Insulation Efficiency

[tinaloven]

Re: Insulation Efficiency

Thanks mate,

I just wanted to keep the thermal mass even all around on base I have 4" of concrete then about 1.57" of insulation 2.95" of brick floor and 2' cook tile surface. So i thought that creating a matching thickness for the dome would create a even cooking area due to the equal thermal mass. I don't want to burn the pizza base and not cook on top. I have plenty of fuel so I dont mind taking a little extra time to heat up the whole oven. Is this going over the top? Am I over engineering it? Im in Canberra it gets cold but never as cold as Alberta thats for sure

[Spunkoid]

Re: Insulation Efficiency

I can't say I know of anyone who used full bricks. But then again, I don't know anyone personally in these parts that built an oven. I think it would be hard in that there was quite a bit of cutting involved to reduce the amount of mortar used. To get an idea, take some bricks and lay them down on thier sides in a rough circle. You will see that while they fit tight on the inside, the gaps on the outside will get very large. It would be quite a job to cut them to size. Another area where you would be challenged is when you merge the dome and the arch together. These are two compound curves meeting and it is probably one of the biggest challenges in building the dome. If you managed to do it, I expect it would take longer to heat, it might be subject to cracking, and it would take more area or a larger stand to hold it. The weight would double as well.
I insulated my dome by putting about 15 cm of vermiculite around it. It holds the heat very well and I cook roasts the next day. Meat cooked in the forno is very, very moist....
Where about's in Oz are you? Looks like we might be taking a long over-due trip someday soon.

Rick

[tinaloven]

Re: Insulation Efficiency

Thanks mate, looks like I'll have to design something in the flue which now makes sense. I'm tring to make full use of the ovens features and excess heat.
I noticed your from Cochran, I've stayed there a few times as my mates live there. I was even in the Cochran rodeo a few yeas back.. Anyway back to the oven. Do you know of anyone using full bricks for the dome instead of 1/2 bricks or would this take to long heat up, fuel is not an issue as we live on a bush block

[Spunkoid]

Re: Insulation Efficiency

G'day beautiful people.

I wish to wrap copper pipe around my oven that I am building in between the dome walls, I will be using 2 half bricks(solids). The reason for this would be
a) to heat water from oven and use it to clean/wash or possible put back in the hot water system)
b) the wound copper pipe would act as a insulation chamber as air would move freely around it

My question is would it be best if the copper pipe is in the middle of the two bricks or on the outside of the two bricks just before the final render.

The cool water flowing through the copper pipe is being heated by the oven. As such, it is aborbing heat from your oven and is not acting as an insulation chamber.
You can try to recycle waste heat by putting the copper pipe inside or around the flue. I recall an article years ago in a magazine called Mother Earth News where someone coiled copper pipe and put it into the chimney on their wood stove. I don't know how well it worked but here is a link.
Get Hot Water from Your Woodstove: The Blazing Showers Stovepipe Water Heater

[Spunkoid]

Re: Insulation Efficiency

Is it out of the question to use 2" "blueboard" as an insulation under the oven floor?

I would not recommend it. The fire bricks get red hot when you are heating up the oven. You can't see it in the daylight but if you are cooking at night and scrape the coals aside, the fire bricks glow red hot for several minutes before getting darker as the bricks cool a little.

[tinaloven]

Re: Insulation Efficiency

G'day beautiful people.

Just two questions on insulation that may or may not have been covered before.
1. I wish to wrap copper pipe around my oven that I am building in between the dome walls, I will be using 2 half bricks(solids). The reason for this would be
a) to heat water from oven and use it to clean/wash or possible put back in the hot water system)
b) the wound copper pipe would act as a insulation chamber as air would move freely around it

My question is would it be best if the copper pipe is in the middle of the two bricks or on the outside of the two bricks just before the final render.

I have drawn some sketches if this helps, thanks in advance.

[stopass]

Re: Insulation Efficiency

Is it out of the question to use 2" "blueboard" as an insulation under the oven floor?

[SteveP]

Re: Insulation Efficiency

You can find vermiculite or perlite at any gardening supply warehouse. They sell to nurseries in bulk and is usally cheaper. If you can't find a warehouse, try any nursery.

[farrd003]

Re: Insulation Efficiency

Thanks Spunkoid

[Spunkoid]

Re: Insulation Efficiency

You might be able to get vermiculite or an alternative perilite at a gardening center or in a store that sells hydroponic supplies.

[farrd003]

Re: Insulation Efficiency

Thanks Gary for the information. I could not find any one who sells vermiculite or perlite so I have no other alternative as to use clay and portland cement on a layer of fire blanket. The problem is that clay and portland when mixed together does dry up and crack. I will cover it with Stucco. Hope this oven works.Our built oven is a pompei oven but we built a seperate part which connect to the dome to light fire. I will post some photos when its ready. Any advice will be appreciated.

Dorothy

[gdest]

Re: Insulation Efficiency

This is a bit of a cop out this is straight out of Wikipedia

Vermiculite is a natural mineral that expands with the application of heat. The expansion process is called exfoliation and it is routinely accomplished in purpose-designed commercial furnaces. Vermiculite is formed by weathering or hydrothermal alteration of biotite or phlogopite.[1] Large commercial vermiculite mines currently exist in South Africa, China, and Brazil.


Vermiculite is a 2:1 clay, meaning it has 2 tetrahedral sheets for every one octahedral sheet. It is a limited expansion clay with a medium shrink-swell capacity. Vermiculite has a high cation exchange capacity at 100-150 meq/100 g. Vermiculite clays are weathered micas in which the potassium ions between the molecular sheets are replaced by magnesium and iron ions.

As for the rest of your question I really don't understand what you are asking

Gary

[farrd003]

Re: Insulation Efficiency

Hi

Please help
Can somebody explain what is vermiculite? Is it clay? And how can I fix the problem if after I built the dome and put FB than clay.No I saw the clay did not dry well I had done clay with cement and although its not 100% its much better.
DF

[laffingmonk]

Re: Insulation Efficiency

If I have a rectangular oven with an inside layer of firebrick and an outside layer of facing brick, and I add a layer of insulation between the firebrick and the facing brick, how do I get the insulation to adhere to the firebrick and the facing brick to adhere to the insulation? 2 different kinds of mortar? Just pour a layer of perlite and concrete between the bricks? How would I use insulfrax in that application?

[Jonsan]

Re: Insulation Efficiency

Add the insulation first, since that will cover the largest area. You can caulk around the windows to help seal them against drafts until you have the resources to replace them, if needed.