Plastimo Water Bladder - Wish I never bought one...

Agh. A month ago I had the bright idea of replacing a perfectly good water bladder that was just old..... but working fine.

I picked up a Plastimo water bladder from Whitworths. Instantly when I went to install it I thought "jeepers these fittings dont seem too practical". Basically the hose fittings completely rely on an o-ring to make the seal with the bladder. This also means thread tape or some other sealant cannot be used. Very different fittings to the previous bladder.

I installed it. Filled it with a small amount of water. It leaked. I drained it. Reinstalled the fittings. Filled it. It leaked. Tried just tightening. It was still leaking the next day. Going a little mad at this stage. Drained it again. Retried the fittings. Filled it. It still leaked.

Then when I was in Whitworths I asked for some tips but they were not so familiar with the fittings (which is understandable, I dont expect them to know anything). But they said "look if you cannot get it to work just bring it back".

So I drained it. Retried. Filled it. It leaked.

So I took it back to Whitworths (which meant draining it, making a mess etc) but the original person wasnt there and was met with a "huh? I can send it off for warranty but it doesnt look like there is anything wrong with it so they will just send it back" response.... And that is exactly what happened. A week later it comes back with a note saying there is nothing wrong with it. My hose ends were still attached to the fittings so they must have used there own fittings if they tested it (that makes sense as you can visually inspect these for any damage).

They did recommend trying to attach the fittings while its uninstalled to be sure to set them correctly. I did this. This then makes it very difficult to get the hoses onto the fittings without feeling like you are going to damage the bladder.

Reinstall. Refill....... and it leaks..... but less than before. But still it leaks and will rot the wood. But after probably 5 or 6 hours of stuffing around I give up.

In a few months I will throw it in the bin and buy another bladder!

Select to expand quote

ReefMagnet said..
Try coating the O rings in food grade silicon grease. That may help.

I did try detergent without success. I may try the silicon grease in the future.... Thanks for the tip

Why buy a bladder? After similar issues on my mother's boat 30 years ago I build my watertanks out of plywood and multiple coats of epoxy. You get more water in the available space and no leaks. Also an integrated tank gives the boat more areas where the hull can be punctured and no sea water comes in.
Look up the Gougeon brothers but basically you make a box out of ply, and epoxy coat the heck out of it. Put baffles in and an inspection hatch too if wanted. My cat is 20 years old this year and I have never had a leak from her tanks. Plus I get much more volume in the tank than any bladder tank would give, and it drains right down to the dregs.

Select to expand quote

cisco said..
I have a 100L Plastimo tank which came with the boat. It has been trouble free so far.
Originally it was located in the fore peak (less than optimal location) but I removed it and relocated it port midships opposite the 100L Float Pac tank on the stbd side.

I did completely pull the Plastimo apart, wash it out, reassemble and reinstall it. I had some doubts about it but it has been OK.

I think it best to leave the O rings dry rather than lubricate them. Lubrication will tend to make it easy for the O rings to slide and distort when tightening the fittings.

It's common engineering practice to lubricate O-ring seals. In fact, Bunnings will have just such a lubricant available within their plumbing section. It may be a lanolin based product though.

Select to expand quote

Jolene said..

jbarnes85 said..

ReefMagnet said..
Try coating the O rings in food grade silicon grease. That may help.

I did try detergent without success. I may try the silicon grease in the future.... Thanks for the tip

A single O ring is capable of sealing Great pressure. Have a close look at the fitting and find what is stopping the ring from doing its job,,, that is, if it is the O ring that is leaking.
There may be another cause

Correct. They're susceptible to leaking when against a sealing surface that has even reasonably minor irregularities though, and in a low pressure situation the grease can make the difference between a seal and a leak. Over the years I've always lubricated new and replacement O-ring seals in just about every application I've used them in without detriment.

I was prompted to check out a photo of a bladder and noticed that the hose connects via what looks to be a threaded or bayonet style fitting. In a tight space and pushing against a wobbly surface, these can be a PITA to get right, especially threaded which are way too easy to cross-thread. I'd also not discount the hose to tail connection or even the mounting of the outlet and inlet fittings to the PVC bladder material, as it can be hard to determine the actual origin of a leak.