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Skutt 818P w/Environvent


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#1 Benhim

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Posted 23 December 2011 - 05:42 AM

Does anyone have any experience with envirovents on a small kiln? I just moved my 818P into the garage of my new place and started using the envirovent. The kiln is running several hours slower with the envirovent on, than with it off.

I just popped off a load of earthenware which mucks up the atmosphere pretty badly. It was so hazy in there I couldn't see anything. Even at cone 1 the kiln looked like reddish orange because of the gassing off. I was running it with the envirovent off for most of the firing because it had been taking forever to fire. I noticed each time I turned on the vent to clean the kiln out so that I could view my witness cones the edges of the cones would turn black. The firing was good, pretty much on time. I cleaned out the atmosphere for the soak at the end. Once the cone 2 started to soften, I turned the vent on and turned the kiln down to low. The cone barely moved after that, not going down. I soaked for 50 minutes, but the kiln was obviously cooling so I shut it down.

I've always liked this kiln it's been a great performer. It was nearly new when I bought it. A women had been firing off cast doll heads, and got bored. I sure wish it worked the same with the vent on as it does with the vent off.

I've read up on the whole thing and I see a lot of mixed opinions. Anyone have experience with this type of an issue?

BenCo Ceramics


#2 Denice

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Posted 23 December 2011 - 08:39 PM

I hope someone has some experience with the envirovent system and smaller kilns, I just installed a system on my large Skutt and my small Paragon. I haven't had enough time to fill the kiln and try it out, I hope you get an answer before I do. Denice

#3 lynny

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Posted 23 December 2011 - 10:31 PM

Oh I can sooo relate to all these comments!! Great for the ego to be asked, do I understand really what the client wants etc etc
The stress of the unknown is horrid.

So much info has to be given to the client prior to starting- eg this may not work in so many ways, size, shape, glazes, kiln god influences. Clients just so often don't understand clay and its quirkiness. And I would ask for 50% deposit.

I've done lots of these, and stressed the whole way through the process. But the worst is the pick up day, my head just says 'will they like it?, hope they like it?!!" repeat repeat repeat
Then I say never again................ a month or so later theres another one in the studio Posted Image

best of luck and i hope they love it!!

oops this should be posted on the 'special orders' stream!

#4 AmeriSwede

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Posted 24 December 2011 - 03:15 PM

Benhim... Sorry that I can't directly answer your question with a great solution, but I can say that during the late 80's-mid 90's I also had a SKUTT® 818P and had installed the original model Envirovent® on it from day one. I had never encountered any problems with it whatsoever. Firing to cone 9 temperatures was always painless as I was using the KilnSitter control which used the crossbar cone. The pyrometric test cones that I had used in tests were also just as I would want them to be, showing no problems.

My use of the Envirovent was to turn it on when the kiln itself was turned on and to turn it off after the kiln had reached its proper firing temperature, during its cooling curve. There was never a time when it appeared or smelled of any smoke or gases from the interior kiln atmosphere was leaked into the studio space.

It sounds almost to me like the fan is blowing in the wrong direction. A quick test with a lit match held over one of the holes drilled into the kiln lid would show if there is enough suction to be drawing the atmosphere out of the kiln (and room) or possibly even pushing it into the room...



Edited--- After rereading your post, I think I misunderstood. It seems it certainly is drawing in enough air, possibly even too much if it's cooling to the point that the cones start turning black at the tips. Could it be that there are too many holes drilled or that they are too large. (My assumption only from a lack of information supplied). It has been too many years for me to remember the details for accuracy, but if those neural synapsis are still arcing properly, it seems that there was only one hole (3/16") drilled in the top (center) of the lid and the same for the floor. That was (again if the info was remembered correctly) what SKUTT had recommended for the 818P and they had included the drill bit as well.

Hope that can help.... can you supply additional information regarding the setup of the Envirovent. With that type of massive cooling, if it is the vent and not bad elements or other electrical, it sounds like the vent is sucking 100% of the air through the kiln and not the small percentage that the designed 'Venturi effect' would produce. Almost like the larger holes on the plenum chamber are blocked or plugged.

Edited by AmeriSwede, 24 December 2011 - 04:36 PM.



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Above all, it is a matter of loving art, not understanding it. (Fernand Leger
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#5 Lucille Oka

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Posted 25 December 2011 - 03:35 AM

Does anyone have any experience with envirovents on a small kiln? I just moved my 818P into the garage of my new place and started using the envirovent. The kiln is running several hours slower with the envirovent on, than with it off.

I just popped off a load of earthenware which mucks up the atmosphere pretty badly. It was so hazy in there I couldn't see anything. Even at cone 1 the kiln looked like reddish orange because of the gassing off. I was running it with the envirovent off for most of the firing because it had been taking forever to fire. I noticed each time I turned on the vent to clean the kiln out so that I could view my witness cones the edges of the cones would turn black. The firing was good, pretty much on time. I cleaned out the atmosphere for the soak at the end. Once the cone 2 started to soften, I turned the vent on and turned the kiln down to low. The cone barely moved after that, not going down. I soaked for 50 minutes, but the kiln was obviously cooling so I shut it down.

I've always liked this kiln it's been a great performer. It was nearly new when I bought it. A women had been firing off cast doll heads, and got bored. I sure wish it worked the same with the vent on as it does with the vent off.

I've read up on the whole thing and I see a lot of mixed opinions. Anyone have experience with this type of an issue?



When the vent was turned on during the firing, air entered in and lowered the temperature of the kiln and therefore the cones. The tips of the cones being thinnest are the first parts of the cone to reduce in temperature and become visible. This is how you were able to see the cones. And it is in fact a 'trick' used to look inside kilns at the cones. The cones did not continue to melt because they 'froze'. Cones can 'freeze' even in a high temperature atmosphere, especially if there is a 'burst' of air hitting them. There are other factors that can cause cones to 'freeze' such as, being stored in a damp atmosphere, if they are old, or if they are being reused after a partial firing, etc.

Is your Envirovent the older model that is attached to the bottom of the kiln and stand? Skutt states about the older models of the Envirovent 'that the total firing time is increased'. The older models of the Envirovent were intended to stay on throughout the entire firing.

Do you have a KilnSetter/Timer or a pyrometer? Are you measuring temperature rise only by looking at the cones? If you are just looking at the cones and you are turning on the vent to do it, you are constantly lowering your temperature and then it must rise up again. If you have no KM you can possibly install a wall mounted version. Check with Skutt. If you do install one you won't have to constantly look at the cones, the KM will reveal the interior temperature. At the end of the firing and cool down, the cones can reveal to you the heat work of the areas in which they were placed in the kiln and give you a lot of information about the firing of your kiln.


John 3:16
"For God so loved the world that He gave His only begotten Son, that whosoever believeth in Him should not perish but have everlasting life".

#6 Benhim

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Posted 25 December 2011 - 06:23 AM

First off let me apologize for sort of ranting and not really supplying a lot of hard facts. This is the old style Envirovent mounted on the bottom with 4 small holes in the bottom and lid which I'd guess are 3/64". This envirovent was installed by the Skutt manufacturer at the time of purchase. The kiln elements are A+, all relays are working perfectly all wiring is code. There are no known issues with the kiln what so ever, it was used a half dozen times be the previous owner and now a handful of times by me in the midrange temperatures.

This is a Kiln Sitter, and I fire it with a guard cone in the sitter (just in case) but monitor my kiln by color. I have yet to find the money for a decent pyrometer to measure rise. I was taught to measure temperature by color, by an old school potter who fired pots off flawlessly with out really relying on cones (I'm not that good). He taught me to make cone packs with the standard large size (not self supporting) cones and recycled clay. I have some bags of a groggy cone 10 stoneware which I use to make my cone packs. Considering this is oxidation I'm not really worried about any lower temperatures (such as I would for body reduction) so I just put the top two or three cones to measure the final temperature. I do rely on cones for my peak temperature indicators, but I'm doing my heat-work based on color change of the ware and furniture as well as timing. I'm comfortable doing this, but a pyrometer is a handy tool to have, especially when you have a problem.

I've always began a soak by reducing the input of heat when the target cone begins to droop. I adjust the input to keep the kiln at peak temperature or in very slow decline for about a half hour or slightly better after the target cone falls touching. With the envirovent going, the kiln stalls as the cones get blasted with cold air from the plugged but slightly leaking ports as the envirovent cycles the air through the kiln. So as I've began to want to vent the atmosphere my soak has turned into a much steeper decline in temperature than I want. I have yet to solve this problem, and don't see an easy answer except stop venting the kiln with the envirovent, however this leaves me to either open my studio up to what ever atmosphere is going on outside to help vent my space with the garage door, or cut a hole in something to vent the room with a large hood vent or wall fan.


I've been making periodic checks to manage heat-work in the kiln. At first when I started firing at this location I ran the environvent all the time through the firing. This made a rapid one day firing process into an all day all night next morning thing. In this last firing I'd only run the environvent for checks only when the clay was gassing off obstructing the view of the kiln. I also run the environvent at the end for a soaking period to clean up the kiln at the end of the firing. With out the envirovent going this kiln flies along, and with it on it's sluggish and will have periods of stall. Nearing cone's 1 - 6, I just can't run the envirovent at all or it will sit for hours with out dropping the cones in a stall. I've resolved to briefly run a heat gun in the port during gas off to view my cones so as to not interrupt my heat-work substantially. I've also resolved to put another cone above my peak and so I can keep it on at least medium or even high while I soak with the environvent on, or to just stop using it entirely.

Prior to running the kiln in the current location in my garage I ran it outside on a covered porch. I never ran the envirovent in this location because I wasn't concerned about breathing any gasses or having toxic materials build up in my studio area. Since moving here I've had to install the kiln inside because of the amenities of the residence and studio space. I don't want to breathe these gasses and especially the metals, so I'd like to figure the best way to solve my problem and actually get matured glazes that look nice and not breathe these materials.





BenCo Ceramics


#7 Lucille Oka

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Posted 25 December 2011 - 11:19 AM

With my first small Skutt I did not use cone pads, I just relied on the junior cone in the KilnSitter. I also had a Skutt wall mounted pyrometer. My first few firings were taking a long time to trip the KilnSitter. The pyrometer had the reading but the Sitter wouldn't trip. I eventually started turning off the kiln manually. I reread the Skutt manual, the Dawson KilnSitter information, and Orton Cone information to see what I was doing wrong. I discovered that I was over firing the kiln. I was using a junior cone 6 in the KilnSitter which trips at 2291°F. I needed to use a junior cone 5 which trips the KilnSitter at 2230°F. My maximum kiln temperature was 2250°F. This one change made all the difference, it reduced the amount of firing time by several hours.




John 3:16
"For God so loved the world that He gave His only begotten Son, that whosoever believeth in Him should not perish but have everlasting life".

#8 Dinah

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Posted 02 January 2012 - 07:20 PM

Talk to Scott at Skutt. Email him all the facts and temps.
Dinah
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#9 Benhim

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Posted 03 January 2012 - 02:49 AM

Found a second problem on top of the draw from the envirovent. The rheostat on the bottom element went out. Which means it was probably burning out the last couple firings which I'd been having the most severe stalling. Going to get a new one and replace it tomorrow. It's a good thing that Skutt is in the same Metropolitan area.

BenCo Ceramics





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