1 hour to go! click here for the kickstarter
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
permaculture forums growies critters building homesteading energy monies kitchen purity ungarbage community wilderness fiber arts art permaculture artisans regional education skip experiences global resources cider press projects digital market permies.com pie forums private forums all forums
this forum made possible by our volunteer staff, including ...
master stewards:
  • Anne Miller
  • r ranson
  • Pearl Sutton
  • Leigh Tate
  • jordan barton
stewards:
  • Nicole Alderman
  • paul wheaton
  • Liv Smith
master gardeners:
  • Carla Burke
  • Jay Angler
  • John F Dean
gardeners:
  • Nancy Reading
  • Beau Davidson
  • Heather Sharpe

Cob oven with internal cracks

  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Hi all, I built a cob oven recently, and when I removed the sand from inside I found some fairly substantial cracks inside (around 1cm wide, running for at least 40-50 cm each), which luckily do not appear to be structural. I have not yet fired the oven, what I would like to know is whether I should patch the cracks before firing, or just leave them be? Any assistance given would be much appreciated!
 
Posts: 221
Location: Zone 6a, Wahkiacus, WA
26
goat hugelkultur purity forest garden trees woodworking
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Yes, patch them with a mix that is heavy on the sand.  It could be that your cob mix was not sandy enough to begin with,  or a combination of  not enough sand and not enough fiber.  

1cm from the get go is a big crack IMO.  If the original mix was not optimal, you may find that the over continues to crack as it heats and cools.  Patching it will help, but it may never be as durable as an oven made with a proper mix.  Again, assuming it is an issue with the initial mix.
 
Power corrupts. Absolute power xxxxxxxxxxxxxxxx is kinda neat.
1st edition of Living Wood Magazine--Now free for a while
https://permies.com/wiki/150455/st-edition-Living-Wood-Magazine
reply
    Bookmark Topic Watch Topic
  • New Topic