How do solder guns work?

[Dave]

I have two different solder guns (a 100W Radio Shack and a 325W
some-other-brand) with the same problem, low heat output. The big one will
work properly if held at just the right (fairly verticle) angle, and you can
feel something shifting inside as this is attempted. Looks like it has a
couple of transformers in it, one of which (standard coil of wire through
which the AC current controlled by the switch runs) induces a current in the
other (roll of sheet metal electrically connected to the heating element).
At least that's what I *think* is happening. Can anyone give a better
description of how a solder gun works? I would like to fix them rather than
buying new, as I am on disability. I got them each to work briefly for the
original projects they were purchased for, but then they each decided they
didn't like me

TIA

Dave
[email protected]

 

[Boris Mohar]

I have two different solder guns (a 100W Radio Shack and a 325W
some-other-brand) with the same problem, low heat output. The big one will
work properly if held at just the right (fairly verticle) angle, and you can
feel something shifting inside as this is attempted. Looks like it has a
couple of transformers in it, one of which (standard coil of wire through
which the AC current controlled by the switch runs) induces a current in the
other (roll of sheet metal electrically connected to the heating element).
At least that's what I *think* is happening. Can anyone give a better
description of how a solder gun works? I would like to fix them rather than
buying new, as I am on disability. I got them each to work briefly for the
original projects they were purchased for, but then they each decided they
didn't like me

Resistive heating of the soldering tip. The current flow is impeded by the
lousy connection. Tighten well the two bolts the hold the tip.



Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs http://www3.sympatico.ca/borism/

 

[John Miller]

Resistive heating of the soldering tip. The current flow is impeded by
the
lousy connection. Tighten well the two bolts the hold the tip.

I second that motion. Because you're trying to break through the corrosion
at the tip connectors, it's helpful to loosen first, then retighten. It's
kind of routine for soldering gun operation.

 

[The Al Bundy]

I have two different solder guns (a 100W Radio Shack and a 325W
some-other-brand) with the same problem, low heat output. The big one will
work properly if held at just the right (fairly verticle) angle, and you can
feel something shifting inside as this is attempted. Looks like it has a
couple of transformers in it, one of which (standard coil of wire through
which the AC current controlled by the switch runs) induces a current in the
other (roll of sheet metal electrically connected to the heating element).
At least that's what I *think* is happening. Can anyone give a better
description of how a solder gun works? I would like to fix them rather than
buying new, as I am on disability. I got them each to work briefly for the
original projects they were purchased for, but then they each decided they
didn't like me

Well a solder gun works with a transformer. A large primary coil for the
mains and a very thick wire or metal pin going outside where the soldering
tip is connected between. The tip heats up by the large current flowing
through it. When there is a bad or no electrical contact at all the tip wont
heat up. Cleaning the contacts helps allot. Those solder guns are very
robust, if you maintain them of course.

Some tip for the tip If you don't want to buy those expensive soldering
tips just get some copper wire, as thick as possible, and shape it like such
solder tip. It works as good as an original one

If you would like to know the current that flows through the tip you can
measure it with some current transformer around a connection for the solder
tip. Once I tried it and measured some 100-150A, no wonder you must make
sure that everything makes a good electrical contact.

Al

 

[DaveC]

I would like to fix them rather than
buying new, as I am on disability. I got them each to work briefly for the
original projects they were purchased for, but then they each decided they
didn't like me

You might try removing those two nuts that hold the tip to the gun. Clean the
copper tip's ends and re-insert and tighten *with feeling*.

It's a regular maintenance thing. With solder guns, way more frequently than
I like. That's one reason I bought a traditional iron.

Good luck,
--
Please, no Google links. I wouldn't ask a
question here if I hadn't done that already.

DaveC
[email protected]
This is an invalid return address
Please reply in the news group

 

[CWatters]

Can anyone give a better description of how a solder gun works?

They have a transformer that steps the volts down and current up. The
secondary winding has very few turns - perhaps only one.

The tips have a low thermal mass (eg not much metal) so thay they heat up
quickly.

They don't work well on larger jobs because the tip does not have enough
thermal mass (eg the work piece cools down the iron).

The solution is to use a conventional iron with the right size tip (physical
size and thermal mass size).

 

[Dave]

I have two different solder guns (a 100W Radio Shack and a 325W
some-other-brand) with the same problem, low heat output. The big one will
work properly if held at just the right (fairly verticle) angle, and you can
feel something shifting inside as this is attempted. Looks like it has a
couple of transformers in it, one of which (standard coil of wire through
which the AC current controlled by the switch runs) induces a current in the
other (roll of sheet metal electrically connected to the heating element).
At least that's what I *think* is happening. Can anyone give a better
description of how a solder gun works? I would like to fix them rather than
buying new, as I am on disability. I got them each to work briefly for the
original projects they were purchased for, but then they each decided they
didn't like me

TIA

Dave
[email protected]

Wow. Thanks to each of you. I'll clean the contact points for the tips. I
originally thought it was a bad switch, and replaced same, but got no
improvement. Suspected it was a microfracture in the wire leading to the
primary transformer, caused by the movement of the same shifting slightly
with motion. Was about to unwrap a couple of turns ansd resolder. Mayby
not necessary after all.

RE soldering tips having low thermal mass: before I got the 100W model I
tried soldering several resistors together for an antenna dummy load, but
realized this was hopeless with the 27W iron I was using when the tip FROZE
to the project under construction. Eight or ten resistor leads sucked all
the heat out of the molten solder as well as the tip it was on. Was I ever
disgusted. And that was the final step I needed to complete before screwing
the cover down.

Thanks again to all of you for your help.

Dave
[email protected]