blazingICE

Hello from Holland! Thank for your reply ! and indeed its called cablecast refectory. in dutch the name used to sell the stuff its called fire concrete for some reason, not completely sure what to use yet as there are many to chose from. i have searched around the net for about 2 weeks now and could not really find a place talking about the surface load of the elements in kilns, i found the document from kanthal, but it would be nice to know ppl there experience in this ,.. This is why i decided to post for a change, as i usually just lurk around on forums so maybe this is a good addition. im deff searching the forum at the moment, getting distracted by the nice things regarding the vaping world.. apparently these ppl wind there own heating coils , most of these wire diameter are below 1mm though, but with the result being that this wire is sold allot! in 30m roles, as vaping apparently is getting popular ... Ps Ozark mountains.. that just looks like a piece of paradise kind regards!

Good day to you all ! im new to the forum, and i hope im posting this is the right section ... I decided to build a electric kiln for in my lab, it should be a small kiln that does not drain my walled in operation so it should not consume to match power, as i never build a kiln i was wondering if ppl here had some experience, and maybe have some input on the current design . doing some research i found a few equations to calculate de amount of wattage needed for a given size kiln. basically its the surface area of the kiln in cm2 * 0.6 as firebricks where im from are quite hard to get, i decided to cast the hot chamber with fire concrete, and then use ceramic blankets for extra isolation. I only need a small kiln that can get to about 1100c, i decided to make a chamber with a surface area of 1036.2cm2 (Cilinder 15cm diameter | 20cm height ) This size of kiln would need about 621.72 Watts according to the above ratio, it is however recommended to give it some extra power to allow for some decent warmup times after the kiln hes been opened. so i was thinking about 1000 Watts should be good, now for the wire to be used i was thinking Kanthal A1 would be best as its hes good temperature resistance. according to this document (page 9) from kanthal, the A1 type wire max Surface load while residing inside groves within the kiln, is about 3 W/cm2 @ 1100c but as im not going using SCR controller i would need to reduce it by 20% so this would be 2.4 W/cm2 max to allow for good operation on a max temperature of 1100c, now as this is the max i thought that 1 W/cm2 would give me a long lasting element.. searching the web, and at the time of this writing i found that kanthal A1 wire was quite hard to get in lengths and diameter that i would need., so i decided to use a parallel network of wound resistors, so that i could use a smaller wire diameter, as these were easier to obtain, Vaping world.. the wire diameter i wanted to use is 0.6mm @ 4.19 Ohms/m as im going to use a parallel setup of 1000 Watts total, one coil should be 500 watts, the mains here are 230v so 500 watts would need a coil with about 105.8ohm doing the math this gives a wire length of 27.12m, this give a total surface area of 475.72cm2, dividing the Wattage by this Area give a surface load of 1.05 W/cm2. using 2 of these coils gives me 1000 Watts @ 1.05W/cm2 surface load. to anyone who have experience in building there own kilns.? would a 1.05W/cm2 surface load be good for a lasting element..? kind regards, Max