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Post by james9 on Apr 24, 2018 16:00:38 GMT
The entrance and chimney section are taking shape I ran out of Kiln Linings ready made cement and are using a Vitcas dry mix which you add water to but its a lot less plastic and messy to work with. The cement in one of the arches hasn't completely bonded with the bricks and there's some horizontal movement (a few mms) in the arch. Vertically seems strong with the end bricks going into the piers. Question is do I leave the arch and build on top or dismantle and reassemble with a wetter mix and leave the form underneath for longer?
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Post by oblertone on Apr 26, 2018 11:25:54 GMT
You've gone to an immense amount of trouble building a dome, why leave a known weak point at this stage. mix up some home-brew fix the arch, spread whats left over the dome.
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Post by james9 on May 11, 2018 15:45:44 GMT
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Post by james9 on May 11, 2018 15:53:34 GMT
I've bought a Selkirk anchor plate and also 1m of flue off ebay, can any one recommend the best way to fix the anchor plate down? concrete screws or expanding metal anchor bolts?
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Post by downunderdave on May 12, 2018 1:15:57 GMT
I've bought a Selkirk anchor plate and also 1m of flue off ebay, can any one recommend the best way to fix the anchor plate down? concrete screws or expanding metal anchor bolts? Screws are not particularly successful because they expand against the surrounding refractory sooner, being more conductive. This constant expansion and contraction leads to them becoming loose. In addition unless they’re stainless the heat will accelerate corrosion. You are better off with small diam stainless Dynabolts.
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Post by james9 on May 14, 2018 12:25:51 GMT
The Selkirk anchor plate was new £35, the 1m Selkirk chimney was £35 from ebay and I thought initially too big but its growing on me, easily screws on-off the anchor.
I lit a small fire to test out the chimney, brick conductivity and wood types (soft v hard wood), surprising how slowly it heats up.
Curing Question: (not starting for 3-4 weeks) but when people say day 1, heat for 6 hours at 200c what part are they referring to, the floor, the back of the dome?
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Post by oblertone on May 15, 2018 16:51:30 GMT
I wouldn't get to fixated about what temp to use when drying out your oven, just remember that the oven must go cold between firings to draw the moisture out to where it can be expelled by the next fire. Slow and steadily increasing is the key, a small fire on day one, next is a bit bigger and so on. I spread my curing over a week then stuffed it full of hardwood and went for a big-boys breakfast, a few minor cracks are to be expected but having dried it out you must protect it or you'll be back to square one very quickly. I found a cheap patio furniture cover from eBay worked well until I got a waterproof coat on mine.
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gez
valid member
Posts: 32
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Post by gez on May 15, 2018 20:32:06 GMT
Hi, what did you use to fix the anchor plate down with after ! I’m going to be doing something very similar, but my chimney will be permanent feature. Cheers
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Post by james9 on May 15, 2018 21:48:53 GMT
It’s not currently fixed down as wanted the bricks to set rigid first otherwise it would be difficult to get boltholes lined up to the template. I’m not 100% sure what to use but was thinking of using one of these:
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Post by james9 on Jun 25, 2018 11:29:44 GMT
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Post by james9 on Jun 25, 2018 11:42:24 GMT
I've started curing and had a burn around 200c last weekend with a few surprises:
The dome insulation seems effective, before the burn the outside shell temp was 50c due to intense sunlight whereas inside the upper dome was 24c so the insulation works keeping things cool. During the burn the inner dome was around 200-250c falling to 95c 13hrs, 74c 24hrs & 50c 48hrs. The badly fitting door is literally ply & foil to reflect the heat.
It took a good 90-120 mins of burn and the bricks heated up slowly, I couldn't judge how big to build the fire and used a mix of woods including softwood so will stick to higher temp oak/beech in future.
Heat transmission in the floor was slow and uneven. The laser thermometer said 250-300c (after wiping embers away) the underside of the same bricks (in contact with thermocouple) said 100-110c so a big difference even within a single brick.
The floor contains 50mm of insulation and I'm not convinced this is enough. There's a thermocouple right underneath between the insulation and the concrete slab to measure heat leakage through the insulation. The slab temperature also depends on weather/sunlight so there can be a 10c variance on different sides of the oven but was roughly 30c before the burn. Post cooking the slab temp (under the ember area) was 60c and I don't know whether that's good or bad? either way its now impossible to change so will need to live with.
A key question is when to start cooking, are you measuring the floor temp or the dome temp and typically was does it need to be?
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Post by Thomobigands on Jun 25, 2018 14:12:36 GMT
Honestly, I think you are overthinking things. Get some food in there and cook! Nothing to say you can't use that curing heat. Just match the temp with what you want to cook. Pizza will be too much of a stretch obviously but just get something in there and once you smell the cooking those figures and stats will fade away....
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Post by devontiger on Jun 25, 2018 17:19:54 GMT
How about a batch of Jacket Potatoes? Pork joint, for pulled pork? Leave it in overnight. Wrap it up well with foil, with a pulled pork dry rub.
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Post by Thomobigands on Jun 25, 2018 19:29:45 GMT
Yeah, just experiment. Curry, chili, stew. If you have a raised grill- BBQ! It's all about using, learning and enjoying. Have fun!
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Post by james9 on Jun 27, 2018 9:03:06 GMT
We did a spatchcock chicken on a grill with a tray of potatoes last Sunday and the oven temp wasn't right hence my questions. I read later recipes on one website suggested over heating, put on the door and let it equalise out so I'll try that approach next time. My door (plywood & foil) is rubbish.
I used some thicker kindling to raise the temp but didn't want to generate too much smoke with food in the oven. After 90 mins (should have taken 45-60) the internal chicken temp was 65c so it got finished off in a conventional oven, I might try using some coals under the grill next time.
Overall the result was pleasing, tasty hot chicken and a subtle smoked flavour to cold leftovers next day.
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