Trying to decide on chamber dimensions

Southside · April 08, 2018, 10:56:16 PM

What size breaker did you run the fans on? I recall the amp draw was pretty small on them. I am running each in its own 3/4" PVC conduit - small section of liquid tight at the very end to make it easier - using four runs of 12 THWN wire per fan. I just did not feel like pulling a ton of leads through a larger conduit.

Southside · April 08, 2018, 10:58:14 PM

Let me clarify that, I am assuming since the fans can run 240 / 120 then they have a neutral tap, thus the four wire, otherwise I guess it will be three. I have not taken the plastic off of them yet to even look, that should all happen tomorrow.

YellowHammer · April 09, 2018, 12:04:18 AM

I don't remember the breaker size, pretty small, I'm thinking 10 or 20 amp. I ran a single home run to the breaker with a three wire 12 ga with safety ground (so four wires, and since everthing is in plastic conduit, I wanted the safety ground wire) fan main feeder line down the conduit and just broke it off into a standard junction box and short 12 inch or so long branch circuit at each fan. When I want to disconnect a fan I just undo the wire nuts at the J box at the fan. So two screws, three wire nuts, the fan is electrically disconnected. I don't have any switches or exposed electrical junctions in the kiln chamber. The fans can be wired at 220, which is how I set mine. I had three main circuits, one for the kiln, one for the fans, and one for the service lights and outlets so I could work inside when the other circuits were shut off.

Southside · April 09, 2018, 08:33:46 AM

Ok. So your fans are all on one circuit / switch?

K-Guy · April 09, 2018, 02:05:48 PM

The fan kits that are for the L200 come with a motor starter that has overload protection built in. The switches are rated at 3.5 amps and can draw power from a larger breaker in the panel. i believe the electrical code requires each motor have individual overload protection.

YellowHammer · April 09, 2018, 09:44:08 PM

Yes, all fans are on one circuit, with no switch other than an external disconnect at the circuit breaker box.

Southside · April 09, 2018, 10:03:41 PM

Ok - thanks. Which side did you put the power exhaust vent on? I have read about it being on both sides of the baffle. Also - and this will sound dumb. When you baffle the ends do you baffle flat against the ends of the boards or does the end baffle drape the same way as the top baffle?

Thanks again.

YellowHammer · April 10, 2018, 12:02:49 AM

The power exhaust vent goes on the kiln machine side, the the low pressure side of the baffle and the suction side of the fans. The non powered intake vent goes on the opposite corner of the box, 40 feet away, on the pressure side of the fan baffle. It's important to have the vents opening against the pressure, so they will stay closed until activated.

The end baffle just hangs down like a vertical curtain between the far end of the kiln and the end of the stack. The other baffles drape on top of the stacks. Depending of what you use, how light a fabric, you may have to hold it down with a board, to keep it from flapping.

GeneWengert-WoodDoc · April 10, 2018, 12:07:28 AM

In a DH kiln, you can put the exhaust fan on either side. However, it will work better when the fans are blowing so that the exhaust fan is on the high pressure side, but open and closing vent louvers is easier if the exhaust is on the low pressure. On the low pressure side, the exhaust will work but not as well. However, this fan does not have to do a huge job, so that is ok. In any case, if you exhaust air from the kiln, you need to have a source for fresh outside air.

If you put an exhaust fan on each side, and if your main fans reverse direction every 3 hours, you will also need to have the exhaust fan that is running on the high pressure side. So it must switch from one exhaust fan to the other when the fans reverse. Opening and closing the vents is complicated.

Note that the exhaust fan is used to exhaust heat when it gets too hot. Larger DH kilns have the compressor outside the chamber and this cuts down on the extra heat.

He end baffles hang down to the floor...the same as the top baffle, but longer.

Southside · April 16, 2018, 09:32:37 PM

Took this video Saturday. I assume this to be a good thing.....

Kiln Running - YouTube

Of course, it could be that we are running mash too I suppose.... :D

WDH · April 16, 2018, 10:05:06 PM

Yes Sir! You got water ;D. That is a very good thing.

YellowHammer · April 16, 2018, 10:13:52 PM

PA_Walnut · April 17, 2018, 06:19:40 AM

Meanwhile, I steered another course, and decided to do a stick-built kiln and have just gotten the slab done. :( I clearly didn't win the race. (if there ever was one) :D

It is super-insulated with mono block forms on the side and polystyrene and plastic under it, which sits on 12" of stone. Did a monolithic pour. Pic is deceiving, but it's sitting 8" above grade. Forgot to put my J-bolts in, so will have to drill and anchor the plate. >:(

Plans to start framing'er up this week.

YellowHammer · April 17, 2018, 07:28:37 AM

PA, looks great
Sometimes its easier to surface coat and seal the slab surface before the framing. I used an epoxy garage floor mix on mine and its still holding up OK, starting to chip a little, but OK. The vapors from the kiln will make raw concrete crumble over the years, so the surface will start powdering and chipping. Also, depending on the door seal configuration, if its sealing against the concrete, the smoother the concrete surface, the better the rubber will seal against it.

Sealing the concrete surface is also useful so that when the pressure treated sill plate gets anchored to the concrete, the caulk bead between them will adhere real well.

PA_Walnut · April 17, 2018, 07:54:42 AM

Yellow, Thanks for the recommendation. I was considering using a real good, high-solids epoxy...then, was wavering with "oh, it's just a kiln..." Now you've convinced me as it will be SUPER easy to do right now.

Only caveat is that you are supposed to wait 30+ days for the concrete to cure. Moisture is also an enemy to epoxy, but I don't think I'll have THAT problem--spent a great deal of time with insulation and vapor barriers.

YellowHammer · April 17, 2018, 11:00:24 AM

I didn't wait 30 days, more like 30 hours. Maybe that's why some of mine is chipping off. Oh well, maybe I should have read the instructions....,, :

PA_Walnut · April 18, 2018, 06:25:21 AM

I can't wait 30 days either. I think I'll give it until the weather warms up again a little (snowing yesterday, after being 85 on SAT) >:( :-\

I really like the 2-part, high-solids epoxy products available. Expensive but really work well.

As for doors/seals, I haven't quite figured how to build and operate them. Nyle has a kiln door kit that is VERY vague in description. Stan, you tuned-in? Any more info? Thanks.

K-Guy · April 18, 2018, 12:55:52 PM

PA Walnut

Call me and we'll figure out what you need.

PA_Walnut · April 19, 2018, 05:59:46 AM

K-Guy,
How can I reach you? Which extension?
When I dial-in, I've gotten into an endless loop or voicemail.
Thx

YellowHammer · April 19, 2018, 06:50:51 AM

Extension 212. I know it by heart. :D
The seal kit is pretty good, I've used it on my L53. It's a good start. The perimeter door seals are face seals and it's helpful to have them in hand when you are doing the interior door jambs to make sure they match up correctly. The floor seal is a sweep and is a big piece of rubber, and it can be a pain. The real difficulty is getting a good seal where the doors meet, at the top and bottom door and frame seals. Since it's a three way joint, where the left door, right door, bottom (or top) jamb seal, all meet, it's hard to get it just right.

Since the door frame face seals require pressure against them to close, I installed a cam locking trailer door kit, and it works the best. The inside of the door skins, where the seals hit should be very smooth, or another piece of mating foam.

Seals on big doors are challenging, since that is the pressure side, any little leak will make a difference when sterilizing.

WDH · April 19, 2018, 07:26:52 AM

I found the door kit to be very nice. There is some aluminum angle that the rubber seals are snapped onto. You can get inside the kiln and have someone shut the doors. You can then position the aluminum angle in just the right position such that the door fully pushes the rubber seal flat and you cannot see any light from the outside. Just make sure it is not your wife or she might lock you in and leave you there :D.

K-Guy · April 19, 2018, 08:00:56 AM

Quote from: PA_Walnut on April 19, 2018, 05:59:46 AM
K-Guy,
How can I reach you? Which extension?
When I dial-in, I've gotten into an endless loop or voicemail.
Thx

PA Walnut
Ext 212 is my direct line. Leave a message if I'm busy, I'll call you back.