Aluminum Water Tank Repair

[Brantleysdad]

Hi Everyone, first post here. Long time Lurker.

I bought a 1975 Columbia 9.6 recently.

I knew the water tanks where bad, lots of holes from where the baffles where welded in. Anyway I have a buddy that does aluminum welding for a living fixing the holes.

I want to paint the interior of the tanks with a potable water safe epoxy, lots of different price points for this stuff but found the Rust Oleum 2 part locally and relatively inexpensive.

Anyway I need to add some access panels to the top so I get my hand inside to clean it up and apply the paint. Anyone have a inexpensive source for access hole covers?

Thanks

[David M]

I use Interlux 2000 or Interlux 3000 as my epoxy of choice for coating aluminum. You will want to check with Interlux to see if after curing that they recommend it for potable water applications. You obviously want to make sure that it does not leech any chemicals into the water after curing. The same is true if you choose to use the Rustoleum.

The alternative to the aluminum tanks would be to consider replacing them with high density polyurethane (HDPE) tanks, which are truly inert. These can be obtained in standard factory sizes or custom sizes.

[Brantleysdad]

Originally Posted by David M

I use Interlux 2000 or Interlux 3000 as my epoxy of choice for coating aluminum. You will want to check with Interlux to see if after curing that they recommend it for potable water applications.

Thanks David, I did find this stuff for lining the tanks and is Potable safe for drinking water. High Performance - W9200 System Potable Water Coating

What I am trying to source is some sort of cover so when I cut the access holes I seal it back up.
I did find these TC TANK CLEANOUT COVERS | Lenz

[HopCar]

I agree with David. Replace them with plastic tanks. Check out Ronco.Plastic Tanks. They sell about five hundred sizes and shapes of tanks.

Oh yeah, Welcome Aboard!

[model 10]

The usual way to coat the inside of a tank is to slosh seal it. Much easier and probably a more complete coating. You are almost bound to miss a spot if you try and do it with a brush. Another way is do the brush work and then slosh it. You won't need any big access holes if you just slosh it.
I'm not sure how it tastes but a product called "Kreem", looks and works well. I have used it on aluminum fuel and water tanks with no problems. It's some sort of fast drying ceramic liquid.

[CSY Man]

West System epoxy is food-grade when cured.
Coated my water with it, works great, last a long time.

[Brantleysdad]

Originally Posted by Guy

The usual way to coat the inside of a tank is to slosh seal it. Much easier and probably a more complete coating. You are almost bound to miss a spot if you try and do it with a brush. Another way is do the brush work and then slosh it. You won't need any big access holes if you just slosh it.
I'm not sure how it tastes but a product called "Kreem", looks and works well. I have used it on aluminum fuel and water tanks with no problems. It's some sort of fast drying ceramic liquid.

This sounds like a great solution, you used on a potable water tank?

[Cheechako]

The custom plastic tanks are pretty reasonable priced. Worth a look I think.

[CSY Man]

.
This sounds like a great solution, you used on a potable water tank?

Yes, a 157 gallon glass fiber/gelcoat built in tank on my CSY 33.
Took 6 weeks to complete the operation.
Small inspection ports, had to sand bad gelcoat away, with one hand while laying on my belly on the floor boards, then vacuum, sand more..
Slowly but surely, one little area at the time.
Then acetone wash the inside of the tank, slowly but surely.
Then start coating using brushes "on a stick", mirrors, whatever to make sure I got every corner. Then do it again for a second coat.
6 weeks with an hour or two a day and a few days off.
(good thing I did not pay me by the hour, I would be broke)
The final result was great, no smell or taste of the water.

[model 10]

Like I said, I don't know how it tastes. If I were to guess, given how the surface looks, I would say it's OK. It's not like it's the only product for slosh sealing. It's just the only one I've used that has a chance of not tasting like PolySulfide sealant or something.
A quick call to Kreem will settle the question.

[Nicholson58]

Originally Posted by Brantleysdad

Hi Everyone, first post here. Long time Lurker.

I bought a 1975 Columbia 9.6 recently.

I knew the water tanks where bad, lots of holes from where the baffles where welded in. Anyway I have a buddy that does aluminum welding for a living fixing the holes.

I want to paint the interior of the tanks with a potable water safe epoxy, lots of different price points for this stuff but found the Rust Oleum 2 part locally and relatively inexpensive.

Anyway I need to add some access panels to the top so I get my hand inside to clean it up and apply the paint. Anyone have a inexpensive source for access hole covers?

Thanks

On the paint, take a look at Sherwin Williams in one of their own stores. They sell two versions of water tank water-proofing 2-part epoxy. I use the white for the inside of the hull in all lockers, bilge etc. One is fast and the other is ludicrous fast. Mix in small cups only as much as you can handle in about 15 minutes. It can be slowed with thinner.

For covers, you could use 6061T6 aluminum. Easily available in sheet/plate from many metal suppliers. Also, check McMaster Carr. You might also use epoxy fiberglass sheet G2. Have your friend make sure there is a heavy strip all around the ports to tap into. With aluminum, use larger taps than you think necessary. The problem is galvanic coupling with SS screws. You could use aluminum or plastic fasteners (also McMaster)


New tanks might be in order. Plastic as others have mentioned or custom SS.

[Paul Mazza]

You should make sure the paint is NSF 61 certified for drinking water contact. It's the drinking water standard in the United States. Not only is the product tested for hazards, the factories have to be inspected and approved for quality control. Water tanks are especially sensitive to contamination because the water can sit and have contact with the coating for long periods of time. I dealt with this issue many times in my 36 year drinking water career. Good luck.