Boiler Barrel Patch Repairs

I am in the process of writing a article on steam locomotive restoration here in Australia, and am interested to learn of any boiler barrel patch repairs and particularly any photos of these repairs being done.

It would be very much appreciated if I can find out about links or posts on this site on the above.

Thanks

Ian

 

I suggest you research the web sites of locomotives being rebuilt or restored, however I am not sure that there is a book in it. For example there is this excellent set here: https://eastsomersetrailway.com/news/view/overhaul-of-5239-goliath. KJ Cook's book Swindon Steam covers copper welding as developed at Swindon in the 1930s.

 

Don't know of these help. The lower section of Stanier Crab 2968's Barrel (the boiler is inverted) was wated at the front, so a small section removed and a patch welded in. The old tube plate was refitted to provide the profile. Only the first run of weld has been completed.

 

Thanks much appreciated!

 

Just to ask out of curiosity would the new welded and bolted piece of boiler barrel plate have to drilled out likewise as on the boiler barrel side on the edges for the smokebox to be riveted in place LMS 2968?

 

Do these help?

https://flickr.com/photos/78335890@N08/sets/72157645690946939

The back story is that the boiler was damaged by shell fire during the Second World War; it was repaired with patches at the time, but at the most recent repair, the damaged areas were cut out and new material let in. (There was presumably equivalent damage on the inner firebox but I believe that was either repaired or fully replaced before the loco entered preservation).

Tom

 

Yes, they would. Apart from the front tubeplate inside the barrel, there is an angle iron attachment outside the barrel to locate the smokebox wrapper. The wrapper is a larger diameter than the barrel, and the front cladding sheet is the same diameter as the wrapper so it all looks to flow from one to the other.

 

Damaged by shell fire - say more

 

With respect I would say that is a welded insert. It isnt a patch repair. A patch repair is placed over the parent material.

Attached is a pic of a full fireside copper patch repair around a new fire hole ring I was involved with on a large Andrew Barclay. It is patch screwed inbetween stays with a riveted ring.

Boiler inspectors are not fond of true patch repairs due to the myth that they weren't a works repair. Fortunately most boilersmith know this is not the case.

 

Why was a patch repair favoured rather than cutting out the old copper plate and welding in the replacement in the repair you show?

 

The copper door plate was in very good condition except for bad star cracking around the fire hole. It was made from tough pitch copper that cant be welded (c105).

So a new fire hole ring and traditional patch was the cheapest and quickest safe repair option available.

 

It's how it's done these days. 2968's firebox has also had replacements for the lower throat plate, both lower side plates and two-thirds of the outer backplate, all with the old metal cut out and the new pieces welded in. There were existing patches in the usual places for Stanier fireboxes, including the throat plate, and these were all discarded.

 

Thanks Tom- interesting back story

 

It’s over 20 years since I saw it but I seem to remember this machine had some interesting patch repairs on the boiler barrel. Presumably dating from pre-preservation. I wonder how the restoration is getting on?

http://www.museumseisenbahn.de/index.php/de/fahrzeuge.html

EDIT: the link goes to the index page, the loco I’m thinking of is ‘7s MALLET’.

 

Patch repairs are not uncommon, certainly the midland and LNER fitted wasting plates in the bottom of barrels from new

 

Raw speculation on my part here but wouldn’t a patch repair be viewed less favourably due to the potential for crack propagation?

yes you are patching over the area of concern, reducing its duty, but why wouldn’t you cut out cracked material and insert new uncracked material if you can?

 

Which is probably why it isn't allowed today, although it was successfully used by BR and the Big Four for decades.

 

It most definitely IS still permissible to patch a boiler traditionally. Please dont propagate a myth. Of course welding is more common these days. But in certain circumstances patching is far better.

 

That's not what we were told by the boiler inspector at Bridgnorth. If a patch was already in place and ND testing showed it to be sound, it could stay there, but new repairs have to be welded in and not patched.