### Author Topic: vermiculite/ portland/pearlcrete difference  (Read 2354 times)

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#### dheeraj

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##### vermiculite/ portland/pearlcrete difference
« on: December 12, 2013, 03:13:17 AM »
can someone please explain these 3 and how it ca be used (hearth insulation / dome insulation etc

thanks
« Last Edit: December 12, 2013, 03:18:56 AM by dheeraj »

#### stonecutter

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##### Re: vermiculite/ portland/pearlcrete difference
« Reply #1 on: December 12, 2013, 06:10:28 AM »
Either one works well as hearth insulation.  Perlcrete = perlite/portland - vermcrete=vermiculite/portland.   Ratios vary depending on what the builder wants and what is used for thermal mass, but a good working range is 5:1 - 8:1 (the lower number is portland)

If there is more OPC in the mixture, you gain more compression strength, but lose insulaton value.  Less OPC in the mixture yields greater r value, but it is more friable.

It is a cheap and very effective way to insulate the oven floor.
When we build, let us think that we build forever.
John Ruskin

#### dheeraj

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##### Re: vermiculite/ portland/pearlcrete difference
« Reply #2 on: December 13, 2013, 12:36:00 AM »
hi mr stonecutter sorry i dont have ur name, i have one more question in case i want to make a precasted dome with 48 inch diameter can i use the same calculation of  H = D/3.4 for the internal height , i got this calculation from the forum for low dome / or aggressive dome  but that was for brick oven and can u give some insight on mould i got this pic from the internet and am thinking of replication it , is there a any other option and could you commet on the pictures also
is the mould made with thermocol
or wood
or POP

thanks

#### stonecutter

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##### Re: vermiculite/ portland/pearlcrete difference
« Reply #3 on: December 13, 2013, 06:31:34 AM »
hi mr stonecutter sorry i dont have ur name, i have one more question in case i want to make a precasted dome with 48 inch diameter can i use the same calculation of  H = D/3.4 for the internal height , i got this calculation from the forum for low dome / or aggressive dome  but that was for brick oven and can u give some insight on mould i got this pic from the internet and am thinking of replication it , is there a any other option and could you commet on the pictures also
is the mould made with thermocol
or wood
or POP

thanks

I don't see why you couldn't use that formula ( H=D/3.4) if that is what you want.  As far as how it is applied to a specific material, it doesn't matter....brick or castable are both thermal mass, oven dimensions aren't based on what kind of material it is made from.

Other options besides brick and castable?  Cob, clay earth, elephant crap....almost anything can be used to build an oven.   What is used and how it is built is entirely up to the individuals ability, available material, budget,time......a multitude of reasons.  There is no one size fits all answer to the question  of what is the right or best oven, because everybody has different circumstances and goals.

Just select something that is manageable to build, material that is affordable and easy to find.  You can always build another....in fact most people do.
When we build, let us think that we build forever.
John Ruskin

#### Tscarborough

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##### Re: vermiculite/ portland/pearlcrete difference
« Reply #4 on: December 13, 2013, 08:17:30 AM »
That looks like a professionally built mold.  The main thing to notice is the lap built into the edges.  That is very important to incorporate into a segmented dome.  It looks like is a plaster or fiberglass mold, hard to tell.

#### dheeraj

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##### Re: vermiculite/ portland/pearlcrete difference
« Reply #5 on: December 13, 2013, 08:59:43 AM »
hi thanks for the reply, i actually had brick in mind but now i would like to have a recasted oven and its for commercial use, i have to check best avilable cement which i will but i was conscerned about the casting and wondering how i should go about it, options i have in mind is

1 . make a oven out of plaster of paris and clad it with cement entirely

2 . make a model out of thermocol and clad cement all over

3 try this one i have inserted pics

pls advise me on how  to cast or mould

as i had mentioned its for commercial and the size would be 48 inch

#### stonecutter

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##### Re: vermiculite/ portland/pearlcrete difference
« Reply #6 on: December 13, 2013, 09:04:31 PM »

1 . make a oven out of plaster of paris and clad it with cement entirelyThis will fail...POP is not a refractory material

I have not made an oven mould, so I don't have anything to offer except to say that all the info is out there on the net.  Google is your friend.

A far as what material to use, look for a bagged castable.  Shop around, read the specs or speak with a ceramic engineer.  I haven't used any castables yet, so I don't have any recommendations there.
When we build, let us think that we build forever.
John Ruskin

#### dheeraj

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##### Re: vermiculite/ portland/pearlcrete difference
« Reply #7 on: December 13, 2013, 10:06:10 PM »
hi just found something u might want to see, i googled and found thin intresting infor on casting

http://www.fornobravo.com/forum/f6/mr-gs-aussie-castable-oven-9230.html

i think someone looking for the same info as me could use this thread

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