Cello Strings Soldering Question - HELP

Hey all, I am almost complete with the re-installation of a fairly large Cello Rig. I am stuck on the soldering of the fisher connectors to the custom length Cello String interconnect wire. This wire is copper (coated?) and does not seem to want to take the solder. I am not a master at soldering to begin with but this Cello String wire is really hard to work with. Does anyone out there have any tips?

If I take a length of the wire, strip it, I can't even test continuity between the ends - I gather this is because of the copper (possibly coated). If I could 'tin' the ends effectively, I could take this work - but no luck. I need help! - Andrew

Are the Cello interconnects made of some type of litz wire? If so than you would need a solder pot to tin the ends first.
Lostbears, that is a good tip (ha!). Is a solder pot an expensive item? That should tin the end of the copper wire to make it conduct signal?

Litz wire has each strand of wire coated with a type of varnish. This is why the solder will not stick. When you dip the ends of the wire in the solder pot it melts the varnish and tins the ends. A solder pot is not that expensive. You can probably pick a cheap one up on ebay. But in the end it might be cheaper to have someone else just tin the ends for you. You might try calling repair shops and ask if they have a solder pot. Especially older shops than have been in business for a long time.
That sounds like the issue then. I need to find someone in New York City who can do this. Separately, the Fischer 104 connectors are such a pain to terminate. I only have one set of male and female ends and they are currently part of a single interconnect. I am weary of disconnecting the connectors from perfectly terminated wiring. Is it totally 'not audiophile friendly' to cut the wire back 10" from the connectors and solder those pre-terminated ends to the wire run in the walls?
If you have a powerful soldering iron and some solder with plenty of resin flux you can manage to terminate the cables. If you supply a good flux of solder the tinny bare copper tip of each wire will became tinned and slowly the heat will remove the varnish. I have re-done a few of these cables - a small block of resin was very useful to keep a "bath" of nice and clean bright solder while tinning the wires.
In some types of String the screening braid was also Litz type wire - it was much more difficult to solder as the insulation was much thicker.
Thanks guys. I found someone here is NYC to help - he's got a solder pot! But I need to find some Fischer 104 Male and Female ends so I can afford to mess one up in the process.