setting the floor and home recipe mortar

[gtofani]

1. I am ready to place my floor over the 2" fb board which does not have real even seams, some minor differences. Do I spread the sand clay mixture over top of the fb board to level the surface or under the fb board?

2. I have read so many posts on the homemade mortar mix that my head is spinning. The local masonary store said to use 3 sand, 1 portland, 1 fireclay and 1 lime. I have not read these ratios anywhere but they are close to all the different ratios I have seen on the posts.
I may just use the premixed (expensive stuff) for the initial setting of the dome and spread the homemix over the outside to fill in the large spaces of the outside of the dome. They say not to use the premix for larger joints.
I just want to do this right.

[GianniFocaccia]

Re: setting the floor and home recipe mortar

First level your boards on the sand/clay mix. Any variances in your bricks can then be leveled individually. You may want to slope your boards slightly towards the front of the oven to drain water in the event it gets in.

The 3-1-1-1 homebrew ratio is exactly what is prescribed here and for me, was one of the easiest elements of my build. Use a finer grain silica sand if you can get it. There is no reason to use expensive premixed mortars. There are plenty of threads here touting the benefits (especially crack resistance) and effectiveness of homebrew.

[gtofani]

Re: setting the floor and home recipe mortar

Thanks, that puts my mind at ease about the mortar.
My stand has a very slight slope towards the front, left and right are level.
The 2" fb board is what has the slight differences in thickness.
I will even it out first with the fireclay mix and then the brick as needed using the same mix.
I have the floor drawn with crayon on the floor bricks, I have to cut them and then reassemble the floor. I numbered them to hopefully get them back together correctly.

[Dino_Pizza]

Re: setting the floor and home recipe mortar

I too used the home brew for the last 2/3rds of my build and highly recommend it. I would use it for the if I ever do another (instead of 1/3 purchased Refmix and 2/3 homebrew on the entree brick oven). Here is the recipe in case anyone else is reading this and needs the details

1 pt Portland Cement
1 pt Lime
1 pt fireclay
3 pts Fine Sand

I REALLY! recommend going to the brick-cement yard and looking for SILICA #60 (or even higher if they have it, but 60 is great) . It's extra fine sand and makes a smooth peanut butter-like mix. Stay away from Home Depot Play Sand, it looks nothing like the silica sand I bought at the brick yard and I'm really happy with how the mix worked out for me.

Also, those ratios are used by most of us on this site and you may see a slight variation on some threads but there's no need to get too esoteric about it. Keep this ratio and you'll be fine.

My FB board was mostly flat but concerned me too at some seams that were not perfect but it really doesn't matter. I used a wet slurry of fireclay/water to set my floor bricks as flat and even as possible but you do your best and imperfections arise. The point is: that's why we go with a herringbone pattern: there WILL be some floor bricks that tilt up or down on a some corners but it doesn't matter at all. A pizza peel or grill or iron crock will work as intended and slid right over these.

Good luck, Dino

[gtofani]

Re: setting the floor and home recipe mortar

thanks for the information and help, I had my floor layed out to cut all the outter bricks but I think I will just set my dome on top of the floor and save a lot of cutting. This mortar mix recipe will save me about 270 dollars by making my own compared to the prepared refractory mix.
thanks,
Gino
(by the way, I have a brother named Dino)

[GianniFocaccia]

Re: setting the floor and home recipe mortar

I have the floor drawn with crayon on the floor bricks

After playing with blocks, white paste glue and crayons, I guess it's true: We learn all we need to know in kindergarden.

[wotavidone]

Re: setting the floor and home recipe mortar

I too used the home brew for the last 2/3rds of my build and highly recommend it. I would use it for the entire dome if I ever do another.

Hey Dino, do you mean you would use it to mortar your bricks together, or would you actually cast/mould a whole dome from it?
Regards,
Mick

[Dino_Pizza]

Re: setting the floor and home recipe mortar

Hey Mick,
I meant I would use the homebrew for bricking the entire oven. I just said that because I had bought super-fancy Refmix imported from Italy (that they stopped selling) and that got me thru my 1st 2 courses and arches, but then when I lost my source, I went with home brew for the balance of the oven (using all firebrick, like the traditional Pompeii design calls for) all the way thru final keystone and feel the homebrew for mortaring your bricks worked as good as either pre-made or fancy mixes.

I found building the oven by cutting fire bricks in 1/2, 1/3rds & smaller and mortaring the joints was stretching my construction skills as it was , and casting or molding is way over my head (although I've enjoyed and appreciated those on the site that have )