[Bones13]

I am building an AudioNoteKits Dac4.1, and have upgraded the XLR connectors to some nice Cardas Rhodium plated connectors.  I use Cardas Quad Eutetic solder, but I cannot get it to stick to the solder cups on the connector pins.
 
Short of grinding off some of the chrome-like finish, does anyone else have a suggestion for getting solder to stick to this surface?

 

[nikongod]

Cardas parts aren't meant to be soldered, they are meant to be admired. 
 
Liquid flux on the cup&wire. 
Heat it with the iron until it smokes, then feed solder into it. 
It requires a bit of technique to get the cup to heat at the same rate as the wire. 

 

[Bones13]

Thanks Nikongod, will give it a try.

 

[Bones13]

I had to also scratch the inside of the solder cup to get adhesion, but I did solder up the XLR connector for the AES SPDIF input.

Did learn a method, so the output jacks won't be a mystery when I get there.

 

[Steve Eddy]

Did a rhodium plated Cardas 1/4" TRS the other day without any problems.
 
I use a Weller WES51 set for 750F, Kester 63/37 with "44" flux, and paste flux from Radio Shack.
 
Pre-tinned the contacts as well as the wire. Applied a little paste flux prior to soldering and Bob's your uncle. Used a larger tip for the big ass ground contact, but just my regular small chisel tip for the others.
 
se