Water tank blacking

[Old Al]

My first attempt at posting worked so well I'm going to have another go.

Can any of you wise sages tell me, do i need a special type of blacking for my water tank, I only use it for washing, cooking, and cleaning, not drinking, or will ordinary black bitumen paint be OK.

Thanks in advance, I have great confidence in you guys.

 

Old Al

[Higgs]

I've had to black a fair few water tanks. The one bit of advice I'd give you is, put it on thin, in several coats. Give it plenty of time to cure. Excess will build up in the lower corners and may not cure properly.

 

If your water butt is in the forward locker it will be subject to condensation, due to the outside water temperature, the air and the steel. I'd wait until condensation period is passed. Well into Spring.

 

Condensation may not be so much of a problem if your boat is out of the water.

Edited April 3, 2013 by Higgs

[jodansgang]

I'm also very interested in OP replies to this question.

[Timleech]

My first attempt at posting worked so well I'm going to have another go.

Can any of you wise sages tell me, do i need a special type of blacking for my water tank, I only use it for washing, cooking, and cleaning, not drinking, or will ordinary black bitumen paint be OK.

Thanks in advance, I have great confidence in you guys.

 

Old Al

 

Some 'ordinary' bitumen paints used to be accepted for water tanks, but now you're expected to use special water tank black (easily obtained from the usual culprits but more expensive).

Using ordinary bitumen did lead to tainted water for a while after painting.

One incidental benefit of using the 'proper' stuff is that the fumes are not so bad in a confined space.

 

 

Tim

[Troyboy]

I painted my water tank a few years ago and it was the worst job I have ever had to do on my boat . Having said that it was nice to see the rusty tank transformed into a nice shiny black tank . I used the special water tank black bitumen but it wasn't that much more expensive than the normal bitumen . There was a slight tainting to the water for a short while but that didn't last long . Goggles and mask are a must when cleaning the tank and cover yourself as best you can hat / overalls / gloves , the rust gets everywhere .

[The Bagdad Boatman (waits)]

I once made the mistake of using hull blacking in the water tank. It tainted so badly that I had to use a paint stripper to remove it all then repaint with proper potable tank blacking.

[Dekazer]

Vile job, but satisfying.

 

I'd recommend using 'potable' (i.e. safe for drinking water) bitumen, even if you don't intend to drink the water. It's easier in case you sell or lend the boat out. I think it's likely to be more suited to the purpose (in terms of how easily it goes on and cures etc) but having not tried both I can't prove that.

 

Litre for litre it doesn't look much more expensive, given that you'll only need a small amount.

 

http://www.midlandchandlers.co.uk/Products/PaintBoatCare/HullTankBlacking.aspx

[PaulJ]

Alot of none potable bitumens are infact potable-its just they are not certificated as is not worth the cost of doing this to the makers. Not thats of any help to the OP.

I used International Intertuf on mine (and others)several times with no problems or tainting.Same as I use on the hull so is free (as long as you have some left of course)And I do drink,cook etc from tank too..

As Higgs said- the trick is not to put it on too thick

[sharpness]

You must use a bitumen paint that is suitable for potable water tanks.

Everbuild do one called Everbuild Black Jack Black Bitumen Paint 901. Can be found on google & ebay.

 

Steve

[blackrose]

I was told by my chandler that the bitumen-based paint suitable for potable water was exactly the same as ordinary bitumen and that the reason that the former was twice the price (and half the size), was because they'd paid to have the testing done and could now label it as "Suitable for potable water".

Edited April 4, 2013 by blackrose

[Djuwenda]

a few things that may help...

 

I found the main difficulties with the job were

-drying the tank sufficiently to be able scrap the rust off

-removing the rust/dust

-the application of edible bitumen, depending on the shape of the tank can be nightmarish, not much fun if you are claustrophobic

-the drying problem again when it comes to allowing the bitumen enough time to dry... (remember its got to be dry before the evening due to condensation)

 

 

I will be doing this job this summer, but will first source an aqua vac or similar and a portable drier/heather airblower thing. Also you dont really want to start the job unless you know you have a few days of sunny weather ahead.

[nb Innisfree]

Alot of none potable bitumens are infact potable-its just they are not certificated as is not worth the cost of doing this to the makers. Not thats of any help to the OP.

I used International Intertuf on mine (and others)several times with no problems or tainting.Same as I use on the hull so is free (as long as you have some left of course)And I do drink,cook etc from tank too..

As Higgs said- the trick is not to put it on too thick

A few years agoI was told by an International agent that they had given up their certification because so many people were having problems due to the fact that they didn't allow enough time for Intertuf to dry and cure, this was giving their product an undeserved bad reputation. The agent wouldn't state that it was still ok to use Intertuf for tank blacking due to any legal issues but did confirm it was still the same formula. We have used it repeatedly on our tank with no tainting whatsoever though I wouldn't use any other brand of hull blacking for this purpose. For example we

use Rylard's Rytex for our hull but wouldn't consider it suitable for tank blacking.

[Hawkmoth]

Going lightly off topic, when faced with having to re-black my water tank I took an easy way out. Instead of having to thoroughly clean and then paint several coats onto the inside, I bought a tank liner from Duratank.

It wasn't too difficult to fit, it comes with instruction.

This may be an answer which you could consider.

Bob

[KJT]

Going lightly off topic, when faced with having to re-black my water tank I took an easy way out. Instead of having to thoroughly clean and then paint several coats onto the inside, I bought a tank liner from Duratank.

It wasn't too difficult to fit, it comes with instruction.

This may be an answer which you could consider.

Bob

 

 

If you fit a Duratank, would you still have to remove the rust and then paint the tank before fitting? I would assume that any rust in the original tank would get worse with any condensation between the metal and and the Duratank.

Or am I talking rubbish?

[Hawkmoth]

If you fit a Duratank, would you still have to remove the rust and then paint the tank before fitting? I would assume that any rust in the original tank would get worse with any condensation between the metal and and the Duratank.

Or am I talking rubbish?

I did scrape out the loose stuff, then used a rust converter followed by red oxide just to keep the surface reasonable.

they do recommend lining the tank. I used bubble wrap bought from ebay.

Bob

[n.b.Goldie]

You must use a bitumen paint that is suitable for potable water tanks.

Everbuild do one called Everbuild Black Jack Black Bitumen Paint 901. Can be found on google & ebay.

 

Steve

 

Toolstation are selling 5lts of the above for £14.41 inc free delivery. cheapest I have seen so far.

 

Regards

Ditchdabbler

[Québec]

Off topic - a bit ...As, like you, we don't use the tank water for drinking, we - and some others on here - haven't bothered with blacking the tank but have just used Vactan (de-rusting treatment). There's disagreement - as always on here - as to whether this is safe, but it has served us well for over three years, and we did it after contacting the company to check whether this was OK. Our integral tank is easy to access, and I'd much rather do the once/twice a year re-treatment which is relatively quick, straighforward and - importantly - clean, than do the 'dirty job' of blacking.

 

But that's my choice...others choose differently.

Edited April 7, 2013 by Québec

[Bimbly1]

Off topic - a bit ...As, like you, we don't use the tank water for drinking, we - and some others on here - haven't bothered with blacking the tank but have just used Vactan (de-rusting treatment). There's disagreement - as always on here - as to whether this is safe, but it has served us well for over three years, and we did it after contacting the company to check whether this was OK. Our integral tank is easy to access, and I'd much rather do the once/twice a year re-treatment which is relatively quick, straighforward and - importantly - clean, than do the 'dirty job' of blacking.

 

But that's my choice...others choose differently.

 

It's not so much about whether it's safe to use in a potable water tank now, as to what long term, i.e. decades, ill-health effects there may be.

[Higgs]

I've had my boat about 10 years and lived aboard all of that time, drinking the water stored in the forward locker butt. The most I do is blast the the bottom on some fill ups and do about ten flushes of the few gallons used to blast. The water is very clear, right down to the dregs. Don't know what condition the tank is in.

 

I know it sounds disgusting, but they say kids eating what they find up their noses is good for their immune system. I think the same about what may be in the tank.

[Grace and Favour]

It's not so much about whether it's safe to use in a potable water tank now, as to what long term, i.e. decades, ill-health effects there may be.

 

after 8 or 9 decades it's probably fatal

[MikeV]

I've had to black a fair few water tanks. The one bit of advice I'd give you is, put it on thin, in several coats. Give it plenty of time to cure. Excess will build up in the lower corners and may not cure properly.

Agree with the above. To get it "thin" I stand the tin in a bucket of recently boiled water for about 30 minutes so it's nice and warm and runny. Better to put on 3 thin coats than two thicker coats.

 

I did mine recently during the cold spell and (hopefully) overcame the issue of condensation by taking a fan heater and hot air gun in the tank with me. Had the fan heater running all the time and blasted the area I was about to paint with the hot air gun. Despite it being near zero outside it was quite cosy working in the tank!

 

I assume if the tank did have condensation the blacking would not stick and it would start to peel off? Keeping my fingers crossed I kept the condensation at bay!

[Higgs]

I assume if the tank did have condensation the blacking would not stick and it would start to peel off? Keeping my fingers crossed I kept the condensation at bay!

 

You'd have a hard time getting the blacking to leave the brush with moisture around.

[rustydiver]

On 4/6/2013 at 18:50, ditchdabbler said:

 

Toolstation are selling 5lts of the above for £14.41 inc free delivery. cheapest I have seen so far.

 

Regards

Ditchdabbler

Have you got the link, so i can see it the same as I'm looking at. Please

[rustydiver]

https://www.toolstation.com/shop/Roofing+%26+Drainage/d250/Roof+Compound+%26+Waterseals/sd2809/Black+Bituminous+Paint/p88792

??

 

Daft question time if i redo in a few years, while it still it is good is there a need to take it right back or just remove all the loose stuff and re-coat.

[matty40s]

bit of an old thread but advice is good. 

Rytex actually do a specific water tank bitumen which is very low odour. the main problem with water tanks is getting the stuff to dry(even in summer) as it is such a closed environment.

Just pressure wash and keep pumping out water,remove rust patches, grind away any delaminated steel and overcoat whats left.

I have seen some horrific ones recently, a washing up bowl full of rust and sludge in more than one.......and more in the wet vac!!!!