Modular Build In Deepest Lancashire

[tonyb]

Yes te fire needs to be big. I think I saw it described once as big enough that your child goes 'more,more' and your wife says 'less,less' and threatens to call the fire brigade .

I tend to run my fire such that the flames are trying to reach the base of the flue. For my diy build it takes 2 large sacks of wood, though I understood modular ovens took quite a bit less.

[spinal]

My oven is fairly large (almost 2m) and needs roughly 4-6 logs to get it hot. This takes about 2 hours. At this point, I'll add another 4 logs to bring the hearth from 400Cish up to 600C ish before cooking.

I think the oven materials will count a lot as to heating speed - the more alumina in the bricks, the faster it will heat.

Also, position of the fire - I'll start it near the front, but move it as far back as possible once it's going to keep as much heat "inside".

Funnily enough, I've had neighbors come over thinking my house was burning down due to the reflection of the flames onto my kitchen windows...

M

[albacore]

Thanks to both of you - looks like I need to wind up the volume!

[cannyfradock]

Albacore

Looking back over your build you couldn't have done a finer job than you have done in insulating the oven. Your oven perhaps HAS got some moisture still in it as you shouldn't need to be using so much wood to achieve good results/heat retention.

Maybe other members who have used a Woodfire Gourmet modular kit who see this post can add their comments on this oven.

Terry

p.s... love the last set of pics (and the wood-store is simply showing off.....I love it!)

[albacore]

Well, things were going pretty good. I sussed out the heat thing; I think it was a case of lots more wood. I also got some kiln dried, which really does seem to burn hotter - but at twice the price!
I also, rightly or wrongly, decided to line the whole of the cooking floor with 1" firebricks. A bit tricky to get them in, but possible.
But fired her up tonight, cooking pizzas like a good 'un, and just noticed a nasty little crack has arrived in the rendering:





It runs through the front arch mortar as well

I can only think it's from the expansion of the outer wall of the twin flue which gets warm but not hot. In hindsight, I should have a created a gap all all round the flue and filled with silicone, but didn't think it necessary, being twinwall.
For now, I think I'll grind out the crack and fill with silicone, but any suggestions for a permanent repair in the spring? Ideally, I think I need to create that gap round the flue pipe in the render, but not sure how at the mo'.

[bookemdanno]

Hi Albacore, i'm sorry to hear about your crack.

There's all sorts of heat related expansions at the extreme temperatures that these ovens see, and all the materials react differently. It must be hard for the materials we use to handle it, and i feel that cracks are pretty inevitable. It feels liek such a kick in the teeth though after we labour so much on them. The main thing right now, is not to allow winter into the substrate of the oven. Frost, rain and snow will penetrate that crack and at the least saturate the nice dry materials below. Then come springtime really all you can do is like what you said, open up the offending crack, and decide on a method to repair it. Trouble is though, its likely to continually reappear. Its not likely to create a fail, or anything serious, which is a positive that you can take.

I had a major render failure, which meant that it all came off. This was cracking, then frost damage to immature Lime Render. I then replaced it with K-rend, but to be honest i'm a little scared of getting a fire into my oven before the winter, so haven't ventured anywhere near it. Any fires going into my oven will be in the spring next year!

[albacore]

Hi 'Danno; yes I remember reading your troubled lime render saga - such a shame when you seemed to have done it all by the book!
I certainly don't want to take all mine off just yet!
I'm starting to hatch a future plan now: I think I'll drill down into the render all round the flue with a small long masonry bit, as close to flue as I dare. Then clean out the render crumbs and fill the gap with silicone to allow for expansion.
I would now advise anyone planning to build an oven to leave an expansion gap round the flue, even with twinwall.
I would wrap a few turns of self adhesive neoprene closed cell foam tape round the flue prior to rendering, if I was doing it again. We learn by experience!

[bookemdanno]

Yeah exactly, and its never that much of a hardship when you love to potter about like i do!

[albacore]

I finally got the area round the oven landscaped (ran out of good weather last year), so I thought it was worth a "finished" picture. It's nice not to have to cook pizzas on a mud floor!

[cobblerdave]

G'day
I've just read your build and I've enjoyed the read. I must say I'm glad to hear that someone else has found V-Crete a sh@t to work with I hate the stuff but you got to admit the stuff does work well.
All this talk about burning logs I find a little strange. I never burn anything that I can't wrap my thumb and forefinger around. If I can't I split it down. Wide and fierce fires .. If it licks out the chimney tone it down as its wasting heat. Usually a barrow of loose "sticks " will have you at pizza heat, and give you enought retained heat for cooking into the next day at the least
Again nice oven , I admire the white but it's not possible in my climate
Regards dave

[albacore]

Thanks, Dave. I guess the original "look" I wanted was Italian; I think it's ended up more Greek, but that'll do for me. I'm happy with it.
Yes, the quantity of firing wood is a cause for concern for me. I do seem to need a lot to get a decent cooking temperature. I'm not clear if modular ovens are worse in this respect compared to firebrick domes - I don't see why they should be. I get through around 1 - 1 1/2 bags of wood to cook 8 pizzas (of course I wouldn't need too much more to cook 16!). Bags weigh 20 - 25kg. Kiln dried gives higher temperatures, but at a price premium. My logs are all split - I can't get full logs and don't know if they would be better.
Lance

[cannyfradock]

Albacore/Lance

Just had a chance to look back over your build.....you've done a fine job. The chimney area is always a problem spot in .....construction (the dome/inner arch transition on a self build) and protecting the render from cracking around this area when fully firing. Try to address any cracking by chasing out the crack with a thin blade on a 4" angle grinder and fill with a lime mortar or fire cement. The cracking won't affect the performance of the oven but may lead to further cracking which may let the rain creep in.

I don't know the refractory qualities of a Wood-fired gourmet modular oven, but you have done a fine job on extra external insulation AND you have laid an extra 1" fire-brick hearth so you should....after fully firing your oven be baking 2 minute pizzas.

When I have to fire a pizza oven up for a long evening, I always fire the oven up the day before with any old crap. Off-cuts or broken down palletts etc. On the day/evening kiln dried hardwood will give the best results, but kiln dried is just anther method/word for "well dried" seasoned hardwood. If you have an aired dry area you can easily achieve this with normal seasoned hardwood.....Again, start your fire with with any dry wood, soft....or hard wood then after (it depends) about 40 minutes the top of your dome should start clearing itself of soot and you should see a clear line descending down from the top of your dome. When this clear line has descended to 6" of the hearth, spread the embers over the whole hearth. Wait 10 or 20 minutes then push the embers over to one side (I use a cast iron grill from an old fireplace to keep the embers at the rear/right hand side of the oven....this makes it easier to chuck the occasional log on to keep a flickering fire going). Following this method the oven is usually way too hot so I wait 20 minutes for the oven cool and retain it's "mass" heat.

This is a bit of a long drawn out process but get it right and the hearth should stay "good" for a few hours of pizza baking. Usually when you let people "have a go" at making and baking their own pizzas....guests tend to spread the base sauce too close to the outer rim of the dough base, plus they overload a pizza.....this may cause spillages on the hearth. If the oven has been correctly fired the hearth can take many mishaps.......if there are many mishaps and the hearth gets full of pizza toppings, simply take a 20 minute pause and pull the embers again over the whole of the hearth and let the heat from the embers/small logs clean and sterilise the hearth. If there is enough heat in the embers, this should take just 20 minutes......after this time push the embers to side and start again.

A lot of this you will learn by "trial and error"....the best way to learn!!

Great oven btw......and.....happy bakin!!

Regards...

Terry

[albacore]

Thanks Terry - and for your useful tips. I'm slowly getting the hang of building up the fire and baking the pizzas.

I think that when you've just finished building an oven (which is a pretty big task for most people - it was for me), then you expect to be cooking perfect pizzas from session 2. Of course they are edible at that stage, but, at least in my case, a long way off perfect. For instance, I had a tendency to place the pizza too close to the fire and before you know it, you have a section of burnt crust!

As a southpaw, I also appreciated your point about building the fire on the left, so that I can easily load and unload the oven. I've also tried with the fire at the back, but I think the side is better.

As in your sig - I'm still learning! Next stage is to build myself a door so I can make use of all that leftover heat to bake some bread.

Cheers,
Lance

[richieh]

Hi Lance ,
Enjoyed reading about your build !
This thread is a bit old now but I'm looking at the very same kit , can i ask if its a kit that you can recommend given that you will have been using it for the last 2.5 years , and any type while building it up ?
Cheers
Rich

[albacore]

Hi Rich, yes, it's still going strong! We had some great pizzas from it on the day after Boxing Day.

I would happily buy the same modular oven again:

• good size
• good proportions
• aesthetic shape once insulated and rendered
  
• well made

• good customer service

Regarding construction, I would say the following:

• Put the firebrick on a layer of good insulation; min 50mm calsil, foamglas or vermiculite board. Thermalites and vermicrete are poor substitutes, in my opinion.

• If you are rendering the dome, ensure you leave a gap round the chimney (even if it is twin-wall) to allow for heat expansion, otherwise the render will crack. Mine did! Use Cobblerdave's trick of wrapping the chimney with a layer of corrugated cardboard. Remove once the render is set and fill with silicone.

• Make your wood store opening as big as you can, commensurate with good appearance - and don't spoil your wood store with internal support walls.

• External arches are not self supporting in a lateral sense!

A few others on this forum have also used the WFG modular since I did - just do a search and you will find them.

Lance