Stone.

[John Rumm]

Sounds like it would make a nice article - also we have not got much along those lines in there at the moment, so it would be handy...

[newshound]

Thanks. What do I need to do? Get access privileges from someone? I've never updated a Wiki but I (sort of) know my way around markup languages.

[newshound]

I'd be OK with bronze too. I'd probably look at "quality" plugs like Fischer, they tend to have stronger plastic but more "space" to ensure that the volume does not go solid when the screw is inserted. You don't need a very strong fixing (compared to shelf brackets, say), make sure the screws are not oversized for the plug.

[John Rumm]

Drop me an email with your preferred account name, and I will create an account for you.

Wiki markup is pretty straight forward for the basic things. But even if you just slap in text and upload the photos, there will be someone along who can help you tart it up.

Getting started instructions here:

(we use the same software as wikipedia; "Mediawiki" - so there are tons of help pages out there)

[John Rumm]

Roof ladder hooked onto their side of the roof adjacent to the stone?

[Nightjar]

On 29-Jul-17 9:05 PM, newshound wrote: ...

Which is more likely to cause problems in the long term; assuming it could rust and being wrong or assuming it won't and being wrong?

[Nightjar]

I like bronze for outside fastenings. I made a pair of gates for a driveway about 40 years ago, using silicon bronze ring barb nails. Apart from the weather capping strip needing to be replaced after about 20 years, the gates are still doing good service for the current owners. A custom made garden bench, not made by me and using brass fastenings, fell apart after only 20 years.

[Dave Plowman (News)]

Absolutely not at my age. ;-)

[newshound]

My eminent old colleague Jack Harris advised on repairs to St Paul's, although I can't immediately locate details of the replacement metal parts.

However, the very long studs which now hold together the corners of the tower of York Minster are certainly made from austenitic stainless steel.

[newshound]

These people sell stainless steel fittings so are hardly unbiassed, but they seem to think it is OK in mortar and stonework

[John Rumm]

Get a bit added onto to the scaffolding then... cheaper now than having a whole new lot up later.

[Dave Plowman (News)]

That would be up to my neighbours. I can't have scaffolding extended onto their land.

[harry]

The stone at the end is called a kneeler. Always good to know the terminology. Example:-

[Dave Plowman (News)]

I've had another look. Used a mirror to look at their side better. And if anything it's in a worse state than my side. A couple of large chunks just ready to fall off. Not quite sure how to proceed.

[Vir Campestris]

Water doesn't count. There have been cases where the stainless steel keelbolts on boats have rusted through - and when the keel falls off that kind of boat they'll be upside down in seconds.

Andy

[newshound]

Well, you say "rusted through". My guess is that keel bolts are highly stressed in extreme conditions. With the chloride in seawater, unsuitable stainless steels experiences stress corrosion cracking. They will therefore fracture, rather than "rust through". Whereas in the sort of case we are describing for the coping stone repair, the stress levels will be very small compared to the tensile strength of the steel, and SCC is not a problem.

Disclaimer: I'm not a metallurgist either, I'm a physicist. But I have spent a career convincing engineers that I know more chemistry than them, chemists that I know more metallurgy, metallurgists that I know more physics, and physicists that I know more chemistry, engineering, and metallurgy! Oh, and I can bluff anyone except a mathematician about statistics.

[John Rumm]

Can you get a photo of it (selfie stick?) and show them? They might be keen to go halves on the scaffolding cost, sine the alternative to them will be at least double later...

[Dave Plowman (News)]

Yes. The problem is neither of them do anything even vaguely DIY, so I'm not sure will understand. And I don't want to be in the position of being responsible if anything goes wrong. Perhaps I'm just over thinking things.

Ideally, if I had good access, I'd remove the entire stone and cast up a new one out of concrete. But as it is, likely just repair my side and the top.

[Vir Campestris]

I have no first hand experience. Lots of links, such as this

suggest that only some sorts of stainless will survive bilgewater, which is often low in oxygen.

Andy

[Dave Plowman (News)]

Been reading the instructions that came with the Conserv repair mortar, and they mention SS reinforcement.