Wetting sides for Hot Pipe bending.

I've got the hot pipe built and working. 1 1/2 inch diameter aluminum bar with a 250w die heater buried inside it. Wetting the wood with a spray bottle of water seems to work. Would longer term soaking before starting improve the process?

I only ever use a spritz bottle to wet the area I'm bending. Re-Spritz as you are working the bend. For really cranky timber I will apply a veneer softener.

I keep a barely-damp rag handy and wipe the section that needs it as I bend. Wood is only really wet for minutes or seconds. I try to use minimal water, just enough to help distribute heat. Soaking can be dangerous for figured woods in thicknesses we use on sides since it can cause the fibers to swell enough to start splitting all on their own. Give it a try if you have a scrap of curly maple or koa - soak it for an hour and it'll basically self destruct when you try to bend it.

Do you have a controller or rheostat on the heating element? My iron is a 300w element in a steel pipe wired to a simple dimmer, and I find I have to keep it turned down about halfway or a little less to be in the ballpark for most bending. On full blast the pipe gets hot enough to scorch wood on contact.

Thanks for the quick replies. I do have a controller on the heater and at 50% power I get water drops dancing on the top of the pipe and no sign of scorching. Bending seemed to progress in a nice predictable manner. I'll carry on.

dwizum said:

My iron is a 300w element in a steel pipe wired to a simple dimmer.

Click to expand...

What kind of heating element are you using?
Something "off the shelf"?

Mine is a 2 wire 110v 250w cartridge heater. 12mm x 60mm. Amazon 2 for less than $13. I have a Variac for voltage control but a dimmer switch would work. Only draws a bit over 2 amps.

I don't wet sides unless I have to have the iron hot+

emkc said:

What kind of heating element are you using?
Something "off the shelf"?

Click to expand...

So I just went and looked and it turns out I was wrong, it's 500w. No wonder I have to keep it turned down so low! It's an electric charcoal starter, I got it at a local hardware store for maybe $12 I think. I see there's a similar one on Amazon for a few bucks more:

https://www.amazon.com/Char-Broil-1258466R06-Electric-Charcoal-Starter/dp/B06W5VR3ZF

If I were to do it again I'd use a cartridge heater like Ron did if I couldn't grab one of these easily. The charcoal starter was convenient because it features a "handle" that made mounting easy, but it was inconvenient because the element barely fit in the pipe I used. A cartridge heater would be easier to fit in a smaller diameter pipe.

Finally got a decent temperature check on the surface of the aluminum bar. 350 degrees F at 40% power. The wood moves nicely with no sign of scorching. English Walnut. Dampened with a spray bottle.

Yes, of course, the longer the soaking, the better it is for you and the result in general.
I was working with material that was almost impossible to stand up in a mortar, and generally, the pipe was made by a beginner, so it was not easy for me to bend this pipe.
I was working with a pipe bender https://www.lakeside-hire.co.uk/tools/conduit-pipe-bender-on-stand/, and I was only with effort able to bend the pipe normally so that there were no defects left on it.