Vactanned water tank - two years on

[Québec]

There've been various threads in the past on whether it's OK to use Vactan on its own (i.e. without adding blacking afterwards) in integral water tanks. We've always just used Vactan (after asking the company that makes it for advice) especially as we don't use the water for drinking. One argument for using blacking is that it lasts longer. I vaguely remember being advised to check a Vactanned-only tank every six months or so. We last opened and Vactanned our integral water tank in July 2011 (when we were out of the water for hull blacking). I've been thinking for a while that, after two years, I really ought to check it.

 

Today I finally got round to it. We have a large hatch in the cratch, so having removed the 28 bolts that keep it firmly in place, I gingerly raised it to peer inside expecting to find, as we did the very first time we looked inside after we'd just bought it, to see it covered in rust. To my utter surprise there were only two small spots of rust in the whole tank - floor, sides and ceiling. The rest looked as it did when we first filled it after the Vactan had dried two years ago.

Edited August 24, 2013 by Québec

[Neil2]

Interesting - I'm acquiring a boat which has a big hatch covering the water tank and though I haven't looked inside yet I suspect it will need a similar treatment. I note you don't drink the water out of the tank, we tend not to but our dogs do... is Vactan supposed to be safe for potable water containers?

[Québec]

.... is Vactan supposed to be safe for potable water containers?

 

Again, lots of disagreement on here. It does say in the Vactan spec "has been tested and certified for use for the use for the carriage of grain and use in potable water systems. It may also be used in sensitive foodstuff areas". So we went with that. Our choice. But we don't use our tank water for drinking, but we do use it for everything else including brushing teeth. Always clear (which of course doesn't necessarily mean it's safe) and tastes OK whenever I've had a sip. There are others on here convinced that it shouldn't be used on its own. Here the whole spec: http://www.paco-systems.co.uk/pdfs/vactan.pdf

 

ETA:Important, we found, to ensure it's applied in warm, dry conditions, and given plenty of time to dry properly and fully.

Edited August 25, 2013 by Québec

[JDR]

I found using a heat gun necessary to get Vactan to cure properly. Even in good weather it can take days to go off by itself. The heat gun transformed doing the tank from a week long will it/won't it chore ino a one day effort.

[blackrose]

I don't understand why you were so surprised to see so little rust. It's only been two years. If I got rid of all the rust and blacked a tank properly I'd expect it to last at least double that.

 

If the idea is to reduce or eliminate the amount of work then the best idea is to black the tank and then fit a tank liner. It would then be very easy to empty the tank once a years and check behind the liner for any moisture.

[Québec]

I don't understand why you were so surprised to see so little rust. It's only been two years. If I got rid of all the rust and blacked a tank properly I'd expect it to last at least double that.

 

.

 

I agree...if it had been blacked....but it hasn't ...just Vactanned. That was the point of my OP.

[kendo]

Hi Quebec. Just a quick post to back up what you've said. I went with vactan only on our water tank, about two years ago. Still fine.

 

Well chuffed.

[Wee Vee]

On 25/08/2013 at 00:25, Québec said:

There've been various threads in the past on whether it's OK to use Vactan on its own (i.e. without adding blacking afterwards) in integral water tanks. We've always just used Vactan (after asking the company that makes it for advice) especially as we don't use the water for drinking. One argument for using blacking is that it lasts longer. I vaguely remember being advised to check a Vactanned-only tank every six months or so. We last opened and Vactanned our integral water tank in July 2011 (when we were out of the water for hull blacking). I've been thinking for a while that, after two years, I really ought to check it.

 

Today I finally got round to it. We have a large hatch in the cratch, so having removed the 28 bolts that keep it firmly in place, I gingerly raised it to peer inside expecting to find, as we did the very first time we looked inside after we'd just bought it, to see it covered in rust. To my utter surprise there were only two small spots of rust in the whole tank - floor, sides and ceiling. The rest looked as it did when we first filled it after the Vactan had dried two years ago.

Hello Quebec! I'm dredging up a very old post of yours here because I'd be interested to know your thoughts on Vactan after the years have passed. 

I'm about to start the unenviable task of sorting out our rusty water tank in the bow and choosing the right product(s) seems to be a bit of a minefield.
Your insight would be greatly appreciated.

Thanks :)

[doratheexplorer]

29 minutes ago, Wee Vee said:

Hello Quebec! I'm dredging up a very old post of yours here because I'd be interested to know your thoughts on Vactan after the years have passed. 

I'm about to start the unenviable task of sorting out our rusty water tank in the bow and choosing the right product(s) seems to be a bit of a minefield.
Your insight would be greatly appreciated.

Thanks

I'd be interested to know.  I've been putting off this job for far too long!

[Québec]

Hello Wee Vee, thanks for getting in touch. Would happily recommend using Vactan for the water tank without the need for blacking. We did it again last year after a two year gap, and again there were only a couple of small rust spots.
 

Although we don’t, thorough habit, drink the tank water we tested it recently - a friend offered to drink a glass! - and she said it was absolutely fine....and she’s still with us! 
 

The crucial thing, especially if you’re Vactanning  the tank while in the water, is to make sure the Vactan dries/cures properly before re-filling the tank. We’re talking days here, depending on the weather. The damper the weather the longer you need to wait. One way to test, though it’s a drag, is to start filling the tank with a bit of water. If the Vactan turns milky it hasn’t cured. Just drain and let it dry and cure some more. We used a small electric fan heater to help the process. if it stays black in contact with water it is cured. 
 

We’re lucky in that access to our tank is very easy, via a large hatch in the cratch. Others aren’t so fortunate. 
Hope that helps. 

Paul on Québec

[Wee Vee]

That's just the news I needed, thanks Paul!
We do drink our water, and my plan is to add a decent water filter inline once this refurb is completed.
After 15 years of drinking from the current tank I think we're pretty hardy. Certainly no iron deficiencies on this boat anyhow.

I can climb into our tank with relative ease so I should be able to do a really good prep job on the metalwork prior to painting the stuff on.
The lads at the boatyard where we are have rigged me up a separate water tank so that I can bypass the boat tank for as long as the project requires.
I'll be sure to check a weather forecast to get favourable conditions.

One last thing – do you give it just one coat, or two?

Thanks again for your help, really appreciate it.

Vickie

Edited April 17, 2020 by Wee Vee
Request for more information.

[doratheexplorer]

How much vactan did you need to buy?

 

I can't climb into my tank, the opening is too small.  I'm picturing having a long stick which I can attach a scraper and then a brush to.  Is there an easier way that I've not thought of?

[Wee Vee]

6 minutes ago, doratheexplorer said:

How much vactan did you need to buy?

 

I can't climb into my tank, the opening is too small.  I'm picturing having a long stick which I can attach a scraper and then a brush to.  Is there an easier way that I've not thought of?

1L will cover approximately 8 – 9 sq m. So have a reccie at your tank dimensions.

That sounds like a pig of a job. How will you get the rusty crap out when you're finished scraping?
Perhaps a small sand blaster might be an easier solution, though I'm sure if you start a separate thread on it you'll get some better advice.

Edited April 17, 2020 by Wee Vee
More info

[Tracy D'arth]

Wet and dry vac is a godsend for jobs like this.  Perhaps you know a very small person?  There is a need for child labour sometimes.

[jake_crew]

On 25/08/2013 at 10:27, Neil2 said:

Interesting - I'm acquiring a boat which has a big hatch covering the water tank and though I haven't looked inside yet I suspect it will need a similar treatment. I note you don't drink the water out of the tank, we tend not to but our dogs do... is Vactan supposed to be safe for potable water containers?

I reckon if the dogs drink it, its almost bound to be CHEMICALLY good enough for humans.

 

For example our dog wont drink sterilised water (stero-tab treated) when camping, preferring the mountain stream.

 

My experience is that dogs are very canny about strange tastes and smells.  They don't mind a bit of good clean dirt - but chemicals no.

 

 

[doratheexplorer]

38 minutes ago, Tracy D'arth said:

Wet and dry vac is a godsend for jobs like this.  Perhaps you know a very small person?  There is a need for child labour sometimes.

I have a wet vac.  I am a small person, but I'd need a toddler to get in there.  I'll just have to do what I can eh?

 

I've read that vactan won't cure properly at low temps so was planning to wait until summer, when the canal water will be warmer.

 

Also, my tank is a mixture of rust and non-rust.  Will it cure properly on the non-rusty bits?

[David Mack]

2 hours ago, doratheexplorer said:

 

Also, my tank is a mixture of rust and non-rust.  Will it cure properly on the non-rusty bits?

Yes. This is one of the big advantages of Vactan over other products such as Fertan. It cures to form an acrylic paint layer, whether reacted with rust or not. Fertan reacts with the rust, but surplus has to be rinsed off, leaving the non-rusty areas untreated.

[Richard10002]

I did my very rusty engine hole by scraping, wet and dry vac, then Vactan x 2 coats. As it is an engine hole, I followed this with 2 x primer, undercoat and top coat. Couple of years ago, so far very good  

 

I recall a friend painting the inside of his water tank on a GRP seagoing boat with some kind of paint... light grey IIRC.

 

I wonder if there is a paint system which could be used in our water tanks, on top of the Vactan treated surfaces. I think I would like to look inside a light grey tank, rather than a dark one and, presumably, any flaws would show better.

[doratheexplorer]

21 minutes ago, Richard10002 said:

I did my very rusty engine hole by scraping, wet and dry vac, then Vactan x 2 coats. As it is an engine hole, I followed this with 2 x primer, undercoat and top coat. Couple of years ago, so far very good  

 

I recall a friend painting the inside of his water tank on a GRP seagoing boat with some kind of paint... light grey IIRC.

 

I wonder if there is a paint system which could be used in our water tanks, on top of the Vactan treated surfaces. I think I would like to look inside a light grey tank, rather than a dark one and, presumably, any flaws would show better.

I try not to think about my engine hole too much.  How am I supposed to paint down there?  There's an engine in the way.

[Wee Vee]

24 minutes ago, Richard10002 said:

I did my very rusty engine hole by scraping, wet and dry vac, then Vactan x 2 coats. As it is an engine hole, I followed this with 2 x primer, undercoat and top coat. Couple of years ago, so far very good  

 

I recall a friend painting the inside of his water tank on a GRP seagoing boat with some kind of paint... light grey IIRC.

 

I wonder if there is a paint system which could be used in our water tanks, on top of the Vactan treated surfaces. I think I would like to look inside a light grey tank, rather than a dark one and, presumably, any flaws would show better.

I have read of some people using Jotun 2 part epoxy over the top. It comes in white and light grey.
It's around £250 for a 15L tin – we'll have to start a syndicate.

[doratheexplorer]

12 minutes ago, Wee Vee said:

I have read of some people using Jotun 2 part epoxy over the top. It comes in white and light grey.
It's around £250 for a 15L tin – we'll have to start a syndicate.

Or get a smaller tin?

[Wee Vee]

4 minutes ago, doratheexplorer said:

Or get a smaller tin?

That is the smallest tin.

[blackrose]

7 hours ago, Wee Vee said:

That is the smallest tin.

Yes, that is the Jotun water potable epoxy, not ordinary Jotun (Jotamastic)

 

https://www.jotun.com/us/en/b2b/paintsandcoatings/products/tankguard-dw.aspx

 

 

Edited April 17, 2020 by blackrose

[Wee Vee]

20 minutes ago, blackrose said:

Yes, that is the Jotun water potable epoxy, not ordinary Jotun (Jotamastic)

 

https://www.jotun.com/us/en/b2b/paintsandcoatings/products/tankguard-dw.aspx

 

 

Correct. I wouldn't use the other products you quoted in your earlier edit in a potable water tank.

[Wee Vee]

12 hours ago, Québec said:

 

8 hours ago, Richard10002 said:

 

8 hours ago, doratheexplorer said:

 

Hello all,

 

Thought I'd share some info on a product I came across today, just in case you think it may be a top coat solution for our water tanks. 
Have a read, see what you think.

https://www.maxkote.co.uk/shop/maxline-100-flexible-water-tank-lining/

I've ordered the Vactan, now to dig out the face mask, goggles and wire brush. ?