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I have noticed a couple posts about mica strip heaters with voltages other than 120 volt - for a rule of thumb if you half the voltage - IE the strip heater is designed for 220 volt - than the output (watts) will be about 1/4 - in the example I read the person that posted had 2) 220 volt strip heater rated at 1000 watts each - if this person were to supply them with only 120V the COMBINED output of the 2 strip heaters would be about 500 watts which would be far better than to use in a oven then the higher output of 1000 watts - this will cause less overheating swings and help to create a more interior temperature.  (Wayne Cattanach)

Rule

So what should I do if my heater strips came without mounting holes.  I assume it is important to raise the strips off of the oven floor, right? Can I just rig up a clamping system with a bolt and a couple of large fender washers, to clamp the strip between the washers, to the conduit piece beneath, so as not to put holes in the strip? Does the conduit or pipe pieces need to be secured to the floor also?  (Mark Bolan)

    I'm far from an oven expert, but I don't recall seeing any mica strips with mounting holes.  Most folks rig some sort of arrangement similar to what you have described.  That's how mine is rigged.  (Harry Boyd)

    I used sections of an old aluminum ski pole to raise the Mica strip off the bottom.  Drilled a hole at each end and used fender washers on top of the strip to hold it in place. Got this method from Wayne's book. He did not use a ski pole section, I think he used Copper tube.  (Tony Spezio)

Rule

I am building a new oven and am having difficulty finding a Chromalox strip heater, 120 volts, 1800 watts, 1 ½" wide x 72" long. Chromalox web site does not respond to my inquiry.

Can anyone point to a usable strip and where I can purchase it? Have exhausted all suppliers in the Spokane area of appliance parts.  (Denny Conrad)

    That may be hard to find. A 1800 Watt, 120 Volt element will draw 15 Amps. That does not leave any safety factor on a standard 15 A household circuit. You would need to be sure to have a special 20 A circuit the is wired with at least 12 Ga wire not the 14 Ga used in most 15 A house hold circuits.

    If you went to an Appliance Repair Parts Store and got a 5000 Watt, 240 Volt Oven element that had not been fired and straightened it out before firing it, and connected it to 120 Volts, it would give you 1250 Watts of heat. This would be 10.5 Amps and would give some safety factor on a standard 15 A household circuit.  (Dick Fuhrman)

    I got mine after doing a Google search, it is made by Watlow. Good luck.  (Henry Mitchell)

    I ordered my Watlow Mica heat strip through A-Tech in Tulsa.  Here's the contact info for the salesman that processed the order for me:

    Jim Cox
    jim@atech-inc.com
    800-225-6102 FREE

    If I was doing it again, I would give serious consideration to what Dick described in his response.  I think he has commented on that before on the list.  You might search the archives or visit with him about it before you make a purchase ($65.50 before shipping for a 650 watt strip two years ago).

    One characteristic of a heat strip that you may find annoying, is that it will have a hot spot in the middle (about 25 degrees higher than the terminal end and 45 degrees higher than the other end in my oven).  I think most folks flip their strips half way through the heat treating cycle to compensate, but I've talked to several that have modified their ovens to level off the temperature.  I had to convert to a convection setup to level off mine - no more flipping strips.  The oven element that Dick described might not have a hot spot since it would be a continuous loop through the length of the oven - but I haven't tested that.  You might want to ask him about it.  (David Bolin)

      From my years in the heating & cooling industry, most heating elements seem to have a hot spot some where along their length. It ha to do with the composition of the material from which the element is made. If a lot of work is put into the manufacturer of the material the better the heat density. However, a  lot of factors have to be just right to get good even heat density.  (Dick Fuhrman)

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