A build from the North

[Calaf]

Hi Al! Looking fab so far, shipmate.

Quarry tiles are a fired product. They are made by firing at 1100'C for 80 hours, so I reckon that, notwithstanding the occasional rogue faulty tile, our modest ovens pose little stress to them.

Having said that, my tiles are also B&Q so if anyone's going to experience exploding tiles it's me. If that happens I'll post the picture as an info-warning. But I wouldn't worry about anything.

[cannyfradock]

Apr 14, 2012 9:52:31 GMT Terry Hardwood said:

All the reading I have done indicates that tiles should be perfectly fine. There are many examples of oven builds using tiles over firebrick so you should be fine. And they have been used in many old ovens in times gone by. One incident shouldn't tar the whole idea.

There are now 3 builds that have used quarry tiles as a finished cooking hearth. I really hope (after reading Terry H's post), that they perform fine. At best...they will work fine.....at worst.....1" fire-bricks laid flat on the quarry tiles should solve any future problems (about £30)

Terry

n.b........As much as I'd like to dismiss Woodfiregourmet's comments and say "everything will be fine".....I cannot and truly appreciate the input. Sharing knowledge and experience is part of this forum's set up.

[turkey]

I think clay tiles are most likely to fail with sudden heat changes, so be very careful placing large cold items on them when hot, and don't rinse the floor whilst its hot, but if its stuck down I would hope even aggressive cracks would not allow much to go flying....

otherwise if they clay used to make them is pure then are they not fairly similar to pressed reds people use.?

[bighairyal]

Nothing better than a bit of healthy debate! All comments/input welcomed, be they positive or otherwise.

I've made my bed, and am about to lie in it, but if these tiles do go belly up it'll only:

1. Result in an oven rebuild - more fun!
2. Serve as an advisory to future builders.

Personally, I can only see the tiles exploding at wfo temperatures (which are far lower than the temperature at which the tiles are fired) if I've been foolish enough to leave any air bubbles in the adhesive between tile & brick. As dictated by Charles law, heating & expansion of the bubble could cause a tile to fracture or explode.

Fingers crossed!

[benjibong]

Apr 13, 2012 19:53:12 GMT cannyfradock said:

I have been involved with 2 clay builds using "clay pavers" and after 18 months 1 paver has cracked but haven't heard of any spalling. Quarry tiles on the other hand are similar but quite different.....glazed finish' different composite....half the depth etc.

quarry tiles are not glazed

there are dozens of builds on fornobravo using quarry tiles and not a single report of exploding tiles. seems a bit negative to me to say their choice of floor is not ideal. just my opinion.

if quarry tiles were a problem someone should mention it to Dingley Dell as they use them in their ovens. also a couple of books on breadmaking mention quarry and clay tile floors and racks.

but have a look at other forums. for reassurance and as Terry H says they have been used in ovens for donkeys years to get a nice clean floor.

b.

[surfingspider]

If you are Kiko's book says a lime render will be fine as a final coat as it is breathable. I was considering it for my oven before I decided to build the full roof.

[woodfiregourmet]

The tiles I mentioned on previous posts were Ruabon quarry tiles, unglazed and 12mm thick. They are the type that are normally used in commercial kitchens etc.
Can't see the scientific relevance of the manufacturing process/ temperatures etc as this is for the purpose of turning the raw material into a tile. Also, don't think the manufacturer would ever have recommended these tiles be used in what is basically a furnace, being repeatedly cycled from 0C to 500C and back to 0C.
Would be interested to hear if anyone has tested the refractory qualities of tile too. I'm aware the ancient ovens used certain types, like tomettes in French bread ovens, which were a very different product, and before firebrick was locally available.

[Terry Hardwood]

Woodfired, we would all like to reach for professional quality kiln approved refractory materials but cost constraints mean we reach for whatever materials are available that others have shown work well. One anecdote shouldn't cause alarm.

As I understand it the manufacturing process determines the physical characteristics of the finished product. As you said, turning the raw material into a tile.

[rivergirl]

looks like you are nearing the best bit of the build ( well it was for me LOL ) cannot wait to see another clay oven

[bighairyal]

Apr 16, 2012 19:21:28 GMT rivergirl said:

looks like you are nearing the best bit of the build ( well it was for me LOL ) cannot wait to see another clay oven

Offshore again in a few days, you'll be waiting a while yet....... To the chopper!

[bighairyal]

Catastrophe! Protective tarpaulin blown free of it's ratchet strap captor by spring winds, and poor proto-oven left open to the elements overnight.

The whole affair is soaking, but most disconcerting - the (not cheap) high temp tile adhesive has turned to goo around the edges of my hearth. Can only hope it'll go off again slowly whilst I'm away.

[Calaf]

If it's anything like the stuff I used (air-setting refractory cement) it does not like setting in dampness. But kept dry it'll eventually set like rock. Sounds like a little clean-up is all that is required and when you return it'll be set.

[bighairyal]

Well I'm home again, and a nervous peek under the tarpaulin reveals no major damage. Everything appears to have dried out nicely. Those contentious quarry tiles appear well stuck down, and the grout has settled good'n'proper.

I then toyed with the idea of popping to Jewsons and getting a load of sand in to build my dome form, but not half an hour later it began to rain - and the forecast is for rain all the way until Sunday, when I'm off to Denmark to start a new job.

Watch this space, I suppose. Bullocks!

[bighairyal]

Well, this is highly unsatisfactory, but not unexpected.... As is quite usual, the weather at my place of work (this time, the tiny town of Grenaa, NE Denmark) has been splendid enough for me to return with a farmers tan - but only to find the sort of weather at home that is not conducive to finishing off a WFO.

Anyroad, these continued delays are causing me to have rash ideas. My current plan to finish off the oven with alacrity is to build the standard 1st clay/sand dome layer + brick arch, but then build a wooden box around it, using the same dimensions as the decking board base, fill said box with lime/vermiculite as insulation, and top it off with a fetching clay tile roof.

At current build speeds, I forecast this all to be finished in time for the arrival of Saint Nick.

[bighairyal]

Good weather! I'm cock-a-hoop. Three (3) days of sun forecast, so it's oven building I go.

A trip to Jewsons sees me furnished with building sand, and a visit to Sedgefield Pottery Supplies (http://www.sedgefieldpottery.co.uk/) completes the list with 50kg of lovely quality clay. Yeah, it's something like 20x more expensive than turfers clay, but I've only got 3 days - and convenience wins here.

So, the sand form was finished today. It ended up taking approx 125kg of sand. It's only 14" tall, a bit lower than the seemingly standard 16" - but the oven is only going to be 26" diameter anyroad. Please note that the copper pipe will be removed, and the sand nipple at the top of the dome will be flattened off before I start to throw clay at it.

Tomorrow I shall make up a few test batches of clay before I use it in anger. I'll start at 3-1 sand/clay and dilute from there. I imagine pure clay will require a ratio of 5-1 or something like that. We'll see!