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Post by tomsauce on Jun 14, 2020 10:18:42 GMT
Hi all,
Just completed my Perlite dome.
Used a ratio of 5:2 Perlite and Portland Cement.
It's set nicely and I'm contemplating my next step to add some insulation and waterproofing.
I've looked at ceramic fibre insulation where you add that and then some chicken wire and then render.
On top of the render I was going to add some tile adhesive, broken tiles as mosaic and then outdoor grout. Hopefully this would give me enough efficient insulation and waterproofing.
My questions if you can help are:
Can anyone recommend a cheaper alternative to the ceramic fibre insulation?
What you recommend as a render?
Thanks in advance.
TS
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Post by downunderdave on Jun 14, 2020 19:25:26 GMT
Making your own perlcrete or vermicrete insulation layer rather than blanket is a cheaper option, but the problem is getting the stuff dry. As you’ve already used an insulating mix for your inner dome rather than a dense mix, you simply apply it over your existing casting. However, the more the cement you add to the mix, the less insulating value it will have. A 10:1 mix is about as lean as you can go and still have it remain workable. For every 10 parts of perlite it will require 3 parts of water. A handful of powdered clay for every litre of cement will help make the mix more workable. If you make the layer any thicker than an inch and a half it will take ages to dry so allow a week drying before adding a second layer.
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Post by sam1 on Jun 17, 2020 8:03:25 GMT
I completed my perlite oven last month with a 50 mm layer of ceramic blanket with cement render. Two advantages that i can appreciate I am able to get my pizzas out in 2-2 1/2 minutes and the dome remains at the same temperature as surrounding. Very new to wood fired oven. Looking for advice.
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Post by tom1 on Jan 17, 2021 13:39:14 GMT
Really new to this but with a perlite oven, is the perlite mix the inside of the finished oven?. I 'm asking this as I did not think portland cement is fireproof and it wood crumble or crack when heated?
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Post by downunderdave on Jan 18, 2021 22:57:16 GMT
Hi all, Just completed my Perlite dome. Used a ratio of 5:2 Perlite and Portland Cement. It's set nicely and I'm contemplating my next step to add some insulation and waterproofing. I've looked at ceramic fibre insulation where you add that and then some chicken wire and then render. On top of the render I was going to add some tile adhesive, broken tiles as mosaic and then outdoor grout. Hopefully this would give me enough efficient insulation and waterproofing. My questions if you can help are: Can anyone recommend a cheaper alternative to the ceramic fibre insulation? What you recommend as a render? Thanks in advance. TS Try a 10;1 mix of perlite or vermiculite and portland cement. |
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Post by daverook on Apr 13, 2021 7:38:16 GMT
I have gone with a mix of 5 parts perlite, 2 parts water and 2 parts white Portland cement.
It is still in my front room and will remain for at least 8 weeks, where I have covered it with sheets and I try to water it every day so slow down the curing and hopefully, increase strength. (if I've done my homework right, otherwise I'm sure it's a strange thing to admit - watering an oven).
I will report how it goes in a few weeks time!
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soren
New Member
Posts: 3
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Post by soren on Jun 15, 2021 19:58:20 GMT
When you mention the ration "5 parts perlite, 2 parts water and 2 parts white Portland cement" is that given by weight or by volume?
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Post by downunderdave on Jun 16, 2021 19:53:35 GMT
Recipe is by volume not weight. For a 10:1 (by vol) perlcrete mix there is an equivalent mass of perlite and cement.
As Portland cement begins to fail north of 300C and the addition of perlite or vermiculite to any mix reduces the resulting strength enormously, expect your dome to have problems in the long term. I’ve not heard, despite invitations to do so, of any perlcrete domes having long term serviceability.
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