So I bought a 20W soldering iron a while ago and I found the experience very frustrating as the tip does not get hot enough quickly and when it does melt the solder it gets cold so quick I cant get the solder to flow long enough i.e. I end up with blob all over the place.

A friend of mine heard all my cussing and praying for a more powerful iron when I was putting a circuit together and out of the goodness of her heart she bought me 100W soldering iron from Hong Kong. I was praying for a 60W model. This new soldering iron gets hot, about 420 C and I an easily get the solder to flow but I am worried about this high temperature killing my pcb or components.

So main question to ask is this?

Is a 100W iron safe to use on Arduino type projects? What are the risks I run with using this type of iron?

Just a safety check before I destroy something valuable.


Been soldering for a while now with both the 20W and 100W and they both have very different uses. The 100W is NOT recommended for smaller job and finer components it is way to powerful. I replaced the tip of the 20W iron and tinned it properly and been keeping it tinned. It is actually not that bad so I suspect my blues started with the tip not being maintained properly. Lesson learned experienced gained.

Update 2:

Finally invested in a proper soldering station(Hakko-FX888) and I am in soldering heaven. I felt like I have been trying to paint the Mona Lisa with rock with my other irons. Life is beautiful again.

  • 3
    \$\begingroup\$ Safety in most soldering is proportional to skill and care. When you really get into this stuff though you'll want a temperature controlled iron. \$\endgroup\$ – Sean Boddy Mar 1 '15 at 1:26
  • \$\begingroup\$ @SeanBoddy I did soldering at high school as part of my electronics course however over the years I did very little soldering so initially I was a bit rusty. I try to keep the heat as low i.e. make enough contact to just get the solder flowing and get the joint done before breaking contact. However I was more concerned that there is some sort of hard limit I forgot about over the years. \$\endgroup\$ – Namphibian Mar 1 '15 at 1:32
  • \$\begingroup\$ Its about timing and control. That 20W iron would destroy just about anything - eventually. A temp controlled iron gives you better control and can ramp power to maintain a given temperature, which gives you much more flexibility. \$\endgroup\$ – Sean Boddy Mar 1 '15 at 1:38
  • \$\begingroup\$ You might be able to use a dimmer to reduce the output of the 100W soldering iron, but I don't recommend trying it and you certainly didn't hear me suggest it. \$\endgroup\$ – Ignacio Vazquez-Abrams Mar 1 '15 at 1:50
  • \$\begingroup\$ Whether an iron is too powerful or not depends partly on the skill of the user. I've used a 250W iron (likethis one grainger.com/product/AMERICAN-BEAUTY-Soldering-Iron-5ZGV1 but more primitive) to repair a television. Not recommended for daily use, but it can be done without frying everything around it. The barrel of the one I used actually glowed cherry red in use. Scary. \$\endgroup\$ – JRE Jul 1 '15 at 7:41

Using a 100W soldering iron will obviously get the job done. It will melt nearly any width electronic solder, and maybe do some moderate plumbing jobs too. With an iron like this you will likely never learn the important aspects of soldering sensitive electronics. You will possibly destroy many parts as you learn.

A 20w soldering iron should be well enough for most electronic soldering applications, (except for very thick wires or heavy duty solder lugs). One of the most important things is to learn how to keep the tip "tinned". This helps transfer the heat to the item being soldered. Tinning a solder tip involves cleaning the tip and getting a thin coating of melted solder on it. This is easy to recognize as the tip will stay shinny with the liquid solder. When using the soldering iron it is also important to frequently clean the tip using a damp sponge (often sold with a soldering set). See some additional tips here:



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  • \$\begingroup\$ I find using brass tip cleaner more appropriate. The schock when dipping hot iron tip into cold moisty sponge can cause microfractures. \$\endgroup\$ – Golaž Mar 1 '15 at 18:53
  • \$\begingroup\$ @Nedd I kept the tip tinned on the 20W one but I am pretty sure it is faulty now as it just does not heat up properly. I use a brass tip cleaner as well as a sponge. Now that I think of it the iron must be faulty as it just heats up a a little then almost dies. I have had it for just over a year and about 2 months ago the performance just went very bad. \$\endgroup\$ – Namphibian Mar 1 '15 at 20:11
  • \$\begingroup\$ @Golaž: Only poor-quality soldering iron tips shatter when subjected to these hot-cold cycles. If your tip breaks because you're using a sponge, that's your hint that you need to get a better iron. I'm not talking about extravagant expenses here; I've used US $9 irons that easily withstood use of a sponge. \$\endgroup\$ – Warren Young Mar 1 '15 at 21:11

With practice yes. Don't stay on the part too long, and everything should be OK.

I have a 100W that I use when not at work, never had a problem.

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  • \$\begingroup\$ Thanks as I suspected it should be fine. I guess a tip would be if the pcg starts melting you kept the soldering iron on the board too long. \$\endgroup\$ – Namphibian Mar 1 '15 at 5:12
  • \$\begingroup\$ If your 100W iron is temperature-controlled, you can't compare it to a 100W pencil iron. \$\endgroup\$ – Warren Young Mar 1 '15 at 20:54

A good compromise is 40W iron for larger components and 20-25W for small, sensitive ones. 100W is way too much.

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