Cap for carbon steel pipe

[wildtypitch]

Hi have surplus water feed and return pipes in my home. I can't isolate them so will need to freeze. House built 1970's. They're as far as can tell Carbon/mild steel pipe, 28mm dia. Wish to cap them off. Can I use brass compression fittings? Like in the pic. Or do I need to use steel fixings? Like a 28mm threaded plug. Local plumber wanted to order in very heavy compression caps at £24 ea. seemed a bit much. Advice appreciated. Thanks

 

[Last Plumber]

They are galvanised steel.
It depends which way you intend to cap them. If it is the elbow that will be left over, use a plug.
If it measures around 1" externally then it will be 3/4" tube but it should say the size on the side of the fittings/elbows.

 

[wildtypitch]

They are galvanised steel.
It depends which way you intend to cap them. If it is the elbow that will be left over, use a plug.
If it measures around 1" externally then it will be 3/4" tube but it should say the size on the side of the fittings/elbows.

Ah galvanised steel. Thanks @Last Plumber.
Yes attatched is what the plumbers merchants were offering. All depends on whether it can be frozen at or before the elbow. Plug would be easier though. As for galvanised compression fittings. Not sure why they are so expensive. Is it accepted practice to use brass fittings with galvanised steel. I believe brass fittings are of a brass mix to reduce galvanic corrosion to a minimum.

 

[Last Plumber]

Ah galvanized steel. Thanks @Last Plumber.
Yes attached is what the plumbers merchants were offering. All depends on whether it can be frozen at or before the elbow. Plug would be easier though. As for galvanized compression fittings. Not sure why they are so expensive. Is it accepted practice to use brass fittings with galvanised steel. I believe brass fittings are of a brass mix to reduce galvanic corrosion to a minimum.

I would not use brass and galvanized steel together.
Compression fittings are OK but I avoid them and only use as a last resort.
If you can get the pipe out of the elbow and use a plug, that's the best way.

I presume this is heating?

 

[wildtypitch]

Communal supply to old water cylinder I believe. Return is dry and been capped off for a while now.

 

[DAVE the old git]

Ah galvanised steel. Thanks @Last Plumber.
Yes attatched is what the plumbers merchants were offering. All depends on whether it can be frozen at or before the elbow. Plug would be easier though. As for galvanised compression fittings. Not sure why they are so expensive. Is it accepted practice to use brass fittings with galvanised steel. I believe brass fittings are of a brass mix to reduce galvanic corrosion to a minimum.

YES this will work 100% on GB I did this many moons ago on 1inch GB Tested this on 1/2 GB it held Ten Bar Pressure IF its 28mm Galvo You will have to go up to the next Size Which Would be 35 mm uk copper size The copper Ring on the Galvo will compress You might have to do a Bit of Filing but it will work and you will not need a pair of Flippers and a Snorkel or the Fire brigade to bail you out