About 60% of the cast iron materials have been rescued.

Now they have been de-rusted and thoroughly repainted on the exposed faces.

 

But what about inside the downpipes?

 

I don't know if these were ever painted.

Should they be?

Of course the insides of the pipes are regularly wetted, and never see daylight.

Does that make them constantly exposed to rusting conditions?

Or do gravity and rising air do enough to dry the insides?

 

If painted, somehow,  it will not be as thorough as the exposed surfaces, and may cause more harm.

 

The best method I have so far is to paint a ferret and send it up and down many times.

 

Or perhaps use a wax spray as used to be recommended for rusting old cars.

 

I really don't know, and so any proper knowledge or best guesses are welcome.

 

 

 

5 hours ago, saveasteading said:

The best method I have so far is to paint a ferret and send it up and down many times.

 

Or perhaps use a wax spray as used to be recommended for rusting old cars.

Is there a risk that pollutants can leach out of the coatings?

 

I thought part of the advantage of cast iron is that the surface rust protects the underlying material.

Originally they would not have been painted on the inside, they have probably lasted a long time already and will do for many years without doing anything to them. They tend to rust more around saddles and connectors because dirt allows moss and grass to grow trapping moisture against the surface

They are probably 70 years old I guess, as it has been  re-roofed at least once. My own house has similar and they seem to be 90 years old and the only problems are at bolted gutter connections.

So I think I agree that we leave the insides alone.  Clean and probably drier than I would have imagined.

 

It reminds me that my dad (joiner) told me that all leftover paint from every job used to be tipped into a barrel  and mixed, then used to coat the insides of gutters. Whatever colours went in, the resulting colour was khaki.

7 minutes ago, saveasteading said:

So I think I agree that we leave the insides alone.

Phew!