Zak wrote:
I had always lived in the belief that a 15W soldering iron ran cooler
than a 35W iron but recently I read something which said they both
run at the same temp.
Presumably the real difference is the speed at which the iron reheats
once the thermostat kicks in to say the iron is too cool.
I'm in the Uk and I currently use a 25W Antex. It seems to "run out
of heat" all too often when I am soldering undemanding things like a
fine wires to small tag.
If the temp is the same then would I be ok using something like a 35W
iron even for working on electronics components.
As others have said, irons come as uncontrolled or temperature controlled.
The temperature of an uncontrolled iron is dependant on the wattage and
ambient conditions. Wave one around in the air and it will be
substantially cooler than if you put it in an insulated stand. One of my
irons is 250W, uncontrolled, and will soon start to glow red-hot, unless
in contact with a LOT of metlwork being soldered. Great if you are doing
plumbing - not so great for electronics work. The tip is about 1 1/2"
across. It dates back to the 1940s - they may not be avialble
anymore...I got given it by my great uncle, an RN submariner electrician
in WWII.
The temperature of the tip of a controlled iron in its stand should be
near enough the set temperature, irrespective of iron wattage. Once you
start using it, the tip temperature will fall. The key point is how much.
The end of a very long, thin, tip, in contact with a large chunk of
cold metal, will quickly fall in temperature and stay at that low
temperature. It is simply not possible to transfer enough heat down a
very long thin tip, irrespective of the wattage of the iron. So, if you
only use very long thin tips, practically any wattage of iron will do.
I have a very tiny 15W temperature controlled iron which is as
comfortable and easy to use as a 'scope probe. The element tube is about
1/8" in diameter and so is the thickest part of the tip.
However, if you have an iron with interchangeable tips and can use a
thick, short, tip, then the tip is capable of transferring much more
power - so you can make good use of a higher wattage iron. Hence my next
bigger iron up from the teeny one is a 40W. The element tube is about
1/4" in diameter and so is the thickest part of the tip. But the
business end varies from something about 1/16" across for one tip to
1/4" across for another.
I could do with something to fill the gap between the 40W and 250W - I
sometimes end up with an iron in each hand and feeding solder in from a
tube clenched between my teeth...
I reckon that it is the tip that makes the iron. My favourites are a
weller 40W that takes interchangeable tips, each tip with a preset
temperature. But there are places where those irons are simply too big
or too small.
I have a Maplin
www.maplin.co.uk BP53H soldering station that I hate -
I can't get along with any of the tips. Unlike plain copper tips, you
can't just shape them the way you want. They also do a very cheap one
N78AR, which I haven't tried. It may be worth a look - it's a 50w
variable temperature adjustable model for 13GBP.
--
Sue