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Ground my floor tiles. Showing more pitting. How to grind / polish fire brick?

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  • Ground my floor tiles. Showing more pitting. How to grind / polish fire brick?

    Hi, My floor was uneven so I took a diamond grinding wheel to it. Floor is level now but firebrick looks more pitted, not smooth.

    Tried sanding brick a little and pits are still there.

    Did I permanently damage firebrick? Is there a method to smooth off firebrick?

    Thank you, Steve

  • #2
    Look at #3

    I think you should try on a scrap brick first. Dilute Sodium silicate with water 1:4 and apply it thin in several coatings with until you're satisfyed.

    You can add equal amount of fire clay to concentrated SS to create a paste that could fill larger (still mm-range) gaps. Let it set and then heat it slowly to about 150 C to remove the last bound water. Then coat it like the rest of the hearth.


    • #3
      i’d doubt very much if this brew would be effective over floor bricks, but give it a shot and report back.
      Last edited by david s; 05-01-2020, 03:56 PM.
      Kindled with zeal and fired with passion.


      • #4
        Thanks very much for input. I never heard of Sodium Silicate - found this video here for all you newbs out there.

        Going to try on test brick. Will let you know!

        I was going to buy a belt sander, but even a fine 200 grit paper would probally leave brick looking pitted etc.


        • #5

          Is this the right stuff, powder form? Thanks!


          • #6
            Before you buy, I suggest you look at the MSDS on this. This is you oven floor you are talking about where pizzas will lay directly on it. In my brief reading on Sodium Silicate, it is very toxic in an uncured state.
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            • #7
              Welcome, that's a good video. You should try to find a SS with SiO2 : Na2O in the 2-2.5 : 1 range. Too high SiO2 gives a harder but less flexible coating. The hardness is still very good for our needs. Flexibility is good to prevent spallaton during thermal cycling.

              Try source it locally ready mixed. $10 per liter in Sweden. Should find it in a hard ware store or where you buy paint.


              • #8
                Yes, thats true. It polymerize above 100 C and becomes silica.


                • #9
                  Can you post a picture of what your floor looks like? My floor certainly has what you might be calling pits in it from sliding cast iron cooking ware, pizza peels etc, and it cooks just fine. I figured anything that was going to come loose already has and it is just normal wear and tear. Just wondering if you are trying to fix a problem that really isn't going to effect your cooking.
                  My build thread


                  • #10
                    This sounds like a bad experiment to me! Great if it works, but I've been a member here for more years that I care to think about - and it's not any sort of normal repair.

                    Personally, a bit of pitting on the floor is no big deal. Doesn't need to be perfectly smooth, as it won't affect cooking results. If anything, I'd suggest pulling/flipping/reseating the bad bricks. They should go back at the same level.

                    Edit: and FWIW - the post that Petter referenced is 10 years old... and the product referred to has a MSDS that suggests it belongs nowhere near food!

                    Last edited by deejayoh; 05-01-2020, 12:05 PM.
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                    • #11
                      Sure, I will take a vid and upload later tonight.

                      Thanks for all input guys. It just seems from factory bricks have smooth finish. Any sort of sanding reveals pits. I will show you later what I mean.

                      Vids/Pics soon to come.....!


                      • #12
                        I'd be tempted to get some heat stop mortar and fill any pits in the floor, then fire it as if it was a new oven and see what happens.


                        • #13
                          Please see this picture of brick pitting here

                          Top Brick: Cut with wet tile saw. Smooth finish
                          Middle Brick: Example of grinder on brick, grider does not create a smooth finish, neither does sanding. This is what my oven floor looks like.
                          Bottom Brick: Smooth from factory brick


                          Example of grinding floor on single brick


                          Link to entire album here


                          • #14
                            can you just flip the bricks over to the other side?
                            My Build Pictures


                            • #15
                              They have about 1/2" in of 3:1:1:1 fire motar under them, stuck to bottom.