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Post by truckcab79 on Dec 3, 2019 15:35:44 GMT
Not sure if you’ve already decided what to seal with but I used Thompson’s Water Seal. Think it was only about £25 for 5 ltrs. Sprayed it on as it’s much quicker than brushing. No change to the brick colour or finish. Water just beads off. Just about to cover mine up for winter but I’ve got more than enough left to treat it again in Spring just for the hell of it.
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Post by markmckenzie on Dec 4, 2019 16:58:23 GMT
Don't worry Dave. I used Stormdry brick cream - it's water vapour permeable but repels water drops. Has a 25 year performance guarantee and went on easily with a roller. I hope it all absorbs though because my oven looks like a dog's dinner now! It's due to rain on Friday so it'll have a clear 48 hours to soak in.
If the oven cracks I'll let everyone know.
The air bricks mean that the vermicrete is permanently exposed to the air anyway and any water vapour has an easier escape route than pushing through the bricks.
Started making the oven tools today.
Regards,
Mark
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Post by downunderdave on Dec 6, 2019 19:21:22 GMT
Don't worry Dave. I used Stormdry brick cream - it's water vapour permeable but repels water drops. Has a 25 year performance guarantee and went on easily with a roller. I hope it all absorbs though because my oven looks like a dog's dinner now! It's due to rain on Friday so it'll have a clear 48 hours to soak in. If the oven cracks I'll let everyone know. The air bricks mean that the vermicrete is permanently exposed to the air anyway and any water vapour has an easier escape route than pushing through the bricks. Started making the oven tools today. Regards, Mark Reducing permeability for most products works equally in both directions. Most commercial renders and products applied to the exterior are designed to be specifically partly waterproof to repel moisture. This reduces water entry whilst also allowing water to exit. If they were made to be 100% waterproof then problems can occur because moisture entering walls then has an equal difficulty in travelling back out. Stormboy’s claims of their product being breathable may be correct to a degree, but I’d doubt whether it would result in 100% waterproofing at the same time as being as breathable as an untreated brick. You may also like to investigate the product’s ability to withstand heat. Another problem for this application on an oven is that we tend to use insulation materials that are highly water absorbent, unlike a building where non absorbing materials like polystyrene or urethane are used in areas likely to experience damp issues. Traditionally Italian ovens were finished with a lime render which is quite porous and whilst allowing moisture in also allows for easier drying out. They were also traditionally outdoors and exposed to the weather. A lot depends on the weather conditions in the ovens location. My view is that the best solution is an un-waterproofed oven sheltered from rain by a roof. Unfortunately this is an expensive option and many builders prefer to waterproof the exterior instead. In my own case our location is in the tropics and during the wet season the extreme humidity alone can make the oven wet resulting in reduced performance even if it hasn’t rained. Waterproofing the exterior or even a roof in that case makes no difference. However, a couple of firings prior to use restores the performance back to normal again. My own oven is waterproofed and has no roof over it. I use an elastomeric acrylic coating which results in a 2-3 mm coating that is both fully waterproof and also covers any cracks in the render coating. Being elastic also allows for the thermal cycling and expansion problems. My apologies for the long winded answer, but the problem is a complex one and I’m sure there are a number of different approaches. My concern is that when firing a new oven, the water contained in its construction is far greater and requires longer to eliminate than most people would think, so take it slow. |
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Post by markmckenzie on Dec 9, 2019 14:32:23 GMT
Today I added the slate landing in front of the kiln brick hearth - should make using the oven easier and help to shed any driven rain away from the oven. Made this from an offcut - I think it looks OK. Dave - please be reassured that, having spent 3 months building it, I'm not going to destroy my oven in a fit of over-zealous fire frenzy. As I've said before, my plan is lots of small fires, kept small and burning for 4-6 hours - I keep the fire going as I potter around the garden and let it burn out completely at the end of the day. The inside of the dome is as black as coal at the moment.Floor/walls max temp is around 120 deg C so far. My plan is a trial pizza run at the end of February. I hope that is slow enough for you. Bear in mind that humidity is 88% tonight - we could get into a long pointless debate about the pros and cons of 100% impermeable coatings with an oven open to the elements. Don't forget that the air bricks are there to allow ventilation of the vermicrete layer. (You can just about see them in the picture). Few pics of the landing slate and work surfaces treated with a stain protective coating. Regards, Mark    |
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Post by markmckenzie on Feb 2, 2020 17:37:53 GMT
Drying fires continue and I've been busy in the workshop making some accessories for the oven... This is a log support made out of a few pieces of stainless square bar..  Then I cannibalised a grotty old BBQ grill and made a Tuscan grill with a set of skewers. Using this I can grill as normal or turn it 90 degrees and use the skewers in a hot oven to do Tandoori-style chicken etc  I also made a turning peel, pan hook and embers rake along with a brush for sweeping the oven floor clean.  I used up some old sycamore and oak offcuts to make a couple of peels - one is aluminium.  Everything gets hung up inside a locked shed nearby.  There last thing I'm making is an insulated door - I cut all the sheet aluminium today and engine-turned the front face (it's a bit wonky) - more pictures when I've finished it.  Bye for now - looking forward to spring! Mark |
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Post by oblertone on Feb 5, 2020 19:40:14 GMT
V smart work.
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Post by albacore on Feb 5, 2020 21:03:57 GMT
Nice oven tools! How did you do the bends in the handles?
Lance
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Post by markmckenzie on Feb 5, 2020 21:53:16 GMT
Hi Lance,
Bends were made using heat from oxy-acetylene torch and application of brute force.
Same with the aluminium pizza peel blade - heat along the bend line to a dull orange then bend. Got to be careful as easy to melt through this. Can't just bend with brute force as it develops stress cracks.
The rectangular bar for the oven brush and the square bar for the log support was v-cut with a disc cutter then hammered over to make the bend. Everything was then welded to clean it up.
Still working on the oven door. My 200A tig machine is proving a bit feeble!
Regards,
Mark
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Post by markmckenzie on Feb 21, 2020 18:12:28 GMT
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Post by markmckenzie on Mar 15, 2020 17:47:11 GMT
Drying fires continue and now the dome clears after a 2 hour burn. No cracks yet. Interior of the oven is 350-450 degC - outside brickwork and bottom of slab is 10DegC (air temp today).  Can't wait for the better weather. Time to start experimenting with pizza dough recipes. Mark |
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Post by markmckenzie on Apr 6, 2020 19:20:11 GMT
First use in anger. Much praise from the kids so all the effort has been worth it. Obligatory photos..    Wish I'd taken more. Garlic bread/pizzas/dough balls all wolfed down! Definite learning curve and great fun. |
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Post by simonh on Apr 6, 2020 20:34:25 GMT
Looks good, that first pizza is always special  |
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Post by markmckenzie on Apr 7, 2020 8:38:09 GMT
Thanks Simon.
So much to learn - the pizza on the plate is the result of hours of preparation.
I have a lot to learn!
Mark
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Post by albacore on Apr 7, 2020 9:55:49 GMT
Yes, first you bust a gut building the perfect oven, then you have to start learning how to make great pizza!
Lance
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Post by oblertone on Apr 8, 2020 15:41:59 GMT
Very nice to see some product after your labours.
A personal favourite for a group session (current conditions permitting) is a couple of plain bases loaded with garlic butter, accompany these with a fireproof dish containing two slabs of Feta chopped into cubes, a little chilli oil and scattered with chilli flakes. Melt this in the entranceway while cooking the garlic breads and spoon it on the GB; your guests won't be disappointed and it'll allow you to judge the temp of the cooking floor without sacrificing too many ingredients.
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