[time-nuts] HP 5065A rubidium lifetime

[Neville Michie]

On 21/03/2010, at 11:58 AM, Bob Camp wrote:
>
>
> To make the heater work right you need the proper resistance / foot  
> heater wire. Cupron is a pretty typical material if you want to  
> solder to it. Nicrome is fine if you are welding to it.  THe real  
> trick here is to find somebody with a spool of the right stuff and  
> then beg a few feet from them.
>
>


Hi,
Nichrome, stainless steel, iron, nickel, copper, brass in fact most  
metals other than aluminium, (zinc is messy) solder very easily with  
a trace of phosphoric acid as a flux.
Clean the soldering iron of resin residue, put a trace of phosphoric  
acid on the wire, and is solders like new copper. The soldering iron  
and wire are very easily cleaned with water afterwards leaving a  
tinned nichrome (etc) wire for normal resin cored solder assembly.
The phosphoric acid may be of any strength as the water boils out to  
leave a P2O5 paste on the article.
For large items use a huge soldering iron, paint acid on the cold  
iron/nickel whathave you and it solders very easily. Do not gently  
heat an iron article with acid on it as within
a half minute a protective phosphate coat (like Parkerising) will  
form to make it impossible to solder.
It is worth keeping a tiny bottle of phosphoroic acid just for the  
odd bit of resistance wire or thermo-couple.
You have to see it to believe it.
Cheers, Neville Michie