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Post by h12rpo on Apr 23, 2013 19:34:29 GMT
If you can stand on the rebar where it joins the concrete and pull the end of the rebar up , it should be bendable......I know mine was
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Post by johnaero on Apr 23, 2013 19:38:24 GMT
No way to get up on it sadly
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Post by cannyfradock on Apr 23, 2013 19:42:19 GMT
.....it seems like you have just poured the concrete....I agree with Ian.....you should be able to pull the re-bar up enough to give you piece of mind......even if it moves a little, it will mean some concrete has gone underneath.
If possible tap the shuttering (from underneath)...GENTLY.....this will also allow the concrete to flow under the re-bar.
Terry
p.s ......wear some plastic gloves if you put your hand in the concrete.
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Post by cannyfradock on Apr 23, 2013 19:58:33 GMT
John
Just managed to get a good look at your last picture (wouldn't work earlier on)....you haven't copied the silly idea from FB of resting the re-bar on the walls and casting the slab inside the the walls.......you have cast the slab ON TOP OF your walls so there is no need to panic. the dome or vault will sit virtually on the walls anyway so the re-bar is just an added recommended addition.
DON'T PANIC.......your slab will be OK.
Terry
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Post by h12rpo on Apr 23, 2013 19:58:46 GMT
Or, if you have some more rebar just add that on top ?
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Post by cannyfradock on Apr 23, 2013 20:00:07 GMT
......why didn't I think of that Terry
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Post by johnaero on Apr 23, 2013 20:14:28 GMT
tried pull 2 corners up with claw hammer 3 hours after poured it and got mm or so up.
no more rebar left. should got some extra as its usefull. could have braced across the section messed up.
but the top layers of rebay are still up in concrete just lower layer.
ah more annoyed when had planned pour it in lift them up and the pour last 2inch on top.
as your said oven should be over walls and lintel anyway so your right terry should be ok.
worst case can always build support wall if find it cracks
had hands in concrete with gloves, was getting eatin by flies and midges so packed it in
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Post by johnaero on Apr 23, 2013 20:18:52 GMT
just opened pdf file of forno oven. i never read the start as new how i wanted do walls and slab. didnt realised they poured slab inside walls whats the point that a suspended floor? also whats story with their walls? swear were building a sky scraper they reinforced them do much. easier buy solid blocks that cavity blocks. man i hate cavity blocks with a passion...give me a 6inch solid any night..........
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Post by cannyfradock on Apr 23, 2013 20:23:55 GMT
John
If it cracks.....I'll eat my pizza paddle....sideways.
Time to clean off your tools and and have a well earned coffee...or fruit juice....or fermented apple juice......which is what I'm having now.
Terry
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Post by johnaero on Apr 23, 2013 20:29:01 GMT
beer i think now hahahaha.
something about building i find relaxing as much as working on bikes.
had hoped have all done last year just had re floor house
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Post by tonyb on Apr 24, 2013 11:26:21 GMT
The slab inside the walls with air gap comes from Alan Scott's book and is to try and thermally isolate the oven and slab for increased efficiency. The gap also incidentally acts as a damp proofing mechanism. I think the idea is good but complicates the build for a diy wfo project, but certainly something commercial builders/bakers should consider.
I wouldn't be worried about the rebar, given the slab is cast onto the walls, I do think we have a tendency to overdo the margin of errors on the build, and whilst a diy firebrick wfo will weigh up to a tonne its usually spread pretty equally over a wide footprint, and mostly near the supporting walls.
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Post by johnaero on Apr 24, 2013 11:28:43 GMT
well yes ye are right slab should be fine concidering weight be on walls and lentil
now have re concider my brick selection as few on forno site saying the heavy duty furnace bricks i have may not work very well in the oven
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Post by tonyb on Apr 24, 2013 11:49:35 GMT
John, not sure what you mean by 'heavy duty' but modern firebricks tend to come with different ceramic composition/properties. I think the high alumina bricks have some chemical/thermal properties more suitable to harsh foundry environments. I've no personal experience of using this type of firebrick but it depends what you mean by 'unsuitable', I think they will be mechanically and thermally fine but will probably take a bit more firing to get up to temp, also not sure how easy they are to cut.
Since you already have (only) 55 of them, I'd be tempted to use them for the floor, (assuming they are in good condition), also since the floor is not mortared in, if you do have a serious problem with them you could subsequently replace them, (not easy but could be done) or put some thin 'ordinary' firebricks on top.
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Post by johnaero on Apr 24, 2013 12:02:49 GMT
well floor was my ideal position but as they are tapered they wont give goot fit as would leave gaps between them .
they are 60-70% alu think if not more.
easy cut as tested on last night and 2 passes around with bolster and chisel it broke
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Post by johnaero on Apr 24, 2013 17:52:04 GMT
Just copped on that if split tapered bricks in half by hand i cant turn them to make walls 4.5 inch think and join wont be as neat as cant turn rough end out due to taper
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