How to Make a Variable Soldering Station

Introduction: How to Make a Variable Soldering Station

About: Why pay for stuff when you can make, build, hack, macgyver it. They are better and cheaper 100% DIY.

Having a way to controle the temperature of your soldering iron it's a good thing to have on any workbench, depending what type of work that you are doing you will need to change this settings.

On this project i will show you how to make a variable soldering station using a very common light dimmer.

Step 1: Watch the Video

Watch the video and see how easy it is to make this project.

Step 2: Gather the Material

You will need for this project:

- Light Dimmer

- Power Plug

- Soldering Iron

Step 3: Get Started

This project is very simple just connect the power plug to the light dimmer, plug your soldering iron to the light dimmer and your ready to go.

You will need figure out what's the best setting for you and mark the dial according, you can have different marks for different temperatures.

Not also this make more easy to work on very types of projects, it will extend the life of your soldering iron because in some occasions you are not using the maximum temperature.

Step 4: Final Thoughts

This is a very cheap hack to make.

Tell me on the comments below what applications you will use this for.

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Thanks for reading

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    12 Discussions

    I use a similar approach to control the temperature for a soldering iron for stained glass. I mounted an ordinary light dimmer and a household plug on a small plywood box, then wired them together inside the box. Adjusting the dimmer switch controlled the power of the plug. Worked great. Years later I used the box again as a speed control for a single-speed electric drill.

    1 reply

    It´s the same concept, i´m using this idea for 15 years now.

    Why would you want to vary the temperature? Solder always melts at the same temperature, doesn't it? Of course, depending on what you are soldering, you might need more power to do some jobs. Which is why your project may seem like it is changing the temperature to you. You are really just adjusting the power output by regulating the input though. Which in some cases would affect joint temperature.

    But it isn't really the same thing. As in true temperature controlled irons they adjust based on the actual iron temperature, as opposed to relative need.

    7 replies

    Depending on the work that you are doing you will need to set a different temperature, in this case i'm using a 30w soldering iron.

    With the light dimmer i can reduce the voltage to the iron reducing the temperature also.

    If you change de input voltage to the iron this is no longer outputing 30w.

    I'm using this trick for a longe time now and it work great.

    How do you know dimmers change voltage? Have you measured this change? Because the way dimmers work they really shouldn't. What dimmers do is change the duty cycle of the power. There is a part inside dimmers (usually an SCR) that acts like a switch, and it automatically turns the power on, and off, quickly. The duration of on, and off, is varied by the knob you turn. Together this whole arrangement is called Pulse Width Modulation (PWM).

    Everything is done this way because it is cheap, and efficient. It works well enough that most folks think they're adjusting the voltage too ;) Ohm's Law is kind of hard to figure out on AC anyways. The voltage is always rising, and falling.

    Most dimmers don't use PWM. PWM is digital signal modulation. Only few dimmers use PWM (one such dimmer is digital balast for fluo lights). You are right on SCR part (SCR is just another name for thyristor). Most dimmers are build around triac (bidirectional thyristor), diac and some pasive elements (resistors, potentiometer, capacitor). The circuit is self regulating its output power. If you would do some measurments on output voltage you would see that average voltage is the same as voltage without dimmer (0 V). But peak voltage vary and efective voltage is lower. The same is for current.

    On this picture (first one on Google Search) you can see that the frequency stays the same (50/60 Hz). With potentiometer you set time when circuits is conducting power and this time is the same for both halfperiods (if you are using thyristor instead of triac, this only works in positive halfperiode, in this case average voltage is not 0 V). All this comes from thyristor's, triac's and diac's characteristics combined with some pasive elements (that is why this is not PWM).

    Also, with PWM and with dimmer you get lower voltage and lower current. This is becouse power is P = V * I * p (p is duty cycle). And with switch (which thyristor and triac are) you can not just adjust current with no efect on voltage (and via versa). This could be presented with old light bulbs. Old light bulbs works as ohm load (it works as resistor). To adjust power on ohm load you can adjust voltage and current always want to stay around stable point, which is given with I = U / R (Ohm's Law, it is the same with AC circuits, you should always be aware what you are calculating - efective, peak or average valuve). So with same resistance and lower voltage, you can only get lower current. Also you should know that UI characteristic is (sort off) linear only for basic pasive elements and it is exponental (or polynominal or some shapes that are hard to explain with math) for semicondustors (diode, transistor, thyristor, triac, diac) and derived elements.

    I hope all this was instrumental in any way. =)

    Don't feel bad. A lot of folks just don't get how AC power really works. The reality of course is in practical use the zero crossing is a meaningless event. As the ground potential is not used then either. If your house panel there are 3 busses. 2 hots, and a neutral. Between the 2 hots is 240VAC. Between either hot and the neutral is 120VAC Now if you're using 240VAC then you're not using the neutral at all. But that voltage is still clamped to ground through the grid. Which is a good thing.

    Some elements (ICs, transistors...) are very temperature sensitive. Every manufacturer recommends highest temperature for soldering. From my experience I know that 30 W soldering iron is not ideal for IC becouse it is too hot (best emperature for IC is beetwen 230 °C and 280 °C - ideal soldering iron is around 20 W). For soldering connectors and other elements that are not as sensitive 30 W is good enough (temperature can go up to 350 °C or higher, depends on soldering iron). This is why investing in soldering station (or making one) is a big deal! Many cheap soldering stations use dimmers. So making one like Engineer of None did in this instructables can be the right way to start.

    Varying the power is not ideal. Controlling temperature is. Duration is just as important to control as the heat you work at is. Work too cold and you'll end up working too long. The common maximum rating for electronics is 300C for 10 seconds. Hot and fast is my preferred method of soldering.

    Great job!

    One thing to consider:

    Choose 3 or more position on potentiometer and measure temperature of soldering iron. Then make a scale so you could set the temperature you need. =)

    1 reply