still no sign of the ceramic fibre blanket that i ordered last tue so my progress has been slowed up - really frustrating. I should have ordered ages ago - lesson learnt.
I built the support for the chimney - my next decision is to either go ahead and get a stainless steel flue or build a brick chimney. I'm concerned that the arch wouldn't take the weight of the brick chimney given the weighty bricks im using. I've checked other forums regarding which is the best option and havent really found an answer yet. I also wish i made the flue space wider as the shape ive got (6 inches x just over 3) might not be big enough and will prob cause me a problem if i use a stainless steel flue. I've had a couple of small fires burning to start to curing process. I've also knocked up a very temporary door which i will replace when i find something more suitable
I've got the blanket on and now working on the layer of insulation using a 6:1 mix of vermiculite/cement with a shovel of lime added. I'm putting it on using my hands as i did when i previously built a clay oven - seems to be going on ok so far.
Nest stage will be to think about the external render/waterproofing. I am wondering whether the final external layer can be pebble dashed - I've got a bag of the stones left over from our house extension and wanted to make the oven blend in with the house. I'm def intending to pebble dash the base but wasnt sure about the oven itself although i don't see why not.
I'm not a plastere/renderer but when I have to do my own sparring, I've been told (by plasterers) to put waterproofer in the first "scratch coat"...then throw the dash onto the second normal render coat (4:1 sand and cement)...with some plasticiser (of fairy) in the mix.
Cheers Terry/Danno - i'm going to give it a go although i'll need to wait a week or so to try and ensure that the dome has dried out - I've finished the verm/cement layer - i ran out of vermiculite and got more from Jewsons (using the forum account - cheers and their's seemed to be easier to mix etc than the vermiculite i got from Travis Perkins.
I've had yet another re-think regarding the chimney I'm going to try and use the twin flue i had previously bought. See photos below - i've separated it and will only use the top section. I've built up the dome with vermiculite as given it is 9inch diameter the base of the chimney isnt big enough - i'm assuming this won't be an issue. Any advice on the best way to secure the flue would be appreciated. My initial thoughts are to cement the base section of the flue to the chimney support, then add mabe two more layers of bricks around the flue when its in place - i'll put loose vermiculite between the flue pipe and bricks although given its a twin flue i don't think it will get to hot. My wife isn't overly keen on the flue given its size but i'm hoping once the dome/base etc is rendered it will look better and the flue will work better given its bigger diameter. I could also cut it down in side using a grinder but i understand the taller the better for performance.
Danno - rain in Glasgow? We do get the odd bit - Your right about the rain cap - the flue i have has a cowl so hopefully this will keep out as much rain as possible.
Ps - I've been using a camp stove to help the drying process, going to get another fire going today.
I'm still trying to dry out the vermicrete - I definately used too much water in the mix so its going to take a while to dry but hopefully im making progress - the dry weather over the past few days has helped. I had a bigger fire on the go for about 3 hours at the weekend and i noticed two expansion cracks in the homebrew within the external arch - I made a mistake and forgot to add a thermal break between the two arches and the external arch was quite hot. Given the weight on the arch i'm concerned about the cracks - they are fine (and disappear when cool) but over time they may cause a problem. I've also got the stainless steel twin flue fitted.
I was intending to put a render over the external arch - will i still be able to do this despite the fact that it is getting hot? Next stage is to start planning the roof
Managed to make a bit more progress although I'm still giving the oven time to dry before thinking about the waterproofing and final layer. I've picked up just over 200 original roof slates so hoping to start work on the roof soon as well. I'm not intending to fully enclose the oven hence the reason for both a waterproof layer and roof.
Since my last post ive added some more bricks at the front and started to built the supports for the roof structures. I've also got reclaimed quarry tiles on gumtree for the oven floor and entrance. I did a trial run last night with a three hour burn and the pizzas turned out well along with a nice port belly.
After taking a break over the winter I've managed to get some more work done on the oven during the Spring. i'm just about finished now, I have a couple of hundred tiles for the roof but not sure if i'm going to put them on. I've also got another section of the flue which i'll attach when im using the oven as it should help with the air flow and ensure that any smoke will go higher which will hopefully keep the neighbours happy. Once again thanks to those on the forum who have offered advice over the past year - its been a vital source of info. Good to see many more ovens currently under constuction - i'll keep on logging, looking forward to some good pizzas/bread over the next few months.
So glad you posted the finished pics of your oven as it allows me to play catch up on the previous pics of your oven firing.
Now then.....that'e ONE special finish you have created, and it looks spectacular!!......Apart from the complicated oven build, you have gone a great step further in created a bespoke design on the finish of your oven.....I respect all the work you have put into your oven build and I truly appreciate you sharing your build with us.....Thank-you.
It looks like all the hard work is now behind you and you look very close to having your first pizza party....now the fun begins.
Trial and error are the best methods in creating the perfect pizza. All the best with your first pizza party and......pretty please, post us some pics of your first full firing.
thanks terry, your advice/support has been much appreciated. I will be posting as few more pictures of the last few wks of the build along with giving my own thoughts of the entire project. One thing that I still need to finalise is the flashing etc for where the flue comes through the wooden roof. I'm going to check the forum as I know a few other people have had this issue. Although its a twin flue it gets extremely hot due to it just sitting on top of the brick chimney so I've had to leave a couple of inch gap. I've bought some hit temp sealant. As I mentioned on previous message I have got roof tiles which maybe I could use around the flue and then seal. Any thoughts on alternatives would be appreciated.
I will certainly post a few pictures from the first real firing, cheers
The picture below shows where the flue comes through the roof - i got the rubber type flashing with the flue but i'm not sure if it would withstand the heat from the flue once the oven is fired up. I took it off when i had a full burn going (the flue temp was measuring around 70) so I might keep it on the next time to see what happens.
Now i have just about finished i have been thinking about what i would change if i had to start over again...
1) buy a good pair of gloves - cement/lime isn't kind on the old hands and the cheapest gloves i used weren't up to much. 2) Given the time i invested i would prob buy actual firebricks instead of using storage heater bricks. The storage heater bricks do work but they are very dusty etc to cut and they take longer to get to the right temp (more wood needed etc. 3) I bought two bags of fire clay for 36inch oven but in reality one would have been enough. 4) only mix home brew in small batches esp when working later in the evening - i seemed to waste quite a bit when i ran out of light/time 5) i would prob make a larger vent for the chimney as the early indications may be that my one is maybe too small. 6) spend more time on measuring the dimensions of the initial slab as i was a bit tight for space when it came to the layers of insulation and external render. 7) buying tools on gumtree (brick cutter etc) worked well instead of the extra expense of hiring - i've managed to re-sell them all.
Overall i have enjoyed building the oven - i happy to answer any questions esp if you are using storage heater bricks in your build. I'll post some pictures of my first full firing in the next post.
After months of hard work (and a break over winter) i finally managed to get the oven fully operational. It took just about 3 hrs to get the oven to max temp, the flue seemed to work ok (esp as the oven got hotter) but at certain times during the 1st couple of hrs smoke was also coming out of the door esp when i put more wood on. I had the extended flue on so the height should not of been a problem although i didnt use the cowl so maybe gusts of wind didnt help. I have a infra-red thermometer which has a max reading of 550 and the oven well exceeded this. the oven was still reading about 200 twelve hrs later even without the door being on the entire time. The pizzas took about 2 1/2 mins to do - you'll see from the photo that i keep a small fire on whilst the pizzas cooked. Next time i have the oven on will be for a bigger pizza party night so looking forward to that. Cheers for now