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Post by nky84 on Nov 18, 2017 22:01:36 GMT
Hi all,
Discovering this site once I'm almost finished wasn't ideal but I'm hoping I haven't done anything too disastrous!
Was a bit of a make it up as I went along kind of build and I was pretty proud of myself until I saw some of the builds on here. The time, skill, effort and budget some people have put into these is scary!
Ive just got to the insulation stage and not quite sure which route to go down to finish things off. I've also got an "ash system" and door to construct and that should do me!
After having a look through here I was a bit concerned about my lack of fire bricks, dome angle and size of door but I had a decent size fire in there today and it seemed to work really well and hold temperature despite the lack of insulation.
Will post some pics asap.
Cheers,
Nick
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Post by nky84 on Nov 18, 2017 22:25:52 GMT
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Post by nky84 on Nov 18, 2017 22:33:40 GMT
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Post by Thomobigands on Nov 19, 2017 6:43:56 GMT
Looks good. Can I ask, what's the beam through the centre of the oven?
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Post by MikeyC on Nov 19, 2017 19:34:01 GMT
nky84 we should Meet!
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Post by nky84 on Nov 19, 2017 19:34:27 GMT
Looks good. Can I ask, what's the beam through the centre of the oven? The bit of stud was there originally just to maintain an equal spacing between the 2 slabs during the build. This was meant to be replaced by a bit of channel or similar which could then be slid back and forward to expose the 2 cavities below allowing somewhere for the ash to go... but i havent got round to that bit yet and now what is left of the stud has fallen below! If this idea turns out to be a failure in practice then i'll probably just brick it up. |
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Post by Thomobigands on Nov 19, 2017 19:48:57 GMT
Ah, I thought it was an ash drop. Just hadn't seen any like this as they normally go across the mouth of the oven. Fair play for trying something different though.
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Post by nky84 on Nov 25, 2017 11:07:21 GMT
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Post by Thomobigands on Nov 25, 2017 18:18:08 GMT
Hi,
If it helps, I used 2 x big 100l bags of vermiculite for my 36 inch oven. This was the minimum I would do and I still had a bit to put between my flue and brick chimney. If your oven is a similar size, i would match the 2 bags but go to 3 if you can afford it and you have room. Have a look at my build thread photos to see what kind of depth you get for that. Don't pay any more than £20 a bag and look to fireplace, aga shops as that's where I got mine.
Also, don't mix on a windy day, the stuff is so light it will blow away. Have faith that it will set too. Very fragile to work with but apply it gentle, spraying as you go if it's looking a bit dry in places.
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Post by Thomobigands on Nov 25, 2017 18:20:09 GMT
Forgot to say, don't forget the chicken wire after the blanket as it helps the vermicrete to stick. Wilko do a roll of it cheap  Just had another look at your photos too. You have no room for insulation on the sides unless you can engineer an extension to the hearth slab. Don't worry if not, you will just have to go very thin on the sides and accept the the heat will bleed out a little in those spots. You will have a similar problem with the blanket. Not the end of the world though, just find a way round it or live with it. Sure it will still be a great oven when you have finished. |
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Post by MikeyC on Nov 25, 2017 22:07:23 GMT
2.5 100l bags for a 43" dia oven. Thomobigands makes a valid point about having enough room to kick off your insulation from. You could perhaps put a secondary layer of tiles around your oven base which extend/cantilever beyond the current line, and give you a large enough platform to get the desired thickness of Vermicrete. I aimed for minimum 25mm blanket insulation plus 75-100mm vermicrete. Vermicrete is easy to mix. I did mine by hand. Good luck! PS you can buy 100l bags from G Christies in Leith. Around approx £23-25 a bag. www.gchristies.co.uk |
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Post by downunderdave on Nov 26, 2017 19:47:03 GMT
Forgot to say, don't forget the chicken wire after the blanket as it helps the vermicrete to stick. Wilko do a roll of it cheap I don't use chicken wire in my builds, mainly because it^s fiddly and very time consuming. Also it doesn't make sense putting a very conductive material like steel in the middle of an insulating layer. Because the CFB cuts so beautifully and sits nicely on a compound curve there is little need to cover it with the wire in order to get the shape to conform. The vermicrete layer does the job of ironing out inconsistencies in surface. Starting from the base where you are asking the vermicrete to stand up vertically is the most difficult part of the application so doing about 6 inches high and letting it set for 24 hrs before continuing helps. I use a 10:1 mix which i find is about as lean as i can go without making placement difficult. A handful of powdered clay for every litre of cement added helps enormously in making the vermicrete more worksble. Likewise adding the correct amount of water is crucial. Around 3 litres of water for every 10 litres of vermiculite is about right if using medium grade. Fine grade with smaller grains requires more. If water is pooling in the bottom of your barrow then you^ve added too much. It will wash the cement off the grains of vermiculite. I also find a 50/50 mix of perlite and vermiculite makes a superior mix than using either of them alone. Hope this helps. I've mixed tons of this stuff for the last 10 years. |
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Post by wild on Oct 18, 2018 13:59:05 GMT
Hi all, where east lothian ru im in longniddry , Discovering this site once I'm almost finished wasn't ideal but I'm hoping I haven't done anything too disastrous! Was a bit of a make it up as I went along kind of build and I was pretty proud of myself until I saw some of the builds on here. The time, skill, effort and budget some people have put into these is scary! Ive just got to the insulation stage and not quite sure which route to go down to finish things off. I've also got an "ash system" and door to construct and that should do me! After having a look through here I was a bit concerned about my lack of fire bricks, dome angle and size of door but I had a decent size fire in there today and it seemed to work really well and hold temperature despite the lack of insulation. Will post some pics asap. Cheers, Nick |
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