Solder

OK, sorry, I am sure like car forums discussing engine oil, solder has been discussed before. But I would appreciate advice from people who have tried some of the more expensive solders available. I buy parts from Farnell which have several solders with Silver content, but also from HIFi Collective in the UK, which has this lovely selection to choose from: https://www.hificollective.co.uk/components/solder.html

Currently I'm using Oyaide 4.7% silver, simply because it's a good, clean mid-priced solder from a reputable source, with what seems a good specification.

I'm wondering if it's worth using 9.5% silver Mundorf solder, because silver is considerably more conductive than tin ? Has anybody tried these and compared to a more basic solder ? Is there any difference in sound quality.... OK, as I typed that a little part of me did wonder if that's even a sensible question... but I'm interested in other people's experience. I'm not advocating for costly solders, I've no experience of them, hence asking.
 
I have Mundorf lead-free MSolder Silver & Gold and use it with the occasional silver wire. The hardness is high compared to leaded solder and it works very well with a tip temperature about 30C above what is normally run. The solder has a hardness almost like piano wire versus the predictable softness and flexibility of 60/40 leaded solder.

Compared to a leaded 60/40 solder, like MG Chemicals 4880, the silver content solder gives a different appearance. When it cools the MG looks like chrome, but the Silver Gold gives a matte appearance. It wasn’t difficult to get a feel for the liquid region, having never used eutectic solder prior. Some people may struggle with silver content and lead-free solders at first.

I would not use the silver content solder to solder temperature sensitive components.

Once the MG is depleted there is a spool of AIM RMA 3% eutectic to test. A first time for everything, they say.
 
Thanks, I'd not thought about solder being primarily to anchor the component, I thought it was also part of the conductive path. So really, any solder that's clean and doesn't leave a residue is pretty much OK. I'm not a fan of the way it looks when solid, the matte appearance isn't as pleasing.
 
I guess the silver content in solder mainly serves to avoid dissolving silver from silver plated surfaces in the liquid soldier.
The 4% silver alloy is chosen as it is a eutectic. Non-eutectic alloys don't solidify at one temperature but go through a pasty phase over a range of temperature and are prone to dry joints. They are horrible for re-work.

SAC solder is standard for lead-free hand soldering, standing for SnAgCu, tin/silver/copper. About 4% silver, 0.5% copper, remainder tin.

Eutectics also melt at the lowest temperature possible for the components chosen, another reason solders are best as eutectics. Google "phase diagram" and "euctectic" for more explanation.