a couple of refmix questions

[Matt916]

I have been reading posts for quite a few days to answer this definitively, but am still unsure as to the difference between fireclay and this refmix. If I understand correctly, fireclay/sand/water are mixed together to hold the cooking floor level and tightly together. Then the refmix is used to mortar the bricks in the dome into place...i don't know if this is right, but why couldn't the floor be moartered into place with refmix?
I know that there's a way to make your own version of refmix, but i'm planning on ordering it from the store on this site. About how much would be needed to complete a 42 inch oven?

[dmun]

Re: a couple of refmix questions

You can use refmix or another dry refractory mortar to level your floor. It's expensive stuff, and some of us were constrained by cash. In the event, my insulation boards were level enough to dispense with this step entirely.

As to the difference, fireclay is just that, dried refractory clay. Refractory mortar mix is a powder that mixes with water and sets hard and waterproof, and adheres the bricks together.

You can mortar your dome with the sand/fireclay mixture, Frances did, but it never solidifies and you have to keep your oven scrupulously dry.

Finally, I think the original thought in using the fireclay/sand mixture to set your floor was that a damaged brick could be replaced without chiseling it out from set mortar.

[Matt916]

Re: a couple of refmix questions

oh, i see. That makes a little more sense to me now. I was concerned that there might be gaps between some of the bricks (no brick is made perfectly) and mortaring them might ensure that there are no gaps for heat to escape from, but now that i think of it, its insulated on the bottom, so no heat will get through. I guess i'm worried about making mistakes at this point in the build. Sometimes going through pages of posts and reading the installation directions over and over can get a little confusing. I've never done any type of masonry before so i'm probably going to have a lot of questions that might seem obvious or downright ridiculous...

...I actually have one right now. I attached a picture of what i've built so far. Today i picked up some firebrick and laid out brick to make sure a 42 inch oven would fit in the space i have. Does it look like there is enough room for the oven landing? I've actually neglected to plan ahead for it and it comes right up to the edge of the hearth which actually makes me a little nervous. any comments or suggestions...or any advice as to what the next step of this build should be?

[wood-fired]

Re: a couple of refmix questions

matt,

you're doing ok but you're right there's not going to be much space for a landing, except the small space at the throat of the oven. If you get stuck you could always either fix a stone shelf edge with brackets or cast a simple shelf with steel pins protruding and drill holes back into your concrete oven slab to attach. Neither is ideal but I presume its a home oven so who's going to criticize!
As to the fireclay/refmix question. Fireclay is just used for levelling your hearth slabs or mixing with high alumina cement to make refractory mortars and castables. You could make your own refmix if you have a source of the other materials.

amrit

[ThisOldGarageNJ]

Re: a couple of refmix questions

hi matt,

you could also extend your foundation enough to lay a cinderblock on.. and put your landing on top of that, limestone, marble, etc,,,

looks good so far
Mark

[wood-fired]

Re: a couple of refmix questions

mark,
even better idea! the foundation is wide enough to take another layer of blocks but I suppose matt was going to clad the thing. You can always extend your footing a bit if you wanted to clad it.

amrit

[Matt916]

Re: a couple of refmix questions

Actually extending my footing isn't a bad idea, thanks for the advice on that. i was planning on pouring concrete all around the area where my oven is any way...it's going to be a slow process but i want to build an outdoor kitchen. I've actually run into a money problem, so i have to wait until the beginning of september to buy a few peices of FB board off this site before i lay the cooking floor, so until then i don't think i'll be able to do much except stare at my project out the window.

What exacly is the purpose of the landing anyway? I thought it was just basically a llittle extra work space. if so, i suppose i can worry about it after the oven is built...the dome at least. But if it takes away from the functinality of my oven, i definitely want to change up my design plans and find some way to include it. haha i would probably have some sort of melt-down if i finished the oven and it ended up not working properly. LOL, Basically i have no idea what i'm doing and i'm just winging this whole project, so i would never know if, along the way, i missed an important step of the oven building process...which is why this forum is like a gold mine...i dont even think i would have been able to build the foundation slab if it weren't for the advice i got on here!

[wood-fired]

Re: a couple of refmix questions

The landing is just extra space to place your pizza or whatever before and after cooking, don't underestimate how useful it is. You're right that you could build an extension after as long as you've got the throat and dome in one construction but its useful to have all the prep work done first so you can visualise how its going to look; it always helps to do a little doodle to help you formalise ideas. matt, there's a free cd rom you can get from Forno Bravo with ALL the step by step building instructions plus a load of other stuff like recipes etc. just send them an email and they'll send one out. I am a dealer for FB in the UK and an oven designer/installer as well as a landscape designer so any specific help just ask. The forum is very good for finding answers but could be bit of a slow way if you're in the middle of something and don't know what to do next- better to have a print out next to you to follow.
Actually, for someone without any experience you're doing pretty well!!
amrit info@wood-firedoven.co.uk

[ThisOldGarageNJ]

Re: a couple of refmix questions

september to buy a few peices of FB board

have you priced out vermiculite or perlite for the oven floor insulation,, call your local pool supply, gadendening center etc,,,,

[ThisOldGarageNJ]

Re: a couple of refmix questions

Matt,
My eyes arent as good as they used to be...In your pictures Do you have a vermiculite slab on top of your Foundation or are you planning on just using the FB board ?

Mark

[Matt916]

Re: a couple of refmix questions

Amrit- Yeah, i was thinking the same thing about making a doodle. I can see what I want my oven to look like in my head, but its hard to draw it out accurately...i have some artistic talent, but drawing isn't included in that! I'll definitely be sending you an email though.


Mark- I just finished the vermiculite hearth actually. My original plan was to pour three inches of rebar enforced structural concrete and directly on top pout a 4 inch vermiculite hearth. However once i heard about how well the FB board insulates and how much easier it is to work with, i decided to only pour 2 inches of vermiculite atop my normal concrete hearth slab and put a layer of FB board directly under the cooking floor of the oven.

Hopefully once i get my FB board it will be easy to assemble the cooking floor. i've built out the cooking floor just to see how many bricks i'll need and what it will look like on the hearth. I've used some of the straightest bricks i have but it doesn't look like some of the pictures ive seen on this forum where bricks fit together to form a seemingly airtight seal. Is that a problem?I'm still wondering if i should offset the bricks, or do the herringbone pattern...ahh seems like so many things to keep track of! But it's ok, i'm pretty anxious to start building again!

[ThisOldGarageNJ]

Re: a couple of refmix questions

Hey Matt,
I did a herringbone, after you get the first row in and where you want it, it will come together easily, Take a few practice rows and see which setup you like the looks of best. Pick out your best bricks and use them, where you have little spaces it will pack full of ash quickly and hold them tight, And if you find your floor isnt flat enough for you, You can always grind or sand down any high points with a grider or sander....
Mark

[testadom]

Re: a couple of refmix questions

Hi, I just had the firebricks delivered this morning. I have a 4 in. hearth poured, with rebar. I was planning on pouring an insulating layer but am now considering buying the ceramic board. Can I just lay it out on the hearth and go? Should I cut the insulation to the circumfrence of the floor and build the dome around it, or should I cut it so the insulation goes under the dome wal as well? Can the board support all the weight without compressing? Thanks for any help.

[Gromit]

Re: a couple of refmix questions

Can I just lay it out on the hearth and go? Should I cut the insulation to the circumfrence of the floor and build the dome around it, or should I cut it so the insulation goes under the dome wal as well? Can the board support all the weight without compressing?

Yes. No. Yes. Yes.

You can also build your dome on top of your oven floor. Just make sure no part of the dome is in direct contact with your slab; the dome should be completely surrounded by insulation.

[testadom]

Re: a couple of refmix questions

Thanks, David, That's pretty much as I thought, but I don't want to screw things up at this point. Or at any point for that matter.
Dom