Hi,
A fellow boater here in Trinidad has rusty steel water tanks with a
couple of pin holes in them. He doesn't have a lot of money but does
have a supply of cold tar epoxy.

Question: Should he drink the water from the tanks if he paints them
internally with said cold tar epoxy? Are there any isocyanates or such
that will leach into the water that would be harmful to his health.

If so, what would be the most cost effective (cheapest) internal
coating?

Thanks and regards
Peter Hendra

Peter Hendra wrote:

A fellow boater here in Trinidad has rusty steel water tanks with a
couple of pin holes in them. He doesn't have a lot of money but does
have a supply of cold tar epoxy.

Question: Should he drink the water from the tanks if he paints them
internally with said cold tar epoxy? Are there any isocyanates or such
that will leach into the water that would be harmful to his health.

If so, what would be the most cost effective (cheapest) internal
coating?

Not a good idea to use coal tar epoxy on potable water tanks.

SFWIW, I used CTE on my holding tank.

There are resins specifically made for coating potable water tanks.

They are known as tank resins.

I'd use two (2) coats, white followed by some other color.

SFWIW, that's what I did based on the suggestion of the supplier.

Makes it easy to see if you missed anyplace.

Have fun.

Lew

On Sat, 24 Mar 2007 18:06:22 GMT, Lew Hodgett
wrote:

Peter Hendra wrote:

A fellow boater here in Trinidad has rusty steel water tanks with a
couple of pin holes in them. He doesn't have a lot of money but does
have a supply of cold tar epoxy.

Question: Should he drink the water from the tanks if he paints them
internally with said cold tar epoxy? Are there any isocyanates or such
that will leach into the water that would be harmful to his health.

If so, what would be the most cost effective (cheapest) internal
coating?

Not a good idea to use coal tar epoxy on potable water tanks.

SFWIW, I used CTE on my holding tank.

There are resins specifically made for coating potable water tanks.

They are known as tank resins.

I'd use two (2) coats, white followed by some other color.

SFWIW, that's what I did based on the suggestion of the supplier.

Makes it easy to see if you missed anyplace.

Have fun.

Lew

Lew,
weren't you a contributor to the Yacht-L boating news group about 10
years ago? If I recall correctly, you were building a rather large
vessel.

Please enlighten me. What is "CTE"
Also, as you seem to know your stuff, does anythbing harmful leech out
of tanks constructed with ordinary epoxy resin? When I built this
boat I made my diesel and water tanks from glassed over plywood. I
just used the ordinary epoxy resin I sheathed the hull with.

We have lived on-board and cruised for about 14 years now and drunk
the water from these tanks filtered by a standard household granulated
carbon cartridge filter.

cheers and thanks for the advice
Peter Hendra

Peter Hendra wrote:
On Sat, 24 Mar 2007 18:06:22 GMT, Lew Hodgett
wrote:

Peter Hendra wrote:

A fellow boater here in Trinidad has rusty steel water tanks with a
couple of pin holes in them. He doesn't have a lot of money but does
have a supply of cold tar epoxy.

Question: Should he drink the water from the tanks if he paints them
internally with said cold tar epoxy? Are there any isocyanates or such
that will leach into the water that would be harmful to his health.

If so, what would be the most cost effective (cheapest) internal
coating?
Not a good idea to use coal tar epoxy on potable water tanks.

SFWIW, I used CTE on my holding tank.

There are resins specifically made for coating potable water tanks.

They are known as tank resins.

I'd use two (2) coats, white followed by some other color.

SFWIW, that's what I did based on the suggestion of the supplier.

Makes it easy to see if you missed anyplace.

Have fun.

Lew

Lew,
weren't you a contributor to the Yacht-L boating news group about 10
years ago? If I recall correctly, you were building a rather large
vessel.

Yes.


Please enlighten me. What is "CTE"

coal tar epoxy

Also, as you seem to know your stuff, does anythbing harmful leech out
of tanks constructed with ordinary epoxy resin? When I built this
boat I made my diesel and water tanks from glassed over plywood. I
just used the ordinary epoxy resin I sheathed the hull with.

Built my tanks the same way.

My supplier of epoxy laminating resin suggested talking to my coatings
supplier when it came to tankage.

Laminating resin contains no VOCs.

Tank resin, AKA: "high build primer" definitely contains VOCs.

As a high build primer, it provides the tie between the laminate and the
L/P paint used to get a high gloss "yacht finish".

As a tank resin, it is approved by US gov't for use in tanks.

Never got deep enough into it to get all the techie answers, just did
what was suggested by the pros in the business.

As far as your friend is concerned, think I would investigate the usage
of bladder tanks inside the existing steel tanks.

My guess is you try to repair existing tanks, might get one year, if lucky.

A lot of work and high risk of early failure IMHO.

Lew




We have lived on-board and cruised for about 14 years now and drunk
the water from these tanks filtered by a standard household granulated
carbon cartridge filter.

cheers and thanks for the advice
Peter Hendra

On Sun, 25 Mar 2007 00:33:08 GMT, Lew Hodgett
wrote:


As far as your friend is concerned, think I would investigate the usage
of bladder tanks inside the existing steel tanks.

My guess is you try to repair existing tanks, might get one year, if lucky.

A lot of work and high risk of early failure IMHO.

Lew



Thanks for this Lew,
I shall pass it on.

cheers
Peter Hendra

Peter Hendra inscribed in red ink for all to know:
On Sun, 25 Mar 2007 00:33:08 GMT, Lew Hodgett
wrote:



As far as your friend is concerned, think I would investigate the usage
of bladder tanks inside the existing steel tanks.

My guess is you try to repair existing tanks, might get one year, if lucky.

A lot of work and high risk of early failure IMHO.

Lew




Thanks for this Lew,
I shall pass it on.

cheers
Peter Hendra


I'm not sure how much actual Coal Tar is in Coal Tar Epoxy, but since
coal tar was one of the earliest listed carcinogens, I wouldn't want to
drink water that had been steeped in a tank lined with it...


bob
s/v Eolian
Seattle
(where what would be a Super Fund site got grass planted on it, and
labeled a park: Gasworks Park)

"Peter Hendra" skrev i en meddelelse
...
Hi,
A fellow boater here in Trinidad has rusty steel water tanks with a
snip
If so, what would be the most cost effective (cheapest) internal
coating?

Coal Tar Epoxy not a good idea.
A temporary fix might be a cement wash. Never tried it myself, but I believe
it was a commonly used treatment in "the old days".
HTH
Bob Larder

On Mon, 26 Mar 2007 19:07:13 +0200, "Robert Larder"
wrote:


"Peter Hendra" skrev i en meddelelse
.. .
Hi,
A fellow boater here in Trinidad has rusty steel water tanks with a
snip
If so, what would be the most cost effective (cheapest) internal
coating?

Coal Tar Epoxy not a good idea.
A temporary fix might be a cement wash. Never tried it myself, but I believe
it was a commonly used treatment in "the old days".
HTH
Bob Larder

Thanks Bob and Bob,
I shall pass it on.

cheers
Peter

Water etc. tanks can be remediated with special 'lining' epoxies. For
water tankage you really should consider an epoxy that meets NSF or FDA
regs. for compatability to 'potable' water .... so you dont wind up
drinking a lot of toxic 'leachables'.
The Commercial Marine Industry uses 'lining epoxies' from Interlux
Commercial Division. For small quantities for potable water tank
lining, I use: www.epoxyproducts.com/nsp120.html
In any event when mixing such epoxies you MUST use the 'two-pot' method
for mixing to be SURE that the epoxy is precisely, correctly and ****
thoroughly ***** mixed.

For simple rust on intact steel, just grind, sand or blast, etc. to
bright metal, then roll-on the lining epoxy. For surface corroded
tanks you might want to consider first lining/strengthening with glass
cloth, tape, etc. then overlay with the lining epoxy.
;-)


In article , Robert
Larder wrote:

"Peter Hendra" skrev i en meddelelse
...
Hi,
A fellow boater here in Trinidad has rusty steel water tanks with a
snip
If so, what would be the most cost effective (cheapest) internal
coating?

Coal Tar Epoxy not a good idea.
A temporary fix might be a cement wash. Never tried it myself, but I believe
it was a commonly used treatment in "the old days".
HTH
Bob Larder