Fiber Glass over S.S. Tanks.

[Krogensailor]

Thought exercise. If one has pinholes, or rusting seams in S.S. tanks, and the tanks are easy enough to remove, What about glassing over the tanks? I have applied fiberglass over metal many times. Use a good etching solution, coat with epoxy, let it kick. When it has just become tack free to the touch, lay the glass and wet out. I'm thinking the tops would not require glassing. Add coats to fill the weave every three or four hours. Following day glass tape the seams. S.S. is very stable with regard's to expansion and shrinkage, compared to wood. I don't have leaking tanks, as of yet. I'm restoring a Krogen 38 cutter, and haven't gotten to that system as yet. No leaks currently. The tanks are thirty years old and I suspect something will show up at some point. I think glassing the tanks might be an interesting possibility. What say you? Second thought. What if one uses 1/8" S.S. sheet cut to cover each side and bottom then weld the seams sheathing the whole tank. Re-skin the tanks, sides and bottom. The tops generally don't rust or leak. I'm interested in others thoughts.

[mike d.]

I would question the difference in expansion rate of the epoxy verses the S.S. and then the difference between the Glass resin and the epoxy. My other thought is why not take the tanks out wash them then take them to a welder and let them give the tanks the once over and fix what needs to be fixed. Peace of Mind!?

[Cheechako]

SS needs to breathe.. enclosing it is the worst of all cases... unless you can somehow guarantee no condensation or moisture will ever get in there. If it does, it can take as little as a couple years to make a hole. If you do enclose it, do it all to avoid the moisture.
If they are readily removeable, have a new bottom, side or other panel welded on where the hole is. This is often done.
Are they in the bilge? If not where they are moist, they may be fine for a long time. If in the bilge, they are likely due for replacement.

[David M]

Eventually the glass will delaminate from the stainless where there are leaks.

Don't mess around. Replace the stainless tank with high density polyethylene when it comes time to replace the tanks.

[ryon]

I agree with Cheechako. The reason stainless doesn't corrode is because it DOES corrode, just a little bit. When exposed to air, an oxide coating forms, protecting the metal beneath. If you cut off that reaction, the metal is left open to corrosion.

[Nor'Sea 27]

David M is right. SS as part of any tank construction is foolish. (ABYC limits stainless tanks to 20 gallons max. for example) However, the potential for failure justifies a much greater limitation. Aluminum is better but second worst.

These metals survive only if they are completely isolated from water, surrounded by plenty of ventilation, and painted with no possibility of paint coating being damaged. Meeting these standards is virtually impossible.

Choose plastic, aluminum, stainless in that order. If metal is chosen the tank surfaces and the tank mounts and supports must be kept bone dry.

Charles

ps Remember - some amount of water inside the tank is impossible to avoid.

[minaret]

Read my Nauticat 52 refit thread for the run down on my approach to this. I put a lot of thought into it and it came out really nice. Totally more than worth doing in the case of tanks which are too big to easily remove. Superior product for much less money, totally DIY doable.

[nimblemotors]

cut them apart check the metal replace if needed and weld back together,
good as new to last another 20 years.

Or you might get a bladder to put inside.

[JPA Cate]

To the OP:

If you want to look at Minaret's tank replacement scheme, first find his thread, then go to p. 20. It starts with post #287, dated 04-03-13. The whole thread is interesting, with many pix. Minaret also recommends against bladders.

Our experience with bladders was pretty discouraging, as well.

Ann

[RaymondR]

For a short term fix drill the pin holes and put in closed SS blind rivets with a good gasket compound to get a seal, could outlast the boat.

[cszosler]

[QUOTE

Don't mess around. Replace the stainless tank with high density polyethylene when it comes time to replace the tanks.[/QUOTE]

polyethylene is "rotamolded". it means amount of this is poured into female mould. then mould is " rotated" to "evenly" coat interia of the mould (fingers crossed). after cooling mold is split and it is done .
after you did removed your s/s tank, pour "calculated-estimated" amount of food grade epoxy inside and rotate (fingers crossed). epoxy without glass is no match to poly as far as strength, so you leave s/s tank on and be not bothered by rust any more.
this is what I would do if epoxy cost is less than new tank.

[nimblemotors]

Originally Posted by Ann T. Cate

To the OP:

If you want to look at Minaret's tank replacement scheme, first find his thread, then go to p. 20. It starts with post #287, dated 04-03-13. The whole thread is interesting, with many pix. Minaret also recommends against bladders.

Our experience with bladders was pretty discouraging, as well.

Ann

What problem did you have with bladders?

[ranger58sb]

Originally Posted by Krogensailor

Thought exercise. If one has pinholes, or rusting seams in S.S. tanks, and the tanks are easy enough to remove, What about glassing over the tanks? I have applied fiberglass over metal many times. Use a good etching solution, coat with epoxy, let it kick. When it has just become tack free to the touch, lay the glass and wet out. I'm thinking the tops would not require glassing. Add coats to fill the weave every three or four hours. Following day glass tape the seams. S.S. is very stable with regard's to expansion and shrinkage, compared to wood. I don't have leaking tanks, as of yet. I'm restoring a Krogen 38 cutter, and haven't gotten to that system as yet. No leaks currently. The tanks are thirty years old and I suspect something will show up at some point. I think glassing the tanks might be an interesting possibility. What say you? Second thought. What if one uses 1/8" S.S. sheet cut to cover each side and bottom then weld the seams sheathing the whole tank. Re-skin the tanks, sides and bottom. The tops generally don't rust or leak. I'm interested in others thoughts.

If the tanks are easy to remove, they're easy to replace.

-Chris