42" in Hungary by Slovak guy ;)

[alex.g]

Re: 42" in Hungary by Slovak guy

either way, i will need then two rolls onlt, so it will be 120 or 160 EUR (100 kg/m3 or 130 kg/m3)
dont need to bother with rockwool

[UtahBeehiver]

Re: 42" in Hungary by Slovak guy

Alex,

Are you enclosing your oven? Any consideration of perlite or vermiculite? Not a thermally efficient by could be substantially less costly. If you are doing an enclosed build you could just pour it in dry or if you are doing an igloo use a cement/perlite/vermiculite mix.

[alex.g]

Re: 42" in Hungary by Slovak guy

thanks for tip but i want it to be bare, no housing
something like

[gorazdr]

Re: 42" in Hungary by Slovak guy

did you use it? How thick?

I used 2 layers of 4 cm and and extra 4 cm on top. Because it already has chicken wire on the back it is really easy to make nice dome shape. I then covered it with 5cm of Baumit ThermoPutz (perlite / cement mix).

I am using my oven for two months now and here are some temperatures:
- oven completely clears in one hour and reaches 710 deg C on top. I let fire burn for additional hour to soak heat in to the bricks. I remove embers after waiting another hour. At that time dome bricks are 450 deg C and floor bricks at 430 deg C.
- Outside is cold!!!, under floor slab heats up 10-15 deg C

- After two days I can still cook "Gulas" temps: dome 190 deg C, floor 160 deg C.

If rockwool binding would be affected by heat it would smell but it does not. After all there are over 100 rockwool variants and some are ment for high temperatures and some are not.

[alex.g]

Re: 42" in Hungary by Slovak guy

Wow, 12 cm on top then, right?
Good tip for thermoputz, thanks. How did you apply it? Mentioned thickness at once or few layers? Did you put DuoContact as a primer layer?

[gorazdr]

Re: 42" in Hungary by Slovak guy

Yes, 12 cm on top. I aplied two layers of thermoputz (max 3cm in one layer). Get some reinforcement fibers and mix it in to prevent cracks.

I used tile glue as prime layer.

[alex.g]

Re: 42" in Hungary by Slovak guy

what fivers did you use, please? how much did you put into the putz mix, a bucket?

[gorazdr]

Re: 42" in Hungary by Slovak guy

Hi Alex

I used glass fibers about one fist full for one bag of thermoputz. You can get small bag of fibers (1 kg), that is all you would need. Mix 1 40 liter bag of thermoputz with 18-19 liters of water. You can trowel it on but I found it is much easier to just throw it on and use trowel to level it. I used 3 bags of thermoputz.

You must dry thermoputz for about two weeks before covering it with final layer, althou it is hard the next day.

I covered it with additional 2cm layer of high strength concrete (baumit hobybeton), added hydrated lime to make it stick and again fibers for reinforcement.

[alex.g]

Re: 42" in Hungary by Slovak guy

so once again, 12cm of rock wool, 5 cm of thermoputz and finally 2cm of concrete mix?
is thermoputz ok for final finish? is it white?

[gorazdr]

Re: 42" in Hungary by Slovak guy

so once again, 12cm of rock wool, 5 cm of thermoputz and finally 2cm of concrete mix?
is thermoputz ok for final finish? is it white?

Yes that is what I have. Thermoputz is light gray when dry but must be protected from rain! Do you get any snow? If yes then you need to add concrete.

[alex.g]

Re: 42" in Hungary by Slovak guy

i would probably buy Baumit SilikatTop as final layer
thanks for tips

[alex.g]

Re: 42" in Hungary by Slovak guy

photos from yesterday
today i closed the dome, finally. At one time i thought i will brake all with hummer, so much stress.



Today also bought ceramic chimney part. First one (installed) is 33cm long, about 5cm is inside the entrance part. Will add additional 50cm to it. Inside diameter is 20cm. Would it be enough for 42 oven? 83 overall length.

also, tomorrow will clean inside of the oven, add some sand to fill small gaps on the floor, will mix it with firebrick powder left from firebrick cutting.

Will start to fill the gaps from the outside and cover it with ceramic blanket. Question is, do i need to cover whole entrance of the oven with 7.5cm (3in) thick insulation (will be using 3 layer by 1in each)?

Thank you

[UtahBeehiver]

Re: 42" in Hungary by Slovak guy

Just goes to show that a nice build can be done with brick bolster and a BFH.

[alex.g]

Re: 42" in Hungary by Slovak guy

Done


still thinking about, do i need to cover whole entrance of the oven with 7.5cm (3in) thick insulation (will be using 3 layer by 1in each)?

[alex.g]

Re: 42" in Hungary by Slovak guy

Update:


For the rest of gap-filling i bought 12pcs of clay bricks. (special clay for oven and stove makers)
One brick ~2.5kg and price is 1EUR

(will make some creatures with kids)