[Elecraft] Tororids

[Tom Hammond]

Hi Al (or is it Dianne?)... no sig, can't tell... sorry!

>I'm having trouble tinning my toroid leads. In spite
>of rigorous cleaning they just don't want to accept
>solder ( Kester 44 ). Will adding some paste flux
>interfere with electrical qualities of the leads ?

Adding flux won't hurt... BUT, it won't help either!!!

Chances are that it's HEAT you're lacking!

1) What are you using for your soldering device?

2) Is is controllable with regard to temperature?

3) How long are you applying the heat to the wire?

4) Are you starting at the CUT END of the wire, or
    at the middle of the wire?

Here's the technique which I've used for years. It's seldom failed
to yield satisfactory results:

1) MAKE CERTAIN THE WIRE YOU WANT TO TIN USES HEAT-STRIPPABLE ENAMEL
    (otherwise, you'll waste a LOT of time...)

2) Cut the wire to length

3) Set soldering iron to STUN (actually, 750-800 deg F) and allow
    it to come up to temp.

4) Set iron on desk so the FLAT of the tip is horizontal.

5) Melt a small blob of solder onto the flat side of the tip.

6) Insert the CLIPPED TIP(!) of the wire into the solder blob and
    leave it there for 3-4 seconds. If you really DO have heat-
    strippable enamel AND if the iron tip temp is adequate, the
    enamel should begin to bubble and smoke in 3-4 seconds (IF you
    stuck the CUT (bare copper) tip of the wire into the solder).

7) Once the enamel starts to bubble and smoke, apply a bit more
    solder to the tip and advance the wire thru the 'blob', until
    you've melted all of the enamel and left a coating of solder on
    the wire.

8) Reverse the process... slowly remove the wire be pulling it out
    of the blob in the same manner as when you inserted it. This
    should leave you with a nicely tinned lead, but possibly one
    with some 'dross' remaining on the lead. 'Dross' is the burnt
    enamel which can usually be pretty easily stripped off the lead
    by merely scraping a fingernail against it.

It is IMPORTANT to insert the CLIPPED TIP of the wire into the solder
blow, because you want the bare copper to be the first thing to
contact the heat... bare copper conducts heat MUCH more quickly than
trying to 'force' the heat thru a layer of enamel.

Good luck,

Tom Hammond   N0SS