Help Advice....replacing an old galvanised water storage tank with a plastic one

REDLINE@

Hi folk’s

Just about to start a job and looking for a bit of info/help before I start.
I’m replacing an old galvanised water storage tank with a plastic one.
The tank connector’s which are ¾ compression don’t seem to come with any washers.

I might be wrong but I believe I need an inner rubber sealing washer and an outer plastic slip washer .is this right, and if It is does anyone know were I can pick up the inner black rubber ones I cant seem to locate them.

Also I have heard a few stories’ of tanks leaking because the hole for the tank connector was drilled slightly too big, even a couple of millimetre too big.

My plan is to cut the hole exactly and be nearly treading the tank connecter into the tank with ptfe tape.

But I can’t find a hole cutter saw that’s the right size they are either too small or too big. I think the outer tread size is around 26/27/or 28mm but I’m not sure….does anyone know the exact size.

I’m thinking a cone step cutter bit might work. But I vaguely recall using one some years ago on car plastic trim and that they had a tendency to move around a bit not giving a clean round hole. Again not to sure so if anyone knows if this will do.

Any help would be greatly appreciated

tomthumbe

REDLINE@ wrote: »

Hi folk’s

Just about to start a job and looking for a bit of info/help before I start.
I’m replacing an old galvanised water storage tank with a plastic one.
The tank connector’s which are ¾ compression don’t seem to come with any washers.

I might be wrong but I believe I need an inner rubber sealing washer and an outer plastic slip washer .is this right, and if It is does anyone know were I can pick up the inner black rubber ones I cant seem to locate them.

Also I have heard a few stories’ of tanks leaking because the hole for the tank connector was drilled slightly too big, even a couple of millimetre too big.

My plan is to cut the hole exactly and be nearly treading the tank connecter into the tank with ptfe tape.

But I can’t find a hole cutter saw that’s the right size they are either too small or too big. I think the outer tread size is around 26/27/or 28mm but I’m not sure….does anyone know the exact size.

I’m thinking a cone step cutter bit might work. But I vaguely recall using one some years ago on car plastic trim and that they had a tendency to move around a bit not giving a clean round hole. Again not to sure so if anyone knows if this will do.

Any help would be greatly appreciated

Hire a plumber

aujopimur

I installed 100's of storage tanks with just the white plastic washer on the inside, the holes in the tank were usually slightly larger than the connector.

JohnnieK

I take it the tank your replacing it with is longer than the original (should be) so the base will need to be extended. Dont forget your lid and jacket for it.

If the hole is too tight you will also get a little leak. (that sounds so wrong):D:D

Joey the lips

Make your life simple and make all the fittings into the tank down stairs.

Also dont dare use an angle grinder to cut the old one just push it aside

The washers that come with these fittings are usually rubber and ****e. Buy nylon ones and you will need a seal. Silicone will do nicely.

anthonyos

Joey the lips wrote: »

Make your life simple and make all the fittings into the tank down stairs.

Also dont dare use an angle grinder to cut the old one just push it aside

The washers that come with these fittings are usually rubber and ****e. Buy nylon ones and you will need a seal. Silicone will do nicely.

silicone as a seal on tank connectors is not what id call a permanent solution to sealing them considering the life span of a tank could be 30 plus years ..nylon washers are the only job

Calibos

Joey the lips wrote: »

Make your life simple and make all the fittings into the tank down stairs.

Also dont dare use an angle grinder to cut the old one just push it aside

The washers that come with these fittings are usually rubber and ****e. Buy nylon ones and you will need a seal. Silicone will do nicely.

Presumably because of the excessive quantities of sparks. What about a Jigsaw with a metal cutting blade? I've an old tank I'd like to get out of an attic before I insulate and floor it.

Joey the lips

anthonyos wrote: »

silicone as a seal on tank connectors is not what id call a permanent solution to sealing them considering the life span of a tank could be 30 plus years ..nylon washers are the only job

Says who on the silicone?

Most lads only use nylon washers but diyers generally use bose white which is a no no so given the choice silicone smudged on the washers will be fine.

Additionally most water if the fitting is fitted correctly will never actually get near the seal on the tank connector. Its the tank connectors for the shower and taps that will be important and considering these will be subject to a lot of movement and covered in water a silicone seal around the washers will be fine. Just dont use cheap silicone. Use a netural non fungal silicone and there will be no need to use silicone on the inside tank washer just the outside one.

Additionally ensure the fittings are high enough off the bottom to ensure no silt travels down the pipes. If it were me i would buy a hollowed out 350 for the shower feed and push copper about 2" into the tank through it.

But to be honest. Each to there own. The attaching the hydrodare to the tank fitting at mains pressure will be the real test.

DoneDL

Calibos wrote: »

Presumably because of the excessive quantities of sparks. What about a Jigsaw with a metal cutting blade? I've an old tank I'd like to get out of an attic before I insulate and floor it.

Jigsaw will do it but a Sabre saw is quicker and easier.