Water Tank Cleaning/Rust removal

[Dibble]

Hi all, it would seem that the water tank on the narrowboat I've purchased hasn't been cleaned for 20 years! I've scraped and ground it back to the bare metal as best I can, but there are parts that I just can't get to. I've spoken to some grit blasters who say they can't complete the job, due to access issues. The underside of the tank is still quite corroded. Is there anything I can use to remove the rust, or treat it before I can coat it with two pack epoxy. Thanks.

[Tracy D'arth]

Phosphoric acid ( Jenolite ) will neutralise thin rust, you need to get all the scale off.

Like wise, Fertan will also work but you have to wash it off afterwards.

Vactan will do the same job but leaves a vinyl layer.

All will accept two pack epoxy afterwards.

 

Traditionally only watertank bitumen was used but many have used two pack epoxy without harm.

[Dibble]

Thanks Tracy, I'll look into it (quite literally).

[David Mack]

10 minutes ago, Dibble said:

it would seem that the water tank on the narrowboat I've purchased hasn't been cleaned for 20 years!

In common with many other boats with integral tanks.

 

11 minutes ago, Dibble said:

I've scraped and ground it back to the bare metal as best I can, but there are parts that I just can't get to.

And having done that, you know why so many boat owners don't bother! And boatyards generally don't do it either since there are easier ways of earning money.

 

All you can do is your best. Wire brushes and flap discs on an angle grinder are best, but won't get into all the corners. And as both involve sticking your head into the dust filled tank space, a decent mask is essential, but even so you will be working largely blind.

[IanD]

28 minutes ago, David Mack said:

In common with many other boats with integral tanks.

 

And having done that, you know why so many boat owners don't bother! And boatyards generally don't do it either since there are easier ways of earning money.

 

All you can do is your best. Wire brushes and flap discs on an angle grinder are best, but won't get into all the corners. And as both involve sticking your head into the dust filled tank space, a decent mask is essential, but even so you will be working largely blind.

...possibly permanently if you don't also wear goggles... 😉

[BEngo]

If you can get hold of one,  a needle gun is pretty damn good for cleaning off rust.  It will get into corners easily  and produces a good surface for painting.

 

I have never seen an electric one, though I believe they exist, but most are air driven and horrendously noisy in action so not only do you need to rent a compressor and needle pistol but you need to find a spot where your neighbours are away and add quality ear defenders to your PPE list.

 

N

Electric one on Amazon.

https://www.amazon.co.uk/HUMNZR-Electric-Derusting-Hand-Held-Cleaning/dp/B0BRTQMF88/ref=mp_s_a_1_5?adgrpid=124609823719&hvadid=536555632314&hvdev=m&hvlocphy=9046140&hvnetw=g&hvqmt=b&hvrand=1422898684663863739&hvtargid=kwd-447909736487&hydadcr=24953_1816938&keywords=cordless+electric+needle+scaler&qid=1681209421&sr=8-5

Edited April 11, 2023 by BEngo

[David Mack]

You can hire electric needle guns. This one is 110V so you would need to hire a transformer as well.

https://www.hss.com/hire/p/power-scraper-needle-hilti

[Dibble]

Thanks guys, these are really helpful comments. Cheers 

[Higgs]

16 minutes ago, David Mack said:

You can hire electric needle guns. This one is 110V so you would need to hire a transformer as well.

https://www.hss.com/hire/p/power-scraper-needle-hilti

 

Also requires very good ear defenders, if my experience with a needle gun is common. And with these kinds of vibrating tools, you should wear gloves made to reduce vibration in the hands.

 

 

 

 

Edited April 11, 2023 by Higgs

[Alan de Enfield]

38 minutes ago, Dibble said:

Thanks guys, these are really helpful comments. Cheers 

 

The other option is to do as much as you can, screw the hatch back on, fill with water and check again in another 20 years,

[Lady M]

I had a 'plastic' tank put in mine years ago.  It's quite solid not one of those plastic bag affairs.  I used to black the integral tank every Spring until I found I was still getting rusty water because the inside of the feed pipe had corroded.  No regrets (yet).

[Higgs]

I cleaned and scraped my tank, in the bow section, well over a year ago. Haven't coated it with anything yet, and it's in regular use. Wanted to get rid of all the bitumen, for good. I do get the odd rusty bits of water, but usually, just after a refill. I do intend to coat it with a two pack, eventually. The water usually looks clean, but I still use filter jugs for drinking water.

 

 

[Richard10002]

2 hours ago, Dibble said:

Hi all, it would seem that the water tank on the narrowboat I've purchased hasn't been cleaned for 20 years! I've scraped and ground it back to the bare metal as best I can, but there are parts that I just can't get to. I've spoken to some grit blasters who say they can't complete the job, due to access issues. The underside of the tank is still quite corroded. Is there anything I can use to remove the rust, or treat it before I can coat it with two pack epoxy. Thanks.

Given that you have done most of the hard work, assuming you have got rid of any loose rust, I would coat any rust remaining with Vactan before the various topcoats.

 

I did this in my engine bay to good effect.

[Dibble]

55 minutes ago, Alan de Enfield said:

 

The other option is to do as much as you can, screw the hatch back on, fill with water and check again in another 20 years,

🤣🤣

[Silent Flight]

Could anyone tell from these pics what this is painted/ coated in ? 
 

[ditchcrawler]

On 11/04/2023 at 11:57, Higgs said:

 

Also requires very good ear defenders, if my experience with a needle gun is common. And with these kinds of vibrating tools, you should wear gloves made to reduce vibration in the hands.

 

 

 

 

I think it was @DMR who cracked painting the water tank

[Tony Brooks]

11 minutes ago, Owls Den said:

Could anyone tell from these pics what this is painted/ coated in ?

 

 

A yellow surface coating - yes, a flippant answer because how can one tell from a photo. Is there any texture to it?

[David Mack]

15 minutes ago, Owls Den said:

Could anyone tell from these pics what this is painted/ coated in ? 
 

My guess is a two pack epoxy, hopefully suitable for potable water, and presumably applied to a properly prepared surface.  Whatever it is, judging by the almost complete absence of rusting, it has done its job.

 

Not cheap though!

https://www.smlmarinepaints.co.uk/products/tankguard_DW

 

Edited April 13, 2023 by David Mack

[Silent Flight]

Your right has done itself proud so far. But there is a small amount of rust so can’t seal it back up just yet.

 

Tbh I wasn’t sure what to expect when opening it up!

 

Could I put new two pack epoxy over the small rusted area?

49 minutes ago, Tony Brooks said:

 

A yellow surface coating - yes, a flippant answer because how can one tell from a photo. Is there any texture to it?

It’s a bit of a long shot I know, my hunch was two pack epoxy seeing so was seeing if anyone concurred.

[David Mack]

16 minutes ago, Owls Den said:

Could I put new two pack epoxy over the small rusted area?

I think you'd need to abrade the whole thing for new epoxy to stick. That will shift rust staining from the surface. But presumably there are some areas where either the epoxy is damaged or perhaps was not properly painted in the first place where the steel has rusted. Those areas should be properly prepared back to bright metal before repainting.

[Bod]

On 11/04/2023 at 10:27, Dibble said:

Hi all, it would seem that the water tank on the narrowboat I've purchased hasn't been cleaned for 20 years! I've scraped and ground it back to the bare metal as best I can, but there are parts that I just can't get to. I've spoken to some grit blasters who say they can't complete the job, due to access issues. The underside of the tank is still quite corroded. Is there anything I can use to remove the rust, or treat it before I can coat it with two pack epoxy. Thanks.

Be aware the drying time will be much longer, due to the enclosed nature of the tank.

 

Bod

[Silent Flight]

Awesome thanks! 

[philjw]

12 minutes ago, Bod said:

Be aware the drying time will be much longer, due to the enclosed nature of the tank.

Is this true for epoxy coatings? I thought it cures chemically rather than dries through evaporation of solvent.

[dmr]

2 minutes ago, philjw said:

Is this true for epoxy coatings? I thought it cures chemically rather than dries through evaporation of solvent.

 

Yes, you are correct, though setting does depend a lot on temperature so the parts of the tank below the waterline might take a little longer.

 

I believe that epoxy does contain a bit of solvent, otherwise it would be like painting with araldite 😀, but this should evaporate quickly so you don't need to worry about it.

[Silent Flight]

And what is the favoured two pack epoxy used?

 

There is a shed load of variety.