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Post by carlh on Mar 20, 2014 19:26:23 GMT
Alum I am at the same stage as you and I am also planning to use stove rope to create my thermal break with some lime mortar to seal the outside . Carl
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Post by cannyfradock on Mar 20, 2014 19:31:22 GMT
Alun
Make sure you use homebrew or a lime based mortar to fix the thermolite slips into place. This will allow for expansion/contraction (seems I already posted this......maybe early senile dementure is creeping in).
Try to get a minimum 5" flue.....1 meter length is the optimum height.....I don't practice what I preach and have used stubby little pots about 2' high which work. (but, the longer the better)
Just looked back over the interior finish of the top of your dome.....I have done better...AND I have done a lot worse. The integrity and strength of the dome will not be compramised by minor cosmetic details.....and anybody who pops their head in to have a butchers, will be truly impressed......
You have still a fair bit to do to complete your project but I'm already looking forward to the results of your hard work.
Regards....
Terry
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alun
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Post by alun on Mar 20, 2014 22:40:26 GMT
Thanks to all for the responses. Since I already have the thermolite and plenty of fire clay to make homebrew I think I'll go down this route with no fire rope or mastic. Now just to source a flue. I think having an anchor plate will make things easier to attach the flue. Now just to find somewhere that I can get one (preferably in black) for a decent price.
And thanks again Terry for the encouragement, it really helps!
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alun
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Post by alun on Mar 25, 2014 12:19:22 GMT
A bit further this weekend. Some form work in place. I made the inner arch with something much more makeshift. Just a few blocks and bits of wood, but decided I needed something more substantial for the outer arch: The completed arch, formwork in place: I ended up 1.5 bricks wide rather than 1 as I wanted space for a 6 inch internal diameter twin wall flue: The opening is just over 155mm square. I will built up a small square platform with a circular cutout for an anchor plate. I removed the formwork too early to start pointing the underside of the arch and suffered a collapse Very disappointing (no pics - I couldn't bring myself to take photos). I'm hoping that with some curing the arch will be ok but I'm now quite worried that it is not substantial enough. The formwork is still in place right now...
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Post by cannyfradock on Mar 25, 2014 17:40:04 GMT
Alun
Brilliant...absolutely brilliant! (honest)....I laughed my conkers off when I read you took away the form to your outer too soon and ...it failed/slipped. Exactly the same thing happened to me when I built a Pompeii for the People of Corris village (N.Wales)....except about 16 people were watching me at the time. Only 2 bricks slightly slipped but I still decided that the grab between bricks and mortar had failed so I decided to pull the lot down and rebuild it. There's nothing worse than "re-doing" something but I'm sorry......I would recommend you do the same......at least your former is still there if you decide to foe a re-build.
You've done a nice neat job, parging up the the exterior of the dome.
I really like the way you created the vent in the outer arch. Too many times I have just built a 1 brick entrance archway. The brick slips that create the vent in a 1 brick arch need to be so thin it affects the strength of the arch.(even then you only achieve just over a 4 inch square vent......Your 1 and a half brick entrance arch is perfect. Your pictures are also excellent....as there aren't many pics of this stage showing the correct way to create a suitably sized vent.
I'm interested in seeing your "anchor plate". I presume that you are fitting some sort of flue into your anchor plate. If you were building a fancy brick chimney, I would suggest a buttress or 9" wall that supports your external arch......I don't think this is the case.
Terry
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Bo
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Post by Bo on Mar 25, 2014 19:20:15 GMT
Looks good to me, my arch also collapsed when I removed the form to early but that's part of the fun!!!!
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alun
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Post by alun on Mar 25, 2014 21:40:54 GMT
This is starting to feel like an AA meeting...
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alun
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Post by alun on Mar 27, 2014 7:40:10 GMT
For the anchor plate I'm thinking if something like this: As seen here: I've also found a supplier in London(ish) for these at what seems a reasonable price: www.docherty.co.uk/products/metaloterm_mf.htmlI'll update with more details later.
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alun
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Post by alun on Apr 2, 2014 19:54:15 GMT
So this time I waited a few days before removing the arch support/formwork: And it stayed up! A bit of pointing and it looks pretty good: Now for the blanket. I found the box where I'd put it last year and opened it up. The blanket looked a lot smaller than I thought it should... It was then that these words came back to me: hmm. Ok, so what to do. Well I looked online for a bit to see if I could get some blanket at short notice but, like a lot of the things that seem to go in to a pizza oven it was not readily available. So I improvised. I skimmed the blanket in a few places, reducing it from 50mm to about 25 (a bit like shearing a sheep!) mainly towards the base. I then used these to cover more of the dome. Not quite enough blanket.... until it looked more like this: From there it was on with the vermiculite. This was very strange stuff. I ended up using a 75L plastic/rubber bucket that I got from Jewson a while back. To this I added three buckets of vermiculite and then 1/4 to 1/3rd of a bucket of cement with a few cups of lime. Using a garden hoe I mixed this together dry and then sitting the bucket under a tap, slowly added water, mixing all the time. This seemed to work out well for me, achieving a consistent texture though I do wonder if it was a bit dry. Anyway, here's how things looked: And now all finished with the vermiculite I ended up being a bag short (I'd bought 4) and had to source another from Jewson. I'm thinking of trying to find a one coat waterproof render but I'm a bit unsure what I can get locally that will do the job. Any suggestions?
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Post by starseeker on Apr 2, 2014 20:38:01 GMT
Lovely looking job you have made of the vermicrete layer,
As for a water proof render,how about K Rend which has been used successfully on some builds.
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alun
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Post by alun on Apr 3, 2014 11:31:33 GMT
Thanks starseeker. I've tried to find some K-rend nearby (in London) but not had any luck. Anyone used weber.pral M ?
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Post by cannyfradock on Apr 3, 2014 18:19:12 GMT
Alun Another great set of pictures....and I also love the vermecrete layer. It is truly ..."the devil's porridge". I must have a word with Liam (kilnlinings) to suggest the next length up from the normal roll of thermal blanket that he sells for a 90cm oven. ...another half meter would probably do the trick (you done a great job btw of making that roll work). K-rend was just the first product name that appeared on the market for "mix with water....waterproof rendering"....there are now quite a few different trade name's of the same product. On a new build a base coat is laid then a plastic memberane is applied to the base coat. The second finished coat is then laid on top of this. I'm not sure if you will need a few bags of each (perhaps the base coat is the waterproof coat and the finish coat is without waterproofer) ??....or perhaps they're both the same......I'm not sure. The plastic memberane should be substituted with chicken wire....perhaps? Terry
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alun
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Post by alun on Apr 4, 2014 8:19:17 GMT
Looking at the K Rend (and weber) sites there seem to be different types of render, including some that go straight on without a base coat and still create a waterproof (but vapor permeable) layer. I'm hoping to use something like that as it would be easier (which is always better).
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alun
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Post by alun on Apr 7, 2014 10:12:47 GMT
Curing fire. Yay! And then some rendering yesterday. I went with the any-colour-you-like-as-long-as-it's-ivory K-rend from a local-ish place. As others have said, it's not too bad to work with and mixes up nicely. I bought 7 and used 6 bags in two passes to achieve my dome. The photos below are before I scraped the finish (more photos to come) with a wire brush to even it up and open it out. Hopefully this gives me a nice waterproof finish. Now to decide what to do about the base. More render? Tiles? Bricks? Also need to sort some tiling ot similar to create some workspaces either side of the dome.
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Post by cherrycolavodka on Apr 7, 2014 19:52:13 GMT
Looks great. Well done
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