Epoxy coating the water tanks

[POG]

With reference to my earlier query about water filters I am copying some of the text from it below and then proceeding to a fuller description of my water tank epoxying project:

"The summer of 2010 I spent 22 days struggling to open my water tanks, sand and clean, repair loose baffles and coat with "Brewcoat" - a solvent free epoxy coating approved by the FDA for food and water storage tanks - and then glassing the tanks closed again.  This epoxy coating was truly the concoction from hell to work with, like trying to paint with thick molasses.  While I was at it I also cut off the forward part of the bow tank at the baffle plate and rebuilt it as a smaller tank using the plate as the forward wall.  I did this to get my 100 feet of 3/8" chain further aft, instead of right up at the bow.

When I was finished I was so sure I would now have water of spring-like quality that I removed the water filter that was in place in the galley sink cabinet.  No such luck.  The result of all my work is a disappointment and the filter is coming back on again."

The "Brewcoat" is made and sold by a company in Seattle.  I was assured by the lady in the office that this was exactly the right stuff to put over my grotty and somewhat blistered tank gelcoat.  One gallon of hardener and one gallon of white epoxy (min quantity sold) plus a couple of very short nap mohair rollers cost me $200 and some.  It was explained to me that the rollers were the only thing that would work in the application as the concoction when mixed would be very stiff and thick.  They were right about that!  To get to the narrow spaces where the roller would not go I had to cut  the bristle of a brush down to just a short stub to be able to push the mix in place.  I actually added micro balloons to the mixture to make it more like putty for those hard to get to spots.

After I had opened the tanks I cleaned and let them thoroughly dry and then sanded and cleaned up with MEK.  The Brewcoat instruction is to first roll on a thin coat and follow when it has become tacky with a thicker application.  This may very well be the worst paint related job I have ever attempted but in the end I was pretty happy with the result and glassed my cut outs back in place.

After letting the epoxy set I first filled just the bow tank.  After a couple of weeks  I discovered blackish, filmy slime threads floating about in the tank and accumulating at the bottom.  The tank sides above the water level also felt positively slimy.  The same thing happened to the salon tanks when they had been filled for a while.

The Brewcoat lady had no explanation.  I went to the offices of my local water district and was told by an expert that they had had problems with some epoxy coated storage tanks themselves.

As I suspected the water connection to my rented private dock might siphon in dirty harbor water I emptied the tanks and made a long connection to the owner's house tap and filled from that.  The result has been somewhat better.  Less stuff floating about and the color of it has become a more cheerful pale orange.

In spite of the manufacturer's claim that the Brewcoat is FDA approved for food and beverage storage the plastic taste of my water is prominent after a short time in the tanks.

All in all I will certainly not call this project a shining success.  My solution for now will be to chlorinate my tank water to kill bad stuff and try to remove the awful taste with a charcoal filter.  Anyone else should think twice about the procedure.  Though there might be room for some doubt I would be wary of the Brewcoat coating.

I will now try to attach some pictures.

Carl


One of two cut outs in starboard tank.  Note cut away front part of forward water tank and mark left by loose baffle.



Brewcoat applied - Baffle in place.  Repair patches waiting to be coated.



Three openings in port tank.




Restoration under way with fiberglass Bondo



Restoration complete.




Forward water tank cut down and rebuilt around baffle.



Brewcoat applied.  Note new PVC filler tube connection.



Ps:  These pictures are dedicated to Dale Tanski who falsely accused me of buying a "Bristol" yacht and pretending to be working on it...  Carl

 

[Leo]

My tanks were a mess so I had new stainless ones made that fit inside the fiberglass tanks once I cut the tops off. The only problem I had is that they are made with I think 10 gauge metal. The top would flex a bit when full so I had to stiffen the area around the new inspection ports. If I were to do it again I would have them made of a thicker stainless or have some stiffeners to keep the flex under control.

[POG]

After 6,100 miles of sailing across the Pacific I am happy to report that the use of a 5 micron charcoal filter turns the water in my tanks into spring water.  It was all worth the hours.

Carl

[P69]

Has anyone been opened their water tanks like POG did and been able to close them up  with something that can be easily remove for future cleaning?  Maybe somekind of 12" x 14" or so water tight hatch, one for each baffled section?

Thanks