Dome insulation/chimney query

[nissanneill]

I have just pegged out my 1000mm internal Pompeii oven ready for excavation and construction commencement. I am restricted as to it's location, in the corner of an existing pergola covered patio and only 900mm from a concrete retaining wall which supports the boundry fence. I therefore need to swing the oven around from the planned 45 degrees to the corner. Here is where the problem lies:
I want to retain the igloo shape for the oven, tiling the insulation layer rather than incorporating a housed oven with roof. Since I have limited space, I was thinking of using the insulating blanket as it is recognised as being the prefered and best BUT to cement over this and then to tile it would be difficult - YES? - especially when I need to relocate my chimney.
I could of course use copious layers of cement/vermiculite insulation (again little room for the 6" that is required, (which makes for the ideal base for tiling), This would of course be best when/if I locate my chimney over the centre of the igloo in order to clear the new polycarbonate patio roof.
Then again I could also just double layer the chimney and run it through the roof! Decissions, decissions.
Which is the best way to go?
I would appreciate ideas from those with more experiences in such matters.

Neill

[dmun]

Re: Dome insulation/chimney query

You are not planning to run the chimney out the top of the dome, are you? Your oven will never heat up.

You can angle the chimney to avoid the roof, but I think it would look better if it went straight up through the roof.

They sell a liquid to make the blanket insulation rigid enough to put stucco/tile on it, but I don't know if anyone here has used it. Maybe someone else will chime in.

[Hendo]

Re: Dome insulation/chimney query

Neill,

There is a ?rigidiser? available here which may be suitable - it binds the surface fibres of the blanket, forming a skin over the ceramic fibre lining. See Consolidated Refractories - Specialist Shapes for further info.

Cheers, Paul.

[CanuckJim]

Re: Dome insulation/chimney query

Dmun,

Good advice on the chimney. Please don't run it from the center of the oven, Neill; it just won't work. If you have access to double-walled, insulated, stainless chimney sections, there are elbows available in 15, 30, 45 and 90 degrees. Depending on the height of the existing roof, these may allow you to angle your chimney back from the front vent to clear the roof, but, personally, I'd go straight up through it by using a heat shield in the roofing material. Your oven will draw much better that way.

Jim

[nissanneill]

Re: Dome insulation/chimney query

Thanks for the rapid respons crew.
dmun,
No I am not about to run the chimney from the dome, only redirect it from the vent area to above the dome to clear the roof. I have read that it is unwise to bend the chimney as it will reduce it's capacity to draw properly, but on planning the 'whole exercise', I felt that it would be more aesthetically pleasing to run it up outside of the proposed new arched roofline rather than sealing it around the chimney.
Paul,
thank you for the information from Consolidated Refractories. I was about to contact them and order the ropr seal for the doors. Now I have another enquiry with them.
Jim,
I will check out the availability of the elbows as they are commonly used with slow combustion and pot bellied stoves. I was trying to keep the project a little simpler and neater, especially in this location with the rolled steel trusses being relocated and cantilevered to avoid the oven.
Thanks again guys, your input is much appreciated.I have included a picture of the chimney idea from the 2006 Masonry Heater Assoc of North America and a small pic of the location, Note the fire bricks at the ready.

Neill

PS. Just had delivered my 14" diamond saw blade for the cutting of the bricks and expect a 9" one later in the week for the angle grinder. I already have numerous 4.5" diasmond blades for my small grinder but mainly only used for tiles.

[Bacterium]

Re: Dome insulation/chimney query

Hi nissanneil,
I have a similar situation with my dome oven....in that I want to retain the igloo shape rather than a housed over roof.

Can't help you on the flue as I'm taking mine straight up from the smoke chamber
But
on the coating.....Have you spoken to Heartfield Constructions (in Beverly - South Australia) about some of the coatings that he sells?
Last time I was there he showed me a product called Insulcast (now I wish I had written down the details as that probably is the brand name and now the particular product name) .
Once applied it goes rock hard (good for exterior use) and is used as an insulator. He recommends putting it on at least 40mm thick and some guys have used this on their ovens in the past.

Once I get to that point (and I had more details of it) I was going to ask on the forum but this seems a good time to mention it.

[nissanneill]

Re: Dome insulation/chimney query

Thanks Damon,
No, I haven't contacted Heartfield Constructions at Beverley but I have been in contact with Thermal Ceramics also from Beverley where I am about to order my vermiculm and board.
I will seek him out tomorrow as I will be out and about.
Regards.

Neill

[Hendo]

Re: Dome insulation/chimney query

Neill,

You may also want to view http://www.fornobravo.com/forum/f6/h....html#post9818 where a vermiculite/cement mix has been placed directly over the insulating blanket, with what appears to be chicken wire holding it all together. I understand that the dome was then covered with some sexy looking curved bricks!

Luis may be able to expand further, but it doesn't look like any sort of binder has been utilised.

Cheers, Paul.