Toast Your Bread With Cinder Blocks And Rebar

Adi Zafran made his toaster out of cement blocks and rebar. He writes that he built it because pita bread is a staple food for him. Oh, I get it: It's like a little brick oven.

The toaster has just five components: rebar, part of a cinder block, wood, a wire and fasteners. I'm not exactly sure how he gets the rebar hot enough to toast, but I imagine power travels through the rebar, and the resistance makes it heat up. And he seems to be in Israel, where outlets pack a 230V punch, which would help.

One less cheap burnt-out toaster headed for a landfill. [FastCoDesign]

Image: Adi Zafran



    The amount of juice required to make that (we call it Reo here) rebar glow would be ridiculous. You would blow the switch board before it got that hot. Absolutely ridiculous!

    It's the current through the resistance of the rebar that causes the heat, not the voltage! Static electricity built up from dragging your shoes on carpet in dry weather alone reaches thousands of volts.

      So whats your point? It will still take way too much friggin juice for it to get red hot!

        The story says "he seems to be in Israel, where outlets pack a 230V punch, which would help".

        Since the author is in the US where outlets are ~110V, I think he thinks that more voltage = better heating.

    ok if that rebar is really glowing red... why isnt the wood burning?

    Comments... Both the Journalist and Commenter (Stew) are wrong...

    Its not the voltage or the current which heats up the element, it is the Power. Voltage x Current.

    Unless you are driving it with an electronically limited current source you can only control the current by controlling the voltage, not the other way around...., the voltage allows a certain current to flow through the Bar... Joules per second= Power.

    Nice Idea, But how do they stop the wood from burning.. (adding a smoky flavour to the Bread.)

      You're right, but also slightly off in your explanation.

      It's current that makes it hot. You only need enough voltage to create the circuit (i.e. overcome the resistance of the Reinforcement Bar).

      Once you've made the circuit the only thing that will make it hotter is more current. Increasing the voltage at the same current will do nothing for you. Hence why we use high voltage wires for long distances, to reduce current and reduce the need for heavier cabling, which reduces resistance and therefore heat.

      With that said, Voltage and Current are directly related. If you have a 10A circuit at 240v (Normal power circuit in Australia), and you use a transformer to reduce it 10x (Assuming the transformer is 100% efficient), you will have a 24v circuit with 100A capacity.

      There's no way that any domestic power supply could heat that bar enough to glow red. There's not enough resistance in the steel to make it usable as a heating element. That's not to say you couldn't use a heating element to heat the bar though, which would be the more likely scenario.

    This isn't how electricity works. I call fail.

      I'd also like to repeat the point made above that it is a DESIGN, the photo is that of a rebar painted red (there's no glow, that much should be obvious) and of course the wood isn't burning, the rebar isn't hot at all.

    aren't cinder blocks made of concrete? doesn't concrete have little air bubbles in it that expand when heated?

    i'd love to be around for the exploding toster. awesome design!

    If it works well in Israel, with 230V outlets, Australia will probably burn our toast to a crisp with 240V.

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