how to drill hole in kiln

[redbourn]

Hi,

I posted earlier about buying an oyprobe from the swiss company Econox.  We now need to install it in our Olympic Torchbearer updraft gas kiln.  What should we use to drill through the metal layer and the soft brick?  In terms of location, I've read all the threads, but none refer to this type of kiln. We're thinking a few inches either side of the thermocoupler.

 

Thanks for your help.

[Mark C.]

In downdraft kilns-Really the best place is in the chimney just behind the exit flue jusr above floor level. Geil kilns suggest this locationa and here is the reason. The temperature is cooler there-why does this mater you say. I have two oxyprobes -one in the door of my downdraft and one in the door of my updraft-I have had to repair the platuim wires 2-3 times over 30 plus years of firing as they get cooked in those hot spots . The flue on the other hand will give you great readings and be cooler so they last much longer. Another side benifit is they are out of the way and in a safer location. All that said you want the probe away from the burners-Since you have an updaft like I do  the door area  is best in a place that you will not hit the tip of probe. As far as drilling any metal drill will work on the sheet metal. _if I recall its about 1 inch-so a bi-metal hole drill is best there. The soft brick is easy so speed bit or metal drill (harbor freight sells oversize drill kits) say 1 inch with a steped down shaft to 1/2inch. I used my harbor frieght 1 inch drill bit in a 1/2 inch makita drill to drill the soft brick. (I'm a tool person). I mounted the  probe to a stand screwed to the door. I'll take a photo today and attach it to this thread later_I have other work to do 1st today-wait for the photo which will help you decide where to mont it. You need to stablize the whole meter/probe as well.My probe has the wires wrapped and I plug the meter in ona nearby table-your location may not have that option.

My ceramic tip just protrudes about 1/3 inch into kiln-its does not need anymore than that and could be less.

[redbourn]

Thanks, Mark.  I'll wait for your photo.  The Econox people say to have the probe inside 5 centimeters. We're using the ceramic tube they sent as a sheath.  Does the probe stick outside the sheath or is it entirely covered by it?  Finally, my kiln has a lid, not a door, so we were thinking somewhere on the side.

[neilestrick]

A bi-metal hole saw will cut through the steel jacket, and any type of drill bit will go through the soft brick.

[Mark C.]

Yes keep the probe tip inside the sheath tube but at the end. The side of your kiln is fine-it will have a more steady reading away from burner flames  racing by.

Since it sounds like a electric style gas kiln I suggest 1/2 to 2/3 up and where you will not bump it lkoading and unloading. I'm in for lunch I'll take a photos soon.

[Mark C.]

A few notes-make sure you keep the probe tube supported so its not hit. They break vey easy and since one end is super hot the other end is cool so as you cab see I used aluminum and steel bracket to rigidized the support. a simple tie wrap holds it in place. I drilled this thru the old school asbestos board that surrounds this old updraft and then thru the brick. I cracked a tube from to tight a hole once so I make it a bit larger and stuff some  ceramic fiber in and have two gaskets -one on each end..Figure out a support bracket and install it after drilling your hole.

I had a few more images but for some reason even though they are super tiny the system here will not allow them (yes they are under the limit in size)Been fighting with the upload for a while. It would not surprise me that its a glitch with this software.

maybe I'll add to another post and see if that works-heck these images are 23kb each and I can only add two and the limit is like 150kb-I'm tired and sometimes this site has issues and tonight is one of those times-maybe its got covid-seem to be going around. . rant over

 

[Mark C.]

More images super small at 23 kb lets see if I can post two more-I have been a good little boy and drank all my milk so please can I go play now??

 no my limit is 153kb it says maybe I need to clean out my image file-lets go remove photos from old posts nobody ever needs to see how to do things right-second rant over

 

[Mark C.]

Ok I threw out some photos from posts-as nobody need to know how to anymore as its all on YOUtube

My photo image file is full and the only way I found to edit them was in the actual post-3rd rant over

heres some 23kb images more of the same different views

Now I will spent some time removing old photos-seems I have been around  here to long and filled up my limit.

 

[Mark C.]

This thread may also do you some good-I almost threw out these photos but since they show what you need I saved them

 

[redbourn]

Thanks, Mark.  Very helpful.  Yes, the kiln is converted from electric to gas.  Tomorrow will be our first glaze firing--we've managed two bisques.  So Today's project is the oxyprobe and support, and kiln wash.

[CactusPots]

I waited until I got the oxyprobe to measure the jacket and get the exact right size hole saw.  The directions from Bailey say a 3/4" hole but in actuality a 11/16 was the perfect size.   It fits smoothly and needs no packing.   I get all my drill bits from a vendor on ebay called holehog.

Second question about the probe in the flue box.  At high temperatures is the reading more stable than in the kiln itself?  My one firing with it the reading jumps around quite a bit.

[Bill Kielb]

20 hours ago, CactusPots said:

I waited until I got the oxyprobe to measure the jacket and get the exact right size hole saw.  The directions from Bailey say a 3/4" hole but in actuality a 11/16 was the perfect size.   It fits smoothly and needs no packing.   I get all my drill bits from a vendor on ebay called holehog.

Second question about the probe in the flue box.  At high temperatures is the reading more stable than in the kiln itself?  My one firing with it the reading jumps around quite a bit.

My experience, the jumpy reading represents what’s going on so wherever that probe is located  oxygen is wafting through that area and hence the jumpy reading.  We see these readings as we are putting the kiln into reduction and when everything is dampered  adequately with a neutral pressure updraft kiln the reading becomes stable. Additionally, Temperature is an important component to the accuracy of the probe so given a choice it’s probably more accurate somewhere that represents the average temperature of the kiln.

So as an accurate sensitive indicator we chose the middle of the kiln and an area that was sensitive to secondary air infiltration to ensure when stable readings were obtained, the whole kiln was truly in reduction. That spot was not necessarily the best location for the longevity of the probe however. So If your kiln behaves well and has uniform reduction without dead spots then anywhere as a general indicator is probably fine.

We viewed it as if placing a thermocouple only slightly more critical.  Do I want an accurate reading or indication of the temperature at that spot in the kiln or can I live with putting it in a cool spot so it lasts longer because my kiln basically fires even throughout.

[Mark C.]

In my 30 +years of firing with these probes-if you place them in places with constant flows the readings do jump around  a bit more but as Bill noted under a solid redution they stabilize somewhat .

 Geil places all his probes in the flue on his downdraft kilns-down low just as the exit gases get into the chimney. I have never had a probe there so I cannot give any data on that location. On my updraft in the door the gasses move at higher velocities so the reading move a bit more but when in a good reduction they tend to stablize into a zone say 57-60 on the meter.

[CactusPots]

Thanks for the freeback.  I really need more than one firing with my new toy.  The first time it seemed stable at lower temp, say 1600 to 2000, but jumped around over 2000.  I could move the probe to the flue box.  I'd have to drill 4" of castable refractory, and would want to remove it after every firing as the back of the kiln is more exposed to weather than the front.

[Bill Kielb]

59 minutes ago, CactusPots said:

Thanks for the freeback.  I really need more than one firing with my new toy.  The first time it seemed stable at lower temp, say 1600 to 2000, but jumped around over 2000.  I could move the probe to the flue box.  I'd have to drill 4" of castable refractory, and would want to remove it after every firing as the back of the kiln is more exposed to weather than the front.

I believe it’s telling you your reduction at that point at those settings is unstable. So if you had  a pot in that  area of the kiln, at that time of the firing  it might begin to oxidize.  Good knowledge to have I think