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What comes next?

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  • What comes next?

    ive been searching and just want to verify...please. I have my bricks mostly done-my dome is 98% complete. (Super yay!). Now, I just want to make sure I get my next steps correct. Do I put a layer of refractory mortar on the outside of all the bricks, before I wrap it in fire blanket? I知 also planning on (at least) a few inches of vcrete as more insulation on top of the ceramic blanket. Do I also need to skim coat with concrete (regular Portland mix) on top of vcrete? I plan to time on top of that as well.
    I知 just doing this once and need to make sure to do this all correctly. It痴 very rustic but I知 so very excited to use it!!!
    final question, please, is it AFTER i get all the layers on and dries, that i start my curing fires?
    Thanks so very much!!

  • #2
    I don't think there's any need for additional mortar on the outside of the bricks, nor for vcrete if you're using insulating blanket. Additional mortar would add thermal mass, making the oven take longer to heat and then stay hot longer for baking on subsequent days. More insulation is hard to argue with (other than $$), and will have the effect of keeping the oven hot longer. My oven already takes plenty long to heat (consuming a surprising amount of wood), I wouldn't want ti to take longer. It is still at ~250 deg on the third day after firing, which seems like plenty of heat retention.

    Most people doing an igloo design put vcrete on the outside of the fiber blankets as a substrate for stucco or tiles. Mine is a "house" design and I've just got 5-6" of blanket and it's working great as is. Though I've given some thought to filling the house with perlite before it's fully sealed, just for the heck of it.

    Lots of discussion about beginning curing before completing the insulating layers, I'm not sure if there is a real data-based consensus. In most of the build threads I've read people seem to cure after the insulation is on, especially if it is vcrete. I started curing after insulation and after I had a roof on.
    My build thread:


    • #3
      I'm curious about this as well. I'm about to add my blanket (about 3" or so) and then my outer coats.

      Do I *really* need any refractory material after my blanket or will regular Type-S or N be adequate?

      Obviously more insulation is always better but will there be any problems with just adding regular stucco / mortar to the outside of blanket?


      • #4
        IMHO, you do NOT need to have a refractory coating on top the the 3" of blanket, just standard masonry. I put pcrete over my blanket to give my dome shape prior to stucco (which gave additional insulation as well as shape). You could just stucco the blanket but it will be harder to get thickness you need if there are some areas you need heavy adjusting.
        Last edited by UtahBeehiver; 10-15-2018, 06:33 PM.
        Google Photo Album []


        • #5
          Thanks Russell, that is what I was hoping I'd hear as I couldn't understand the need for extra refractory.

          I'm hoping to spend a little more time with the insulation and lath so I can avoid fighting with the masonry. It's such a shame we need / want that insulation. The dome is almost perfectly spherical now but I really want to do bread too...


          • #6
            Agree with Russell.

            I insulated with 4" of blanket, four 1" thick layers with seams offset. Covered that with stucco mesh, used wire rebar wire ties to snug it all together. Covered that with two coats of 1:3 portland;sand, combined total thickness about 3/4" thick. Covered that with two coats of Thoroseal.

            It all went amazingly easy. Blanket conformed nicely to the dome, stucco mesh was nice and tight to the insulation, all that allowed the portland coats to go on so easily. Like icing a 52" diameter half-sphere cake. lol

            I do need to update by thread.

            Been busy digging into a slope and building retaining walls for a bluestone seating area down by the water.
            Last edited by mongota; 10-15-2018, 05:33 PM.

            My Build: Mongo's 42" CT Build


            • #7
              So here痴 a question:
              i put my 1 blanket, got the wire mesh on, started my vcreate and realized I do have a big air gap at the top of the dome, where the vcrete isn稚 totally touching the fb. Should I make a little hole in there and pour in straight vermiculite or just skim coat my done as to water seal it a little before tiling the dome?? So. Many. Questions.
              Thanks everyone!!