Post by fuegos on Jun 7, 2020 10:30:34 GMT -8
Before i begin i would like to thank everyone on this forum & in the wider Rocket Stove community for all the hours of research & experementation so freely shared but especially Matt Walker for the riserless core & the advice & encouragement given to me & others.
First a little background .We're off grid in a remote mountainous region of Spain , been here for nearly 20 years & have been baking at home for a long time.Our philosophy is to live lightly ( & cheaply! ) , re using & improvising . Solar power , milling our own timber & generally building things from what we have is a big part of our life here so getting a copy of the Rocket stove book by Ianto Evans & Leslie Jackson got me thinking.Although we have unlimited firewood here we built a well insulated small wooden cabin but a RMH just didn't seem practical or necessary given the local climate.So after reluctantly abandoning the idea of a RMH a few years later we managed to get a load of second hand fire bricks from an old water mill that had a bread oven - something its self that warrants another post - & decided that we would build a conventional barrel arch bread /pizza oven .Well that was the plan & a site was cleared & a stone base was built but then for various reasons the project stalled for 2 years...
Once i saw Matt Walkers outdoor oven video i decided to go for a riserless core.Searching through the threads on this forum gave additional inspiration , the post by Bram & his sketchup drawing were particularly helpful , but bad weather & of course the Covid situation has meant that the build has taken more than 2 months & it's still not finished.
The bricks we used are old hand made ones & the dimensions are slightly different to modern ones - 25 cm X 12 x 5.5 . the firebox is 50 cm x 20 x 25 the venturi is 70 mm , the oven chamber is 55cm x 50 x 50 .As you can see from the photos the firebox was going to be wider but i miscalculated & had to narrow it so the oven floorbricks had a smaller span.I decided against secondary air because the confinement meant getting any metalwork done was impossible. The lightweight bricks on the outside are really cheap here & of course insulating.The mortar is 3:1 sharp sand & clay , dug out of the ground when we excavated to build the footing of a new compost toilet.It appears to be almost 100% clay as the pucks we made dried & were the fired in our woodstove without cracking.After various test samples we cast the oven roof slab in place a arlite (1) sand (2) /clay((1) mix.There was some cracking so we re finished the top with a screed of clay sand mortar - 3:1 On top of this weve poured loose arlite for more insulation .The oven door is faced on the inside with aluminium tread plate & fits tight top and bottom but isn't air tight .Maybe an angle iron frame with fiberglass rope wolud be an improvement? maybe i'll try the rope on this door ?
To finish off the outside i'm thinking of doing a scratchcoat of clay/sand & then a lime mortar on top to waterproof , the idea being that if need to rebuild i can re use the bricks.
The first firing was with a small amount of kindling , it was really easy to light & soon started to roar, going smokeless very soon.
Subsequent firings have confirmed for me that this is indeed a powerful core as demonstrated yesterday when i got carried away , filled the firebox with a mix of pine & holm oak & and manged to burn the bread !
So far so good.....