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**enz** · 07-03-2007, 09:14 AM

Re: Vermiculite fire bricks

These are insulative concrete blocks. They would work for insulation under the cooking surface, but never for the oven itself, it would never heat properly.

Enz

**nissanneill** · 07-03-2007, 03:21 PM

Re: Vermiculite fire bricks

Simon,
I have jist completed a Pompeii and covered the outer dome with 3" of vermiculite cement and also buried a 1" thermal blanket under that. When it is 500?C inside the oven, the outside dome is COLD. Vermiculite is an insulator and basically does the opposite to what you want. You need a brick that will ABSORB the heat rather than repell it.
As far as the cement is concerned, I would check with the manufacturer some more specific detail. I am not sure whether these pre-mixed products have a use-by date which needs to be known before spending your money. The company selling the goods look like they specialise in refractory materials and may be fine.
It looks OK from the scant detail provided but then again I built my oven using a simple mortar containing cement, lime, fireclay and sand. The ancient Romans didn't have these special high temp cements and their ovens have stood up for over 1000 years.

Neill

**Archena** · 07-03-2007, 05:16 PM

Re: Vermiculite fire bricks

Yeah, but some Roman geek would have used them if he'd had them! Anything worth doing is worth overdoing!

I should leave now, huh?

**readie** · 07-03-2007, 10:58 PM

Re: Vermiculite fire bricks

Thanks for comments: I didn't make myself very clear: I was thinking about using them as the insulation layer under the base of the oven (ie instead of pouring vermiculite or using Superisol insulating block), so it sounds like they would be suitable for this. I have been looking into the insulation layer and it seems that Superisol (or the equivalent) is hard to get hold of in UK without buying largish quantities. I thought that using these vermiculite bricks might be the equivalent of a "vermiculite pour" without the "pour"! (not that I'm lazy or anything..).

**nissanneill** · 07-03-2007, 11:39 PM

Re: Vermiculite fire bricks

This particular "pour" is a very easy task and is very efficient insulator.Simply dry mix vermiculite, 5 parts to 1 part portland cement, add enough water to make an oatmeal consistency, place in position and float off level.
This would be far better than the bricks because you need to insulate the whole floor area, even out under the dome bricks.
See my Pompeii oven construction pics and description on:

http://www.fornobravo.com/forum/f8/n...-1-a-2005.html

permalink #2.

Neill

**dmun** · 07-04-2007, 09:43 AM

Re: Vermiculite fire bricks

The old vermiculite block is an underrated insulator. I use a little hunk of it for hardening steel parts: I hold one corner with my fingers and bring the part to red heat with a torch a couple of inches away. My fingers don't even get hot.

It's been superceded by superior materials like cal-sil and mineral wool, for furnaces and such, but we're talking about under 1000 degrees f. here guys. Use it if it's affordable and available.

**readie** · 07-05-2007, 08:03 AM

Re: Vermiculite fire bricks

Thanks again for the info everyone.

dmun, you say to use it if affordable and available: the bricks are 25mm thick: do you think one brick layer (ie a 25mm thickness) would be enough to adequately insulate, or would I need to use 2 bricks worth? I am quite keen on using as thin a layer of insulation as possible as the hearth height is already at 90cm, and I am worried that after a 4inch vermiculite pour plus the oven brick it will be over a metre to the opening.

Simon

**dmun** · 07-05-2007, 09:44 AM

Re: Vermiculite fire bricks

I don't think one inch (25.4mm) of vermiculite in any form is going to be enough insulation. With the best insulation available (cal sil) you can get down to two inches, but one inch of vermiculite is going to leak heat and waste wood. You're in the UK, right? Firewood is an expensive import there. There's another thread this week about the front of an oven being to hot to work in, and how to vent it. I suspect that this is an underinsulated oven.

**Archena** · 07-05-2007, 05:12 PM

Re: Vermiculite fire bricks

?

A meter is just over standard counter top height - why would that be a problem? Actually, a bit over standard would be a good working height for an oven, I would think.

**readie** · 07-06-2007, 07:51 AM

Re: Vermiculite fire bricks

Yes I am going to just get on with the vermiculite pour and stop faffing around. Thanks for the link to your construction Neill.

**nissanneill** · 07-06-2007, 09:34 PM

Re: Vermiculite fire bricks

Readie,
the first post of my oven construction was mistakenly put under 'Pompeii oven construction' but the continuation of the oven is found at:
http://www.fornobravo.com/forum/f21/...-4-a-2045.html
where I was continuing with the build. I lost #9 posting (James put it under 'Pizza' thread:
http://www.fornobravo.com/forum/f10/...zzas-2117.html
and I continued with the build and illumination at:
http://www.fornobravo.com/forum/f21/...10-a-2119.html
The cooking parts are at:
http://www.fornobravo.com/forum/f25/...-veg-2158.html
and the last posting, ie. the oven doors is:
fornobravo.com/forum/f30/looking-inspiration-1909.html
I hope this helps you out with your build.
It really is a very simple task to build especially with the help and assistance gained through this forum.
If you have any queries, please feel free to contact me direct through the link 'send a private message to ?????' located when you click on Nissanneill.
Good luck and enjoy!.

Neill

**readie** · 07-09-2007, 01:06 PM

Re: Vermiculite fire bricks

Thanks Neill, those pictures are really helpful.

Simon

**nissanneill** · 07-09-2007, 05:49 PM

Re: Vermiculite fire bricks

Only too happy to help out.
I just recieved a parcel from one of your fellow UK residence, a 10 station thermocouple switch. He undersold it to me with a gross underestimate for postage.
Forewarded the difference to him this morning.
Please feel free to contact me should you have any queries with your build.
I have tried to give a straight foreward photographic building progress and explanation as I see it as a relatively easy task if you look at one simple task at a time, rather than at the final overall project.
This forum makes life very easy if you take the steps, one at a time.... you will get there and if you keep working on it, quicker than you think. I found that I was excited at the progress and consequently built mine in the rain, just got around the inconvenience with a simple tarp strung up over the actual oven. It was in fact fun to build and now I am enjoying it, as are our family and friends.
Now I need to get into the patio and pergola renovations that will take a lot more time and money, but what the heck, live and enjoy!
Still have a lot to learn about cooking as this is now getting me into unknown territory, but have not had a 'disaster' as yet, first pizza didn't look too flash, but by hell it tasted fine, first bread - one was a little scorched, but know and have solved that problem!
I hope you enjoy it as much as the rest of us.
All the very best.

Neill

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