Replacing cast iron downpipe

[JohnBarleycorn]

Hi All,

One of my cast iron downpipes is shot, so I've picked up a couple of lengths of reclaimed downpipe to replace it (also in cast iron). As usual the reclaimed stuff is slightly rusty down the side that was facing the house. I'm planning on wire-brushing it, then painting it with some Hammerite derust primer I have. However it strikes me that it might be sensible to add an extra layer of something down the side facing the house wall. The wall-side is pretty much hidden from view, and is always going to be susceptible to rusting, so is there some kind of substance I could apply to that edge to thicken it up and provide an extra layer of protection?

Also can anyone recommend a particular type of mastic which I should use when sealing into the hopper, sealing on the shoe etc?

Thanks in advance,
JB.

 

[Mw Roofline]

Years ago some of the cast iron downpipes were fitted to the houses and then painted

To be honest with the quality these days of the likes of Hammerite, a good few thick coats will see it lasting a long time.

Just a decent tube of black or clear silicone will do the job, good luck

 

[Nige F]

YeaH I remember those pipe nails One coat of smoothrite .....or if .it`s on a church....one of Bitumonastic

 

[JohnBarleycorn]

Great, thanks for the tips.

A couple more queries if you don't mind - I'm starting to think about how I'll fit the thing after it's painted. What is the recommended tool for cutting cast iron given that it is quite brittle? Also is there an easy to remove the current downpipe from the hopper without damaging it?

Thanks,
JB.

 

[masona]

What is the recommended tool for cutting cast iron given that it is quite brittle?

I don't know of any other tools apart from using a 9" angle grinder with a disc for cutting metal.

Also is there an easy to remove the current downpipe from the hopper without damaging it?

It's 50:50, depends how old and if the joints can be raked out or undo the fittings, this is the job where you have take your time, so don't rush it.

 

[kevnurse]

I used a 4in grinder to cut a 2.5 in down pipe satisfactorily. Make sure that both sides of the cut are supported.

 

[Nige F]

Hi All,


Also can anyone recommend a particular type of mastic which I should use when sealing into the hopper, sealing on the shoe etc?

Thanks in advance,
JB.

...........er, fresh air you don`t have to seal the joints ...........did you get Bitu.......Monastic .....a pun on Bitumastic (paint) or