Pre-Construction Questions

[KiwiPete]

Hi Guys!


thanks for all the comments!

I will modify my structural bottom concrete layer to 3" rather than 4" with 3" of perlcrete on top.

Marcel: Yes we do call each other "mate" here in Kiwi country

Marcel: my firebricks are approx 30-35% alumina, so should be OK.
Here is another reason for going for bricks cut in "thirds" : I have just priced firebricks: they are NZD$4.68 (US$ 3.22) a piece.... ( I am not just a Kiwi, but also a Dutchman ) so anything I can sorta do to keep that cost aspect down seems like a good idea.

Re the insulating blanket: I have found an alternative: its called "Rockwool" and has a maximum service temperature of 650C (1209F) so I think it should be OK. It comes in various thicknesses: e.g. there is one that is 25mm (1") thick and 750mm wide and 6mtr long (for NZD$135). The nice thing is that this stuff is stuck onto a backing of 1" wire mesh, which allows me to 'shape' the thing pretty much the way I want and then stucco straight over the top.

I suppose my philosophy is: not too much thermal mass, but insulate the sh*t out of it, so you can still retain the heat for a "reasonable" time.

Marcel: re being 'independently wealthty..' No I am sorry to report that I am not. But to put things into perspective: a guy that I know reasonably well, had a pizza oven imported and built into his back yard for about NZD$25000!!! He definitively has more money than sense! Once I have my oven up and running, I'll invite him around..

James: thanks for the comment about your Firenze oven, my thoughts have also been based on that info.

Rounding up: the info and thinking on here has been invaluable so far. I am quite looking forward to (most likely) having the first Pompeii oven in NZ.
Next weekend I will start on the base. I'll make heaps of pics and keep you guys posted.

Cheers

Peter.

[dmun]

Originally Posted by KiwiPete

Here is another reason for going for bricks cut in "thirds" : I have just priced firebricks: they are NZD$4.68 (US$ 3.22) a piece....

Just a suggestion: In the US, 3 inch fire bricks are a speciality item available from refractory suppliers only, and they are expensive. You may want to do some more shopping: don't neglect architectural salvage yards, they may have a quantity of used fire brick. You want the ordinary ones that are used in fireplaces.

Not that I'm opposed to thirds cut bricks: I think I came up with that suggestion in the first place.

David

[Marcel]

Originally Posted by KiwiPete

Hi Guys!
# 44

(P) thanks for all the comments!

I will modify my structural bottom concrete layer to 3" rather than 4" with 3" of perlcrete on top.

(M) OK, you can do that and still be our friend, mate!

<snip>

Marcel: my firebricks are approx 30-35% alumina, so should be OK.
Here is another reason for going for bricks cut in "thirds" : I have just priced firebricks: they are NZD$4.68 (US$ 3.22) a piece.... ( I am not just a Kiwi, but also a Dutchman ) so anything I can sorta do to keep that cost aspect down seems like a good idea.

(M) I don't know if you were serious about being a Dutchman, but I was born in Amsterdam, hence the reference to Piet, your name as spelled in Dutch. But US $3.22 is still more than twice what I paid. I guess shipment from wherever to NZ will be more than to most US ports, plus, we probably make firebrick here too.

<snip>


(P) Rounding up: the info and thinking on here has been invaluable so far. I am quite looking forward to (most likely) having the first Pompeii oven in NZ.

(M) Congratulations, Piet.

(P) Next weekend I will start on the base. I'll make heaps of pics and keep you guys posted.

(M) Some unsolicited advice, Piet:

1-To post pictures on this forum you need to use the Manage Attachments button, below.

2- You will get a message rejecting your image if you submit any .jpeg images greater than, I believe, 97 KB so you need to first reduce them.

3- James had earlier encouraged us to post to the "Photos" forum so you might want to also Copy-Paste your images there.

4- You are limited to, I believe, 4 or 5 images per post.

5- If you have the time &/or energy, consider referencing your images to an external host such as PhotoBucket, or Yahoo. Both Paul and I use PhotoBucket. Go to http://photobucket.com/albums/a318/marceld/?sc=1

for examples of one way to organize your pictures.

(P) Cheers

Peter.

(M) Tot Siens, (Ciao)

Marcel

[james]

Going back to KiwiPete's posting about the $25,000 (NZD) oven. If you can find another one of those, we would be happy to provide the oven for that price -- and we could throw in a 6 pack of beer for the referral.

Send 'em our way.

James

[james]

Marcel and KiwiPete,

Dutchmen everywhere. Our partner who installs outdoor kitchens in the wine country using Forno Bravo ovens and fireplaces is Dutch (deJong), as is one of our daughters' music teachers (Masselink). They knew each other before we met them individually. I gather you pronounce deJong -- de young.

Is there a large Dutch ex-pat community in the states or New Zealand, along the lines of the English?

James

[KiwiPete]

Hi Guys,

James: with regards to the $25,000 pizza oven: I'll take a picture of it and post it on here.
And yes: I'd be more than happy to refer your products to people here - hell, I could become your NZ representative... but then again, total population of NZ is only about 4 million, so that is a pretty small market. And Kiwis are inveterate Do It Yourselfers. (supposedly a Kiwi can fix anything with a piece of no.8 wire)

There are indeed a lot of Dutchmen here. The bulk of them came after the second world war. I came here 25 years ago, chasing a kiwi skirt...

And there are lots of Dutchmen everywhere, including the US. Hey: New York used to be "New Amsterdam" you know...

Marcel: My *real* name is actually Peter. (not that I mind a helluva lot.. )

Now for some more questions:

I went and saw my fire brick supplier about the type of bricks I am getting. They are 9" X 4.5" X 3" with about 37% Alumina content, so should be good, from a thermal point of view.

He suggested I shouldn't be using refractory mortar between the bricks, but rather refractory concrete ("castable"). He reckons mortar is only good for gaps between bricks of a 4-5 mm. (just over 1/4 inch) Because the bricks are going to angled on both the horizontal plane as well the vertical, the gaps will be (much) wider than that.


Also he reckoned I would not be able to cut the bricks with a skill saw with a diamond blade, because they are way to hard. He would allow me to use his big industrial saw to cut them, but at a cost of $1.50 per cut... !!! (Dutchman getting very sensitive now )

Is it really that hard to cut firebricks?

Anyway, I am going to be buying a grinder with a diamond blade, and see for myself...

[aikitarik]

Originally Posted by KiwiPete

Also he reckoned I would not be able to cut the bricks with a skill saw with a diamond blade, because they are way to hard. He would allow me to use his big industrial saw to cut them, but at a cost of $1.50 per cut... !!! (Dutchman getting very sensitive now )

Is it really that hard to cut firebricks?

Anyway, I am going to be buying a grinder with a diamond blade, and see for myself...

It's easy to cut, but you WILL burn through the blades. We cut every brick more than we needed to trying to get better angles and even mounted on a wet saw (tile), we burned almost through one blade. Dry cuts will make SURE you burn though the blades and you will raise enought dust to make all the mortar you require... assuming you could collect it (we did from the water bath under the tile saw).

[dmun]

Everything is relative: firebricks are harder than common red brick to cut, but with modern sintered diamond blades, you can cut them easily. Fire brick is not nearly as hard as granite, say.

There are a few basic ways to cut brick. The cheapest good way to do it is with a 7" tile saw, that works like a table saw with the blade running in a tank of water. This won't cut all the way through but you can make a second cut, or break the brick cleanly at the cut. The bad news is that this sort of saw throws up mud into your face. The good news is that they are really cheap.

A ten inch masonry saw has a bigger blade and a more powerful motor. The blade is fixed above the work, which is carried on a rolling table underneath. It has a pump that keeps the blade wet. This saw can cut a brick in one pass. This is a professional machine that that can cut masonry all day.

Some people dry cut bricks with a segmented dry blade in a skill saw. This seems bad for the lungs and the saw to me.

There are also people who break the bricks with a wide chisel called a brick set. This is not a skill that I have ever been able to acquire, but that doesn't mean that it can't be done.

Real refractory mortar is expensive (and nice to work with - I've used a brand called heat-stop here in the states). The pompeii instructions call for a fireclay-portland cement mixture, which seems to work fine - I think real refractory products don't have portland cement in them.

Good luck with your project.

[aikitarik]

Originally Posted by dmun

Everything is relative: firebricks are harder than common red brick to cut, but with modern sintered diamond blades, you can cut them easily. Fire brick is not nearly as hard as granite, say.

Yes, indeed. Or concrete.

A ten inch masonry saw has a bigger blade and a more powerful motor. The blade is fixed above the work, which is carried on a rolling table underneath. It has a pump that keeps the blade wet. This saw can cut a brick in one pass. This is a professional machine that that can cut masonry all day.

This is what I used, and believe me, we cut all day for 3 days. But then we cut every single brick at least 5 times, trying to get a better fit.

If I'd done the math for the horizontal curve of the dome, I would have been able to darn near dry fit everything. Instead, we ended up with a tight fit at the outside with gapping on the inside as the taper was too extreme.

Some people dry cut bricks with a segmented dry blade in a skill saw. This seems bad for the lungs and the saw to me.

Face mask. Mandatory, IMO. Just cutting a few bricks this way with my grinder generated a LOT of dust.

There are also people who break the bricks with a wide chisel called a brick set. This is not a skill that I have ever been able to acquire, but that doesn't mean that it can't be done.

I have been able to develop some skill at this, but it is definitely a challenge. You need to work around all surfaces just the right amount to develop fractures within the structure to get a nice clean break. It seems easier (to me) with larger blocks than smaller ones.

Regards,