$10ish DIY Variable Temp Soldering Iron Controller

Picture of $10ish DIY Variable Temp Soldering Iron Controller
This instructable will show you how to make your Radioshack "firestarter" soldering iron into a variable temperature version using around $10 in parts. This idea came to me after i started lifting traces on a circuit board because I was using a 30w soldering iron to solder on a chip. Plus, I am cheap and variable temp soldering irons cost a lot more than $10. Caution: this instructable deals with household AC current. If you don't feel comfortable wiring things up or plugging things in, this is not for you. Also, this is my first instructable so I'm sorry if it sucks.
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Step 1: Parts You Will Need

Picture of Parts You Will Need
Flat Head Screwdriver
Wire Stripper
Tin Snips or a dremel

Grounded wire pigtail (mine came from a florescent light, you could just cut the end off an old computer cord. Just make sure it has clearly defined wires. (i.e hot, neutral, ground.)
Romex Connector
4" x 4" Handy Box
4" x 4" Handy Box Outlet / Switch Cover + included screws
600w rotary light dimmer + included screws and wire nuts (mine is made by Leviton and was the most inexpensive model at home depot.)
Lamp with incandescent bulb for testing.

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kinderio made it!5 days ago

Fun to make!

jwgottabass1 month ago

I wish I had read this a week ago before I finally sprang for a variable temp soldering iron, funny thing is I have had it favorited on here for at least a couple of weeks, I must have found it during one of my crazy Instructables tornadoes and promptly forgot to actually read it.

But I won't forget it again, I'm sure I'll have need of it in the future. Thanks for taking the time to work this up.

andrew.l.arth3 months ago

i really have no idea what im doing but you might be able to help.Im working on a model train layout, what i want is for a kid to press a button the train goes for 2 min then stops. the child does this 4 more times. after the train stops for the 5th time it activates a cool down clock for 10 min. it would have to work with electricity from an out lit. Any ideas?

use a arduino with a relay shield(or without shield, but with a relay) and make sure you switch the hot wire, not the neutral.

also make sure your relay can handle the volts and amps.

Bamby1012 months ago

I MADE IT and it works PERFECT!!! Thank you, thank you, THANK YOU! And if a female who is afraid of breaking her fingernails can do it, ANYONE can! GREAT instructions, simple to follow and easy to understand.

rrokzz6 months ago
rrokzz6 months ago
rrokzz6 months ago
HVACRguy3 years ago
ALSO you could use an amp meter to see how many amps the iron is using then multiply amps by volts and that will give you watts! you can then mark on your dimmer control box where 15 watts is 20 watts 25 watts 30 watts 35 watts and 40 watts are!!! hope this helps

i've read that current draw might be proportional to tip-temperature, and will therefor vary as temp varies. Anyone know if this is correct?

Just test the amperage after the soldering iron has fully heated.

tutdude981 year ago
what if i use 100w just for soldering iron? here in europe voltage is 240 does that matter?
MROHM2 years ago
This is a Great and Handy Project!! This does NOT SUCK!! I may build one someday!! Thanks...You Rock!!
atlantica2 years ago
Can I use this to plug a 1500 watt heater into, thereby controlling the temperature?
titaniumw41 (author)  atlantica2 years ago
No! Don't do it! It the dimmer is rated for 600 watts max, and some of the aluminum for cooling has to be cut off to fit it in the box. It would be a good idea to stay under the 600 watt rating.
Do they sell higher wattage rated dimmers we could use instead?
After doing a little research I found the Harbor Freight has a Router Speed Control. Basically used the same was as this dimmer. The Router Speed Controller is $19.99 online.

The controller is 120 v x 15 amps. Wattage = Voltages x I (current). So, the Router Speed Controller is rated as 1800 watts.

I found some companies to have 2000 watt dimmers. Did not see one on Home Depots website. Maybe a lighting store would have one. Also, homedepot has a 20 amp Plug/Receptacle. You could probably use that in Titaniumw41's plans with the 2000 watt dimmer to control the heater temperature.
sdtacoma5 years ago
Great INS. Very easy project to complete.

Quick question... Does it matter which silver screw is used for the white wire? You specify the "hot" side for the black wire, is there a certain side for the white wire? I just picked one and it works but I just want to make sure.

I'm not an electrician, but this much I DO know to be true.

On outlets like the one pictured, you will see 4 screws on the back....

it does NOT matter which screw you use, as long as the screws are both the same....

what I mean is this: if you hold the outlet like shown in the pic you will have 2 top screws(1 on each side) & 2 bottom screws(again, 1 on each side).

It does not matter if you use the top screws or the bottom screws, as long as BOTH are on the top, or BOTH are on the bottom.
If you have 1 on top & 1 on bottom it makes it easier to short out BOTH the outlet AND whatever is plugged into that outlet.
When looking at the outlets... If you remember that "White Is Bright, Black Is Gold and Ground Stands Alone" then you'll never go wrong. MOST times you want to be controling the Phase (Hot(Gold Screw, Black Wire)) as most things are made that way. Neutral is used to return the unused power back to the source (ie: Power plant). You Can control the Neutral but I wouldn't do this for anything that is servicing electronics. This is also why you will always find the Fuse or Breakers on the Phase (Hot).
TY Sir....
I never thought of it that way before...TY
;) I hope it helps!

I SHOULD mention that this lil poem only works for outlets in North America...I'm not too sure about other countries that use 110-120 VCA.

....and I want to thank Everyone for all the Great Instructables!
if it works in North America, chances are, it will NOT work across the pond....
Europe, Asia, near east, far east & middle east, etc.

what I have been told thru the years is that they have a different set up for electricity over seas than us Americans have.

Now weather that is true or not, I do not know...that is only what I have been told.
Another question...

Does anybody know where in this circuit I could put an LED to show me when the unit is on/off? I would like the LED to be either on or off and not to dim with the dimmer.


another thing you can do is have a single junction box attached to the double junction box. & then inside that smaller box, have a switch that has a light already in would come on when there is power running thru it & off when there is not.

For those who may not know the terminology, a junction box is that galvanized steel box shaped thing in the pic. what is in the pic is a double junction box....a single junction box is half that wide.
MROHM sdtacoma3 years ago
Yes I Do!!! But It's Far Too dangerous especially at a Beginner's Level!!! Led's draw 10 to 20Ma and shouldn't load down the Dimmer!!! I have used a Led as a Ac Voltage Indicator but feel this project should be geared to our Advanced Electronic Builders!!! Sorry,,That's just how I feel about This.
Look for a dimmer switch that lights up when it's on.
 you would need a relay
not saying it WILL short out, it just makes it easier for the electricity to produce a short.
SIRJAMES092 years ago
Ya did great Chief. :)

you explained it well, the pics reinforced your explanations, if there are any errors in this Ible, the errors(or omissions) were on the side of safety...which is good.

TY for sharing
its2l8men3 years ago
I used a utility box for this project and put it in the wall, just like a normal outlet but has a dimmer for my soldering jobs.
CB20013 years ago
Ironically, you not only made a Variable Temp Soldering Iron Controller, you also made a dimmer switch for a DIY lighting kit. :D
KJ4ZVQ3 years ago
OK THIS IS SHEER LUCK!!!!!!!!!! and kinda wierd too. i logged on to finish up my publishing an an i'ble on the SAME wiring circuit, in the SAME desighn, but for a different purpose. lol i built mine for a church event where we needed to dimmcanned lights for special effects. i wondered too, if this would work for an iron, but never tryed. great job and very nice i'ble. you did it more justice than i would have no matter how long i worked on it:)
thank you for this instructable... i was actually in the middle of doing this with the same exact dimmer switch, but i didnt know which ground should go where... so thanks a bunch
MROHM3 years ago
If this is your first project you did a fine job!! It's cheap and serves a useful purpose. What else can I say??
milsorgen4 years ago
 Couple thoughts... The Romex Connector I found at Home Depot as 3/8" Clamp Combination Connector sold in packs of 5. They didn't have the exact face plate nor did they have 4x4' Handy Boxes, but that's easy to improvise.

It should be noted the Clamp Combo Connectors come in various sizes and you need to match it to the hole in the electrical box you plan on popping out.

I ended up using a Lava Lamp for testing and remembered the comments about an indicator lite. Well it's not pretty or efficient but it's very easy and gets the job done if that's a feature you desire.
bluize705 years ago
I can't tell in the pics if you have done this but the ground wire should also be connected to the 'handy box' which in turn would be grounded thru your outlet which is ground thru your breaker panel...the way it is now if something went wrong inside it would be looking for a good ground which could be you...
The ground terminal on the outlet is usually attached to its mounting points. When you screw the outlet to the cover and the cover to the box, the box should be grounded if you have paid attention to the rest of the instructions. (i.e. green wire from your power cord going to the outlet ground connection.) I did one of these a long time ago with a few refinements... not sure if I should submit my own 'ible or if I should just post the enhancements here... What sayeth the collective?
 Do your own instructable, threads have a way of going zombie and the relevant info is lost for most.
Pauper bluize705 years ago
No ... since the ground wire is connected to the outlet ground, and the outlet is mounted to the outlet box by the mounting screws, the box IS grounded thru the outlet ground. The mounting lugs on the outlet are at ground potential. This is standard code for electrical wiring.
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