Think this will work for a heated bed?

I just recently got my Techzone Mendel up and running and the need for a heated bed has become apparent. I think the fact the last couple days up in Edmonton have been like 7 degrees and it's in my garage might have something to do with severe warping. So I came across this 170W hair straightener for a bit over 20 bucks. I'm sure if I shopped around I could find it even cheaper. It has thermal fuses built in and the contact area on the heating pads is about 23mm X 89mm. The thermostat is a bit on the hot side but shouldn't be too hard to mess with. I haven't got a chance to strap it to my aluminum print bed yet. I'm thinking I'll have to put something to diffuse the heat a bit but I thought I'd share with you guys.

You might need to think about a heated chamber if you're extruding into ambient temperature much below room temperature. Even at room temperature, large parts will warp due to uneven cooling.

It's supposed to warm up to a reasonable temperature tomorrow. I had just moved it out to the garage because I thought it was June and was supposed to be nice. Jokes on me I guess.

Well I threw the two heater plates on the aluminum plate just now. The ambient temperature is about 11` and the plate hit 50` in about 2 and half minutes. Then gradually leveled off around 70. I'm sad to admit all I have handy is an electronic oven probe so these numbers are probably a bit off. At least it gives me an idea that it works. I'm just going to have to dig up some thermal epoxy and a little insulation and see what I can get it up to. Either way it's nice and low profile and a pretty quick way to hack some heat into your bed.

Glued them on with some Inferno Metal Repair and a bit of insulation over the back and the lowest setting seems to sit around 60 degrees. The highest setting seems to level out about 125 or so. Works pretty damn good if somebody needs a heatbed in about an hour plus time for the epoxy to set. Time to get serious now!

They also sell hair straightener mats for a few dollars that are basically a 200mm square chunk of foamy insulation rated up to 260`C!

Sublime pointed this post out to me, and I decided to give it a go.

Milled a aluminum mounting plate up that allowed me to screw the two heater elements from a $25 crappy walmart hair straightener. How they price those so cheap with 2 ceramic heating elements is beyond me. When I was tearing down the existing control board, I found two extra leads on one of the elements.... hmmmm...... measured them with a multimeter while testing different temperatures with a heat gun and discovered that they are a negative correlated thermistor with 160kohms at room temp, down to around 120k at 60C. Immediately started hacking on sprinter firmware to allow the use of that thermistor with PID and an SSR. I'll post again when I get it all worked out (and post to github).

P.S. I have no problem pulling 105C out of those elements on my uninsulated base/prusa. They tend to oscillate with the stock controller if I leave it in the middle, but the lowest setting on the stock controller gets around 60C and the max between 105C and 120C.

pics soon too.

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New Citadel Mendel
Our Maker Faire projects.
677 mm/s rapids.
Old Sherline/EMC2 first run.

What size straighteners did you both use 1/2", 3/4", 1", 1-1/8", 1-1/2". 1-5/8"? I've been thinking about adding a heated bed to my prusa and thought I may try the 1-1/2" ones from Wal-mart

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Tantillus.org	Mini Printable Lathe	How NOT to install a Pololu driver

Hey all, sorry for the delay. I got held up with work stuff and forgot to follow up here.

Long story short, the hair straighteners no worky in the long term, as the nichrome eventually burnt out from the temperature cycling. What doesn't burn out, however, is an even cheaper $19.99 black and decker clothes iron. Mind you I had to use a solid state relay to switch it, but it does work really well, with over 100 hrs of runtime on the Prusa bed. I'll try and post pics and docs on what I did, as I took notes and have plenty of pictures, just no time to blog it right now.

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New Citadel Mendel
Our Maker Faire projects.
677 mm/s rapids.
Old Sherline/EMC2 first run.