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Post by bookemdanno on Oct 15, 2012 12:30:54 GMT
Guys, its seems i've created a bit of a stir/concern on FB for my build regarding trapped moisture in the layers.
How many of you have completed an oven without continual heat curing of the layers in between, or have i missed a rather important fact?
Their worries are that in the bricks, blankets and vermicrete are litres of water that will steam up and crack the outer render as it tries to get out. I fired up with no insulation, then kept covered up whilst adding each layer. Either just under the Gaz or with added plastic if the weather was bad.
I've not used a fully sealed outer layer, but it is water resistant. Vapour can move back and forth through the layers. I'm not sure that they understand anything but cement.
Just go steady with the heating up and seasoning?
I'd say that after a winter in the UK every oven will need a slow ramp up to full temps unless wearing a roof tile hat, wouldn't you?
I'm asking you guys mainly, as we seem to have much more open view of things and although FB are the reason for most of us doing this 'ere WFO thing, their builds follow the "FB Way" more strictly. Someone must have built an Oven relatively quickly, or on a continual timescale with no periods of fire cures, eh?
Cob builds must have a larger amount of water held within the layers, with my materials falling somewhere inbetween i suppose?
thanks, but lots of Qs to answer!
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Post by spinal on Oct 15, 2012 18:11:34 GMT
I'll let you know wednesday... My oven internal dome finished yesterday, blanket's going on tomorrow and first fire is going in Wednesday...
That said, I am using CAC instead of portland, so have a 3-day cure time (as advised by Kerneos) instead of a 28-day cure time...
M.
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Post by cannyfradock on Oct 16, 2012 7:47:48 GMT
Danno
I agree with the guru's on FB and always recommend that as soon as the dome is built.......start those curing fires. Another reason why I say 2 or 3 fires a day for a period of 2 weeks.
I notice some of the builds over there.....and a few here have incorperated a few steel pipes in the insulation layers in order for the steam to escape. Is this OTT...perhaps not, but slow curing will also get the moisture out.
As you mention our climate is damp in nature so if the oven has stood redundant for a long time then again a curing....or drying out process should be used allbeit perhaps the day before for ovens that are used perhaps once a month or a few days drying fires if the oven has not been used for a couple of seasons.
Terry
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Post by tonyb on Oct 16, 2012 8:40:56 GMT
Ideally a long period of drying/curing in a warm weather climate is preferred but we live in the UK so no chance of that I think the suggestion is that the only detrimental effects are the cracking of the render, in which case either fill the cracks (as I've done) and/or put another render coat on at the end of a dry period. Sorry but I don't see this as a big issue, if we accept we are going to get cracks from steam/settlement/thermal expansion etc, then provided they don't affect the structural integrity or prevent you from cooking good food, we need to learn to live with them.
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Post by minesamojito on Oct 16, 2012 8:49:42 GMT
Agree with all the above, I have cracks but my oven still works a treat, and I had a few fires before the final sealing render coat, planning on beefing up the outer coat though now she is under cover. Have a chimney ready to fit too, now just need time to do it all Cheers Marcus
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Post by bookemdanno on Oct 16, 2012 12:12:02 GMT
That's all good fellas! Thanks for replying. I have the same opinions as you, but all the concern from the FBi just made me doubt myself. I'm going to stick with my few days of a 500w halogen, then small fires plan. And, if it cracks...just fill it!
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Post by bookemdanno on Oct 17, 2012 21:16:02 GMT
24 hours into the Halogen lamp phase i removed the 4" Celotex Bung and was greeted by a waft of warm air! I managed to take temperature readings from a laser thermometer of 48C at the floor rising to 120C at the oven keystone! This remained for 5 minutes, making me think that it's a well heatsoaked brickwork. So everything is back in place for more.
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Post by bookemdanno on Oct 20, 2012 9:47:04 GMT
This Halogen Lamp thing seems to be working! Where am i now...erm...80+ hours of constant lamp and temperature readings this morning were 95c at the floor rising steadily through the chains to 150c at the keystone. A massive steamy waft of warm air upon pulling out the Celotex, and the disabled PIR housing on the lamp is showing signs of melting! Might stick a Casserole in there this afternoon...who needs wood!!! Terry!!! New category!!!....Halogen Fired Ovens!!! **Oh i must touch my forelock to Calaf, as i think of him using one during his build last year, and setting the inspiration for me. Here's to you, sire!**
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Post by cannyfradock on Oct 20, 2012 16:06:30 GMT
Danno I'm all for sharing new methods of curing.....or drying the oven before use. It looks like a good way of initial drying....using the halogen lamp...safe and steady heat is spot on. I have a job lately in being able to afford a 40 watt light bulb so it will be the old fashion method of small kindling and smoke in my eyes for me. Terry!!! New category!!!....Halogen Fired Ovens!!! ......Mmmmm...don't think so on a "Wood-fired" oven forum but we do have a board for firing/curing an oven... ukwoodfiredovenforum.proboards.com/index.cgi?board=firingyourovenI've just reviewed your thread from the start and although I have commented now and then there's so much I missed in between. I'm really looking forward to seeing some pics of the food you make......or create. Terry
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Post by bookemdanno on Nov 7, 2012 13:17:05 GMT
Hello again! Had a loverly Halloween nights Pizza party... An absolutely wonderful eveing in the cold with hot pizza! I ended up being a fire monitor, with most people wanting to do the pizza peel waving! A few toppings ended up fuelling the fire! I'd set gradually increasing fires after the halogen week, but an odd crack appeared from the chimney radiating out from that point. Sort of expected that, but thats just a spring repair job. Thanks to you all for your help! Sorry but no pizza piccies, they disappeared too fast! Even the Nutella and Banana ones!
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Post by bookemdanno on Nov 8, 2012 13:43:07 GMT
The Good... I've just finished my oven door. A section of Oak cleaned up nicely which was removed from the house during some extension/renovation works, and an old storage heater front panel, left over insulation, stove rope and the now UKWFOF Classic Clas Olsen Flue gas thermometer! In situ... The bad and the Ugly... I really didn't expect below freezing conditions as yet, and went off to North Devon for a long weekends Surfing, only to hear from the Wife that we'd had a frost...oh no was my reply, knowing that the Lime Render still needed a winter under wraps. So here's what frost damaged render looks like! Next spring i'll be raking out the couple of cracks i knew of from a full pizza night firing, along with repairing the frost damage and either limewashing or finding a suitable paint finish! Keep your work covered up from now on guys!
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Post by tonyb on Nov 8, 2012 16:54:38 GMT
That looks one really fine door. What temp does the thermometer read to?
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Post by bookemdanno on Nov 9, 2012 13:12:04 GMT
Thanks Tony! Those Clas Olsson Thermometers go up to 500c. Way beyond what the door could handle!
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Post by bookemdanno on Apr 14, 2013 9:26:27 GMT
Cor Blimey! Just had to delete that pumpkin photo, it was really messing with the sizing! Right...as frost damage seems to be the new thing!... Mr Jack Frost came to stay for a few weeks over the early part of the year, after a little bit of playfulness in early November too! An unexpected frost on early November and some un-cured Lime Render don't mix, which started the problems. This opened up the render enough for some water penetration, which then expanded nicely in -10 nights and created this rather fetching patterned effect in my render! Even though it was covered up! This was the November "playfulness", which i'd planned to rake, fill and Limewash over. Then the real cold spell came... so, i'll be having some more fun with the oven, apart from cooking this spring...yay!!! Watch this space!
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Post by faz on Apr 14, 2013 11:02:33 GMT
Oh no that really is some frost damage. I feel lucky to have got away with it now.
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