Heating Pipe DIY Question

[Christopher Perkins]

[Christopher Perkins]

[Bob Gramann]

Congratulations. Lock that door when you're working (or move your bench). Someone opening that door could knock you into a nasty burn.

[Bob Hammond]

It looks like you're all set to bend.

While I've been away for a week or so, I've thought about this for a bit, and I remembered that I have a $10 toaster oven that I bought at a thrift store for fabricating some stuff from plexiglass. It has some very useful parts that could be used on a bender -- heating elements, an excellent thermostatic control circuit (I'd calibrated it to insure the correct bending temperature for plexiglass (~210-230F), a timer, and a proper gauge cord with a molded plug. You could fit the heating element inside a pipe, using ceramic wall/floor tile as an electrical insulator and hi-temp mounting plate, and the thermal sensor could be placed on the inside surface of the pipe using an automotive hi-temp glue. Maybe I'll dig the thing out from the junk pile and show you the innards of it.

[Pat Foster]

Mine is pretty much the same thing, a length of pipe and a charcoal lighter with a router speed controller. I use an old darkroom timer. They're all over ebay, cheap and indestructible. Had mine for 25+ yrs. Only thing is, they don't go past 1 hour, which is OK for me. As an aside, when I turn off anything in the shop that poses a fire hazard, I turn it off at least two ways, like turn it off AND unplug it.

gralab2.jpg (32.93 KiB) Viewed 9448 times

Pat

[Jason Rodgers]

Hold up! Is that galvanized fence post pipe? That's some bad stuff to breathe. Not sure if you can burn it off (outside!) before using it on wood.

[Bob Hammond]

Jason,

You're concerned about the release of zinc (in gaseous form) from the galvanized pipe when it's hot, I think. When galvanized steel is welded, there is a known danger of zinc poisoning. But I don't know if this applies at much lower temperatures that are used for bending wood. Of course, if things get too hot... Maybe somebody else can provide better information.

[Bob Hammond]

Hmm, I just took a bunch of pictures of the toaster oven and its parts, and thought about the descriptive commentary. Should I post them and the description, or should I start a new thread? At this time, I don't plan to build another bender, but I think the info could be useful.

[David King]

Zinc forms zinc oxide at it's boiling point of around 900º F. Apparently there's little or no risk below that temperature.

[David King]

Oops, I mean 900ºC or 1665ºF.

[Jason Rodgers]

All the same, take it outside and crank it up to eleven for its maiden voyage.