Material for potable water tanks

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  • 11 Jan 2011 07:32
    Reply # 493318 on 493316
    Kurt Jon Ulmer wrote: Paul,
    Altex Coatings, here in New Zealand, make AltraShield 2000 epoxy paint. 
    The white colour is approved for potable water tanks, with X-100 thinner.
    5 sqm/L per coat. Cures in cool temperatures.
    Tech Support number: 0800 429 527 in Tauranga.
    Kurt

    Hi Kurt,

    Yes, I know it well as I have used it for hull coatings. However it is a solvent based epoxy and I'd rather stay away from solvent based epoxies for potable water.
  • 11 Jan 2011 07:24
    Reply # 493316 on 490035
    Paul,
    As a backup product:  
    Altex Coatings, here in New Zealand, make AltraShield 2000 epoxy paint. 
    The white colour is approved for potable water tanks, with X-100 thinner.
    5 sqm/L per coat. Cures in cool temperatures.
    Tech Support number: 0800 429 527 in Tauranga.
    Kurt
    Last modified: 11 Jan 2011 07:24 | Anonymous member
  • 11 Jan 2011 06:42
    Reply # 493296 on 490483
    Peter Manning wrote:
    Paul Thompson wrote: David,

    I like the epoxy plywood tanks and my diesel tanks are made that way for the same reasons that you choice the material.

    I'd really like to do the water tanks the same way but am concerned about the health risks. Having said that, you were surely frisky and bushy tailed enough when you were here last year, so it would appear that you have not suffered because of your tanks.

    It is however the way I am leaning, health risks and all.  
    Paul,

     I too have tanks made of plywood and coated with glass mat and epoxy just like David. However, I did not finish with a white epoxy as David did (would have been a good idea if I had thought of it). However, being concerned about the suitability of ordinary epoxy for potable water I found a company called E. Wood who supplied an epoxy suitable for water tanks. However, I think it is only available in a greyish colour. The product is called Copon Hycote 162 PW and can be found on the web. E. Wood have now been taken over by 3M Europe. Hope this helps. 
    Thanks Peter, you do not seem to be able to get Copon Hycote in NZ but I found that Jotun make what seems to be a very similar product called Tankgaurd 412 , a solvent free epoxy designed for potable water tanks and it meets a whole lot of European, Oz and USA spec for the product. So I think I will build  plywood epoxy tanks and coat them inside with the Tankgaurd 412. The product is white, so that will be another plus. To meet the various approvals the curing has to be done at a min 23deg C for a week. A 100 watt light buld in each tank should take care of that.
  • 08 Jan 2011 21:16
    Reply # 491763 on 490035
    For someone like yourself, Paul, it's swings and roundabouts because you are an extremely competent builder.  You do have cavernous places for stowage; possibly 2 or 3 gallon jerricans would suit better.  But for people who are daunted at the prospect of building tanks and plumbing them in, the jerrican route has many advantages. 

    Fantail's water tank is the area beneath the cabin sole: a previous owner took this up and obviously bottled (!) out of resealing it, and dumped a 20 litre jerrican under the table and called it a water tank.  In the intervening years, the paint has dried out and cracked.  I've scraped it all back and need to re-epoxy now.  I don't want to know anything about cancer risks thank you very much.  I tried jerricans, but the space is too narrow.  Old pop bottles were considered -  I recycle them for my home brew - but the dimensions didn't work, so it's back to the original design, which holds an astonishing 80 l.  Loads for one person pottering about, or even heading off for The Islands.
  • 07 Jan 2011 06:09
    Reply # 490913 on 490035
    Well my intention is along the line of one 50 gal. and two 25 gal. tanks giving me a 100 gal. in all. I like the one gallon bottle idea but is a 100 odd one gal bottles viable?

    Why a hundred gallons? I am thinking of two people and a 100 days at sea.

    Anthony, La Chica is a 32ft steel double ender similar to a Colin Archer type in profile but the hull is actually much finer with rather less beam (in La Chica's case 10ft 3in beam, 5ft draft, approximately 8 tons displacement, about 650 Sq.ft sail on a softwing (same as David Tyler) schooner rig) she's a heavy boat but not as heavy as a Colin Archer of the same size would be.
  • 06 Jan 2011 19:00
    Reply # 490591 on 490035
    Anthony beat me to it, but I really liked having lots of different tanks on 'Badger'. It made it very easy to keep track of consumption, eliminated worries about leaks and meant that you could isolate any dubious water.

    On 'Iron Bark', we filled up with bad water in Moorea and suffered for over a week, unable to replace it with clean water and with all the water in that tank contaminated.  We collect water from the decks and over the years a large amount of sludge built up in the tanks, which had no access hatches.  The water ended up tasting really bad and when we were beating to windward, would pump out with large amounts of crud, giving a whole new meaning to 'mud in your eye'.  So if you do fit large water tanks ensure that you have several and that they can be cleaned out.

    I'd go for jerricans. 

    On a slight digression, instead of fitting an inline water filter, a filter jug, such as those produced by Thermos and Brita (sp?) are cheap and effective and if you are very thrifty, only needs to be used if the water tastes unpleasant.
  • 06 Jan 2011 17:08
    Reply # 490483 on 490091
    Deleted user
    Paul Thompson wrote: David,

    I like the epoxy plywood tanks and my diesel tanks are made that way for the same reasons that you choice the material.

    I'd really like to do the water tanks the same way but am concerned about the health risks. Having said that, you were surely frisky and bushy tailed enough when you were here last year, so it would appear that you have not suffered because of your tanks.

    It is however the way I am leaning, health risks and all.  
    Paul,

     I too have tanks made of plywood and coated with glass mat and epoxy just like David. However, I did not finish with a white epoxy as David did (would have been a good idea if I had thought of it). However, being concerned about the suitability of ordinary epoxy for potable water I found a company called E. Wood who supplied an epoxy suitable for water tanks. However, I think it is only available in a greyish colour. The product is called Copon Hycote 162 PW and can be found on the web. E. Wood have now been taken over by 3M Europe. Hope this helps. 
    Last modified: 06 Jan 2011 17:08 | Anonymous member
  • 06 Jan 2011 11:41
    Reply # 490370 on 490035
    Paul 

    Not sure how big your boat is, but have you considered a lot of little tanks?  Having spent years and years with built-in tanks, pressure systems, showers, freshwater heads, etc, when I found myself with 20 x 1-gallon containers on Zuleika, I wondered how well it would work, but it does.  They are easy to fill and keep clean, you can take half-a-dozen ashore in the dinghy if anchored or on a mooring, monitoring daily usage on passage is easy, and you can always see how much you have left.  Did I mention that there are no pumps or pipe-runs, and the containers are usually free?
  • 05 Jan 2011 22:57
    Reply # 490091 on 490035
    David,

    I like the epoxy plywood tanks and my diesel tanks are made that way for the same reasons that you choice the material.

    I'd really like to do the water tanks the same way but am concerned about the health risks. Having said that, you were surely frisky and bushy tailed enough when you were here last year, so it would appear that you have not suffered because of your tanks.

    It is however the way I am leaning, health risks and all.  
    Last modified: 05 Jan 2011 22:57 | Anonymous member
  • 05 Jan 2011 21:46
    Reply # 490046 on 490035
    Tystie's tanks, water and diesel, are built-in plywood + epoxy/glass cloth, with a final coat of white-pigmented epoxy, so that with a 1 1/2" deck filler in the top, I can easily inspect the level and state of the contents with a torch. I've been drinking the water for 10 years, and I'm not dead yet. For my CE certification, I had to pressurise the tanks to 3 lb/in2, and show that the pressure was maintained for 1/2 hour.  This would be a good plan, even if no certification is aimed for - it showed up some pinhole leaks that I had to fix.
    In previous boats I haven't got on well with flexible pillow tanks for water (leakage), or metal tanks for diesel (diurnal temperature cycling drawing in damp air through the vent).  Where my clear water hoses are exposed to light, algae grows, so this would be a problem with a polypropylene tank unless it was totally enclosed ( although it would be nice to see the level easily).
    I can't think of any other ways of making tanks.
    Last modified: 05 Jan 2011 21:46 | Anonymous member
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