Background: I have been successfully soldering, both constant watt iron and variable watt station, for over 50 years now. The other day I was attempting to solder a 30ga. wire to a Soundtraxx decoder for a keep-alive cap/diode/resistor. SMD’s are somewhat new for me, but I tried # 3 on my Weller WLC-100. Yes, I cleaned the tip, pre-tinned the wire and used liquid flux. What bothered me was the SMD diode I wanted to solder to, wasn’t heating up fast enough, which surprised me. Not wanting to risk un-soldering a hidden trace on either side of the board, I turned the unit up to about 3.5. waited a bit for temp to stabilize and then it soldered just fine.
I know the WLC100 is widely used in the hobby and was wondering if anyone has nailed down the watts and/or temps for each of the 5 settings. I assume 1 is 5W and 5 is 40 watts, but what of the in-between settings?
I tried a search here, but the only applicable comment I found is that someone uses the 3 setting for everything. I’m sure it works fine for him. But I personally hesitate to use the same setting for an SMD or 30 ga. wire that I would use for soldering a dropped 20ga. feeder wire. Any particular same # setting is surely to be too hot or too cold for one or more of those.
If no one knows the rating of each of the 5 digits, perhaps a quick comment on what setting you use for SMD installs, for SMD removals, solid state, various size wires, CB trace component removals, etc.
As always, thank you for any info you can provide. Ken
Assuming a linear progression of available power, each step is ~20% (or, for a 40W iron, a step of 8W).
Now, that’s just the wattage the iron is using/putting out … I’m not so good with Thermodynamics to accurately convert 8W to actual heating capacity that the iron itself has (e.g. “40W = 400 F” or somesuch).
However, I have been able to find that 40W = a change of 0.02 Celsius per second (~32 and change F), so assuming that it’s a constant change, letting a soldering iron sit and burn 40W of power for 15 seconds should get it up to 480 degrees (less dissipation and all kinds of other mathematical stuff I have no idea about).
Suffice it to say that the higher the wattage, the faster the iron can get up to “operating temperature” and the more stable that temperature will stay when soldering things.
Since this particualr model isn’t a true temperature controlled iron, it’s hard to say what settings would be good. It shouldn;t need to be up very high to do small stuff like decoder wire - before I got a soldering station I used a measly 15 watt iron for such work.
My station is a temperature controlled one, but it doesn;t have a readout so exactly what I’m getting at a given dial setting is up in the air (I guess I could get one of those fancy thermometer thingamabobs and calibrate the dial if I was really concerned) but I usually set it around 40 for most soldering, the only time I crank it up a bit higher is for soldering wires to track or soldering peices of track together. But it really doesn’t make much difference.
The difference is, with mine it’s putting the whole 45 watts into the iron at all times, cutting off to maintain the temperature (within a range - it’s not a precision controlled device, those are far too expensive for hobby use, and really aren’t needed). The way that Weller works, it limits how many watts go tot he iron but it’s always on, just like a basic iron. Left on for long periods, it will ‘cook’ the tip - at low settings this can take a long time though.
I use the WLC100 station. For small wire and PC board, the conical fine tip at half setting. I don’t care what the wattage really is.
For track feeders, the wedge tip that comes with the set at ¾ setting.
Been doing that for many years.
Though it is expensive, I use Cardas Quad Eutectic solder which by far is the best solder I have ever used. No solder balls between PC board traces anymore.
For SMD components, silver solder paste made especially for SMD work. Touch the spot with the conical tip and almost instantly the job is done. Clean with acid brush and alcohol.
I keep a little container or tip cleaner nearby which helps keep the tip cleaner a little longer than just using the wet sponge.
About three years ago I purchased an infra red temp scanner and monitored the heat. Don’t remember what the readings where but i have been happy with the setting for quite some time.
The scanner is about $50.00 and I use it for other temp measurements also.
After reeading your comments, I think the wattage estimation you indicated assuming linear progression is all I need. The watts is what I am used to with irons anyway. But thanks for of this. I never heard of calculating the temp as you showed. I’ll have to save that.
When I was working for NASA, we soldered at a temp of 700 degrees. The thicker or heavier the tip was, the bigger components we could solder because the mass held the temp better.
I have two variable soldering stations at home now. Both are different from each other and only have the reference number dials. The irons are about 40 watt or so. I find that turning the temp up to ¾ of full works best for me in just about all situations. When I am not actively soldering at the moment, I turn the temp down to low or ¼ to prevent the tips from burning.
Keep in mind that there are all kinds of “rules” for thermodynamics I was probably breaking. I have no real understanding of it, and the calculators used were found through Google.