Silver soldering old German silver castings

I have had a part finished 2 1/2" gauge Baltimore and Ohio pacific locomotive chassis for some time awaiting it's turn for some TLC. This was a design of the late 20's by Mr H.J.Coventry, with castings supplied in the UK by George Kennion, there are many casting used in it's construction, even the main loco frames are cast gunmetal.The original work was carried out very nicely, but as so often happens the parts fell into less careful hands, and in attempting to make the coupling rods fit with the wheel quartering all over the place, our hapless mechanic has filed out one of the coupling rod bosses which has then cracked, presumably as he tried to force the wheels round.

The coupling and connecting rods are unusual in that they were supplied as German silver castings, something I had seen in old copies of M.E but never seen before in the flesh. I'd like to preserve this feature, as I feel they are of their time and with some careful filing they could be made to look quite reasonable . I plan to silver solder a bush into the bore of the butchered rod, then bore out to the correct size and the correct axle spacing.

Reason for the post is, has anyone any experience of silver soldering old cast German (or Nickel) silver. I'm quite experienced at silver soldering, but have no knowledge of 80 ish year old cast German silver. I have silver soldered Nickel silver fabrications but never castings. I know their is a wealth of experience out there, so any tips or pointers would be most gratefully received

I have hopefully attached a couple of pictures of the rods and one of the chassis in as found condition, the cracked boss is the left hand one on the second set up.. Incidentally the loco came with an unconnected Basset Lowke tender, which has just been positively identified as being the original to Henry Greenly's Challenger locomotive from the battle of the boilers. Happily it's off to be reunited with Challenger after nearly 80 years apart.

Thanks

Dave

Edited By Dave Wootton on 22/05/2020 19:09:15

I have no practical experience of that, Dave ... but it’s an interesting question !!

Therefore, downloaded this for background info. **LINK**

https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwi0iNSJisjpAhWwWhUIHUk8DoYQFjAJegQIBBAB&url=https%3A%2F%2Fcopperalliance.org.uk%2Fresources%2Fthe-nickel-silvers%2F%3Fdownload%3Dstart&usg=AOvVaw2wV1J9ZOZOHW-0kRaFK0wW

... which is a strange link but seems to work fine

If you have any problem downloading it, I can eMail the PDF to you.

MichaelG.

Thank you Michael, that's very informative and quite readable too, interestingly they say that castings may contain lead or tin, but it seems that it is quite possible to silver solder cast even containing lead providing it's done quickly.

I have some thin easyflow wire I use for steam fittings ( the old cadmium stuff) I will have a go with that, I won't be able to do it until next week, but I will post a conclusion, even if it's just a picture of a metallic puddle!

Thanks again

Dave

As an aside to this ... I noted mention, in that document, of Incralac, which looks like a very useful protective lacquer.

It is still widely available, and there is an interesting research paper about it, here:

**LINK**

https://www.researchgate.net/publication/319717768_Deconstructing_Incralac_A_formulation_study_of_acrylic_coatings_for_the_protection_of_outdoor_bronze_sculpture

MichaelG.

Hi Dave,

Silver brazing alloys do not respond any differently with german silver be it old or new!

They will respond to the composition of the parent material. It will behave differently if there is any lead present. Alter your technique to compensate for any lead to improve your chances of success.

Good luck with the idea that trying to make the joint quicker will alleviateany problems the lead may create. Expect more trouble!

Keith

Thanks Keith and Michael, I managed to get out in the workshop this morning and make a bush to silver solder in, I'm pleased to say it all went very well, I took Keith's advice and did not try to complete the job quickly, or heat too fiercely.

I used some thin wire silver solder I keep for steam fittings, It's not cadmium free but it does flow very nicely. I cleaned everything carefully and pickled it before I started and used standard easy flow flux. I did attempt a picture but it didn't really show anything up worth looking at, if I get close enough to show the joint it just gets blurry! Must get a decent camera!

One bonus is the nickel silver is about the same colour as silver solder so the crack repair is almost invisible.

Thanks again for your help.

Dave

Edited By Dave Wootton on 24/05/2020 13:35:35

Hi Dave,

Pleased to have been of help. It's part of the package of being a customer of CuP Alloys.

Keith