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Post by highlandladdi on Sept 21, 2014 19:48:57 GMT
Hi All, Been looking around this forum for a while, so thought it was about time I contributed... Anybody else got experience of building an oven in 'proper' winter conditions? (-15 to -20°C) Got the stand all sorted, but winter is FAST approaching... Will post more photos as and when the work gets done ? RGB
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Post by cobblerdave on Sept 22, 2014 4:37:13 GMT
G'day Sorry I'm the last person to as about such low temps. I'm from the subtropics and built in winter with the temperature about 20C ! But was very interested by building in those temps and I did a little goggle. This is what I found out. If you planed to build with the homebrew, Portland ,lime, fireclay and sand it probably woundnt set. Portland based cement will only set slowly down to 0C under that it will set but be weakened till finally at -20C it won't set at all. Ciment fondu is usually added to concrete to hasten curing in low temp situations . But with the lime in the hombrew might just set the ciment fondu of in secounds. That leaves making your mortar with ciment fondu and "grog" ( crushed firebrick or finly crushed basalt ) which is a bit more expensive but certainly a high temp mortar. In warmer temps you have about 20 mins working time around here you have to use chilled water to gain that in summer. How it would react at lower temps I just haven't been able to find out, but it would be worth investigating further. Regardless of what you use as mortar I'm sure you'll need some sort of cover a tent perhaps and heating as well because you and you materials have to be warm enough to work . Interested to see how your build progresses, I'm glad it you not me building at those temps Regards dave
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Post by highlandladdi on Sept 22, 2014 20:30:29 GMT
Thanks Dave! I'm going to use the dry mix Vitcas High Temp Cement. Doesn't say much on the tub, but I'll be sure not to use it below 0°C. On another note, I was going to use 1" 'mica lite' board and full thickness firebricks lying on their side for the cooking floor. Will that be sufficient? Oven will mainly be used for pizza/bread, so no cooking marathons!!! When the snow starts I'll update with some winter action shots RGB G'day Sorry I'm the last person to as about such low temps. I'm from the subtropics and built in winter with the temperature about 20C ! But was very interested by building in those temps and I did a little goggle. This is what I found out. If you planed to build with the homebrew, Portland ,lime, fireclay and sand it probably woundnt set. Portland based cement will only set slowly down to 0C under that it will set but be weakened till finally at -20C it won't set at all. Ciment fondu is usually added to concrete to hasten curing in low temp situations . But with the lime in the hombrew might just set the ciment fondu of in secounds. That leaves making your mortar with ciment fondu and "grog" ( crushed firebrick or finly crushed basalt ) which is a bit more expensive but certainly a high temp mortar. In warmer temps you have about 20 mins working time around here you have to use chilled water to gain that in summer. How it would react at lower temps I just haven't been able to find out, but it would be worth investigating further. Regardless of what you use as mortar I'm sure you'll need some sort of cover a tent perhaps and heating as well because you and you materials have to be warm enough to work . Interested to see how your build progresses, I'm glad it you not me building at those temps Regards dave
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Post by highlandladdi on Sept 28, 2014 7:17:01 GMT
Some progress has been made at long last!
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Post by highlandladdi on Oct 3, 2014 18:26:56 GMT
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Post by cobblerdave on Oct 5, 2014 7:48:50 GMT
G'day Your moving along at a cracking pace. Great work. If I could suggest one thing. I don't know to much about freezing but I've certainly know a lot about soaking rains! And how water absorbant fire brick is . Try this one, drop one in a bucket of water and watch the bubbles rise it fizzes up like soda water. They have no water resistance at all. Frozen water in a firebrick doesn't sound like a good thing. I've used house bricks for my entrance and chimney, and eventually bricked over the whole dome in 1/2 brick. House bricks are water resistant and with an entrance cover my oven can survive a tropical storm dry. You might also consider to fully enclose the dome in a full structure and roof. Or at least a roof to protect it from the elements Regards dave
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Post by highlandladdi on Oct 12, 2014 17:27:33 GMT
Formers made from an old sheet of insulating foam and some wet sand. Propped up on a bit of plasterboard and 4 x chopped lengths of curtain pole!
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Post by highlandladdi on Oct 12, 2014 17:30:57 GMT
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Post by highlandladdi on Oct 12, 2014 17:37:04 GMT
CobblerDave - thanks for the advice about the bricks freezing. Not sure if it's going to help me, but I've brushed on a watery mortar mixture to try and stop the bricks absorbing moisture (though I hope water never gets that far). Also, a question for the group: where I've got about 1/4 of the brick still sticking out like a porcupine, can I 'dilute' the pre-mixed mortar/screed say 1:2 or 1:1 with sand to make it go a bit further when filling the big gaps? The bricks are very well sealed up to that point as hopefully you can see from the photo. Thoughts?
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Post by cobblerdave on Oct 14, 2014 6:44:46 GMT
G'day Definitely needs a sparging layer. I don't know if your premix mortar is designed to use with sand. If you not sure or turns out its not a heatproof render.... 4 parts sand, 1 part Portland cement,1 part builders lime> Its the same as the poor mans mortar mix minus the clay content, you'll not need that it only makes the mix a workable mortar and this is a render Regards Dave
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Post by highlandladdi on Oct 19, 2014 19:57:03 GMT
Took your advice Dave. Mixed a ton of home brew and just covered the whole damn thing! Insulation, chicken wire and Vermecrete now done, just not enough time for photos. Few more days and the drying out fires will commence
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Post by cobblerdave on Oct 19, 2014 23:44:55 GMT
G'day I'm a big fan of starting out with charcoal or heat beads. Gives you a heat source without the flame. Doesn't need to be tended and will go for hours. You got to tease the water out rather than driving it out. When you get around the flame in the oven. Keep the same size fire built each time, don't just make the fire bigger each time. As the oven dries the temperature rises for the same size fire. Making them bigger only increases the chance of the heat rises to fast on you Looking great by the way. That internal dome is a neat as! Regards dave
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Post by highlandladdi on Oct 21, 2014 2:25:53 GMT
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Post by highlandladdi on Apr 12, 2015 18:07:06 GMT
Not posted for a while, but been cooking all winter ? Few more jobs to do to the stand this year, but more than happy with the performance!!!
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Post by highlandladdi on Apr 29, 2015 18:47:25 GMT
Pretty much there now... Nothing tastes better than pizza in your own DIY oven!
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