FINALLY!!! - Start Of Building My Oven

[Johnny the oven man]

Far too soft for a compression application.

[Oven_Man]

Hi Guys

Thanks so much for the feedback on the Calcium Silicate Board. Atleast now I have that as an option and a better one too.

I'm also buying my Mortar, what sort of questions do I need to ask my supplier to make sure I get the right Mortar. The supplier just told me it's Dry Mortar but no further info so I want to be prepared when I question him about certain technical specifications.

I will be cutting the brick on Saturday, a task I've never done before.
Heck! I haven't used a angle grinder in my life but hey, I've never worked with refractory cement before and that wasn't too much of a disaster, so wish me luck guys.

Look forward to hearing from you guys.
Thanks
OM

[Oven_Man]

Hi Guys

Good news. This weekend I managed to cut all of my bricks and it wasn't as difficult as I anticipated. I bought a 115mm Diamond Cutting Blade for a Angle Grinder and it was like a "Hot Knife Through Butter".

However I would like to advise those that are going to use a Angle Grinder to cut bricks to rather buy a 230mm Ginder or larger if possible. Mine, even after turning the brick over and cutting from both sides still did not split the brick, i had to use a 10 Pound hammer and tap the brick to make it split, anyways i was happy to do so, only cost me a Diamond Blade.

Now my project continues.

Haven't had any response about the type of questions I need to ask my supplier to make sure i Purchase the right Mortar. Please Help.

Thanks again guys.
Regards
OM

[Oven_Man]

Hi Guys

I'm ready to lay the base of my oven (Insulation and Hearth)

I've been reading some threads and found this in the pompeii guide as well. I've already purchased High Heat Mortar to use beneath the Ceramic Board and the Hearth but some threads I've read say to use only fireclay and some say not to use anything. My concern is the oven is moveable and I would think this may be detrimental to the oven

Basically, I am going to do the following, please tell me if I'm heading in the right direction.

1) Layer of Mortar on a steel sheet upon which the Ceramic Board will sit.
2) Layer of Mortar on the Ceramic Board upon which the Hearth will sit. No Mortar between each brick as advised in the guide.
3) Surrounding the Board and Hearth will be Vermiculite just to hold everything together.

Hope thats the right track I'm heading.
Thanks
Regards
OM

[Oven_Man]

Hi Guys

I'm picking up my Vermiculite tomorrow to layer on the base so it surrounds the Ceramic Board and Bricks.

I need to know, since the primary reason for the vermiculte is not insulation but rather to streghnthen and hold the ceramic board / Fire Brick in place, what mix ratio do you suggest i use in conjunction with Portland Cement and Sand.

Thanks
Regards
OM

[david s]

There is not much strength in vermicrete.If you want strength then use standard concrete. As a compromise you can make a lightweight concrete 4:3:1 vermiculite, sand, cement. Although it will be around half the weight of standard concrete it will also probably be around half the strength.

[Oven_Man]

Hi Guys

Alot of progress I've made over the past few days.
I've managed to lay the floor, added a layer of Vermiculite (Daivd S Ratios - 4 Vermiculite + 3 Sand + 1.5 Cement (Decided to go with a little more strength)) and around the vermiculite I filled all the spaces with Portland Cement.

All looks good, no real problems experienced. I was presently surprised that the vermiculite was quite easy to work with however after completing; I found that Vermiculite is quite sandy and loose even after it drying. I was considering adding a very very thin layer of cement but not sure what cement to use since the dome will be directly on this layer so it needs to withstand the heat. I have some Mortar Mix, Refractory Cement, and Portland. I will just plaster the layer on just so it's smooth because the current vermiculite mixture is not very smooth like I expected it to be. Any Suggestions?

Other than that, I'm now ready to place the casted dome pieces on the slab and begin joining the pieces together. I won’t even think about saying I’m close to completion because I’ve said that soo many times yet I see myself far from it so all I can say is I’m doing well and hope to continue in my stride.

David, one concern just popped in my head. Will the Vermiculite Mixture mentioned above be able to handle the direct heat of the oven (Dome will be sitting on top of the Vermiculite)? I’m just a little afraid of it cracking or worst of exploding because of the heat. Just to recap, beneath the vermiculite mixture is a 4” layer of Ceramic Board so I’m happy with that insulation and still stand by the fact that the vermiculite is not for insulation but rather strength so it can handle the weight of the Dome. By the way the Vermiculite is 1" thick

I look forward to hearing from you guys.
Thanks
Regards
OM

[Gulf]

Originally Posted by Oven_Man

Hi Guys
I found that Vermiculite is quite sandy and loose even after it drying. I was considering adding a very very thin layer of cement but not sure what cement to use since the dome will be directly on this layer so it needs to withstand the heat. I have some Mortar Mix, Refractory Cement, and Portland. I will just plaster the layer on just so it's smooth because the current vermiculite mixture is not very smooth like I expected it to be. Any Suggestions?

OM

The weekend that I poored my vermicrete layer I ran out of the course and the only source was closed. I had to pour the top 1/2" with a fine horticulture grade vermiculite. I was pleased at how smooth it turned out.

EDIT I did not read this as closely as I should have. The part directed to Dave says that your vermicrete is above your 4" of calsil and only 1" thick of vermicrete. Mine was 4" vermicrete/2" calsil in reverse order of what I just read. Maybe a thin coat of fine vermicrete could still help with the surface.

[david s]

The vermicrete will handle the heat ok. You can render over the vermicrete that projects past the outer shell once you have finished. I use the same mixture that I use to do the outer shell ie. 4:1:1 sand, cement, lime

[Oven_Man]

Hi Guys

Thanks for the responses. I'll go ahead with the suggested advices.

Keep you guys posted.
Regards
OM