mountainmade Posted April 5, 2021 Report Share Posted April 5, 2021 Hello potters! After running a Skutt electric kiln for years -we moved to a mountain retreat at 5300 feet and switched to a brand new propane powered Olympic 2831g gas kiln. After running a few bisque firings to cone 04 - we had zero issues. Ran a glaze firing Friday night - cone 10 reduction - started at 10:30pm - topped out at 2283 degrees - could not would not budge beyond that - added gas - lowered the gas - increased air flow - decreased air flow tried closing the damper - opening all the way - literally every tweak we could think of - nada.... wouldn't go any higher and all of our tweaks equalled decrease in temperature - we ended at 2120 degrees at 10:00am and called it quits. Reached cone 8 according to our cones. Most of the ware looks ok though some glazes didn't mature to the color they should - our tenmoku looks celery green instead of dark. We use cone 8-10 high fire clay from Georgie's in Eugene, OR. We make our own glazes. Ran another cone 10 glaze run on Saturday night - started at 3am... same deal - ramped fine until about 2100 and then slowed to adding roughly 30 degrees an hour... then 19 degrees an hour - then 9 degrees an hour - and finally 3 degrees an hour..... we were still reeling from the last glaze run - afraid to touch ANYTHING regarding settings of fuel or air - because of what happened the last time we tried to 'fix it'. At 8:30pm... we were at 2236 - and couldn't get any higher. We waited... and waited - then we tweaked...gas/air/dampers etc... we even switched propane tanks - and yet... we ended at 2010 at 10:30pm. We are running 100 pound propane tanks....connected via a flexible black hose with the regulator that Olympic sent with the kiln - we have three tanks. We had frost build up on the tanks - it was between 35 and 70 degrees during both firings. We do NOT have a chimney on the kiln. Is this the reason? Not enough draw? We are thinking it is either: not enough gas pressure despite the 100 pound tanks or not enough oxygen.... altitude? We fired this kiln to cone 10 successfully ONCE in town in our garage before we took it up to the mountain. We got stuck at 2150 that time too - but were able to break the stall in a few minutes by decreasing the gas and got to cone 11. So we know the kiln CAN do it... but it does not want to do it on the mountain. We built a kiln shed - just for this kiln on our off-grid mountain property - and knew we would face challenges... What do you do... when you get stuck? We spent half the weekend googling "gas kiln stalled' and read and tried so many of the tweaks others have used to break a stall. Should we have just waited it out? Are we too quick to try an adjustment? Link to comment Share on other sites More sharing options...
mountainmade Posted April 5, 2021 Author Report Share Posted April 5, 2021 Link to comment Share on other sites More sharing options...
mountainmade Posted April 5, 2021 Author Report Share Posted April 5, 2021 Link to comment Share on other sites More sharing options...
mountainmade Posted April 5, 2021 Author Report Share Posted April 5, 2021 Link to comment Share on other sites More sharing options...
Mark C. Posted April 5, 2021 Report Share Posted April 5, 2021 You will have to tweek a few things-I would start with the orfice size. Ward of Ward burners says (The rule of thumb is to decrease your orifice by one number (say a 38 to a 39) for every 2000 ft. increase over 5,000 ft_ So since your just over 5,000 feet this should be easy Here is the rest of the article I just googled firing at altitude and got lots of hits-less gas in smalerl orffices is the easy start-they just screw in and are cheap-call Olymic or drill out some blanks with letter drill set. http://www.wardburner.com/altitudefiring.html Link to comment Share on other sites More sharing options...
mountainmade Posted April 5, 2021 Author Report Share Posted April 5, 2021 48 minutes ago, Mark C. said: You will have to tweek a few things-I would start with the orfice size. Ward of Ward burners says (The rule of thumb is to decrease your orifice by one number (say a 38 to a 39) for every 2000 ft. increase over 5,000 ft_ So since your just over 5,000 feet this should be easy Here is the rest of the article I just googled firing at altitude and got lots of hits-less gas in smalerl orffices is the easy start-they just screw in and are cheap-call Olymic or drill out some blanks with letter drill set. http://www.wardburner.com/altitudefiring.html This sounds exactly like what happened... the gas just didn't have enough oomph to get up over 2300. Thank you Mark! Link to comment Share on other sites More sharing options...
Mark C. Posted April 5, 2021 Report Share Posted April 5, 2021 Less gas more air-make sure your air flaps are all the way open and do not choke flue down as much as you used to. Get the smaller offices installed in each burner -have some smaller backups ready to go as well. Link to comment Share on other sites More sharing options...
neilestrick Posted April 5, 2021 Report Share Posted April 5, 2021 I wouldn't expect any significant struggles due to being at 5300ft. My undergrad and grad school years were spent at similar altitudes and it was never an issue. The bigger problem is figuring out how to fire that type of kiln. More gas does not necessarily mean more heat. It's all about moving the heat through the kiln, not trapping it inside like an electric kiln. Do you have a pressure gauge on the system so you can see what pressure it's actually at and can be repeated? Those kilns are not the best design, and we get a lot of people coming here looking for solutions. Even when they do get to temp, they tend to fire unevenly. Do some searches on the forum and you'll find lots of information. Search 'conversion kiln' or 'gas conversion', as it's common for people to build their own out of old used electric kilns. The most success people have had has been to turn them into downdraft kilns using THIS method. Not exactly helpful in using yours as it came from the factory, I know, but good to see what people are doing with this type of kiln. Link to comment Share on other sites More sharing options...
Lo Ratcliff Posted January 6, 2022 Report Share Posted January 6, 2022 hey, sorry its not advice, but I am actually having the same exact issue. Ive reached 2000 degrees once and keep getting stuck at 1900 on my olympic gas kiln. where you able to find any solutions? Lauren Link to comment Share on other sites More sharing options...
Bill Kielb Posted January 6, 2022 Report Share Posted January 6, 2022 I believe you will find the solution in how you tweak the kiln. At 5000 ft you will suffer some decrease in performance but in that size kiln you ought to have plenty of power. Gas kilns are always a sensitive dance with the flue damper and gas pressure. If you are going into reduction you will have way less power so how much reduction you can maintain and still climb is a real thing. First adjust your primary air appropriately as noted on page 10 of your manual and leave it there. Next thing to learn is what pressure range will you operate the burners and then, can you maintain the kiln in oxidation positioning the flue damper at a given gas pressure and temperature. The flue damper often requires the tiniest of movements for this to happen. Often as little as 1/16” or less. The opening is square so movement changes area which is exponential. Changing gas pressure is also not linear with respect to heat output, minor changes have exponential affects. Most folks run out of patience at upper temperatures and over adjust both damper and gas never finding the optimum spot. So start with a schedule, record gas pressure, damper opening (precise) and temperature rise every thirty minutes and post your results. Take pictures along the way to post. Once you can fire this kiln in oxidation at any given pressure / temperature then you will be able to maximize its power on demand and not stall it later while adding some reduction. Unfortunately gas kilns require experience and good teaching experience is exceptionally hard to come by. Link to comment Share on other sites More sharing options...
neilestrick Posted January 6, 2022 Report Share Posted January 6, 2022 10 hours ago, Lo Ratcliff said: hey, sorry its not advice, but I am actually having the same exact issue. Ive reached 2000 degrees once and keep getting stuck at 1900 on my olympic gas kiln. where you able to find any solutions? If you're getting stuck at that low a temp, then the problem probably is either with the settings (how much gas and/or air), or with the propane tank. What size tank are you using? Are you getting frost on the tank? Link to comment Share on other sites More sharing options...
Lo Ratcliff Posted January 26, 2022 Report Share Posted January 26, 2022 I am using a 170 lb tank with a dehumidifier on it that keeps the frost off. I have my valves as low as they will go while still being able to keep my burners lit. I thought I had minimized my gas output as much as I could but I am still blowing through my tanks. I feel like I've tried everything, less gas, more air, all the combos... Im sure I've only skimmed the surface. Link to comment Share on other sites More sharing options...
Lo Ratcliff Posted January 26, 2022 Report Share Posted January 26, 2022 To clarify 100lb full. 23.5 gallons (170lb including tank weight) Link to comment Share on other sites More sharing options...
neilestrick Posted January 26, 2022 Report Share Posted January 26, 2022 7 hours ago, Lo Ratcliff said: To clarify 100lb full. 23.5 gallons (170lb including tank weight) What sort of regulator and hose are you using? Link to comment Share on other sites More sharing options...
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