Best solder for palladium

[Edhelien]

I've been playing little bit with palladium in recent months, mainly mixed metal pieces (with gold), I would like to use it more often, but I am not satisfied with my solder.
I bought the cheapest solder possible from Cookson (palladium medium, high silver content - 89.80% ag and 4.6% pd, melting point 935-955, brazing temp. 990 according to Cookson's catalogue). As expected given the high silver content, it's easy to work with, but it is very white and light, much lighter than palladium and joints are too visible.
I would like to try different solder, but they are all quite expensive, so I am here for advice.
Pd manual by London Assay Office (from page 31) recommends platinum solder or palladium solder, their joint is darker then the rest of the ring and acceptable. They list completely different palladium solders (higher melting points, probably higher platinum content) than Cookson sells.

According to Cookson's catalogue, possibilities are:
Palladium solders:
Pd Easy - 12au, 47ag, 17pd, melting point 705-720, brazing 800 - I prefer "harder" solder for most metals, this seems very "easy"
Pd Medium - 89.8ag, 4.6pd, melting point 735-955, brazing 990 - as I said I am not satisfied
Platinum solders:
Pt X-Easy - 90.2ag, 5pd, melting point 935-955, brazing 990 - basically same solder as pd medium
Pt Easy - 39au, 46.2ag, 5.4pt, 4.7pd, melting point 1010-1030, brazing 1060
Pt Medium - 52.74au, 31.64ag, 15.67pd, melting point 1180-1220, brazing 1260 - this would be my bet, but high melting temp. scares me
Pt Hard - not usable, higher melting point than pd
Gold solders:
9ct white - (37.6au, 33.39ag) and 18ct EWG500, MWG588 and HWG833 (gold content 50.0-83.3) - these three are not fully compliant with EU nickel regulations (I am not sure if it means that they can't be used or if small amount per piece is ok).

What do you think/use? Thank you.

[Dennis]

There have not been many answers to palladium questions on this forum Anna, but if you have not already done so, you could browse here:

https://www.google.co.uk/search?q=Be...BebU8ge-y52QDg

[Edhelien]

Hi Dennis, thank you.
I've searched through most of (maybe all) threads about palladium here. But I hope there is someone who tried some of the options listed in my post. I hope for UK specific, small maker specific (I don't want wholesale shop with large minimum quantity order required) and ideally Cookson specific answer.
I will check Google too, but it seems that fabricating from palladium is very rare. And US websites may be problematic (because of EU regulations on nickel and cadmium).

After very quick look:
Ganoksin says that 19.5 karat white gold hard solder or 20 karat white gold hard solder is best colour match for pd 950.
Other sources usually say palladium or platinum solder (harder better) without specific details.

Hoover and Strong - this could work, but probably is impossible to get from UK:
We have developed easy, medium and hard palladium solders for small jobs. Our 20k white hard solder is recommended and was developed for seamless soldering when sizing rings.

[TeeDee]

Just wondering if anyone has had anyone has had any further experience of working with palladium since Anna's post.
I'm in a bit of a quandry in that a friend has asked me to enlarge his palladium wedding ring.
The ring is 950 Pd and has a bit of history in that his original ring was melted down and re fabricated (as opposed to cast).

I did a bit of research on Pd with the intention of annealing the ring and then stretching it about 3/4 of a size.
Following annealing a cloudy area was visible around the joint (see pics) which I assume is excess solder.
Sadly though when the ring went on the stretched, the joint pinged open before I got to even a 1/4 size up.

Can I assume the joint was dodgy or is it just plain difficult to work soldered Pd joints.

As with Anna's post I can only find Med and Easy Solders in the UK with Easy being about 75% dearer than Med. I've left an enquiry with Cookies on the price difference.

Any info on best solder and working practices would be appreciated.

Thanks
Tim

[enigma]

I haven't worked with Palladium so I could be totally wrong here but from working with rose gold and never finding a decent solder colour match I find that if you get the joints tight enough it doesn't matter anyway as you can't see the line?

[TeeDee]

Good point Sarah, Thanks. A bit of burnishing will probably help too.
I did get a call from Cookies this morning. Their view was that the Easy solder had a much higher palladium content and would thus be stronger thereby making it the best one for my little problem. I see Euro Mounts also do a well priced Easy solder (circa £25+Vat) but the delivery cost is £9.00 or collect! I think their's is by Johnson Matthey looking at the pic on their website.
Still hoping to get some response from other forumites although I think Pd experience is pretty thin on the ground
Tim