new build in Brisbane - Vibrok Caminetti

[cobblerdave]

Re: new build in Brisbane - Vibrok Caminetti

G'day
Again that's a neat job...
One think I've noticed though, your running out of room on your slab real fast. I don't think you will be able to get a thick enough layer of pearlite cement to be strong enough. Kids climb, it's a fact that you'll have one on the top of that oven one day. I would just do cement render for strength, you have sufficient insulation.
Regards dave

[cobblerdave]

Re: new build in Brisbane - Vibrok Caminetti

Hi Applor
Good job on your insulation, see PM's a bit late though.
I believe you need to apply a cement render over your perlite render once that is complete as it is fairly coarse.
I intend to use DryPak Render coat (about 5mm thick) over my pearlite insulation and then paint with Dulux Acratex once I finish the surrounding benchtops.
Interested to know what others think?

G'day
I agree with you, I personally like a render coat its harder and stronger than pearlite/cement and a hell of a lot easier to apply.
I did help apply a pearlite layer to an oven that did not get a render layer because it was to be movable and weight was a consideration.
We used a normal brickies trowel to tap the surface into shape and while the surface was textured I would not call it rough. A coat of textured paint designed for brick and cement it looked really smart.
Regards dave

[applor]

Re: new build in Brisbane - Vibrok Caminetti

Hey if a plain cement render will be easier to work with and dry quicker so I can paint sooner, then that's what I'll do!

As for clearances, I have 50mm on each side to the edge but more like 40mm at the back. Had always intended the finished dome to finish on the edge. I'll be going cement render only now anyways so strength won't be an issue.
How much cement render do you think I'll need and how thick should I make it? Was going to use the flexible conduit technique so could go 20, 25 or 32mm?

As for progress, I did the chicken wire mesh this morning. Harder to work with the insulation but certainly not as messy
Think it's come together OK.
My main question now is the flue. The previous owners had bricked over the oven so you can see in the photos how far up the flue the bricks went to. Should I render up this high? I think I would need to build a frame box to sit around it so that I would get a nice flat finish. I would then be concerned about the render cracking from the heat exiting the flue though.
What are your thoughts?

[Gulf]

Re: new build in Brisbane - Vibrok Caminetti

Hey if a plain cement render will be easier to work with and dry quicker so I can paint sooner, then that's what I'll do!.........................................
My main question now is the flue. The previous owners had bricked over the oven so you can see in the photos how far up the flue the bricks went to. Should I render up this high? I think I would need to build a frame box to sit around it so that I would get a nice flat finish. I would then be concerned about the render cracking from the heat exiting the flue though.
What are your thoughts?

Anything that you render, that is touching a high heat surface, should have insulation separating it from the stucco. In your case, the blanket acts as an insulation, and also as an expansion joint between the two. Unless you treat it the same all the way to the top of your flu, you will have an area that is subject to cracking.

Since you do not have a roof covering, that would be a place for water to enter. If it were me, I would insulate all the way to where the chimney cap starts. That way you can place a chapiter with an overhang that sheilds water from entering

Just Sayin' (that is "redneck" for just my opinion) .

[cobblerdave]

Re: new build in Brisbane - Vibrok Caminetti

Anything that you render, that is touching a high heat surface, should have insulation separating it from the stucco. In your case, the blanket acts as an insulation, and also as an expansion joint between the two. Unless you treat it the same all the way to the top of your flu, you will have an area that is subject to cracking.

Since you do not have a roof covering, that would be a place for water to enter. If it were me, I would insulate all the way to where the chimney cap starts. That way you can place a chapiter with an overhang that sheilds water from entering

Just Sayin' (that is "redneck" for just my opinion) .

G'day Gulf
I agree except with the positioning of the overhanging shield, it can be right down the metal chimney



Davids has mentioned this before as its going to crack around the union put a piece of cardboard when rendering up to the pipe. This leaves a gape to the insulation layer that is shielded from the wheather ......and there you have a built in vent to release any water from the insulation layer! And its conveniently located at the top point of the oven. Bonus.
Now the tricky bit, is such a shield piece available? couldn't find much in Queensland and of course had no idea on size.
So plan B is to make one.
Googled The Hospitality Super Store in the "valley" and sure enough in the serving trays section there are a heap of different sized stainless steel trays with the sloped edge. $10 to $20 bucks depending on size. Recon any competent metal shop sound be able to fit that to the current chimney.

regards Dave

[applor]

Re: new build in Brisbane - Vibrok Caminetti

Thanks for the advice (and pic guys. Just wondering though could I not just leave a gap using cardboard and then fill the gap with a silicon sealant of some sort to waterproof/seal it and act as an expansion?

[cobblerdave]

Re: new build in Brisbane - Vibrok Caminetti

G'day
Yes you could but silicon sealers will not take that sort of heat. My doors stuck together with that but is due to it being used at 300C minus that it works at the back of the insulation!
Their are high temp sealers available, but will they survive the 600C that will be going up that chimney? And for how long?
Davids build ovens ... He never mentions that ... But he still puts a lot of input here. Good solid advice. That comes from experience and care in what he does.
So if you do go with the high temp sealer please report back on your experience.
Regards dave

[david s]

Re: new build in Brisbane - Vibrok Caminetti

Thanks for the advice (and pic guys. Just wondering though could I not just leave a gap using cardboard and then fill the gap with a silicon sealant of some sort to waterproof/seal it and act as an expansion?

I have two terracotta caps that I make and use high temp silicon between the terracotta cap and t the flue pipe. You could get a local potter to make you one, but I think Dave's idea about a stainless bowl is probably better. The high temp silicon holds up ok.

[GianniFocaccia]

Re: new build in Brisbane - Vibrok Caminetti

That's a precision blanket job. Nice!

[applor]

Re: new build in Brisbane - Vibrok Caminetti

Thanks Gianni, tho I think you give me too much credit lol!

David/dave - thanks for the info. If high temp silicon holds up okay, I don't see why i'd bother with a cap as well when the silicon will seal it and keep it waterproof.
I will use cardboard as a spacer around the flue when I render. I am a little concerned I won't be able to remove the cardboard afterwards tho:/

Please note that I have not attached the rest of the chimney yet. It's about a metre long with a cover/exit that prevents water coming in.

[applor]

Re: new build in Brisbane - Vibrok Caminetti

david s what high temp silicon did you use?

Supercheap have two available (typically designed for engine gaskets)
Permatex High-Temp RTV Silicone Gasket Maker - Red, 311G - Supercheap Auto Australia

Permatex Ultra Copper RTV Silicone Gasket Maker - Maximum Temperature, 85g - Supercheap Auto Australia

How hot does the chimney get? Would not expect it to get up to the 500 degrees that the dome does.

[applor]

Re: new build in Brisbane - Vibrok Caminetti

Seems there is a product available designed specifically for what we're talking about.

Fortafix FlueSeal

Fortafix - High Temperature Sealants and Adhesives. Fire Resistant Sealants. Heat Resistant Cements

Flueseal High Temperature Adhesive Sealant NOT Silicone | eBay

Might be worth getting one.

[david s]

Re: new build in Brisbane - Vibrok Caminetti

david s what high temp silicon did you use?

Supercheap have two available (typically designed for engine gaskets)
Permatex High-Temp RTV Silicone Gasket Maker - Red, 311G - Supercheap Auto Australia

Permatex Ultra Copper RTV Silicone Gasket Maker - Maximum Temperature, 85g - Supercheap Auto Australia

How hot does the chimney get? Would not expect it to get up to the 500 degrees that the dome does.

I use the Permatex red silicon gasket one which is good for 650 F (340 C) and performs ok. In my oven design the base of the flue does not get hot enough to destroy the red silicon. I've not tried the copper one but it has a much higher temp rating so could be good for use as a flexible joint for a heat break. That other stuff, Fortafix Flueseal is a water based product and dries "hard and rigid". I've not used it but have used other similar ones which I've not found suitable as they don't remain flexible like high temp silicon.

[applor]

Re: new build in Brisbane - Vibrok Caminetti

Thanks david.

Think I'll get a tube of this stuff then, good to 650 F:

Permatex High-Temp RTV Silicone Gasket Maker - Red, 311G - Supercheap Auto Australia

Going to be painting my dome red too so that works well

[applor]

Re: new build in Brisbane - Vibrok Caminetti

I'll be going to bunnings tonight and buying cement render.

What is the minimum thickness I need to make my dome? I am thinking 32mm should be OK?