Jump to content

Olympic 2831g - propane kiln - can't get to cone 10


Recommended Posts

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? 

 

 

 

 

Screen Shot 2021-04-05 at 8.24.38 AM.png

Link to post
Share on other sites

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 post
Share on other sites
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 post
Share on other sites

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 post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.