OT - Patching a redwood water tank

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PeteM

OT - Patching a redwood water tank

Postby PeteM » Sat Jul 31, 2004 8:28 pm

Anyone have experience in patching a redwood water tank? Ours is 10,000 gallons, fitted boards, with steel bands. The leak is not between the boards, but right in the middle of one board right under the top band. About the diameter of a pencil, but with cracks further along the grain. What I'd like to be able to do is patch from the outside, with the water partly drained, but the wood probably still a bit damp. Epoxy seems like it might not hold up? Drilling and plugging the hole might be worth a try? Anyone had success? Or, is it just time to bite the bullet and buy a new polyethylene tank and foundation?

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UnkaJesse
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Re: OT - Patching a redwood water tank

Postby UnkaJesse » Sat Jul 31, 2004 8:53 pm

Pete, there are epoxies that are supposed to adhere to wet wood, but I have never had any experience with them, but might be worth a try. You could use a putty knife and force the epoxy through from the outside. Use one of the stiff paste types and it will not try to run out of the hole. You might try forcing it into the cracks also, but the thinner "5 minute" type would be better for cramming into the cracks I 'spect..

Of course, it would be better to work from the inside if at all possible, but apparently you cannot do so on this tank. [img]/ubb/images/graemlins/frown.gif"%20alt="[/img]

Unka(I is cheap and would try anything before replacing the tank! [img]/ubb/images/graemlins/cool.gif"%20alt="[/img])Jesse
"The same hammer that breaks the glass, forges the steel" Russian proverb

J Tiers

Re: OT - Patching a redwood water tank

Postby J Tiers » Sat Jul 31, 2004 9:53 pm

The boards probably have a feather down the length on each side. The right way to do it is to drain, loosen the bands, pull the bad board, cut out and replace the bad part.

But if it has been there a while, that might be tough.

How about screwing a patch over the inside with SS screws? Obviously much easier if the tank is open on top!

I suppose you could screw a patch on from outside too. But then water pressure is working against you.

Else-wise, if you can't get at it, drain down, drill out the bad part, and cut so that you have an oval hole. Taper the sides from inside, so inside is bigger than outside.

Ct and fit a tapered patch, which you can fit thru the oval hole like a handhole cover on a boiler goes in. Put a piece across like a strongback, with any sort of sealant you wish to use on the patch, and tighten down..

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Lee
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Re: OT - Patching a redwood water tank

Postby Lee » Sat Jul 31, 2004 11:06 pm

This may sound kinda strange, but could you make a threaded plug larger than the hole, drill and tap the hole and use a silicone based adhesive sealant to hold it in place after it's screwed in? If necessary, back it up with a stainless plate screwed a bit beyond the plug area with silicone behind it too. I'm with UnkaJesse on this one.... [img]/ubb/images/graemlins/grin.gif"%20alt="[/img] Anything but replacing the tank.
I always like to learn, but I don't always like to be taught.

PeteM

Re: OT - Patching a redwood water tank

Postby PeteM » Sun Aug 01, 2004 12:23 am

Thanks for the ideas. The tank has a permanent roof, and I don't have much time to fiddle with this right now, so I'll try a from-the-outside patch tomorrow. Let you know...

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oheider
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Re: OT - Patching a redwood water tank

Postby oheider » Sun Aug 01, 2004 2:08 am

Don't use silicone with potable water, it produces a toxic chemical (I fergit which one). Might not be a big issue in a large water tank, but I wouldn't do it.
Otto
Can make 2 pieces of metal from one piece. 'Most always.

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Steve_in_Mich
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Re: OT - Patching a redwood water tank

Postby Steve_in_Mich » Sun Aug 01, 2004 5:37 am

oheider do you have the source for your statement or did you forget that too. I did a search on "silicone with potable water" and find no such warning but rather several times the statement, "Silicone is the only sealant that should be used for potable water (cisterns.)."

Maybe you will enlighten me with some fact. TIA
Just because you don’t believe it - doesn’t mean it’s not so.

J Tiers

Re: OT - Patching a redwood water tank

Postby J Tiers » Sun Aug 01, 2004 9:12 am

[quote]oheider do you have the source for your statement. I did a search on "silicone with potable water" and find no such warning but rather several times the statement, "Silicone is the only sealant that should be used for potable water (cisterns.)."

Yep, that is my understanding also, silicone is fine.

The "only" part is weird, though. Ordinary pipe dope is obviously used on iron pipe in potable water systems, and counts as a "sealant".

The glues for plastic pipe (which I hate) are also full of toxics, and are used where plastic pipe is allowed ( not here).

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Michael_Az
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Re: OT - Patching a redwood water tank

Postby Michael_Az » Sun Aug 01, 2004 9:31 am

Silicone is a very popular material for surgeons to use in our bodys like valves for hearts. Remember when all the women complained the breast implants were making them sick? To my knowledge it could never be proven silicone was toxic to the body. The gals made some money though with their lawsuits.
Michael
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EdKay
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Re: OT - Patching a redwood water tank

Postby EdKay » Sun Aug 01, 2004 12:50 pm

Pete, just a thought, you might try Gorilla Glue. It needs moisture to set up, expands, and dries hard. I have used it to seal large cracks between floor and wall and it seems to do the job.
Good luck.
Ed

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len
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Re: OT - Patching a redwood water tank

Postby len » Sun Aug 01, 2004 5:13 pm

Most silicone cures by reacting with moisture in the air and releasing acetic acid (vinegar), so I wouldn't be too concerned about toxicity. The problem with acetic acid is that it can corrode copper, so they make a special silicone for electrical use. Fish don't like it either, so they make a special silicone for repairing fish tanks.

I don't think there's any safety issue here, unless you're a big fish in a small tank [img]/ubb/images/graemlins/smile.gif"%20alt="[/img].

len

PS. As Ed suggests, I think Gorilla glue will work nicely. It expands 3-to1 when it cures, so this would be good in sealing the cracks. It reacts with moisture to cure. The only issue I have with Gorilla glue is that it takes a couple of hours to set up, but this may not be an issue in your case.

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stevekunkee
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Re: OT - Patching a redwood water tank

Postby stevekunkee » Mon Aug 02, 2004 1:22 pm

Don't use screws or nails, SS or not. These will cause the wood to rot, yes, even redwood.
Steve


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