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rwiggim 07-25-2007 12:14 PM

Floor question
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So I laid the floor bricks last night and granted I was thirsty and it was getting dark but I swear that in the night my bricks shifted a bit and left bigger gaps between them than when I laid them. Should I mix up a batch of refractory mortar and fill the gaps or will they be fine. There is a solid 4 1/2-5" of percrete underneath. Also if anyone is planning on building and running a thermocouple under the floor I beseech you to put a straw in the structural hearth layer to run the wire through. I tried for an hour to drill through the concrete before giving up and going from the side through the percrete.

dmun 07-25-2007 01:23 PM

Re: Floor question
I don't think the gaps are a problem. They will fill with wood ash quickly enough. I wouldn't mortar them.

RTflorida 07-25-2007 02:12 PM

Re: Floor question
Just make sure the surface feels level and doesn't catch a peel. I actually took a belt sander to mine, made the hearth surface as smooth as a baby's bottom (yes, thats a bit extreme - I just didn't like the end result of using an angle grinder)

Ash WILL fill in the voids bwtween the bricks the first time (and every time) you brush your ashes


rwiggim 07-25-2007 05:05 PM

Re: Floor question
Thanks guys,
I think I am going to try the belt sander method.

Hendo 07-25-2007 06:14 PM

Re: Floor question
I filled my gaps with dry fireclay, left over from bedding down the floor bricks on the Cal Sil boards. It's practically the same composition as my bricks (40% alumina and 60% silica) so I assume it will behave in a similar manner thermally to the neighbouring bricks. Easy to fill even the narrowest of gaps, as it has the consistency of talc powder.

rwiggim 07-25-2007 08:49 PM

Re: Floor question
That was sort of my thought, to fill it with some thermal material. I just wondered
a.) if it was neccessary to the oven's function and heat retention.
b.) if I just used the dry clay if it wouldn't rear its head in my crusts.

I love the response to questions on this forum. How helpful.

Unofornaio 07-25-2007 09:57 PM

Re: Floor question
Ive seen a few of these same posts with the hearth bricks. A good tip to get these nice and flat is to have a rubber mallet on hand when laying them also using a notched trowel is 100% easier than trying to back butter them.
Fire brick are pretty consistent in size, most of the problems people encounter I think is related to not moistening the bricks enough, soak those babies. If the bricks are nice and moist and have not wicked the moisture out of the fire clay mixture it will stay workable for a long time, long enough to beat the bricks into submission after getting them all down... try to keep them level as you go then go back and beat down the ones that are giving you trouble.

As others have stated Don't fill the gaps they will fill themselves. Putting the fire clay in although sounds good in theory would be a disaster come bake time. In my opinion the hearth bricks are best left loose because there is a lot of movement going on. I'm curious about others who have mortared them together with the refractory mortar any separation? I'm on a quest to find out as much "field" information I can about this stuff..I'm Old School--fire clay but this stuffs got me excited if it really does what it says it does.

wlively 07-26-2007 07:36 PM

Re: Floor question
I had a couple of places where the gaps were big enough to bother me. I know it has been said ash would fill those, but I thought it would be better to fill with refractory mortar. The reason being that with the same thermal characteristic as the brick, as Hendo said, the heat transmission would be better. Ash would seem to be more of an insulator. Now, I am glad I did. It is hard enough to get the heat to soak the floor as it is. I have 5 really high temp firings and the floor is as beautiful now as the day I finished it.

As a note. I also wet mortared my floor down with HeatStop. But in reality it still floats. I just wanted it to be a solid mass that floats. I say that, because, I layed the insulation board with a layer of wet mortar for eveness, then did the same with the floor bricks on top.

Unofornaio 07-26-2007 11:24 PM

Re: Floor question
Chalk another one up for the refractory mortar..Thanks

rwiggim 07-27-2007 10:55 AM

Re: Floor question
It still seems that the majority feel that they should be left alone. I don't think that I would do the fireclay by itself thinking that the wet dough would pull up the dust from that everytime I cooked. I am a big fan of waiting on things that can't be undone very easily so I will wait and see if I think the oven's preformance is affected before I use the mortar.

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