Drilling a hole in an immersion tank.

[Stevex]

I checked where to fit my essex flanges for the recirc pump after looking into the water tank.
The hole cutter I have is in the pic. Are the teeth too coarse for thin copper?
Anyone cut into a hot water copper tank? What sort of hole cutter did you use?
Thanks.

 

[exedon2]

I would personally use one with smaller teeth probably a starrett.

 

[snowhead]

If you've never used a hole saw before, then practice on some scrap first and use the drill on a low speed.
If you've never used a hole saw to cut very thin metal, then practice, practice, practice, on some scrap first.
If you've never used a hole saw to cut very thin metal that's curved, like the side / top of a cylinder, then practice, practice, practice, on a tin can or other curved metal suface.

As you'll see if you practice, the teeth can gab and rip thin metal to shreds, not what you want with a cylinder that'll then need replacing.

And as above a cutter with more teeth would be preferable.

This was the original tool of choice for holes in cylinders or tanks, using a carpenters wheel brace.
Still got mine somewhere.

 

[Stevex]

Thx for the replies. I'm going to use a small hole cutter just big enough to get a rotary grinder in.
Just bought one of these.

 

[Ben-gee]

Get someone to hold a vacuum nearby to try and minimise the filings going into the cylinder

 

[ShaunCorbs]

I wouldn’t recommend one of them be better with your hole saw run in reverse before you use a carbide burr

 

[PETE 123]

Could you use a surrey flange instead.

 

[Stevex]

Finally got round to fitting the pump.
Practiced the hole cutting on some thin gauge aluminium sheet I had and then onto the copper tank. To be honest the hole cutter mentioned previously worked a treat with no problems. The Essex fl@nges went in easily. Wired it up this morning and ran the pump for half an hour but it doesn't appear to be working!!. Top pipe out of the tank is hot and the pipe below the pump is lukewarm and doesn't get hot; the pump makes a pulsing noise. Also the temp gauges I've got at the top and bottom of the tank don't change. Fired an email off to Wilo, but I can only presume they'll ask for it back to check it out.

 

[ShaunCorbs]

Does the pump have non return valves in ?

 

[Stevex]

Yes, NRV fitted in the discharge side.