I need to build an aluminum tube annealer

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Ok, I have been tossing around some ideas for a small furnace to anneal 8" - to 10" sections of 6061-T6 round aluminum tubing to a 0 heat treat state. I need the tubing dead soft for bending reasons, and most importantly I need the annealing to be very uniform and exact in the bend areas to yield predictable bending results. Heating with a rosebud on a torch just does not give me uniform enough heat control, and the tube fails every time when bending.From some tube bending books and online research it looks like there is an inverse proportion between target temperature and length of time it must be kept there to complete the anneal. At around 750 degrees it only takes around 20 seconds while at a more reasonable 500 degrees it takes about 15 minutes. I have seen an induction annealing process used on rectangular tube that very quickly heated the tube to a certain temperature (not sure of exact temp, but in that 750 degree area) for about 15 seconds followed by a water quench. This turned 6061-T6 soft enough to bend or even crimp such as in the rungs on a ladder without cracking. This was used on the '96 - '99 Panoz AIV Roadster chassis.While I don't know much about the induction heating itself, I would like to devise a machine to accurately heat 1.5" to 4" OD tube. I was thinking about making a little circular "furnace" that you simply slid the tube into with supports to hold the tube dead center in the furnace. I would use nickel chromium heating element wire wrapped around the inside perimeter of the furnace, and have some sort of theremostatic control on cycle the current on and off. The shorter I can get the annealing cycle the better, as I plan to do this immediately before making the bend. I will only be annealing the bend area as opposed to the entire length of tube.So, does anyone have any ideas or suggestions on a simpler way to get the job done? How about input on induction heaters? Thermostats?Thank you,Jason
Reply:Humm - looks like I had a pretty good idea - seems it's already out there!  http://cgi.ebay.com/Heat-Treat-Annea...QQcmdZViewItem Only problem is that is way over my budget!  Anyone seen something like this in a scrapyard??
Reply:There are some mini kilns for heating glass tube up for glass blowing. Try some of those, maybe they can do the job. Also, maybe some ceramics kilns might work.
Reply:Look around for a muffle furnace being turfed out of a laboratory, and bid 'em. You can (with a good one) control the temperature to within a few celcius, and with a "clever" one modify the atmosphere inside by purging with an appropriate gas. Might not be an issue with aluminium, but with some steels you can greatly reduce the extent of scaling by doing so.