Matt Walker continental stove build

hello and thanks to all , the pieces are coming together and some of it almost looks as if  i planned it all out,, i found the soft set mortar  makes a slower process of lay up for me and that i had to be careful  as even a slight knock broke that bond ---start again --- i could write an essay /short story on the mortar and my working with it ---all a learning curve  but all doable---i think my struggle with the mortar and laying it up was down  was the sand and clay were too coarse --should have used a finer screening from the beginning  ---trying to go less than a 10mm or 3/8 " bond a few times  so as to get back to level  requires too much hammer work ----the sand was a 6 and down screening size---common builders grade --plasterers sand  would have been great  ---and finer clay ---i used fireclay but its supplied un sieved----  had i just followed the advise from P v/d Berg to use fine blend to get the tighter bond/seams ---only on my last layers i home sieved the blend/mix to make getting level and easier workable mix.  As an experiment on the CFB that i used on my core build ---the top of it ---is a double layer of 1/2 " CFB--- his plan show the use of 1" CFB for the cores  ---here the worry is that  its too soft and easy to damage ----but  i do think Matts use of it is the right way ---and the stove does nt have to be force fed fuel --the old habits of having to quickly roughly load wood stoves is hard to break as we don t  want to burn hands------ i have tried an experiment on my CFB ---i have painted the surface area above the firebox core with calcium silicate --it sets up a harder layer that i feel will take more abuse ---as i will not be the only fire tender  i have to see if i can minimise it.   Not very easy to see or any bureau of standards testing  behind this i will try to show how the surface has toughened  up a bit ---piece on the left has a wood screw turned into treated cfb ---see it does not pull up the surface fibre layer as much as the right side test piece into untreated cfb   ----then a pic of the painted core area that will be above the fire box chamber

sorry got my chemistry wrong , its not calcium but sodium silicate i am using ---good old fashioned waterglass was its common name---good for 1000 C it says on the bottle ---sounds like a challange to me

You might be better off coating every CFB surface you can as you really dont want any loose fibers in your living space.
Water glass will help with that, I have found it will flake off if you put on too many coats, try painting on one coat and then another coat one hour later. I am not sure where you live but Vitcas have a ew products that can help to seal CFB.

thanks , i have only painted the cores section above the fire box roof  with 2 coats already ------i don t see its use in the secondary burn chamber as temperatures there could be above its heat  resistance  , and  the rest of any cfb used on the stove is not open to the air/atmosphere around the stove or inside the cabin---its all internal and closed off -protected by brick work  , metalwork  and under the granite slabs---but it can in theory be vented outside via the flue ---but no windows open on that side of the building ---so i expect  the exposure risk to be  minimal---i am aware of metal woodstove health effects from smoke ,ash and heavy metal particle shedding off them at high temps ---which is why i have chosen to build this type of stove plus the lower consumption of wood and less pollution from its exhaust gas---the fibre shedding is why i chose to go for the enclosed white oven ---which i will install later----the steel plate i have in place --is bolted up with a gasket behind it--

as Austin mentioned the soft clay sand mortar means bricks can be knocked loose , i found it needs to set up ---or dry out is really  what is happening --as theres no chemical set up like cement based mortar----for a few days --if some work has to be done on them ---but this can be an advantage i found .  When i gave the front of the stove a brush down ----there it was --on the right hand ---a brick ,,, 2nd row ---and 4 bricks in--- facing the wrong side out----not to noticeable ----but it got worse everytime i looked at it----i was able to use a hacksaw blade ---remove the mortar --clean up the bricks ---slide it back in ----double checking the right face was showing -----spaced it up on the back side with some wooden pieces ---then re mortared it up ----job done -----a bit ott ---but i can sleep beter now

the metal frame work off and being tack welded up a bit more ,so the cfb all cut and in place and the under layer of superwool layers can be seen---would have liked to use a thinner superwool ---as it could have lowered the cooktop down an inch  or so buts its what i had.

Wonderful progress Tony! I'm working on frames and doors this week and hope to lay the first course next week. I'd like to hear more about your white oven design if you care to share. Will it be a steel box that sits in the oven area just above the lower tunnels? Do you plan to weld that to the door frame as a way to keep it sealed from the stove gasses? I'm learning much from your build, so thank you for continuing to document your progress and thoughts.

Thank you so much for sharing your build Tony - you're giving me ideas! I love the use of the checkerplate.

Don't worry - we won't tell your wife about you using the kitchen scissors and the milk pan and I'm sure the knife will be fine after a wash and resharpen - hey Brownie points for that too!

thanks  ,the kitchen stuff is just old mismatched that was destined for the recycle bins---just the flour sieve was new ---but cheap -----but had only just been purchased----so no scones for me---the white oven is nothing special really ---its just a steel sheet  6 mm welded box---i made one some years ago for my current woodstove ---still in use so i cant cut it out for the new stove just yet---had i enough spare steel plate ---i would just make up another one . Size wise it s got to fit into the area that the plans show ---with enough room around it ---keeping in mind the stove has been designed to suit its  CSA  --so i would not let the space/gap be less than an average brick face ----the inside dimensions have to suit a large enough roasting pan and maybe provision for a shelf--- make a sealing flange face for the front of it ---then make up a door to  suit it. The one i have will fit into my plans with a bit of modifying, i will need to weld a suitable flange around the front of it and match up to the framework i have in place --match up the holes ---make up a gasket and bolt it into  place .. this box will possibly need a support leg at the back of it ---as it would be hung off the front framework only   ---Matts design is much simpler in that he shows a black oven so any size suitable door would work and he has brick work inside that projects inwards to act as a ledge of sorts ----these would support steel grills ----the other design of stove ---the continental ---is designed for an "off the shelf "oven unit to be used ---these are mostly of eastern europe manufacture---if you ebay or google sites many of these  will show up and dimensions for them---so if want to build this stove you purchase one before starting and build the stove around it to suit..  I only had the checker plate/tread steel  to hand so thats how that look came about---i did want a flat surface steel sheet but the only other option then ---would have been to cut up my welding bench for its 8mm steel  or invest in a box of grinder cutting discs --and use the 25mm thick steel plate i have---too much over the top.

weather here is so damp its a rain/mist last 2 days and nights --everything is filmed over in water --had to abandon my rewiring of borehole pump house --so back to my stove build--sorry missed the point you asked about the oven being seal/gas tight---the frame is sealed up to the brickwork with the mortar   ,the few metal work joins are welded up behind them  , then there s  a  cfb gasket between the framework and the current metal sheet bolted in place ---to be later removed and the stove insert with gasket and that will be bolted back in. Had thought about welding it in , but now i think it would be handier to have it removable---could clean out if needed ----which i think would be very seldom---make a different improved oven later on ---had i used IFB through out the whole core  i would be confident to the have a black oven option as well ---might get hot enough to make pizza with the black oven

heres where i am at so far  , still need to  sieve up some even finer mortar to make a paste for sealing up the cook plate  and granite pieces ---which i still have to cut to the sizes --then paint the metalwork ---i painted it underneath ---2 days ago but it never dried -----tin says rapid fast drying ---just spent the last hour with a heat gun speeding it up---want to make up a metalframe to suit the cook top  and place the basalt tape under that --to stop edge chipping and the mortar shedding grains onto the ceramic glass---and make some more progress with the chimney and the back heatshield s .

That's looking awesome.  I like your metal framed top but I also like the brick surround for the hotplate.  I'm guessing it's gonna be easier to get the hotplate and stuff to seal with that metal frame.  I assume the handle by the chimney is a starting bypass control?

heres the granite in place , due to be sealed around the edge with a very fine sifted mortar mix  , there is a one piece cfb gasket underneath the granite pieces ---on top of another underlying border layer of cfb gasket , the overlay of each layer would be enough to seal off ---so the mortar is an extra but also needed to stop build up of debri , that handle is the chimney by pass flap/valve  ---the inner pipe sleeve is from s/steel  sheet ---with a badly welded join---had to join up a fiddly little piece -not enough of it to make the damn thing out of one piece--

yes  Austin , that insulated brick surround just worked out , i had some IFB  and  left over cut s plus the offcuts of CFB and i just used what i had ---thats how it looks like a  lego build ---theres only a few bits and pieces of these left now----had to keep measuring and laying up to make sure ---before each cut---the consequence of going off plan and trying to design and build as you go along .  Just been doing some sums and from the ground up to the worktop including all the materials used ,this stove comes in at close to 1650kg--3637 lbs ---- not including the brick wall backing behind it, roughly working out to 1.4 lbs per square inch onto the floor area-----worked out from the surface area of the  ventilation bricks onto the floor .

built the heatshield wall up behind the stove , was going to go a few rows of brick higher at first but then it would start to block off the window , could have started to offset the brick ---but i then i would have run in to cutting a lot more brick for the wall thimble and hood vent pipe clearance as well ----tired of brick cutting now ---just managed to get this lot mortared in place and our temperatures went from 13C  to minus 4C overnight  , so not good for mortar laying----perfect excuse , rest of the heatshielding will be corrugated sheet spaced 2 " from back wall and  paint it  matt-black---next is going to be my attempt to make up a piping bag of  mix mortar ---very fine sifted---and use the gun to spread out a nice bead of it --for the cooktop glass to rest onto

Very well executed build you have there Tony. I'd be thrilled if mine turns out half as good. Couple questions if you don't mind? You mentioned earlier that the cfb got quite soggy when in contact with your mortar. Did you do anything to remedy that or did it stiffen up upon drying?

I'm guessing you used low density cfb; is that all you have supporting your granite slabs or does the metal frame have a lip that the slabs rest on? I'm hoping the cfb will support some porcelain tiles I had planned to use as the topper, but wasn't sure if I would need some bracing; which would further complicate my already complicated build. I'm thinking high density cfb may do the trick if LD is not up to the task. I'm headed down the hill to look at some today and compare prices and such.

I very much wanted to keep things simple, as you suggested, but my space restraints forced deviating from the plans. Thank you for any thoughts!

i found the cfb acted like blotting paper -----it drew  water out of the mortar ---seemed to dry out afterwards alright as long as it was nt compressed or fiddled with-----as it had no strength to it ---could have just been the type of cfb i had bought ---it had ceraboard 100 printed on to it---but thats no guarantee ---and mine was only 1/2 " thick sheets--- this failing   i noticed was on the floor/bottom of the chamber  built to house the water jacket ----which is lined allround with a layer of cfb------excess mortar from brick courses fell down onto it   -----so that was replaced then covered to made sure to have no further mortar  cfb contact anywhere else----- only place i will haveto/intend to place any more mortar onto this cfb will be a 1/2 to 3/4"" strip around the ceramic glass cooktop edge to seal it off .------ As a precaution ---hopefully ---i have painted the cfb strip underneath the cookstove glass with a waterglass solution -----two coats of it --- the granite slab /pavers  rest onto the cfb----- theres no metal lip -----each piece has a full size piece of cfb under it ---which rests  partly onto a gasket layer which is about 4 " wide ---the metal framework is supported on top  of this  4" wide strip as well---under neath that 4" gasket strip is the 2" thick layer ---also approx a 4" wide strip of morgan superwool ---this all sits on top of the last layer /row of brick------none of this is really following the plans ------Matts suggestion or method rather ---is to cut  a onepiece  gasket  made from  1"cfb board  and placed  onto a bed of fine sifted mortar ----then the metal framework will sit on to that cfb ------no mortar required-----the ceramic glass cooktop is bedded onto that cfb gasket with a strip or seam of fine mortar to make a gas tight seal.  My lasagna layer of materials came about to use up what i had and to maximise use of the cfb board  ---only had 4 pieces of it ----1200mm x1000mm ---and last minute plan change to the build meant i would not have enough of it-----and obtaining  some more of it would take to much time------short essay over ---time for pics

Thanks for the reply Tony. Very helpful indeed. Looks like you're getting close to firing the stove up. I'm thinking I will need to support the cfb if I choose to use the tiles I have as they don't span the top from brick to brick. I'll have to experiment a bit. I also plan to coat the cfb, as you did, with a water glass solution and hope that it slows the absorption of moisture. Best of luck on the fire up!