Repainting the water tank

[blackrose]

Repainting the inside of integral water tanks: Is there really nothing better than bitumen that one can use?

 

Surely there must be some sort of plastic resin which would last longer?

[Mick_B]

Repainting the inside of integral water tanks: Is there really nothing better than bitumen that one can use?

 

Surely there must be some sort of plastic resin which would last longer?

This says posted a few mins ago. I'm feeling like it's groundhog day cause I'm sure I read it yesterday...

 

As to the question... I guess there is but don't know the answer.

[blackrose]

This says posted a few mins ago. I'm feeling like it's groundhog day cause I'm sure I read it yesterday...

 

As to the question... I guess there is but don't know the answer.

 

I posted the question on the "worst jobs" thread but nobody answered.

[Mick_B]

I posted the question on the "worst jobs" thread but nobody answered.

Oh... thought I was getting phycic powers.

[n.b.Goldie]

Repainting the inside of integral water tanks: Is there really nothing better than bitumen that one can use?

 

Surely there must be some sort of plastic resin which would last longer?

It is truly an awful job and one I must tackle shortly.

 

I understand there are plastic tank liners available, sort of like a big version of the bags in wineboxes. Does anyone on this forum have any experience or knowledge of them?

 

If they are any good it might be the answer!

 

Ditchdabbler

[Ron Knight]

It is truly an awful job and one I must tackle shortly.

 

I understand there are plastic tank liners available, sort of like a big version of the bags in wineboxes. Does anyone on this forum have any experience or knowledge of them?

 

If they are any good it might be the answer!

 

Ditchdabbler

You could try here

http://www.marinemegastore.com/category.as...2U4U93VWTVQI48G

[KenK]

Repainting the inside of integral water tanks: Is there really nothing better than bitumen that one can use?

 

Surely there must be some sort of plastic resin which would last longer?

 

I used Vactan, had to use a heater to make sure it completly cured, then a topcoat of bitumen. I did think about a liner but you still have to coat the tank before you fit it and make sure there is an air gap all around tp prevent condensation, not cheap either.

 

Ken

[rgreg]

Had a look at my water tank today and completely no access other than the filler hole in the bow floor. Are some not designed to be painted?

[andywatson]

Had a look at my water tank today and completely no access other than the filler hole in the bow floor. Are some not designed to be painted?

 

If that is an integral tank it is badly designed. Even if it was coated with a corrosion restant indestructable material (which is unlikely if there is no access) you might occasionally want to clean out silt and rust

-I would be tempted to cut an access hatch in it.

[blackrose]

Had a look at my water tank today and completely no access other than the filler hole in the bow floor. Are some not designed to be painted?

Are you sure that it's not a stainless tank?

[rgreg]

Are you sure that it's not a stainless tank?

 

Is there a way to check? I can only see the filler top all the rest is concealed within the bow. Shell is 7 yr old John White if that any help

[Teadaemon]

Are you sure that it's not a stainless tank?

 

Even if it's a stainless tank, a decently-sized access panel is best practice (my sources indicate that 15"x24" is an absolute minimum).

[blackrose]

Is there a way to check? I can only see the filler top all the rest is concealed within the bow. Shell is 7 yr old John White if that any help

 

Don't you have an access panel to the bow inside the boat? Under the stairs perhaps? (Assuming its a well deck)

 

 

Even if it's a stainless tank, a decently-sized access panel is best practice (my sources indicate that 15"x24" is an absolute minimum).

Access panel for the tank? It might be a good idea but I'd say most stainless tanks don't have them. You'd need a panel through the deck and then another directly below to the tank.

Edited November 9, 2009 by blackrose

[john b.]

After removing all traces of bitumen and derusting would fibreglassing the tank with say 3coats of 1.5 oz matting be feasible, this would hopfully then be a permanent job. I'm not sure whether a protective coat of paint maybe required (any comments?) Anybody tried it.

johnb.

[blackrose]

After removing all traces of bitumen and derusting would fibreglassing the tank with say 3coats of 1.5 oz matting be feasible, this would hopfully then be a permanent job. I'm not sure whether a protective coat of paint maybe required (any comments?) Anybody tried it.

johnb.

 

It might work but there are two things I can think of:

 

Firstly, you'd have to be completely sure that the fibreglass layer would never leak or suffer from osmosis, because if it ever did you'd have water between the fibreglass and the steel potentially leading to rust. trouble is you'd never know about it and never be able to treat it..

 

Secondly, I think you need to make sure that whatever is in direct contact is suitable for potable water. If fibreglass resin isn't suitable I guess painting with bitumen would work, but then you're back to square one!

Edited November 11, 2009 by blackrose

[granddad]

It might work but there are two things I can think of:

 

Firstly, you'd have to be completely sure that the fibreglass layer would never leak or suffer from osmosis, because if it ever did you'd have water between the fibreglass and the steel potentially leading to rust. trouble is you'd never know about it and never be able to treat it..

 

Secondly, I think you need to make sure that whatever is in direct contact is suitable for potable water. If fibreglass resin isn't suitable I guess painting with bitumen would work, but then you're back to square one!

 

 

The qm2 coats all her fresh water tanks with a cement wash as have all merchant ships for 50 years try it - mine have remained taste free for 10 years.

ken

[rgreg]

Don't you have an access panel to the bow inside the boat? Under the stairs perhaps? (Assuming its a well deck)

 

There is a panel above the bow thruster motor but seems to be a bulk head in front of the water tank. May be access behind front step, I could remove the wood panel if I need to (and hopefully I won't!"). Cheers.

[wrigglefingers]

Hello Mike,

 

It truly is the worst job on the boat, my hair never really recovered after doing mine and it probably explains why face looks like it does. Mine hadn't been done in over 15 years so the muck and slime bloom were a horror to behold, there was rust under the bitumen layer and I had to angle grind some of it off which melted the bitumen and coated any bare bits of skin I hadn't managed to cover.

 

I investigated the tank liner solution bit having done all the hard work (which would have had to have been done in any case) slapping three coats of Bartoline on the metal was cheap, quick and easy. There were so many caveats and the liner was surprisingly expensive that I thought it not worth the bother.

 

Jill

[ChrisPy]

The qm2 coats all her fresh water tanks with a cement wash as have all merchant ships for 50 years try it - mine have remained taste free for 10 years.

ken

please can you provide the recipe?

I have googled for that before and couldn't find a method statement.

[WotEver]

please can you provide the recipe?

I have googled for that before and couldn't find a method statement.

There's a thread on another forum about this here. Post 18 states "As a (old?) Merchant Seaman we used to coat our fresh water tanks annually with a cement 'wash' made up of Portland cement - NO secret Ingedient! mixed with water to a thick mess, 'bout the consistency of porridge and applied it using soft brooms. Let it dry and washed out the tanks by filling once then refilling for use. Sweet as you'd ever get"

 

Tony

[tomandsophie]

I want to do ours using the cement wash mentioned above, but I wonder if I have to remove all the bitumen first? If so, I'll probably just slap on some more bitumen instead

[Tony Brooks]

I want to do ours using the cement wash mentioned above, but I wonder if I have to remove all the bitumen first? If so, I'll probably just slap on some more bitumen instead

 

 

Just a word of caution to think about.

 

I very much doubt if many merchant ships use the hull as one skin of the tank and I also doubt they tend to make contact with hard stone & concrete as often as a narrowboat. Whilst I know about cement washing I fear doing it on a narrowboat where the hull forms part of the tank could easily result in impact causing the cement skin to flake off the tank. I feel bitumen is more flexible and less likely to flake.

 

Having a stainless steel tank I have not had the opportunity to test cement washing though.

[blackrose]

Just a word of caution to think about.

 

I very much doubt if many merchant ships use the hull as one skin of the tank and I also doubt they tend to make contact with hard stone & concrete as often as a narrowboat. Whilst I know about cement washing I fear doing it on a narrowboat where the hull forms part of the tank could easily result in impact causing the cement skin to flake off the tank. I feel bitumen is more flexible and less likely to flake.

 

Having a stainless steel tank I have not had the opportunity to test cement washing though.

 

Good point. I'd worry about any crack in the cement allowing water behind. Then you've potentially got rust you can't see and no way of treating - a real problem.

[saltysplash]

please can you provide the recipe?

I have googled for that before and couldn't find a method statement.

 

 

My old trawler Emblem's water tank had a cement wash which was redone appx every 5 years,

 

It is true the tank wasnt part of the wooden hull but nontheless, during her 30yrs service in the fishing fleet and wartime service she had to cope with plenty of banging around on the north sea in and around the shetlands.

 

The wash does degrade over time and and does flake but this settles to the bottom of the tank and is shovelled out during the next cleaning.

 

The take off for the tank was about an inch off the bottom so i could see some blockages happening if the take off from a tank was directly on the bottom

 

similar cement wash method here

 

Cement Wash .

The simplest form of cement wash is made by taking fresh Portland cement and adding it to water, in the proportion of 14lb.cement to a gallon of water, stirring thoroughly to produce a creamy con­sistency. Only as much as can be used within a period of half an hour - should be mixed at a time. The brickwork or other surface to which the - wash is being applied should be well wetted with cold water. Application should not be made in direct sunlight. The reasons why such washes sometimes fail are usually either that the water evaporates before the cement has become fully hydrated, or that the wash is allowed to stand too long before being applied.

Some decorators make a practice of adding common salt to a wash, the purpose being to conserve the moisture until hydration has taken place.

Not more than ½lb. of salt to the gallon of wash should be added, but it is open to the objection that the salt may crystallise on the surface and form unsightly patches.