# Why won't my solder stick?



## Computerpro3

Honestly, this is one of the most annoying prolem's I've ever had. I'm almost done with my EMU breakout cable using teflon insulated litz braided 99.99% pure wire with LOK rhodium/silver plugs. 

 Now all I have to do is solder the LOK plugs on the ends and I'm all set. For some reason, my HGA silver solder simply will not stick to these LOK plugs. I've tried heating the damn thing for a good 15 seconds and it still doesn't work. I've tried with a 15w, 20w, and a 40w (the solder doesnt even stick to the tip of the 40w, it just falls off and beads up on my desk. Weird). 

 The solder worked great when I soldered to the dsub connector, its only with these loks that it doesnt work.

 What gives?


----------



## michaelconnor

If the solder doesn't flow onto the wire, it may have some sort of a coating that can be scraped off. Otherwise, you could try putting some flux on the wire first.

 Edit: Oh wait, the solder isn't sticking to the iron either? Here are two ideas; 1) your tip is black with oxidization. If it's a cheap iron, file off the black stuff and re-tin the tip. Otherwise replace the tip. 2) Your solder has no rosin flux core. If this is the case (and i suspect it is), it won't flow easily onto anything but very clean copper. You can get a case of flux at Radio Shack for a few bucks. Dab some onto your connections and it should flow.


----------



## ericj

Quote:


  Originally Posted by *Computerpro3* 
_For some reason, my HGA silver solder simply will not stick to these LOK plugs. I've tried heating the damn thing for a good 15 seconds and it still doesn't work. 

 The solder worked great when I soldered to the dsub connector, its only with these loks that it doesnt work.

 What gives?_

 


 Rhodium is damn hard to solder, that's what gives. 

 You're using a solder that's less than ideal to begin with - I don't care how expensive it is, Tin with some LEAD in it is what gives you a good solder joint and silver is just harder to work with. 

 On top of that, you're trying to solder to a metal that's very hard to solder. Harder to solder to than nickel. 

 You're going to need a very hot iron and a VERY active flux. Kester recommends their 2331-ZX. 

 Alternately, some sandpaper will take that rhodium off so you can get a good joint (as good as you can get with silver solder) without having to buy more chemicals.

 Edit: fwiw, rhodium is about 1/2 as good of a conductor as gold is. Rhodium plated connectors? what gives?


----------

