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MIKIPAL 10-03-2007 02:47 PM

perlite -portland mixture for oven floor
Hi all you pompeians,going to pour my insulation 5.5 perlcrete tomorrow and dont know if i have enough material--2 -90 lb bags of portland and 3 -4 cubic bags of perlite--think its enough? hope to finish the stand and shut down for the winter and continue the pompei dome in the spring. couldnt get this far if not for f/b .pretty good for an settegerian.hope I can get help on this.thanx

asudavew 10-03-2007 02:50 PM

Re: perlite -portland mixture for oven floor
How big is the area you are pouring?

Width and length?

MIKIPAL 10-04-2007 06:07 AM

Re: perlite -portland mixture for oven floor
The insulation layer is 72" by 84" ,just dont seem like portland and perlite will be enough volume to fill the 5" layer.what do you think guys,am i wrong?how much did you use?thanx

asudavew 10-04-2007 06:19 AM

Re: perlite -portland mixture for oven floor
84"= 7 feet
72"= 6 feet

5"= .42 of a foot

7'x6'x.42'= 17.64 cubic ft

You have 12 cubic feet of perlite.
For a 5 to 1 ratio of perlite to cement you will mix in about 2.4 cubic feet of cement.
12+2.4=14.4 And usually the wet mix has a lower volume than the dry ingredients.

I think you will need another bag of perlite. Or you might just go with a 4" insulating layer.
4"= .34 of a foot
7'x6'x.3= 14.28 cubic ft.

Hope this helps some.

MIKIPAL 10-04-2007 07:59 AM

Re: perlite -portland mixture for oven floor
hey thankx a lot --that gives me a good idea of how much i need..dont want to run short in the middle of a pour.Is there no sand added? seems like a weak mixture without samd.

asudavew 10-04-2007 08:00 AM

Re: perlite -portland mixture for oven floor
No problem.

Better to have too much than too little.

Plus any extra that's leftover can be used to insulate the dome later.

Don't forget pictures!

MIKIPAL 10-04-2007 08:52 AM

Re: perlite -portland mixture for oven floor
will load pictures as soon as i know how..computers are new to me and just getting to navagate is a problem---will try soon.ciao

MIKIPAL 10-04-2007 09:28 AM

Re: perlite -portland mixture for oven floor
Sand is not added to the perlite -portland mix?seems like a weak mix for support of the igloo .

asudavew 10-04-2007 09:50 AM

Re: perlite -portland mixture for oven floor
1 Attachment(s)
No sand.

Just Portland cement, perlite, and water.

It gets pretty stiff!

1 part cement to 5 parts perlite by volume.

Mix the 2 together dry first. Get a good coat of cement on all the perlite.

It will look like clay cat liter.

Then add water. And just enough to hold it together.
I could just barely squeeze water out of mine with my hand, and it was probably a bit too wet.

I have a whole series of photos that include pouring the thermal layer on Picasa, in the album titled "Oven Mission 4 - The Insulating Layer", if you are interested in looking. They may be helpful.

Good Luck!:)

MIKIPAL 10-06-2007 06:37 AM

Re: perlite -portland mixture for oven floor
needed 3 more bags of perlit to finish stand.seems like 3 bags covered half of the stand---6 feetx7 feetx 4".mix 5 to 1 .but got it done and looks good--thanks for the pics -helped me a lot.great project .will continue in the spring for the igloo..the leaves are starting to fall here on long island and the colors are changing.good luck,ciao.mikipal

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