Mississippi 44"

[deejayoh]

Re: Mississippi 44"

I get serious oven envy every time I read this thread. Feels like I built a junior model oven compared to the queen

I have 100% borrowed the way you sealed your heat break. CF rope + putty. It looks like you maybe used rutland gasket cement for the putty? or was it something else? I looked at that stuff, but then ended up ordering Kaowool CF caulk instead. Supposed to work to 2300 degrees and it's also supposed to be insulating. I haven't seen where it has been used by anyone else on the forum, so maybe it will add a new option -especially since more people seem to be adding heatbreaks.

Anyway, great job.

[Gulf]

Re: Mississippi 44"

Thanks' deejayoh,
A lot of builders are including heat breaks now. Lburou's build was my go to for ideas. Yes,I used Rutland Black rated for 2000 degrees. I think that it is ok for sealing from the rope from the back. But that I will probably end up cleaning that mess out where I sealed the rope from the inside. I did a quick search on the Kaowool caulk that you used. Sounds intersting. Did you seal rope in the break or just use the putty for the gap? What color is it?

[deejayoh]

Re: Mississippi 44"

Yeah, its funny - when I was educating myself on all of this, I read back through some of the builds from couple of years ago. There were a number of comments about heat breaks being totally unnecessary. Now they seem to be becoming more the norm - although I think the community consensus on design is evolving. Personally, it didn't make sense to me why, after spending hundreds of dollars on insulation to help retain heat, I would want to leave a giant exposed heat sink on the front of my oven.

As for the caulk - I had to order online, so I don't have it yet. I had initially planned to push the rope in from the back, and caulk the gap from the inside of the arch. But after re-reading your thread - I am thinking about using the caulk behind the rope on the outside of the arch to seal it in that way. That would leave the gap inside empty. I guess over time it will collect a lot of smoke particles, but I wouldn't have to worry about the caulk wearing out.

I'll report back on color and consistency once it arrives.

[Gulf]

Re: Mississippi 44"

Thanks' deejayoh,
I'm glad that I sealed mine from the back also before it was coverd up. If I remember corectly Lburou packed his from the inside and left it unsealed. I haven't heard of any adverse reactions:>

I removed one piece of metal from each side for what I hope is the last time. I had taken the vent cap off placed it all under the tarp that I had been using since day 1. I layed out and precut all the flashing.

Now the roof is complete and the cap back in place, and I am off of that dadgum roof:>

It has had a couple of good rains with no problems.

I got the blanket on and the MQ is getting a little hefty. By the time I get the brick on the dome she will have one heck of a badonkadonk back there .

To get the lapping and coverage the blanket added a little more than the 3" that I had allowed. To still get as close to the 4" of vcrete that I need I cut 2" out of the inside of the template. That puts the dome hanging over the hearth (sides and back) 2 and 1/2". I used the template to lay out a form to cantelever out over the edges. I placed a piece of flashing I had laying around temporarily beween the concrete and the blanket. It should be fairly easy to remove once the concrete cures.

[Gulf]

Re: Mississippi 44"

One final note to the blanket. To leave access for the template to be remounted, I cut through the insulation on each pass. I started out with about a 1" square and as each pass went on I cut a larger square. I did not want one hole all the way through to the apex so I hope that cutting them in ever increasing sizes will give enough overlap to help save some heat.

I plan to apply the vcrete up to just short of this cut down and let the vcrete set up a little. Then I willl cut the chicken wire, replace each one from the layer it came, and tie a wire patch over the area.

[Lburou]

Re: Mississippi 44"

Thanks' deejayoh,
I'm glad that I sealed mine from the back also before it was covered up. If I remember correctly Lburou packed his from the inside and left it unsealed. I haven't heard of any adverse reactions....snip....

I put some rigid insulation around the gap between the inner arch and the entry, then put mortar over that. Your method shows how to take that to the next level. I didn't want anyone t know, but I had some vermiculite seeping through at the bottom of that air space and I solved that by packing glass insulation in the crack to stop it.

BTW, I sure like your scissor trusses, it gives you a lot of latitude in surrounding the chimney.

[Gulf]

Re: Mississippi 44"

Double thanks' Lburou:
For clarifying your heat break and for those compliments .
Also scissor truss, I am working off of several years old termanology and a bit of AZ and you are correct. I have been calling my roof over an A frame. That is a little bit ambiguous and the wrong term for this purpose.
I also chose the scissor truss to get the over hangs low enough to help keep the oven dry and to leave enough head room for me to work on the dome. I also feel that it will help me show case the finished dome.

[Gulf]

Re: Mississippi 44"

Last weekend I thought that I would tackle the vcrete shell over the dome. I figured that with my template already in place that I could do it fairly easy. Not so. Working in a bent over position under my roof, and one wrong move, I threw my back out . Well, I tried to work through it but, was only able to get 4 courses done on Saturday and just 3 on Sunday.
This is a pic from Saturday.

Still on the mend, I got one more course on monday after work.

Had to work late the last couple of days so, no progress. I hope cold joints ain't an issue with vcrete or this gal is going to be "fridgid" .

[Gulf]

Re: Mississippi 44"

This is s pic of my gliding form which I fabbed to help keep my dome (sphere) true.

I cut a curve in a 2X4 block (scribed from the template) and attached a piece of scrap roofing valley metal. After some experimenting, I cut the metal back to about an 6" overall width.

The cup of the 2X4 on this short of distance helped keep the form true into the corners of the chimney. The wider width, which I started with, was just a little to floppy. It's was a little of a learning curve for me but, I placed the vcrete on each course lightly packing it outward toward the form and downward toward the course below. Although I sort of drug my trial across the chicken wire to put some undernerath I did not want to compress my ceramic blanket. As it turned out my 4" of vcrete will actual be more like 3 to 6" ISH . And that is after widening my original template due to the overlaps.

[david s]

Re: Mississippi 44"

When you do the vermicrete in one big layer it will take ages to dry, that's why I prefer to do it in 1" layers. You can work out the approx amount of water that you've added by dividing the volume of vermiculite by 3. Whatever it comes to it will be LOTS and it takes a lot of time to get rid of it. don't be in a rush. Very neat work by the way you've done really well. if you're really keen do a test batch by weighing the dry ingredients (cement and verm.) then add the required water content, press it into a mould the same thickness as the layer on your dome, then after its dry you can weigh it and calculate how long it takes for the water to dry out. Don't be duped into thinking that it's dry when the outer surface appears dry because it will still be damp underneath.

[Gulf]

Re: Mississippi 44"

Thanks' david,
I hope that your on the mend real soon. I did take your suggestion on another thread to heart about 4 separate layers but, I got in a hurry and 4 layers just did not seem to work with the template application. So I decided, that since I am under a roof, to make it full thickness. After the vcrete is finished I will go on to other work on the oven and just let that set for a long while before rendering.

[Gulf]

Re: Mississippi 44"

Also,
I intend to incude a vent like Neil2 described in pizzahead's steam vent thread. It may take a long time to dry but hopefully she want blow up .

[Tscarborough]

Re: Mississippi 44"

Put a fire in it, it will dry it out just fine.

[Amac]

Re: Mississippi 44"

Hey Gulf Nice work. The scale of your undetaking is almost putting my back out. I spent yesterday rounding the vermicrete in my own dome but using my gloved hands and a trowel and standing back and having a look at it every now and then.

I intend to incude a vent

Have you seen this one by MK1 with an Iron shell and a small valve on the top.

I thought it would be cool to include a steam kettle whistle so that it could sound like a real steam train when the oven was drying out - or even from a small reservoir which could be filled with water and touched the dome

http://www.fornobravo.com/forum/8/mk1-oven-build-6791-2.html#post131783

[Gulf]

Re: Mississippi 44"

Tscarborough,

Put a fire in it, it will dry it out just fine.

"Fire", sounds like music to my ears . It won't be long now. I think that I will start out just using it as a smoker in the first part of the curing process.

Amac,

I thought it would be cool to include a steam kettle whistle so that it could sound like a real steam train when the oven was drying out - or even from a small reservoir which could be filled with water and touched the dome

How about doing something like that with the waiste heat from the chimney?. Now that would be cool . It wouldn't rob any heat from the oven and might could be used for other purposes.

Edit: Yes, I really liked MK1's build. That is one kick ss oven and one hll of a back yard :>.