How does a soldering gun work?

[wdfifteen]

I'm trying to diagnose my problem with soldering.




I cannot get 14 gauge stranded copper wire hot enough to melt solder with this soldering gun. I don't know if it's working properly and just isn't up to this task or what.

How hot should the tip of a 140 watt soldering gun get? Is the heat generated in the gun and transmitted to the tip, or does only the tip itself get hot? Tightening the tip down VERY tight doesn't change anything.

An IR reading at the tip shows a maximum of 330F. I know that is incorrect, because the solder does eventually melt when applied directly to the tip, and this 60/40 rosin core says it melts at 370F. The problem is I can't the gun to heat the wire hot enough to melt the solder. The method I'm using now is to get a blob of melted solder on the tip and hold it against the wire, hoping the liquid solder will transmit more heat than the bare tip, but even that isn't working.

I'm working on a 1956 Porsche and I have to re-tin a lot of wire ends. A 1956 Porsche has a lot of 14 and 16 gauge wire.

[masraum]

I always thought the tip was like the heating element in a toaster/hair drier/oven, and that current runs through the tip and makes it hot. But I guess I don't know for sure. I was under the impression that if you stop getting adequate heat that either the tip could be bad (likely visibly so) or that maybe something in the guts is keeping the gun from creating enough current to heat the tip.

[3rd_gear_Ted]

I use emery cloth to clean the wire strands when i see less than the good copper color it should show on the wire strands.

[wswartzwel]

Sometimes the heating element needs cleaned/ tightened, where it attaches to the gun. There are threaded nuts that can be tightened so it gets better connection. then the tip will get hotter.

[DRONE]

Remove the varnish coating on the copper for best results as 3rd gear suggests
Are you using rosin core solder that will enable the best flow and try an iron from this century.

[whiskyb]

Some of those gun style soldering irons have a 2 position switch/trigger

[LWJ]

I have a Weller gun like this. It is “janky” to quote my son. Just not a good tool for the job.

I would suggest a cheap, pencil style soldering iron. If you are not heating large pieces with significant thermal mass, the little irons are perfect.

Other’s will have more info. I am not a pro at soldering.

[fintstone]

There is not much to one of these. If I recall, that model has a dual position trigger for high and low heat. If it gets hot (but not hot enough) in both positions, the switch is likely good. All that is left is a simple transformer and the connections (other than the tip). These always have tip issues. The tip connections must be extremely tight and the tip in good shape as there are low voltage/high current. If thinning at the tip or dirty, it will not draw enough current. If you don't have a spare tip, you can use a piece of clean solid 12 ga wire to test (like from a ground wire). Put it in and tighten well. 14 gauge or lower is too small. Use pliers to shape it somewhat like the original tip. It should melt solder just fine.

Don't use these guns on circuit cards if you can help it as they get too hot (when working properly).

[70SATMan]

I hate soldering guns. The tips actually wear over time and depending on the age of that gun, might be due to be replaced.

Do yourself a favor, get a decent Weller bench top iron that you can change the tip
Size so that you can optimize what you’re working on. Many have simple temp controls as well.

Or you can get really fancy with a bench top Metcal. I’ve hauled soldering stations all around the world, worked on equipment in some of the hardest site equipment configurations and body contortions. NEVER have I considered this type of iron.

Sometimes it’s just better to punt.

[911 Rod]

I think this gun has 2min/2min setting. Once you have held the trigger for 2 min it shuts off, then you need to release it for 2 min before pulling it again. Rinse and repeat. Or something like that.
Apply paste to the wire for the solder to flow where you put the paste. Hold the tip firmly to the wire and apply solder.
You should be using bare butt connectors + shrink wrap to join wires though. Solder can/will crack on anything that is moving like a vehicle.

[wdfifteen]

Originally Posted by fintstone

These always have tip issues. The tip connections must be extremely tight and the tip in good shape as there are low voltage/high current.

Well I'll be darned. I took the tip off, looked at, and put it back on, tightening the nuts down EXTREMELY tight, to the point where I thought I would break something - nothing left to lose, so why not.
As soon as I pulled the trigger I noticed the buzzing was much louder. The temp came up to 454F in no time.
So all this time I thought getting the nuts really tight was adequate. Nope, they need to be brutally tight.

[Rick Lee]

Not cheap, but my Hakko has been great for years and years.

[jcwade]

I also have the Weller style gun. Way too heavy for delicate work. Thus, it never gets used (in fact, I should give it to the Goodwill).
The pencil style always gets the job done.

[wdfifteen]

Originally Posted by 911 Rod

You should be using bare butt connectors + shrink wrap to join wires though. Solder can/will crack on anything that is moving like a vehicle.

I'm laying on my back under the dashboard of my Speedster straightening out and re-tinning the wires for these screw-pinch connectors, so bare butt connectors are out of the question. But it's fun to say!

[Scott Douglas]

Funny, I have that same gun too, and the same problem most times I go to use it as well.

[masraum]

Originally Posted by Scott Douglas

Funny, I have that same gun too, and the same problem most times I go to use it as well.

My dad had the same gun when I was a little kid. When we bought the house that we're in now, there was a box in the garage that had one of these Weller guns in it (I think it's still out there).

[Bob Kontak]

Originally Posted by wswartzwel

Sometimes the heating element needs cleaned/ tightened, where it attaches to the gun. There are threaded nuts that can be tightened so it gets better connection. then the tip will get hotter.

I was thinking exactly that and I guess I'm not the only one. :-)

I have three of the Weller guns and if one of three are working I am happy.

I like the pencil style as mentioned.

[gregpark]

Originally Posted by wdfifteen

Well I'll be darned. I took the tip off, looked at, and put it back on, tightening the nuts down EXTREMELY tight, to the point where I thought I would break something - nothing left to lose, so why not.
As soon as I pulled the trigger I noticed the buzzing was much louder. The temp came up to 454F in no time.
So all this time I thought getting the nuts really tight was adequate. Nope, they need to be brutally tight.

Glad I checked this thread out, I was about to buy a new gun. My Weller simply needed exactly this and now it works great again. Thank you

[wdfifteen]

Thanks Greg. You know sometimes I come here with a question that I’m embarrassed to ask because I don’t want to look like a moron. It’s nice when I swallow my pride, and ask a stupid question and it ends up helping someone else out too.

[Magyar Kiwi]

Good fix !
More on how a soldering gun works here:
https://en.wikipedia.org/wiki/Soldering_gun
Cheers