electric kiln help

[azdave35]

i have a front loading electric kiln (kinda like an assay oven)....interior demensions are 12x6x6...it takes forever to heat up and i was wondering if anyone had any ideas on making it heat up faster?...does it heat up faster if you have it full or empty?..any help would be appreciated

 

[Bastid]

Not sure if I should move this to Gadgets and Gear or here.

Maybe one of the makers here has modified a kiln.

 

[Stacy E. Apelt - Bladesmith]

The only way to make it heat faster is to increase the coil wattage. This is a major job on many ovens, and may not solve the problem. The best choice is to turn it on an hour ( or two) before use and let it come up to temperature and fully soak to become stable. The inside needs time to heat up...not just the air.

Stacy

 

[SteelSlaver]

Can you see the coils inside the oven and can you see how they are terminated. If so you might be able to replace them with a heavier gauge of Kanthal A1 wire, Then you would have to make sure that whatever device (relay or SSR) that turns the coils on would handle the increased amperage. Unless you are a skilled tinkerer with some electrical knowledge Stacy is probably correct. Another thought is how warm does the outside get? Another layer of insulation might help you a bit there, on the outside you should be able to use fiberglass. Also if there are no coils near the bottom you could add say a 1" a layer of rigidized ceramic fiber or thin fire brick. More insulation and less space to heat. Jim

 

[azdave35]

the coils are pretty close to the bottom...is it better to heat one blade at a time or as many as you can fit in the oven?....also what temperature does the metal have to reach before a magnet no longer will stick?....thanks

 

[SteelSlaver]

It doesn't really matter how many you do at a time if there is room and you can remove and quench them in good order. I take one out and quench, wait for temp to recover and do another, then another etc. The magnet will quit some where a bit over 1400f, BUT, that's not necessarily the temp you need. If the steel is simple 1084 your good. Almost anything else needs more and some needs some time a temperature. Like 1095 is 1500 for a few minutes, 5160 1525 for 15-20 min. Etc etc. Tell us about the steel.

 

[azdave35]

probably 1095 is what i will be using

 

[SteelSlaver]

Ok with 1095 you need to get it to 1500 f and hold it there for about 10 minutes then you need to quench it. you have a second to go from 1500 to say 1300 but when you hit the oil you need to go from red hot to about 700 in about .8 second. Yup less than 1 second. That takes either water or fast oil. I now use a special quench oil . I used to used automatic transmission fluid. I am not sure if it is really fast enough. Water or brine has a risk of making the blade crack while cooling. Let us know how it goes Jim

 

[Bufford]

When you say it takes forever to heat up, how long? Many electric kilns take time to warm up. I use a paragon HT oven and it takes about 2.5 hours to reach 1900 F.

 

[azdave35]

i let it run 3 hours and it only reached 1200 f