There are now a few scientific papers available like this one www.researchgate.net/publica...ent_composites There are other folk experimenting on a more basic level using a basic mix of one part fondu cement, four parts crushed fire brick, one percent carbon fibres (20mm) one percent burn out fibre. More exciting experiments incorporating individual long stands of carbon look very promising too. The basic mix as above is used to line a mold half full, then the long strips of fibres are laid in place and the mold toped up and vibrated. It seems carbon fibre does not really have a melt temperature but decomposes around 3500c.
I have build several pizza oven components using the above mix that do not show any sighs of even small cracks but temperatures are limited to around 550c .
Yes the fibres are used to prevent cracking in high heat areas, unlike metal they will not expand and contract. There are lots of potential benefits like thiner casements and edge durability, leaner mixes and therefor more tolerance to heat expansion and spot heating. The nylon burn out fibres offer water and steam outlets as they melt away a complex matrix is formed within the end product. One % of either fibre is in effect many millions on fibres when casting 25kg I have been using fibergalss fibres in the past but they are only tolerante to 600-800c It seems experimenting is still in its infancy but even with DIY projects the results seem to be outstanding … if you believe the non scientific reports! I think it might mean something like a J tube could be cast in one piece rather than two or four pieces .
You just cut then yourself from carbon fibre weave (mating) available from many outlets in various weights. I just use scissors to cut a 20mm strip a 1mt roll and the individual fibres come apart but you can buy small pieces from ebay if you want to experiment . Have not found anywhere that just sells ready cut fibres. I have read some people have super heated the fibres with a blow torch as they mix in to the refractory cement easier but I just mixed them in gradually, That seems like the biggest issue to me is that they have a tendency ball up when mixing.
"I think it might mean something like a J tube could be cast in one piece rather than two or four pieces " Now that would be something.imagine the benefits of having cheap , mass produced cores available in developing countries.
Yes it would Fuegos but like many small scale operations they need real time and investment rather than a few guys experimenting in their back yard as such. It is very interesting to see proper test papers available but there are quite difficult to decipher into real world circumstances. I am looking forward to doing a bit more experimenting myself, I thought I might make a little 4” vortex stove …..
I know carbon-composite ceramics work well in high-temp applications... and in at least that field, the thermal stability of the carbon is dependent on being both encased in surrounding refractory molecules, and —to some degree— chemically bonded with them.
It makes me wonder what the actual chemical composition of the carbon fiber is.
Because carbon by itself is not refractory, and instead becomes a fuel source when in the presence of heat and oxygen. I mean...that's what charcoal is. (and it's the reason that Starlight puffed-carbon insulation doesn't work as the hot-face in fireboxes. It has to be utilized as a back-up lining insulator where it's isolated from the oxygen-rich and highest-temp combustion zone(s).)
...so I would think that adding burn-out materials to promote porosity would work *against* the entrained carbon fibers, allowing them to gasify and burn-out themselves, given enough time and prolonged use.
That is, unless the carbon fibers were molecularly "alloyed" with something to prevent them from oxidizing, which is... well... burning — into either carbon monoxide or carbon dioxide.
The accuracy of info we share here is more important than my ego, your ego, or Peter's ego. None of us has exclusive ownership over the truth.
I have not followed up the latest results on the pizza oven threads but there had been several full sized, one piece domes cast the last time I searched. With my own experiments, the main issue I encountered was getting the fibers to mix in with the cement without balling up. It seems the longer the individual strands the more effective the mix becomes but in turn the longer the fibre the more difficult it is to mix! In fact it was extremely difficult to mix anything longer than a few mm, even in a small bucket of dry ingredients the fibers are so fine you just end up with a twisted mess of balled up fibers. I was using standard carbon fiber matting and cutting it up with a craft knife but the fibers seem to be too fine once separated from the weave and almost impossible to mix! I think you would need some way to keep the strands together rather than breaking down to microscopic individual fibers? I would like to do more experimenting, perhaps laying some long strands into a part filled mold and encasing them with a top layer ?
deadstarsstillburn: Hi there. I was directed this way by folks on the Permies.com website and am hoping I can get some information on how a total newbie can get started designing, siting, building, and not-dying-in-a-horrible-house-fire with a new RMH in a 160-year old home
Oct 21, 2020 6:52:10 GMT -8
deadstarsstillburn: The people over there recommended either a 6" batchbox or an 8" J-tube. I don't know what those are but am going to try to figure that out. What I need is a blueprint that I can scale to fit the need for my house. I have something likne 5000 square feet
Oct 21, 2020 6:53:00 GMT -8
deadstarsstillburn: but I do not need to heat all of it by any means. probably only need to heat half of that, maybe less.
Oct 21, 2020 6:53:15 GMT -8
deadstarsstillburn: moreover, the house has 3 storeys (large attic) so I assume if I get very efficient heating on the ground floor, that will go a long way toward heating the upstairs as well, no?
Oct 21, 2020 6:53:59 GMT -8
BenAlexanderT: Happy new year everybody. I wish you the best
Dec 31, 2020 15:06:14 GMT -8
Solomon: Anybody in Southern Oregon, in Jackson or Josephine counties?
Jan 16, 2021 21:54:43 GMT -8
gnomedome: i realsie this is from 2009
Apr 14, 2021 8:30:44 GMT -8
gnomedome: i realize this is from 2009 id love to see the photos from this ..as im looking to build a sauna soon similar to this .... if anyody sees this post firstname.lastname@example.org..... the photos in this post did not show up
Apr 14, 2021 8:32:00 GMT -8
dcoyte: I am planning to use a cast iron heat exchanger out of a hydronic boiler set on top of my rocket stove, flue out the top. There will be a pump moving the water through the heat exchanger into an unpressurized 2000 gal tank. Any thoughts?
Dec 31, 2021 6:45:55 GMT -8
syekoms: Yes just found this forum am in Josephine county.
Jun 17, 2022 12:53:32 GMT -8
ecoenergyman: Hi new to forum I was wondering where to buy a masonry stove kit I could install myself ? Fran in ireland
Aug 1, 2022 17:39:58 GMT -8
natureman: I have been following this site for years
Aug 28, 2022 10:58:59 GMT -8
nendo: Can anyone on this forum point me in the direction of detailed plans for a rocket water heater please?
Oct 22, 2022 15:15:43 GMT -8
fierolepou: Hi everybody! Starting a project from scratch, this is a goldmine!
Dec 10, 2022 5:20:09 GMT -8
Solomon: Best way to not die in a house fire is to build a stove where the really hot stuff isn't near the flammable stuff.
Jan 10, 2023 11:34:39 GMT -8
beppe: Hi to everybpdy. I'm new about the rocket stoves and this forum
Aug 30, 2023 22:17:32 GMT -8
beppe: I have a living room+ kitchen of 75 square meters that was heated by an ordinary pellet stove with a power of 8KW.
Aug 30, 2023 22:19:29 GMT -8
beppe: I want to switch to a DIY pellet rocket stove but I haven't found yet a project that is really suitable for my situation. Is there anybody able to indicate to me a good detailed project?
Sept 4, 2023 9:05:15 GMT -8