Benefit of adding kiln insulation?

[lmartine]

Hi,

I have a Paragon Fusion 7 kiln (bought in January). It seems to loose a lot of heat at the interface between the lid and the top of the firebricks as well as through the lid. Just to give you an idea, the real heating rate is 450 dph when I set it to 600 dph. AFAP turns out to be approx 575 dph. Needless to say, my Hydro bill is something else as my total firing times are much longer than expected. And I guess that the elements will age more rapidly as they spend more time on than they should.

From a kilnforming perspective, I think that it does not really matter that I go too slow on the way up. But is this going to increase the likelihood of devitrification as I am not going through the critical zone fast enough? In fact, what is 'fast enough'? I could not find a range of acceptable rates for AFAP.

If I decide to insulate the lid to enhance the kiln efficiency, how about adding one layer consisting of several 3 inch firebricks on top of it? How about putting a strip of ceramic fiber on top of the brick wall (to close the gap)? Or you think that insulating these two areas would provide only marginal benefit?

Another idea that I am toying with is to figure out if whether this difference in heating rate is linear or not (by making a good old calibration curve at different rates) and adapt all my firing schedules accordingly. But that seems a lot of work...

Lucie

[JestersBaubles]

I think it is more of a matter of reaching the "edge", with regards to size, of what a 120 V fiber brick kiln can do. I have a Fusion 14, which is basically a square version of the Fusion 7. It's pretty slow to heat.

Great kiln, though. I still love it even if it is a little slow (I say the same thing about my 20 year old cat )

Dana W.

[lmartine]

I am really surprised that it might be 'normal' for a kiln to loose so much heat that it can barely reach 1575F (and at a turtle pace at that!). Good thing that I manage to get decent melts at 1550F!

Lucie

[rosanna gusler]

i would get some 3 or 4 inch thick fiber blanket and lay one or two layers on top. cheap and easy and it might make a difference, r.

[Rick Wilton]

I'd think the kiln is just under powered, adding more insulation may not help much at all.

If your car is under powered and you're driving up a hill, getting the passenger to walk will technically make it faster but likely not enough to matter.

[jim simmons]

Is the kiln on an extension cord?
If so, please plug it directly into the wall plug.
You might be amazed.
Jim

[lmartine]

No extension cord, only a ground fault circuit interrupter.

I have added insulation on the top (approx R20), and so far so good today: the heating rate is right on target (typically, it takes at least approx 25% longer to complete a firing).

Lucie

[jim simmons]

Congratulations
Jim

No extension cord, only a ground fault circuit interrupter.

I have added insulation on the top (approx R20), and so far so good today: the heating rate is right on target (typically, it takes at least approx 25% longer to complete a firing).

Lucie