Oh no... I just replaced head sanitation hose

[Pandor]

Any suggestions would be appreciated. I just spent a whole day replacing the old permeated sanitation hose on my head. I thought that removing the old hose from the fittings would be the hardest part. But it was surprisingly easy. Too easy in fact. After I removed it, I realized that the fittings on my 30 year old French boat appear to be metric rather than the standard 1.5" fittings I expected.

At any rate, I had already bought and cut to size Dometic OderSafe hosing for replacing it. This is the hard and stiff PVC type. So, I forged ahead hoping that I could clamp the hose tight enough with hose clamps so that it would seal. The metric fittings seem just shy of 1.5 inches.

But no, after struggling for hours to make the runs and attach the clamps, I opened the throughhull only to find a rush of water. I tried tightening down some more, but in the end I stemmed but did not prevent the leaking.

So do I have any options besides ripping out all of the new hose and going for something more pliable? I can't replace the fittings because they are integral to the system I have.

I was wondering if anyone else has somehow made 1.5" PVC fit metric fittings either by heating and clamping or by using some sort of wrap for the barbs?

[DefinitelyMe]

Either would probably work. I've used heat-shrink tubing to increase the diameter of barbs before. Much neater than wrapping the barb in electrical tape.

That hard PVC hose also responds well to heat from a heat gun, though I've never tried it to get it to fit a smaller barb; I'm usually trying to get it to fit a larger one.

[Capt Clark]

Pandor,

Been there, a heat gun is your best friend. Remove the hose and heat the end until it’s fairly soft and slide on & squeeze all around. Good luck

Capt Clark

[Fore and Aft]

Pandor here in Australia we have some cheap clear plastic hose with different diameters. I have successfully cut an inch or two of that hose and slid it over a wrong size fitting then put the larger size hose over it afterwards.
Cheers

[donradcliffe]

Electrical tape smeared with silicone. Worked well for me. Wait a day before you open the valves.

[Allied39]

Better than a heat gun is boiling water. Super hot boiling water heats evenly inside and out and also gives better control over how far the hose is heated.
So if you have it all prepped, put super hot boiling water in a cup and put the hose end in the cup for a minute or so, push onto barb and clamp quick you will likely be fine.
If not you are to far off in dimensions.

[Stu Jackson]

Originally Posted by Fore and Aft

Pandor here in Australia we have some cheap clear plastic hose with different diameters. I have successfully cut an inch or two of that hose and slid it over a wrong size fitting then put the larger size hose over it afterwards.
Cheers

Somebody I know (i.e., the OEM!!!) or PO !!!, did that on the hose from my rw pump to the HX. Worked fine for 10 years before I found it! Good idea, good luck to you.

[PerfectPirate]

Try softening up the hose with either the boiling hot water or the heat gun and then clamping it on. But, and here's the kicker, DO NOT use the regular worm-style of hose clamp. You know, the ones with the endless screw that goes into the grooves cut into the band of the clamp. If you are having sealing problems, these are inadequate. Instead, get some of the "T-Bolt" style hose clamps, which allow for a much greater clamping pressure. I have also used the grey butyl caulking tape to supplement the seal, but the better kind of clamps are the important part. Be careful not to tighten to the point of damaging your fittings.

[ttex]

You can use ptfe tape to make the nipple bigger. It will seal. Put some silicone lube on so the pvc pipe slides over the tape instead of dragging and bunching it.

[Pandor]

Thank you all for the replies. I forgot to mention a few things. The idea of slipping another hose in between the barb and the Dometic hose won’t work in this case because the size difference is too small. Unless it was a thin gasket type hose made for the purpose.

I think that heating with boiling water may be the easiest option. My only concern with that is the fittings on the tank and y valve are black polyethylene. I imagine they will be fine with the hot hose clamped on, but I’d hate for them to soften as well.

I’ll give this a try later this week unless anyone has some bad experiences with this that they’d like to share.

I did order some better hose clamps. So that might help.

[hpeer]

There is self fusing silicone tape sold under a lot of names but often called “Rescue Tape”.

I am not wild about this idea, the tape does not tolerate petroleum products well.

Clean the barb very well and apply the tape. It is important to stretch it to 1/2 its on roll width. It will shortly fuse into a solid mass. I would apply it to the entire barb with it tapering so that it is slightly thicker toward the end of the barb.

I have used this tape on household pressurized water lines and it held. This way you can build up exactly the tight diameter. It is also very resistant to heat, so you can build a little thick and then heat the hose to expand and slide over it.

Just keep any oils out of the system.

I presume you are trying to go into a through hull fitting?

Is it brass, bronze, marlon?

Is it time to change your through hulls anyway? I know you say you cant replace because they are integral to your system. Just asking to make sure the “system” is still safe.

[Pandor]

The through hull is bronze. But the other end of the hose has fittings (y valve and tank connections) made of black plastic. Probably polyethylene.

I am going to try heating the pvc with water first. I think the tape might make it difficult to reconnect the hose.

[hpeer]

Pandor,

Good luck.

I am a bit skeptical of heating the hose to make it fit on a LOOSE connection. Tight sure. Loose?

But you have nothing to loose. I would try it on a bit of scrap hose first.

Ditto my tape solution. Try it with some scrap hose if you have any.

I just redid all my sanitation hose and valving so I feel your pain.

Again, good luck.

[peghall]

Unless I'm misunderstanding the problem, 1.5" hose is too LARGE to fit tightly on the fitting. If so, I don't think heating it or a more flexible hose will make it fit any tighter. Wrapping the fitting with tape makes a lot more sense. Heating 1" hose might stretch it enough, but that runs the risk that the hose will develop tears in it. We saw that happen in the late '80s and early 90s when domestic gray PVC 1.5" fittings that are nominally 1.5" thread x 1.5" barb, but actually 1.5" thread x 1.5/8" barb were common because no one in the marine industry realized that some sizes of domestic fittings use the OD for the threaded end and the ID for the barb end. People were way over-heating the hose to make it fit.



--Peggie

[Pandor]

Thanks for your thoughts. The heating of the hose isn’t going to shrink it. It should hopefully make it pliable enough for the clamps to be able to compress it and get a snug fit.

But as hpeer says, I don’t have anything to lose by trying. Except a little more time.

Peggy, soft rubber hose would definitely work. That is what was on there to start. The fittings aren’t that much undersized. The hose clamps snugged the old stuff right down on the fittings.

I’m away from the boat until the weekend. But I’ll report back whether I’m successful or not.