Solder Problems (PDP-8/m related)

From: Joe <rigdonj_at_intellistar.net>
Date: Fri Dec 3 00:10:38 1999

At 11:34 PM 12/2/99 +0000, you wrote:
>
>Does this mean I should stock up on spare tips, elements, swtiches, etc
>for these irons?

    It wouldn't hurt. But I was told they had quit making them a year or so
ago so that may not be right.

>
>> one. BTW the number on the back of the tip (7, 8, 9, etc) indicates the
>> temperature that it regulates at. 7 = 700d F, 8 = 800d F, etc. The local
>
>Yep. The bit of metal that the number is stamped onto is a special alloy with
>the curie point at that temperature. That's how the thermostat works -- a
>magnet in the shaft of the iron is attracted to the back of the bit,
>closing a switch. When the iron gets to temperature, the alloy stops
>being magnetic, the magnet is pulled away by a spring, opening the switch
>and turning off the element. The iron cools down, the magnet is attracted
>again, etc.
>
>In an emergency you can swap these alloy cylinders between bits if you
>have the wrong combination of shape and temperature.
>
>> surplus place has a large variety of tip styles and temperatures so I have
>> plenty of different ones to work with. I like to use a hot one (800d) for
>> unsoldering so I can heat the joint up and get the iron off of it quickly.
>> But I use a 500 to 600d one for general use.
>
>Be warned that a relatively cold iron can do _more_ thermal damage than a
>hot one. _All_ irons are hot, and if you use a colder one you keep it on
>too long to complete the connection and thus overheat the component.
>
>I find a #8 good for almost all work. A #7 is useable, but I don't like
>it. #5 or #6 is too cold...

   You're right. I meant to add that the solder that I'm using is a very
low temperature solder with silver in it. 500 or 600 degrees would be too
cold for standard solder. I love this silver stuff, it expensive but it
flows beautifully. Most of the stuff that I work on is tiny so a one ounce
roll will last for a couple of years.

   Joe
>
>-tony
>
>
Received on Fri Dec 03 1999 - 00:10:38 GMT