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Post by truckcab79 on Jun 5, 2020 7:44:34 GMT
Edit - delete to avoid messing your thread up.
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Post by trickedem on Jun 5, 2020 11:19:43 GMT
I am thinking about insulation. My oven is going to be sitting on a base of thermalite blocks, which will certainly provide sufficient insulation beneath. I have the room and the time to add an additional layer of vermiculite insulation on top of the blanket. Is this necessary, or worth it?
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Post by trickedem on Jun 12, 2020 7:17:54 GMT
My oven is due to arrive today. So I am now thinking about how to complete the job. So two questions for the experts. 1. Is it necessary or advisable to add a layer of vermiculite render over the thermal blanket? 2. What recommendations do people have for the final render mix. I have read so many different views on this and what to include. Currently thinking of 3 parts plastering sand, 2 parts sharp sand and 1 each of cement and lime,
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Post by oblertone on Jun 13, 2020 6:18:45 GMT
Rule No. 1 - There is no such thing as too much insulation. However, consider your use of the WFO, pizza followed by bread the following morning, then a slow roast. A good layer of insulation blanket, chicken wire cage, render layer will provide all that. If you want to be cooking in retained heat two days after a pizzafest then extra insulation will be required, if not then the above regime will provide. One benefit of a vermicrete layer is that it allows 'shaping' of the dome, I rendered directly over blanket/wire and my oven looks a bit meh in places. A commercial product called K-Rend is often touted as being good for a final covering, I used waterproof tile adhesive as a base for mosaic finish, but the choice is yours.
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Post by trickedem on Jun 15, 2020 18:44:52 GMT
As promised the oven arrived on Friday. on Friday afternoon i was able to get the base laid, so that the heavy lifting could be done on Saturday when my son came round. The rear of the oven is very heavy, definitely a two/three man job. I also managed to get the fire bricks in on Saturday. Then this afternoon I got the sides and chimney in place. It was like a big jigsaw, but after a lot of jiggling finally got it together without any large gaps. Hoping to do some firings over the next few days and then doing the rendering next weekend. Subject of course to the weather.
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Post by pizzapaul on Jun 18, 2020 9:30:31 GMT
Its looking good - neater than mine!!
I am also wondering about the finish/render.
Let me know what you end up doing on that one - I am at the same stage.
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Post by trickedem on Jun 18, 2020 19:15:49 GMT
Still not sure about the render, but I am going to be doing it next week. I am going to use sharp, plastering sand and lime/cement and will probably paint it cream to match the masonary on my my ouse. Further progress this week. I have got the oven installed and put some fireproof putty in the inside joints, then I did a couple of small fires, before a slightly bigger one where the temperature got up to 250 degrees! The rendering that I had on the left hand joint has cracked and needs replacing, but other than that all seems fine.
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Post by oblertone on Jun 20, 2020 7:27:35 GMT
FWIW I used my bare brick dome regularly for over a year before I got around to insulating and applying a finish coat; worked perfectly well for pizza.
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Post by trickedem on Jun 22, 2020 9:14:34 GMT
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Post by trickedem on Jun 24, 2020 11:44:58 GMT
Well it was all going so well. However I started to put some mortar between the oven and the brick arch and it came loose when I pressed it. I think the main issue was the strength of the mortar. I had used 5:1 but this clearly hadn't worked. So the whole arch had to come down and all the mortar then cleaned off. Another issue is that the arch is design is inherently weak because there is no support at the sides. This would be fine once the render is in place because the build recommends the use of galvanised wire to tie all the joints into the render. This is the second time I had to rebuild the arch, so this time I chose a different option. I bought some 12mm stainless steel threaded rod from Tool station and then embedded two uprights into the base. The vertical bricks were then drilled and placed over the bar. I also used a 2.5:1 mix this should stick the bricks together much more effectively. They are really heavy engineering bricks so this should be ok.
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Post by pizzapaul on Jun 24, 2020 16:00:03 GMT
I did my arch yesterday (with pre-cut bricks from Pizzaovensupplies) and checked it today and exactly the same thing happened!! Came completely loose so i took it all down :-(
I am going to redo with a 4:1 and I am going to fill in that gap as I go. Last time I left the gap to do later, this time I am filling as I go. (I soaked the bricks before but I will repeat that in this weather) I am not a builder but these bricks don't seem to like the mortar as much as my very old reclaimed bricks!
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Post by truckcab79 on Jun 24, 2020 22:28:07 GMT
Had you not said you’d soaked the bricks I would have said that was the issue. The amount of mortar in the gaps is pretty tiny so it gets sucked out straight away. My whole build was done with 5:1 mix and was fine but I soaked the bricks and continued to wet them down as they set.
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Post by pizzapaul on Jun 26, 2020 10:26:21 GMT
I did my arch yesterday (with pre-cut bricks from Pizzaovensupplies) and checked it today and exactly the same thing happened!! Came completely loose so i took it all down :-( I am going to redo with a 4:1 and I am going to fill in that gap as I go. Last time I left the gap to do later, this time I am filling as I go. (I soaked the bricks before but I will repeat that in this weather) I am not a builder but these bricks don't seem to like the mortar as much as my very old reclaimed bricks! Re-did my arch and its much better this time. - Soaked all bricks overnight in a huge bucket - Used 4:1 to go a little stronger - Used a much more secure template (wider/stronger) - Filled the gap between arch and dome as I went - yes I expect that will crack due to expansion but the structure is very stable now For me, I am back to worrying/thinking about render or not
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Post by truckcab79 on Jun 26, 2020 10:33:58 GMT
Sure it will be fine. You’ll read lots to tell you that you need an expansion gap between arch and done but like you I thought it (and the galv wire advised), were peace of mind that it might crack but not fall down. Two years on I have a hairline crack if you look close enough but it’s still rock solid. I did the wire, filled the gap and then kind of rendered over the wire to join it all together with the dome. Then it was covered in insulation, mortar and bricks for the final finish. Pretty sure it’s not going anywhere!
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Post by trickedem on Jun 29, 2020 22:07:56 GMT
We had the oven going for over 4 hours of cooking on Saturday and I am glad to report that the arch has no cracks at all and with the amount of stainless steel wall ties in the sharp sand mortar I put in the gap I really don't think it is going anywhere. I am happy that the oven is well and truly dried out now, so we put the insulation, thermal barrier and chicken wire on tonight. I'm intending to do the render scratch coat tomorrow and hopefully everything including painting will be completed in the next week or so.
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