That Darn PO!! - Page 2

JimsCAL · #11 10-19-2012

You can put in a new fitting using a fitting relocation kit.

Marine Water Tank Fittings | Marine Holding Tank Fittings

SloopJonB · #12 10-19-2012

Since it's plastic tank & plastic fitting and it's water, not fuel (or holding

) I'd at least TRY gluing/sealing it in place first. Modern adhesives can be quite remarkable. A tank manufacturer should be able to tell you what will stick to it (3M 5200?)

What's the worst that can happen? - You're back where you started.

BubbleheadMd · #13 10-19-2012

Quote:

Originally Posted by SloopJonB

Since it's plastic tank & plastic fitting and it's water, not fuel (or holding

) I'd at least TRY gluing/sealing it in place first. Modern adhesives can be quite remarkable. A tank manufacturer should be able to tell you what will stick to it (3M 5200?)

What's the worst that can happen? - You're back where you started.

You could poison yourself with the wrong kind of adhesive. That's one thing the OP (not to be confused with PO) said he was worried about.

SloopJonB · #14 10-19-2012

Quote:

Originally Posted by BubbleheadMd

You could poison yourself with the wrong kind of adhesive. That's one thing the OP (not to be confused with PO) said he was worried about.

That's why I referenced the (or a) tank manufacturer for their recommendations.

Minnewaska · #15 10-19-2012

Quote:

Originally Posted by BubbleheadMd

You could poison yourself with the wrong kind of adhesive. That's one thing the OP (not to be confused with PO) said he was worried about.

I respect this point, but have to admit that I think it can be controlled or minimized to insignificant.

Capt Len · #16 10-19-2012

Not much bonds to polyethylene . If removal of tank is not on your list , is it possible to cut an access hatch in the top and install a gasketed thruhull in the problem spot. Neoprene gasket and self tapping screws to a piece of cutting board.to seal the top. Lots of ways to skin cats but re/re still the best fix.

GaryHLucas · #17 10-19-2012

I work with poly tanks a lot, including the Ronco's. I install fittings up to 12" in tanks up to 12,500 gallons, thats 142" diameter x 16 feet tall! Currently working on a job with 6 12,500 gallon tanks, one 900 gallon, and four 65 gallon, all of which we will install about 30 fittings into.

If the tank doesn't have an inspection port, now is the time to install one. Once you have a port big enough for the flange of a bulkhead fitting to pass through you are all set. All you have to do is trim the spin welded fitting off flush with the outside of the tank using a coarse hacksaw blade. Then enlarge the hole to take the neck of the bulkhead fitting. Use a tape measure to reach across the tank to the hole, and slide the bulkhead down the tape measure into the hole from the inside. Don't forget the gasket! Then install the nut on the outside, and your tank is now better than new, because that bulkhead is removable and replaceable if it gets damaged, unlike the spinweld fitting.

Look at Hayward or Spears bulkheads, and get the EPDM gasket for potable water. Buna is fine too.

Gary H. Lucas

dacap06 · #18 10-20-2012

Folks, thanks for your many replies. The knowledge of sailnetters is truly fantastic. I see some great advice here, and a couple of real jewels for my particular situation.

I was not aware that spin welding was a common capability. Thanks for that. Having a local firm spin weld a new fitting on the tank is greatly preferable. A special shout-out goes to Bubblehead, who gave me a firm name in Annapolis! That's less than an hour's drive from the boat. That's what I will do over the winter when I have the boat hauled in Nov.

Other techniques you mention would be equally valid but don't really work for my configuration. I do not want to permanently attach the valve with, say 5200 or epoxy as I have almost no clearance and I'd then have to disassemble the settee and knock out a tabbed bulkhead, or else ruin the tank, to remove it. Trying Teflon tape is a good idea and I already did that -- I used plumber's tape to try sealing the valve. I cannot relocate the valve. It is attached the the lowest point of a roughly triangular tank side. I'd end up with water I could not remove except by manual pump through the tank access, and I would need to cut a new hole in a tabbed bulkhead to put it in.

Regards,

Tom

hellosailor · #19 10-20-2012

Tom, there are compression fittings that are designed to be installed in plastic tanks. No glue, no welding, no threading needed.

I think the link that Jimscal provided is for that type of fitting, we used to use them on chemical storage tanks and they are 100% reliable.

If you think of a plastic miushroom, with a hole running up the center of the stem and through the head? The head of the mushroom has a gasket (often a large flat gasket) under it. You put the mushroom inside the tank, pushing the "stem" through the hole in the tank wall. Then a similar gasket, washer, nut, are screwed onto the part of the 'stem" that is outside of the tank. Snug down the nut, and the tank wall is captured between the two gaskets and there's a 100% seal. Now just put your hose over the end of the stem, clamp it on, you're in business.

No need to pull the tank, just put the new fitting in the old hole, drill or ream the hole as necessary to get the sizes to match.

This is pretty much exactly the same as installing a through-hull in the hull of your boat, if you can't find plastic tank fittings, look for a small marelon through-hull and see what you can adapt from there. The tank kits will have gasket sets, etc, the through-hull will require a little more parts shopping, either way, no big deal, no need to pull the tank!

SJ34 · #20 10-20-2012

My vote would be for the suggestion to tap the outlet for the next size up NPT fitting. If the current size is 1/2 then go to 5/8, if 5/8 then up to 3/4 and so on.

This would be the cheapest and easiest fix and if for some reason it didn't work it wouldn't eliminate the other fixes.