FINALLY!!! - Start Of Building My Oven

[Oven_Man]

Re: FINALLY!!! - Start Of Building My Oven

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]

Re: FINALLY!!! - Start Of Building My Oven

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]

Re: FINALLY!!! - Start Of Building My Oven

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

[Johnny the oven man]

Re: FINALLY!!! - Start Of Building My Oven

Far too soft for a compression application.

[Laurentius]

Re: FINALLY!!! - Start Of Building My Oven

Hi Johnny,

Why, shouldn't it? In your opinion?

[Johnny the oven man]

Re: FINALLY!!! - Start Of Building My Oven

Cal. Sil board is way firmer than fiber. Ceramic fiber board shouldnt be used under the oven in my ooinion. The plus is you save money.

[Oven_Man]

Re: FINALLY!!! - Start Of Building My Oven

Hi Guys

I was about to buy my Ceramic Fibre Board when my supplier told me he's out of stock so i started looking elsewhere only to find that my initial supplier was going to give me Cacium Silicate board instead of Ceramic Fibre Board but he never mentioned so. The only way i found out was when other suppliers gave me hefty prices for Ceramic Fibre Board and then they explained what could be the reason which my initial supplier confirmed.

Never the less, just want to check how well does this insulate heat compared to original Ceramic Fibre Board and would you suggest I go this route?
Also, will it withstand the weight of the oven on this board? (Sorry, i know this is a silly question i keep asking but i just cant imagine how a board like this will withstand a few 100 KG's but then again I've never seen or felt the board so hard to make assumptions)

Thanks
Regards
OM

[Oven_Man]

Re: FINALLY!!! - Start Of Building My Oven

Thanks so much David.
I can't wait to get this baby fired up, it's been overly due now .

[david s]

Re: FINALLY!!! - Start Of Building My Oven

1) Can just an insulating material like Vermiculite be filled on top of the Ceramic Board and is it strong enough to hold the weight of the oven. Yes, but 50 mm calcium silicate board is enough insulation on its own. you can place the floor directly on it.
2) Will Portland cement be fine to fill in the gaps surrounding the oven and how will it fair to the little heat that comes from the oven indirectly? yes providing it does not contact the floor or the dome directly. that is there should be insulation separating them.


1) I’m already dreading the thought of hoisting these dome pieces onto the table. Any tips from you guys to avoid health problems  two or three people should be able to lift them ok as it is only a 24" oven
2) As can be seen in the pictures, the gap in between each piece is quite large so would mortar suffice to fill these gaps and at the same time create a bond with all the pieces? yes, use the homebrew mortar. If you can't get fireclay then use crushed sifted anthills

would it be sufficient to build a vent or do I just go and grab a few bags of cement for the vent? Use some more castable a Portland based castable will probably crack. You might get away with using homebrew to make a castable and add your leftover aggregate in place of (or as well as) sand in the mixture.
Good luck and get this thing fired up,
Dave

[Oven_Man]

Re: FINALLY!!! - Start Of Building My Oven

Hi Guys

My progress has been really slow as I?ve been waiting for my table to be modified further and hopefully I would have it back any day now. In the interim I?ve been thinking about the next part and how to approach it.

I?ve decided to do the following and need some advice on whether I?m heading in the right direction or do I need to rethink this.

Never the less, on the table (Picture attached in previous post) will be laid a Metal Sheet. The oven will sit dead center on the table and have a gap of approx 3? to 4? on all 4 sides of the table. I have the following plan. I will place just on top of the metal sheet a 50mm ceramic board. The board will cover the exact same area as the oven which means it will also leave the same 3? to 4? gap on all sides of the table. On top of the Ceramic Board will be laid 3? fire brick. The fire brick will not cover the entire area of the Ceramic Board, it will only cover the same area as the inner diameter of the oven which is 26?. Never the less, around the Fire Brick but still keeping in line with the Ceramic Board, I would like to fill an insulating material to the height of the firebrick, maybe 3mm less than the very top of the brick so the brick will now only protrude by 3mm. Around the ceramic board/insulating material; I would like to fill the 3? to 4? gap with maybe Portland cement for structural strength of the table as a whole.

A few questions on what I?ve mentioned above.

1) Can just an insulating material like Vermiculite be filled on top of the Ceramic Board and is it strong enough to hold the weight of the oven.
2) Will Portland cement be fine to fill in the gaps surrounding the oven and how will it fair to the little heat that comes from the oven indirectly?

The next part is to put the dome pieces on top of the Vermiculite and then join them. I plan to join them in the following way. First, plaster the bottom of the dome pieces with mortar and then fix it to the vermiculite. Next, once all the pieces are in place, I am already anticipating big gaps in between each piece as I?ve already placed each piece next to each other to see how it looks and I?ve also attached pictures to make it more visual.

Questions

1) I?m already dreading the thought of hoisting these dome pieces onto the table. Any tips from you guys to avoid health problems ?
2) As can be seen in the pictures, the gap in between each piece is quite large so would mortar suffice to fill these gaps and at the same time create a bond with all the pieces?


Lastly, I?m not too sure how my material is going but I may just run out of Refractory Cement for my vent. I may end up with extra vermiculite and mortar and I also have quite a lot of stone pieces from sieving refractory cement earlier in my project to get my cement more smooth so i could fill in the voids on my dome pieces. Anyways, if I were to mix all of this and top up with a little bit of Portland, would it be sufficient to build a vent or do I just go and grab a few bags of cement for the vent?

Looking forward to hearing from you guys.
Thanks
Regards
OM

[Oven_Man]

Re: FINALLY!!! - Start Of Building My Oven

Thanks David, stacking 1" bricks ontop of each other would be a problem and maybe a little expensive too. I did chat with a supplier who said he may be able to source some 2" bricks for me so hopefully he'd come through but he already has 3" so I'm not too worried if he can't source the 2".

Excellent idea about the flue gallery, I will pursue that avenue although i can see some issues locating an elbow since the flue was such a mission to source, i could only find pre-fabricated flues, no one could make me one to spec.
Worst case, I was thinking of re-designing the vent so it doesnt slant and will be straight including the flue pipe; its been a long windy road and i wouldn't want to make a mistake so far down the road since once the vent is in and the oven is completed, theres no going back like removing the vent and correcting it at that stage.

Thanks again for your priceless advice; always appreciated

Regards
OM

[david s]

Re: FINALLY!!! - Start Of Building My Oven

You could do two layers of 25mm, but that doubles the number of pieces and that's not good for a trailerable oven. If it were me i'd prefer either the 3" or 2" thick bricks.
I was also thinking about your flue gallery and it would be easy enough to cast an elbow that could fit the gallery to get back to vertical. It will probably shift your flue pipe back, closer to the top of the dome and away from the front which might be an advantage.

[Oven_Man]

Re: FINALLY!!! - Start Of Building My Oven

Hi David

Yes, I am refering to the floor thickness.
Thanks for your advice, I'll preferably look for a 2" thick brick since you mention it would be better. Atleast i have the 3" to fall back on if I can't find 2".

I did phone 1 supplier and they stock 25mm and 38mm fire bricks. Would any of these 2 thicknesses work or is it too thin?

Regards
OM

[david s]

Re: FINALLY!!! - Start Of Building My Oven

I presume you are talking about floor thickness. I used 3" thick firebrick for my first oven and it worked fine. You are probably better off with 2" but you use what you can get. If the floor is a little thicker than the dome it won't matter because the heat evens out with time and I'm sure you'd notice little difference. Get 'em.

[Oven_Man]

Re: FINALLY!!! - Start Of Building My Oven

Hi David

I'm busy trying to locate firebrick and so far most of the suppliers seem to have the same type. The thickness of the bricks are 3" with a alumina content of 35%. I'm a bit worried that the brick is too thick and maybe we should go slightly thinner.

My dome cast pieces are 3" thick so do you think i should stick with the 3" brick to keep a balance?
I should be able to get my hands on 2" thick bricks if I look hard enough but my concern on the other hand was if my bricks are thinner than the dome, then it would heat up faster and uneven heating wont be good.
Then again, the next question is total heat up time for the oven, thicker bricks = longer heat up time

Sorry i have all these thoughts running through my head and I'm so confused right now, please point me the right directions.
Thanks
Regards
OM