Another UK oven started

[Ken524]

Re: Another UK oven started

Beautiful work Carl!

[Carl]

Re: Another UK oven started

I finished the hearth slab pour last weekend, and am pretty pleased with it. My bodge of using black plastic to hold the concrete in worked well, and this morning I had a nice flat level slab to work on. The slab was reinforced with a 6" grid of rebar tied together, so this thing should be bombproof.



The slab has an 'interesting' edge, but I'll be plastering over all this anyhow, so I can live with that.



I mentioned that I'm going to use Thermalite blocks for hearth insulation - it worked out very quick and easy to get them done to give me 4" insulation.



It only took me an hour and a half to get this done, including cutting all the blocks. I could have laid the hearth firebricks straight away, but I haven't got any fireclay yet Need to get more supplies in...
I'm putting six thermocouples in, on both sides of the insulation, in and out of the oven. I want to know if these blocks are any good, because they were very cheap, and a lot easier for me than vermiculite/perlite concrete.

[sarah h]

Re: Another UK oven started

Looking good! I like your round stand. Great job with the stone face - will you carry that look around the dome?
I'm rather envious of your thermo-couplings as it's something I'd like to have done, however, I felt I had enough to contend with in just building the oven (I'm currently in the midst of dome construction).
Your under-bricks for the floor sound as if they'll be fine.

Sarah

[Wlodek]

Re: Another UK oven started

Carl,
On the blog page you show some thermocouples wiring. Where did you find them? Especially at this price?
Best wishes,
W.
(who has been stalled by formalities)

[Carl]

Re: Another UK oven started

I spent a long time looking for a cheap pyrometer, and found that there weren't any. So a bit of lateral thought led me to buy a 'temperature controller' that accepts a type K thermocouple. I bought it off ebay, and bought four thermocouples at the same time from the same person on ebay. I don't really need the 'controller' circuit, but I thought it would be fun to have it switch a light on outside my oven when it was up to temperature.

I can't find the original seller (I bought it a couple of years ago, while planning a different oven project that didn't happen ), but it looks identical to this one (maybe same seller, but can't guarantee): temperature controller on ebay

I think I paid a bit less than this auction (about ?15), plus about another ?10 for three more thermocouples. I also bought a couple of cheap thermocouples of ebay similar to these ones: Type K Thermocouples on ebay

I plan to use these last two 'low grade' thermocouples for the areas that should only get warm, not hot - under the insulation and in the outside wall, just to see how much heat is lost. To choose between the thermocouples I got a used rotary thermocouple selector off ebay for ?6, which selects between 12 different thermocouples. I'll stick some pictures up when I fit them.

It should be obvious, I hope, but I have no affiliation with any of these sellers

[gjbingham]

Re: Another UK oven started

Carl,
I just found this thread. Really cool ideas on your base. Things seem to be moving along quickly. I look forward to seeing your progress.

Has your family caught the bug, or are they still just shaking their heads as you trudge out the door to work.

George

[Carl]

Re: Another UK oven started

The family are still looking at me with a sense of bemusement (what's wrong with the oven in the kitchen?). Friends look at me like I've finally lost it. The Guardian newspaper did a supplement this weekend on baking - written by Dan Lepard I think - (lots about wood fired ovens, especially from Tom Jaine) - and it said that to build an oven in your garden you had to be 'an ultra-enthusiast or lunatic'. Lots of people are quoting this at me. I think they're implying I'm the second type of person. Here's the link to the baking guide if you're interested - looked good to me: Guardian Guide to baking

Still, I'm cracking on. The brick walls for the base of the 10 foot by 10 foot summerhouse are finished now, and the timber arrived yesterday ready to go up. I'm trying to raise the base of the timber frame above ground level so it doesn't rot away. You can see the bolts embedded in the mortar - I'll be fixing the frame down with this so the whole thing doesn't blow away in the breeze.



I quite fancy putting a roof on this ASAP, because it's no fun building an oven in the cold rain. Hopefully I can get a lot of the frame up this weekend. The cladding for the summerhouse is coming from a demolished fence - more recycled products being used. Also very cheap - good old ebay!

[gjbingham]

Re: Another UK oven started

They will understand completely when your project is done and they've had their first freshly baked pizza or bread from it.

Look forward to seeing more progress photos. Pretty cold out there now, huh? I imagine our climates are very similar. Cold and damp.....

George

[dmun]

Re: Another UK oven started

The cladding for the summerhouse is coming from a demolished fence - more recycled products being used. Also very cheap - good old ebay!

I'm always amazed by the range and quality of the used building materials on ebay.co.uk : of course you have a compact geography and a thousand years of built structures to demolish and re-distribute.

[Carl]

Re: Another UK oven started

Not a lot been happening on the oven build at the moment as it's so cold outside. Instead I've nearly finished the wooden frame of the summerhouse - but haven't taken any pictures yet as I'm working right up to when it goes dark - about 1630 at the moment...

I've decided to build my oven dome out of 'mouldable firebrick' - a mix of gritty firebrick grog and fireclay. I've run a few tests on different mixes - testing to see how strong the wet mix is...



and testing how strong the bricks are after drying (and firing in the centre)...





There's much more info on my blog if you're interested. I've settled on a 50% grog, 50% fireclay mix - this has a small degree of shrinkage, and is really tough when dry. I'm hoping that this will turn out to be a sort of hybrid between a firebrick oven and an earth oven - the ease of moulding of the earth oven, with the strength and heat resistance of firebrick. As ever, I'll keep you posted with progress...

[sarah h]

Re: Another UK oven started

This is a very intriguing idea!
I want to build a second oven on an island this summer but can't see loading and unloading individual bricks and blocks into the car, out of the car, onto the boat and then off again - sacks of materials like this if I can find them, mixed up once on-site, might just be the solution.
I'll look forward to seeing how you get on with this - best of luck!

Sarah

[Carl]

Re: Another UK oven started

Well, the timber frame is up now, covered with a corrugated roof. It took a long time to do, especially since most of it was done in driving rain.

The frame will be clad with timber eventually, but right now I've hung a halogen light in there so I can keep working on the oven masonry. I've started on the entry to the oven and the chimney. Sounds daft, but I want the chimney done before I've done the dome - the roof isn't finished yet because I've got to poke the chimney through it. Once the chimney's done, I can finish the roof, and build the rest in the dry.

Hopefully I can get the entry arch done in the next week, if our very mild weather continues - only going down to 7-8 C at night at the moment.

[gjbingham]

Re: Another UK oven started

Awesome work. Summerhouse huh? Looks like a real house around here.
George

[Carl]

Re: Another UK oven started

More work on the entry and chimney this weekend. The arch was soul destroying - I spent an hour making a beautifully measured mock up, cut two fibreboard supports to size, then wasted 2 hours trying to get the bricks to fit.

In the end I just dropped the support and used wooden wedges to jam everything in tight.



This was the most infuriating bit of masonry work I've ever done - mind you, I've learned from it and would do it differently next time. My bricks are all different sizes too, which doesn't help. Excuses, excuses...



The arch is about 1/2 inch away from the brick ledge behind, with an air gap in between. I want to fill this with an insulation mix to reduce the risk of the arch cracking as the chimney heats up. Making a rod for my own back I guess by making this more complicated than it needs to be. The only recycled bit this weekend was the angle iron supports - free, after 20 minutes angle grinder work on an old bed frame

[Les]

Re: Another UK oven started

Sometimes the easy route is the best path to take

Looking good.

Les...