Combine Mortars

[kriso]

Thanks for that info, I will read the link you have added, I think I will give it a go and make my own, I have a cost of $97.00 for a 100 litre bag of vermiculite (here in New Zealand). That seems to be the cheapest I can find so far.
Thanks again for the info.
Cheers

[azpizzanut]

Kriso,

Perlite is mined and processed in several locations in NEW ZEALAND. You might be able to locate a lower price for your perlite needs by locating the processor.

NZ dollars are roughly 3/4 the value of a USD. I recently bought 4 cu ft perlite for my project (113.2 cu litres) for $33.40 USD. It is hard to imagine perlite priced at nearly $1 NZ per litre.

Interestingly, perlite is processed near my home but the factory does not sell to individuals. The product is sold in bulk to commercial businesses or industry for packaging and distribution.

As a reminder, perlite comes in several grades. You want horticultural grade (used for potting soil/gardens). Commercial grade is also acceptable if it does not have silicone added.

Cheers,

[david s]

azzpizzanut,
I used Hebel as an insulator under the floor of a mobile oven and it has worked ok.I would disagree about it's suitability for use in building the dome though. It is after all Portland cement, aggregate and air. At high temps and direct flame impingement I wouldn't rely on it's longevity.

[azpizzanut]

Hi David s,

I agree with you about the lack of suitability of Hebal for dome construction for the reasons you stated. A builder who used Hebal said he was happy with his oven. Maybe what he doesn't know isn't hurting him.

Regards,

[david s]

It might be ok for an insulation layer but not for the hot face. Apart from the Portland cement issue, it is full of air and not dense where you need density for heat storage.
Dave