One layer or two? It's a worry!

[chas]

For the new season, I'm getting round to thinking about maybe giving Old Smokey an insulating layer - and with ceramic blanket, rather than vermicrete.

I've found a source of 25mm blanket that's affordable, but in a 7m roll which just begs the question 'do I use the spare to make a second layer and beef it up to 50mm?' I suppose I might as well, but it looks like tricky stuff to work with: how do you unite two layers avoiding slumping before securing the lot with chicken wire? With dabs of the adhesive?

And, is there somewhere a nifty cutting pattern that makes flat blanket into a smooth, curved dome?

Chas

[cobblerdave]

G'day Chas
The stuffs great to work with. Push it in position and it with stay in place. It's stiffish and will not flop down like domestic insulation.
I rolled it around my dome and used a hand knife to cut the entrance out. A bit of tie wire to connect it so I ended up with a tube shape. Cut down from the top till the knife meet the dome. Folded the strips formed by the cuts down on the dome. Cut away the extra bits ( of course keep them to reuse in other bits)
When you run out of layers add a roll of wire mesh done much the same way for your render to key to and your Gold.
One warning this stuff when cut gives of short fibers that could lodge in you lungs( every fibre glass can do this) I'm not aware that it's a health concern but it's better not to take any risks. Breathing mask separate wash for your cloths. Same as for working with brick dust. Miners get silicosis from rock dust so better to use protection even for 1 small job, even though it's not a life time of contact.
Regards dave

[chas]

Cheers, Dave... blanket's on its way, so I'll soon know. Thanks too for the tip about dustmasks.

After a few 'early season' tempering fires in the week, I fired up the oven to full operating temperature for the first time yesterday and was oddly gratified to note that at 350C inside, after half an hour or so the outside of the dome was hotter than you would want to keep your hand on. Final justification of the extra work to be done. The very top was, predictably, hotter than the sides - so I'll give that extra attention.

Chas