Posted by
Jeremiah McCarthy on
Mar 09, 2007; 8:58pm
URL: http://elecraft.85.s1.nabble.com/Toroids-tp444595.html
I have wound hundreds of toroids and have an "IMHO" to submit...The flame method is the poorest, most time wasting, most dangerous procedure...Since we need to strip the enamel up to as close to the core as possible, the flame will inevitably damage the first and last few turns by scorching both those turns and the core...The flame method requires 3 steps, (1) burn the enamel off, (2) clean up the scorched wire, (3) tin the wire...You will be lucky if you really can do so...
The "blob" method requires only one step and should be done with high heat...I used to use an old fashioned unregulated 40 watt iron for this...Today I use a Hakko 808...There is no need to first scrape the wire...The object is to burn the enamel off, and the heat of the iron and the solder alone will do that..If the enamel won't burn, the iron is simply not hot enough...Start as close to the core as possible...Put a blob of solder on the tip, immerse the wire in the blob, and slowly work out towards the tip of the wire, adding more solder as necessary...
Starting at the tip of the wire and working inwards towards the core has a tendency to push the wire inward, especially with the 28 gage wire used in the KSB2...This forms a loose turn inside the core, which, when pulled back out into place, will leave enamel on the wire close to the core, in the area where soldering onto the circuit board should occur...
After the toroid is wound, I pin it down flat on the bench with a weight, like a draftsman's paper weight, covering only half the toroid and leaving the wire leads sticking straight out...This leaves both hands free to manipulate the iron and the solder...Tin the top lead, then turn the toroid over and do the other lead...
Jerry, wa2dkg
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