Hearth not dead level

[Greenman]

Re: Hearth not dead level

In the true spirit of sportsmanship I can feel for those south of the border. I expected Queensland to win on home ground but not with a score like that.

Your boys must be shaking their head wondering what happened after the good showing they put up in the first two rounds.

There are plenty of smiles around up here, like watermelons hit with a cane knife!

[Wozza]

Re: Hearth not dead level

No. Any mortar, it can be cement based it doesn't matter cause it's below the the hebel layer and will not be effected from the heat.

OK - I'll do a test with some sand to see how much I need and then maybe spread some ready mix mortar and bed the Hebel into that. I was worried about the clay/sand mix that it wouldn't be a firm enough base for the dome walls.

The Hebel blocks are like sponges. Should I soak them before laying onto the mortar? I've seen you suggest a layer of margarine somewhere. I'd probably need a few kilos! Or maybe lay the mortar level and then place the Hebel when it's dried?

Go Queenslander!!! ( sorry can't help myself )

Lot of long faces around today. Going to take some time to get over that hiding. Hope the cricket is going OK...

[cobblerdave]

Re: Hearth not dead level

G'day
No. Any mortar, it can be cement based it doesn't matter cause it's below the the hebel layer and will not be effected from the heat.
I use silastic to glue hebel to wood door faces and it works because the hebel is an insulation.
You should use the clay and sand mix on top of the insulation because of the heat. But in your case 6 mm is a lot of diference and I would attempt to level under the hebel knowing any remaining small difference left could be taken up with a sand clay mix.
Regards Dave
Go Queenslander!!! ( sorry can't help myself )

[Wozza]

Re: Hearth not dead level

I don't think there is any reason why you cant mortar the hebel to the base and gain a more level surface.

The mortar in this case being the firebrick clay and sand? I may try it just with sand this weekend to see how thick I really need it.

[cobblerdave]

Re: Hearth not dead level

g'day Wazza
The rasp might not work because the areas' bigger than the length of the rasp , no were to hold it. Ive used a brick to file of the edges of the hebel block were they don't quite meet and it works well.
I don't think there is any reason why you cant mortar the hebel to the base and gain a more level surface. Any small adjustments can be planed of with a brick or rasp. I think its important to start the build on a level surface.
Regards Dave

[Wozza]

Re: Hearth not dead level

G'day
Hebels quite soft. You can use a house brick ( the ones with the holes) to plane off any raised edges. You've only got a relatively small area. Perhaps a bit more heavy handed planing will yeld a better level.
Regards dave

I actually got one of the blocks this morning and scraped away with an old saw to check that. I think a rasp or similar would trim it back quite well. I thought maybe just trim back the ones that are supporting the dome bricks just where the brick sits. But I've got insulating blocks sitting on top of the Hebel so if I 'recessed' the Hebel just in one area that would mean I'd have to cut those blocks to fit just that recessed area.

Unless you mean lay out all the Hebel (cut to match the shape of the dome) and then trim the whole lot. Which I guess is possible, but I'm not sure how accurate I could be. I could go from a not-completely-level but very flat surface to one that is pretty level but nowhere near being flat.

Which would you go for?

[cobblerdave]

Re: Hearth not dead level

G'day
Hebels quite soft. You can use a house brick ( the ones with the holes) to plane off any raised edges. You've only got a relatively small area. Perhaps a bit more heavy handed planing will yeld a better level.
Regards dave

[Wozza]

Re: Hearth not dead level

No, it does not. Not sure of your concern, is it that one side of your dome is 6mm lower than the other? If I am reading it right that will not be an issue at all.

Yeah, about 6 - 8mm lower on one side than the other. No way it could be noticed if I build it like that. It might just be noticeable looking directly at the arch, but I can squeeze in a little extra mortar between each course so that they end up level at the top - and hence a level arch.

I was just wondering about the structural integrity of the dome if it 'leans' slightly one way. If it's not a problem (just the sort of advice I was hoping for) then I'll crash on. Whilst kicking myself that I couldn't get the damn thing level...

Thanks Les.

[Les]

Re: Hearth not dead level

Does that mixture set pretty solid?

No, it does not. Not sure of your concern, is it that one side of your dome is 6mm lower than the other? If I am reading it right that will not be an issue at all.

[Wozza]

Got a solid concrete base, blockwork walls (every other hole filled with concrete) and a floating hearth has been poured. All looking good. But...

...I've laid 50mm (2") of Hebel blocks and then 75mm (3") of insulating tiles on the hearth and now I find that the hearth is not dead level. It was spot on when I checked (and re-checked) the formwork, but maybe something moved after we poured the concrete and it's about 6mm (1/4") out across the width of the proposed 36" oven.

Well hell, no big deal, I thought. You really can't tell unless you lay a level across the tiles. If the floor of the oven is just slightly out it's not like my pizzas are going to slide off to the side. But how do I make sure the oven itself is square?

I was just going to lay the Hebel and the insulating tiles directly onto the slab - it's quite flat. So should I use a mixture of sand and firebrick clay to level it all up? I understood this mixture was more a case of bedding the tiles if there were slight bumps and high spots. Could I use it to correct the slight slope? It would mean that I'd have about 6mm thickness of the mixture on one side reducing to zero on the other. Would that 6mm thickness be stable enough to support the bricks making up the wall?

Does that mixture set pretty solid?