideal. 

Alternatively, you've got rust removers like Bilt Hamber's Deox gel, which will remove the rust. For example on exterior of a chassis you could use a combination of flap discs and wire wheels to remove must of the rust, and Deox gel where it's not easy to access. Then paint with a good active primer like corroless S, buzzweld RCP. Then overpaint with top coat like corroless rf16, buzzweld cio. Optionally, you could then add a layer of wax underseal like dinitrol 4941 on top for max protection. 

POR15 is often recommended, however it's best applied to a wire brushed rusty surface. You can't overpaint other paints with it, so not ideal for touching up an existing chassis in situ, unless you can remove all of the existing paint.

Epoxy mastic's are popular too. Personally, I haven't found them as useful as the other paint options. They are a two part paint, so you have to mix with a hardener/activator and so you have a limited work time. I've found they are best applied on thick, and it's hard to get a good finish if doing a number of parts due to the limited working time. I can see the attraction if you've blasted/galvanised a whole chassis and you could spray multiple layers with a quick application time. Again, they are not great over existing paints, as they can be prone to chipping off in these areas.I've had success in using it on blasted parts, that have been cold zinc primed (Bilt hamber electrox) and then two coats of epoxy. Overall, Ive come to prefer the corroless S primer and RF16 topcoat. 

Lastly, upol raptor is another option. Like the others, chassis needs all of the loose rust/paint removing, existing paint prepped with scotchbrite, then throughly cleaned. Upol do a raptor anti corrosive epoxy primer, then you can overcoat with the raptor topcoat. The topcoat has isocyanates, so full face breathing mask is required in EU and you need to fully cover skin too when in use. I haven't tried raptor yet, although I do plan to use it on the plastic sills etc. of the range rover classic and may try it out as an undercoat of the body (not chassis).

For inside the chassis, you could spray dinitrol rc900 then one or two coats of 3125. 

[Eightpot]

It's possible that the advice you are being given is because it is within the scope of the dinitrol treatment centre?  

If I were presented with a 2007 defender with small light patches of rust, I would  physically remove the rust (using a mix of wire cup brushes/polydisc's etc), clean up the chassis and paint it properly which is what they lacked from the outset. 

Even if the rust were so deep it couldn't be cleaned back to shiny metal  I would still want to clean it up as much as possible before putting anything on it. 

[Anderzander]

I read that phosphoric acid is the active ingredient in most rust converters - so I bought some and have started to try it. I'm too soon in to give a definitive review - but it seems to be working fine.