• 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 private forums all forums
this forum made possible by our volunteer staff, including ...
master stewards:
  • Anne Miller
  • Nicole Alderman
  • r ranson
  • Pearl Sutton
  • Mike Haasl
  • paul wheaton
stewards:
  • Joylynn Hardesty
  • Dave Burton
  • Joseph Lofthouse
master gardeners:
  • jordan barton
  • Greg Martin
gardeners:
  • Carla Burke
  • Ash Jackson
  • Kate Downham

Batch core Vermiculite plate alternatives

 
Posts: 28
8
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I have been building batch core from vermiculite. When i needed to transport my rocket stove. The core cracked into many pieces.

Can anyone suggest a material that is like vermiculite but more resistant to transport.


Im in the netherlands. Matt walker is using ceramic fibre board. Inhave no idea where to find that here and have searched but to no avail. Is that as brittle.
IMG-20201018-WA0007.jpeg
[Thumbnail for IMG-20201018-WA0007.jpeg]
IMG-20201017-WA0009.jpeg
[Thumbnail for IMG-20201017-WA0009.jpeg]
IMG-20201017-WA0007.jpeg
[Thumbnail for IMG-20201017-WA0007.jpeg]
 
gardener
Posts: 3772
Location: latitude 47 N.W. montana zone 6A
1039
cat pig rocket stoves
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hi Fraser;
I have not used vermiculite board but it is only good for 780 C or 1400 F. Batch stoves run much hotter than that.
I had 1750 F insulated fire brick fail after five days as the temps in the box were exceeding that.
So my guess is your boards were going to crack soon even if you didn't move your stove.

Most ceramic fiber board is good for 2300 F  1260 C. Some is rated higher.
It is also subject to damage by abrasion as well as (sorry) movement.

If moving your stove is something you plan on doing. Then Firebricks are the most durable.
 
gardener
Posts: 717
Location: +52° 1' 47.40", +4° 22' 57.80"
115
woodworking rocket stoves wood heat
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Fraser, I know of one online shop in the Netherlands which sells the ceramic fibre board. https://kachelmaterialenshop.nl/53-keramisch-board- Before you order online, phone them up and ask if the material you want to buy is available. I'd suggest you line the firebox with firebrick splits, it is too easy to damage the walls just by shoving fuel in. The riser doesn't need to be protected. Over time, the riser's walls are starting to sinter and a rigid layer is formed.

More than one of my experiments were built out of 50 mm (2") material and were just screwed together. Use long stainless steel screws and caulk the seams.
 
Posts: 47
Location: Northern Ca
20
duck forest garden bike bee rocket stoves greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hi Peter-

What is your experience using fire brick splits in a batch box lined with fiber board? Do the bricks tend to last for a long time or do they break and need to be replaced within a year or two?

Thanks!
 
fraser stewart
Posts: 28
8
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Great. Peter thanks. I could not find ceramic fibre anywhere but i guess sometimes you need to know where to search.

I will be making heat riser out of morgens super wool which i have a role of. I head it refered to as 6 minute riser.

Perhaps the updated firebox will be ceramic fibre board with firestone lining and a 6 minute riser.

I had hopwd to couple the bench and the stove as its getting cold in NL
 
fraser stewart
Posts: 28
8
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
"caulk the seams" is that with heat proof stove silicone kit. The black stuff?
 
Peter van den Berg
gardener
Posts: 717
Location: +52° 1' 47.40", +4° 22' 57.80"
115
woodworking rocket stoves wood heat
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

Luke Perkins wrote:What is your experience using fire brick splits in a batch box lined with fiber board? Do the bricks tend to last for a long time or do they break and need to be replaced within a year or two?


I did only one experiment using split fire bricks inside a CFB box, pushed to its very limits as usual. The bricks seemed to hold well, don't forget those are able to get red hot again and again without any visable damage. My concern would be about the CFB.
Do I expect the splits need to be replaced within a year or two because of heat damage? The answer will be a firm no, not likely, think of counting in ten or more years.
 
Peter van den Berg
gardener
Posts: 717
Location: +52° 1' 47.40", +4° 22' 57.80"
115
woodworking rocket stoves wood heat
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

fraser stewart wrote:"caulk the seams" is that with heat proof stove silicone kit. The black stuff?


The heat proof silicone kit is not up to the job in my opinion. What you need is the black stuff, I have good experience with that. The best out of three was the one from Bison saying "Openhaarden Kit" and "Mastic Refractaire" on the tube. Resistent up to 1250 ºC, 530 grams in a tube.
 
fraser stewart
Posts: 28
8
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Thanks for all the help guys. Especially peter for the local knowledge. What a great community
gift
 
19 skiddable structures microdoc
will be released to subscribers in: soon!
reply
    Bookmark Topic Watch Topic
  • New Topic