[sdiy] problematic sh101

[James Patchell]

Heat and Temperature are two distinct properties....although, 
related.  Heat has more to do with thermal capacity.  The problem with 
soldering irons is that you don't want your tip to go over 700C...well, 
maybe 750C tops, because the tin in the solder tends to oxidize (the slag 
you get on your iron is mostly tin oxide, among other things).

One way to increase the heat of a soldering iron is to make the tip 
massive.  This way, when you touch something cooler, the temperature of the 
tip does not change as much.

Massive tips can be problematic with new small components...so another way 
to increase the heat is to use temperature control, this way, when you 
touch something cooler with the tip, the iron can dump lots of power into 
the tip, making the apparent heat of the tip seem much larger than it 
really is.  Still, for some jobs, I will still choose a tip with a lot of 
metal in it even with a temp controlled iron when I am soldering something 
big (i.e...need more heat).

At 12:31 AM 11/8/2004 +0100, Senso wrote:
>>At 09:09 PM 11/6/2004 -0800, harrybissell wrote:
>>>if I might BUTT in here... I'd be very leery of using a 12W soldering 
>>>iron and
>>>then
>>>saying 'traces lifted'.   There is such a thing as too little heat...you 
>>>have to
>>>hold it on so long
>>>that the heat spreads out into a much larger area. (heat affected zone).
>>>
>>>This can looses the adhesive that holds the copper to the board over a large
>>>area, causing
>>>the lift.  I bet a 40W iron and NO time (it will heat in no time, really...)
>>>would cause a lot
>>>less damage.
>>>
>>>Many old timers agree...
>>
>>        This old timer agrees...more heat is a good thing (please notice 
>> I said heat, not higher temperature).  Even back before I started using 
>> temperature controlled irons, I had an Ungar 47 watt soldering 
>> pencil.  It was kind of a pain in that not only did it have a lot of 
>> heat, but it also attained a rather high temperature...keeping it clean 
>> was a problem.  Still, being able to make a solder joint almost 
>> instantly is definitely a good thing.
>
>Maybe a stupid question, maybe I miss the right diy background, but how do 
>I get more heat without raising the temperature?
>Cold fusion?
>
>Senso
>
>-----------------------------------------------------------------------
>When you know absolutely nothing about the topic,
>make your forecast by asking a carefully selected
>probability sample of 300 others who don't know the
>answer either.             --             Edgar R. Fiedler
>-----------------------------------------------------------------------

         -Jim
***************************************************************
http://www.oldcrows.net/~patchell

***************************************************************