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jamesdifede 04-04-2008 11:10 AM

Dome Insulation
OK, I've got my dome finished and covered with a layer of high heat mortar. I have a couple questions about insulation. I have wrapped 2 insulfrax blankets around the dome and covered the blankets with wire mesh. I'm planning to put a layer of perlite/concrete over the wire mesh. Is this correct? If so, how much perlite should I buy? The instructions suggest 8 parts perlite to 1 part concrete, but a friend says he did 1/2 and 1/2. If I'm going to put a 3-4 inch layer of this concrete on, it seems like I'll need an awful lot of perlite.

When the insulating concrete is on, do I need to put wire mesh over that before working with the stucco?

Finally, is it necessary to insulate the entryway in this same way? Can I leave a brick finish on the entryway?


gjbingham 04-04-2008 08:42 PM

Re: Dome Insulation
I'm not telling unless you post a picture. I'm here to feed off other peoples suffering. I don't remember you suffering! I wan't to hear about cuts, falls, failures dammit!

OK, only one answer - no wire over vermiculte/concrete needed prior to stucco. You should re-read the instructions as to your ratios mentioned about. You and your friend are both incorrect - they both might work, but not in line with the plans.

Frances 04-05-2008 06:09 AM

Re: Dome Insulation
I wondered about insulating the entryway, too, and didn't. But next time round I would.

The disadvantage is that it gets rather hot, and as I then covered it with stucco-type stuff, its developing cracks because of the heat expansion. I think an insulated entryway would work better.

But I don't see why you shouldn't be able to leave the the entry entirely uncovered, showing the brickwork. Or what do you others think?

And yeah, pics would be nice... Might generate more answers, too ;)

arevalo53anos 04-05-2008 08:02 AM

Re: Dome Insulation
5 Attachment(s)
The pics are here...
And everywhere in this site, too. <g>

arevalo53anos 04-05-2008 08:04 AM

Re: Dome Insulation
5 Attachment(s)
And here...


gjbingham 04-05-2008 09:58 PM

Re: Dome Insulation
How thick were your blankets?

arevalo53anos 04-06-2008 02:27 PM

Re: Dome Insulation
My blankets were fiberglass ones, two layers of 1/4 inches each, aproximately.


gjbingham 04-06-2008 05:41 PM

Re: Dome Insulation
Sorry Luis,
I should have stated the name Jim -who asked the question, but he seems to be missing in action.

Luis - You really seem to know your bread/baking. Perhaps I didn't go far enough back in the forum to hear your whole story - who you are, what you do. Sounds like your a baker by profession.

jamesdifede 04-07-2008 08:16 AM

Re: Dome Insulation
Ok, I've been properly chastized and I am posting pictures. I've been a leach too long. By the way, the blankets were 1 inch thick and I used two layers. A friend and I put on the portland/perlite mix and I think it worked ok. We ended up using our hands to put it on and both of our hands not feel gritty no matter how much we wash them. We have relatively thin layer on there now, but I'm going to add more this week. We used an 8 to 1 ratio, but I'm planning to do a 5 to 1 ratio for the next layer so I get a hardershell. I think I will do the entryway, but only put one layer of blanket and then the portland/perlite mix.

The pictures are coming as soon as I figure out how to post them.


gjbingham 04-07-2008 10:09 AM

Re: Dome Insulation
Yahoo! More pics!

Re: the perlite layer. If you've truely got two inches of blanket over the entire dome, that is equivalent to 4 inches of perlite/portland. 2 more inches is the minimum recommended in your case. More is better, but you should be in good shape if you get the two inches of perlcrete.

To post a pic, hit the "Post Reply" button then on the next page, click on "manage your attachments". You need to resize most photos to about 60% or they will not upload. Have no fear. Even if you mess it up, you can edit your post and try again without anyone knowing you made such a horrific mistake. ;)

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