Drilling two scary holes today - any tips?

[FoxtrotOscar]

Hi all

Today I'm drilling a hole in the plastic cold water cistern in the attic as well as a hole in the dhw copper cylinder in the airing cupboard.

This frankly terrifies me...so can you share you tips about how not to **** it up please?

I.e. drill bit to use, how fast to drill, any other tips.

The hot cistern cut is to fit an Essex flange (well, a techflange side entry). The Essex is supplied with the appropriate holesaw, but it would still be great to get advice on RPM and any other tactics to reduce my chance of calling this up.

The background is that I'm fixing a bodged shower pump installation, the installer teed off inappropriate places rather than running dedicated feeds. I'm guessing his was cause he didn't fancy drilling cisterns either!

Many thanks, much appreciated.

 

[lightning]

Wouldn't fit an essex flange, your best bet is to fit a surrey flange

 

[bengasman]

The plastic one is easy, melt it out with something hot.

 

[FoxtrotOscar]

Essex will actually be easier as the top pipe connection is old and stiff. Installers only favour Surrey because they're scared of making an expensive mistake, like me . Surrey is actually inferior, because it shares the take off with other DHW outlets and increases the chance of the pump sucking in air.

But anyway, please let's not turn this into a debate of Surrey vs. Essex vs. Warix etc....I'd just like some tips about drilling holes please .

This is that actual product I'll be using:

As you can see it arrives pre-bent so as to grab the water from the hottest possible space of the cistern.

 

[sooey]

Just take your time, it's a doddle. It's only a thin copper wall, the holesaw will go through it no bother. Obviously drill a pilot hole first.

 

[FoxtrotOscar]

The plastic one is easy, melt it out with something hot.

Melting curls up the edges does it not? I need it perfectly flush.

 

[45yearsagasman]

Use a hole saw with a pilot drill and don't go full speed.Perfectly ok for both copper and plastic.Done loads with no problems.

 

[picasso]

If I am the least bit unsure (or the thing I am cutting is very expensive) I do a test cut into a bit of scrap ply and assemble what ever it is your fitting, if all goes well on the scrap it gives you the confidence to do it on the "real "thing,

believe me there cant be much worse than completly f00king up what should be a simple job, there cant be many on here that havent had that sinking feeling in their stomach as they realize they have dropped a clanger, on that positive note good luck.

 

[leakydave]

I have avoided fitting an Essex flange in the years I have been in Plumbing. I remember being shown how to hold a back nut type thing in place with a bit of wire and frankly it scares me. If it fell to the bottom of the cylinder you are screwed!

In theory it must be simple but I have taken out numerous cylinders that are so scaled up that it must be possible to not get a water tight seal.

It's better if the cylinder you are working on is raised above floor level so at least you can get a paint tray underneath to catch drips!

Post on here how you got on. Good Luck!

 

[joinerjohn]

The only advice I could possibly give, is to make sure the DHW cylinder is drained before you start to drill any holes in it.

 

[FoxtrotOscar]

Thanks guys.

It is an old cylinder but if it's so badly scaled that it won't seal on the inside, it's due replacing anyway .

joinerjohn - yep, got the hose pipe ready. Luckily there's a drain cock.

Quick question - should I fit a ball valve right next to the cold cistern outlet? Or just one where it comes down to the airing cupboard? Or both?!

 

[Agile]

Any cheap hole saw will work on plastic but use a slower speed so you remain in charge.

On the cylinder, to avoid sideways wander I would ensure the drill shank is plain at the saw blade point or use a plain rod. Again use a not too fast speed and hold the drill VERY firmly when its about to go through to avoid tearing the copper.

Tony

 

[misterdubya]

Personally, I would not use anything hot for the plastic tank, as it can leave the plastic around the hole brittle & prone to cracking.

Fitting an Essex Flange - be patient.

Mr. W.

 

[Farmacist]

there should be no need to fit any flange to the HWT, just tee off the hot water outlet and fetch the pipe stright down to the pump. For info look at stuart turner or salamanda web sites. I have a 3.5 bar ST pump like this and it gets all the hot water it needs.

 

[echoes]

I'm no expert, but I did fit my first Essex flange last weekend.

Remove enough insulation from your tank witha sharp stanley knife to enable you to get your fingers in to manoevre the split copper washer in place. About hold diameter + 1/2" should be OK.

Make sure your drilling point is not close to the seam of the cylinder, so that the washers will tighten up where the tank is smooth.

Drill a small pilot hole.

Hold the drill nice and firmly when drilling the main cut out, use a slowish speed. Be patient. When you're nearly through, angle the tip very slightly upwards and then the disc of copper should fall back towards the drill rather than fall inside the cylinder like mine did.

When poking the fitting through your hole, attach something firmly to it to prevent it from falling through when you feed the internal washers through, and put the external washers & nut on, or make sure you don't let go.
This is the fiddliest part - you may need both hands to feed the internal washers through, so something/someone needs to keep a grip on the rest of the fitting.
Maybe secure a piece of stout string to the fitting with lots of tape, just in case, or put a compression T-piece on the external open end temporarily that's too big to pass through the hole in the cylinder.
I used a mole-wrench on the end of my Essex flange's wire following some advice on here.

Good luck!