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Over in the MAKE Forums, Chad Oliver has a question about the safety of using a kitchen oven for both reflow soldering and cooking. Anyone know what to do? Let him know over in the forums!

I need to be able to do reflow soldering, but a toaster oven or skillet isn’t really suitable – I travel a lot, and space is tight.

The proposed solution: put a block of aluminium (roughly half an inch thick) on one of the elements on a kitchen stove, and protect all the other elements from lead splashes etc using tinfoil. Attach a thermocouple to the aluminium block to measure temperature, and use an arduino to implement a PID algorithm and signal when to turn the stove on or off. I’d stand by the stove, watch the arduino, and control the stove as directed.

The Question: is this idea safe, specifically in regards to lead poisoning?

Please note that I’m not placing the pcb directly onto the stove, and the stovetop should be fully covered by tinfoil. But I don’t know anything about the effects of fumes or other things that could go wrong.

Photo by Flickr user rileyporter.


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Comments

  1. pben says:

    There is more than just the lead/tin fumes. What flux is being used in your solder paste? I know that the reflow oven at my work is vented to the outside air.

    You have to ask if that comes off and sticks to the inside of my oven this time what happens next time that it heated and come off the inside of that oven.

    Please check what your flux is, how toxic is it, and don’t use any oven for food after you use it for reflow.

  2. jonathan says:

    drill a hole or two into the aluminum block, get some cartridge heaters from mcmaster.

    http://www.mcmaster.com/#die-cartridge-heaters/=9hrox0

    you can also imbed the thermocouple in the aluminum. then all you need is a relay to control the heaters, and something to set it on that can take the heat.

  3. chizz says:

    …indeed I have already got the cartridge heaters (from farnell in the UK) and I’ve built and tested a pic based PID controller, but where oh where oh where do you source thick blocks of aluminium at a sensible price?

    1. pmjett says:

      I’ve had good luck in the past hitting up the local metal salvage for things like that. Of course this isn’t going to work if you a)don’t live near one b)silly liability stuff prevents you going into the yard. We’re down to one scrapyard here that will let you in, but they frequently have odd blocks of aluminum (for reasonable prices compared to McMaster).

      You could, if you were so inclined, try making a simple Gingery-style aluminum melter and pour a plate in an open faced mold (for simplicy). Theoretically… :)

  4. Alan says:

    By the time you assemble the aluminum block, Arduino, and thermocouple, and hack some kind of control to connect the Arduino safely (and reversibly) to a 240V electric stove burner, you really won’t have saved any space or weight over buying a small electric skillet or hot plate.

    If you really want the experience of building it yourself, go for it, but please add a heating element and forget about using your kitchen stove for this. As others have pointed out, eating off a soldering tool is a Bad Idea. If your goal is just to get a working, portable solution up and running, buy the skillet. They’re cheap.

  5. jeff-o says:

    A colleague at work has done this successfully. You shouldn’t need an arduino to control the element, though – just do some experiments ahead of time to determine what dial setting on the stove results in what temperature (using the thermocouple).

    If you’re worried about fumes, use the stove’s range hood to suck them away.

  6. rileyporter.myopenid.com says:

    However, I did use a small skillet I got off of ebay..
    http://www.flickr.com/photos/rileyporter/4157142090/

    Its much smaller than our toaster oven setup.. You can remove the handel I think too to make it smaller.

    Just an idea.

    Riley

  7. Anonymous says:

    The information which you have given regarding the reflow shouldering is very nice and also understanding. It will also help me as well as others for knowing the complete information regarding it. I am very much impressed by this.