Corroless

[midsmatt]

I've been looking around at several options for rust prevention. There seems to be some standard offerings and some fairly expensive ones. As an old Land Rover addict I'm no stranger to rust and use a product called Corroless which works extremely well and is very easy to apply. I buy mine from a chap called Andy at http://www.arc-rite.co.uk/paints/specialist-paints/corroless-rust-control. 

I wondered if anyone here might have used it on their boat as I'm about to hand some to our friends who are doing some work for me on a rebuild project and was going to say they could use the excess on their historic butty if they liked. If not I'd be interested to see what people are using and how well it does given the often damp conditions it might suffer. 

Edited September 1, 2017 by midsmatt

[WotEver]

What is it, just a paint? (I'm not referring to the waxoyl type product of course as that has little relevance on a boat.)

[cuthound]

I used Corroless on cars in the late 70's.  It is a yellow primer, which claimed to stop rust. I don't think it is much better than normal zinc primers.

[midsmatt]

2 hours ago, WotEver said:

What is it, just a paint? (I'm not referring to the waxoyl type product of course as that has little relevance on a boat.)

It is a paint but it's not your usual rubbish such as hammerite. It has nothing to do with waxoyl or similar products which as I'm sure you've found out don't really work very well.

Out of interest what do/did you use for your rust reducing needs? 

 

19 minutes ago, cuthound said:

I used Corroless on cars in the late 70's.  It is a yellow primer, which claimed to stop rust. I don't think it is much better than normal zinc primers.

It's certainly not a yellow primer any more. In fact if you wanted a corroless product in yellow now I think you'd have to request them to mix their RF16 topcoat. 

The red oxide equivalent is called RCP and I can confirm it is a lot tougher than any zinc primers I've used. I can say that with a certain amount of confidence after 25 years of tinkering with classic motors. 

What paint system do you use these days then chap?  

 

[WotEver]

9 minutes ago, midsmatt said:

Out of interest what do/did you use for your rust reducing needs? 

Convert/prime with Vactan then decent primer/undercoat/gloss. 

[cuthound]

My boat is treated with Zinga and then 2 pack blacking to the gunners. Recently taken out of the water at 10 years old, and I was advised to replace the anodes, put it back in the water and check again in another 2 years because there was zero corrosion.

.

[midsmatt]

14 hours ago, WotEver said:

Convert/prime with Vactan then decent primer/undercoat/gloss. 

Ah the old water based rust converters. They work very well as long as you get the whole area then as you say a decent quality paint to go over the top. I always found the solution to work well as long as the area didn't get regular abuse. So no good on a chassis on the land rover for example. Thanks! 

3 hours ago, cuthound said:

My boat is treated with Zinga and then 2 pack blacking to the gunners. Recently taken out of the water at 10 years old, and I was advised to replace the anodes, put it back in the water and check again in another 2 years because there was zero corrosion.

.

Zinga is amazing stuff but scarily expensive. Pure zinc as I recall? Testament to the stuff that it lasted that well. I guess the 2 pack blacking can really do a decent job if it's never getting lifted by rust via deep scratches! Can I ask how much it was to give your boat this treatment? Was it a price per foot? 

edit - Quick afterthought on the Zinga... am I right in thinking the area to be treated has to be taken back to bare metal? ie by sandblasting? 

Edited September 2, 2017 by midsmatt

[WotEver]

33 minutes ago, midsmatt said:

Quick afterthought on the Zinga... am I right in thinking the area to be treated has to be taken back to bare metal? ie by sandblasting? 

That's my understanding.

[cuthound]

1 hour ago, midsmatt said:

Ah the old water based rust converters. They work very well as long as you get the whole area then as you say a decent quality paint to go over the top. I always found the solution to work well as long as the area didn't get regular abuse. So no good on a chassis on the land rover for example. Thanks! 

Zinga is amazing stuff but scarily expensive. Pure zinc as I recall? Testament to the stuff that it lasted that well. I guess the 2 pack blacking can really do a decent job if it's never getting lifted by rust via deep scratches! Can I ask how much it was to give your boat this treatment? Was it a price per foot? 

edit - Quick afterthought on the Zinga... am I right in thinking the area to be treated has to be taken back to bare metal? ie by sandblasting? 

No idea of the cost, as I bought the boat secondhand,  it was however specified from new, so would have been applied to a gritblasted surface.

Yes, Zinga is 96% pure zinc.

http://www.zinga-uk.com/zinga

[midsmatt]

Thanks chap that's very helpful  

I'd say that the coating it smashing for new projects and complete overhauls. I'd be hesitant about grit blasting a heritage grade narrowboat as it would be a sure fire way to find as many holes as possible! That said at least you'd know what's what at that point! 

A very interesting subject seeing what different approaches have been taken. 

[cuthound]

1 hour ago, midsmatt said:

Thanks chap that's very helpful  

I'd say that the coating it smashing for new projects and complete overhauls. I'd be hesitant about grit blasting a heritage grade narrowboat as it would be a sure fire way to find as many holes as possible! That said at least you'd know what's what at that point! 

A very interesting subject seeing what different approaches have been taken. 

Many people with historic boats have them grit blasted and blacked with 2 pack epoxy blacking.

As you say it finds the weak spots so you can fix them, then minimises any further deterioration. 

Putting Zinga under the epoxy blacking prevent to corrosion where the epoxy has been scratched through or knocked off.

Debdale Wharf take it even further by gritblasting, then spraying molten zinc onto the hull, before costing with 2 pack epoxy blacking. This is the current "gold standard" in Hull protection, but it's not cheap.

http://www.debdalewharf.co.uk/zinc-metal-spraying/

Edited September 2, 2017 by cuthound
To add the last sentance.

[midsmatt]

Brave souls ... I guess the folks doing the grit blasting know what they're doing. I've seen a few jobs done on classic motors and the results can be truly horrifying. The fact that the boats just come out of the water would probably send chills into places I don't want to even think about...  

I've heard of molten metal spraying including zinc but I've not seen the process nor the results. It would be very interesting to get a comparison of all the options available and see what's worth what! 

[cuthound]

34 minutes ago, midsmatt said:

Brave souls ... I guess the folks doing the grit blasting know what they're doing. I've seen a few jobs done on classic motors and the results can be truly horrifying. The fact that the boats just come out of the water would probably send chills into places I don't want to even think about...  

I've heard of molten metal spraying including zinc but I've not seen the process nor the results. It would be very interesting to get a comparison of all the options available and see what's worth what! 

But most classic cars were originally made of metal whose thickness would be worryingly thin on a boat 

I guess until Zinga and zinc spraying on boats have been around for at least 20 years, we won't know how good they really are or not, although early results show promise.

[midsmatt]

A very good point regarding the thickness comparison.

Given that the waterline on any boat will generally be the worst area perhaps you could just have this area done with the more expensive coatings? A band say 12 inches deep? Probably a thousand reasons why that would be a really bad idea 

I imagine that the zinc spray would give at least the same effect as a hot dipped galvanised treatment so it should be good for at least 20 years if it's protected with a good primer and 2K paint system. Probably a lot longer!