Author Topic: wich concrete???  (Read 1390 times)

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Offline Franchef

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  • Location: Costa Rica
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wich concrete???
« on: October 06, 2013, 06:29:21 PM »
Hello people,

does anybody knows which kind of concrete is better for a handmade concrete pizza oven thatīs gonna ride on a trailer??? (the streets in Costa Rica are really bad  >:()

I got two different alternatives ??? (that I can buy in Costa Rica)

1- Super Kast Set Plus (max. service temp. 2800 °F)       
      - silica       40 to 44 %
      - alumina  45 to 49 %

2- UR-20 (max. service temp. 1800 °F)

      - silica       66 %
      - alumina  14 %

Can anybody help me with that?
Thanks a lot!

Offline nachtwacht

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Re: wich concrete???
« Reply #1 on: October 07, 2013, 03:05:21 AM »
I don't know them but I would think that with the Super Kast with the high alumina % will heat up faster than the one with 14%. If you are making a trailer, that might be a very important consideration.

Offline FocusHearth

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Re: wich concrete???
« Reply #2 on: October 20, 2013, 08:28:38 PM »
You'll want to consider using re-mesh in any refractory castable that you think will actually crack.

Offline dave s

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Re: wich concrete???
« Reply #3 on: November 15, 2013, 07:18:48 AM »
Actually rebar mesh does not suit castable refractories. Because the steel is way more conductive it will attract the heat to itself and expand more than the refractory that surrounds it leading to fractures in the refractory. To get around this problem the recommended reinforcement is stainless steel melt extract fibres or more commonly referred to as stainless needles. Because they are dispersed randomly in the castable and each individual fibre has less mass than a thick chunk, the surrounding refractory has a chance to absorb their heat eliminating the temperature difference of the two materials. Normal steel is also subject to rust especially in conditions where it is subject to heat.galvanized steel is a bit of an unknown quantity in a WFO because zincs melting point is around 400C, a temperature that is achievable, so who knows what happens to the coating.The stainless needles are a bitch to handle, needle sticks are frequent, but not too bad.You do get used to handling the mix gently and respectfully.Hope this helps.
« Last Edit: November 15, 2013, 02:07:30 PM by dave s »
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Offline Franchef

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Re: wich concrete???
« Reply #4 on: February 04, 2014, 10:59:16 AM »
Hi guys!!!!! itīs take a long time but finaly the oven is almost done. I choose one cement I found with high percent of alumina and itīs seems to work very well.
  thanks a lot for the goods advices!!!!!!

soon I will send more pictures from the trailer
greetings from costa rica   

Offline breadstoneovens

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Re: wich concrete???
« Reply #5 on: February 04, 2014, 11:37:36 AM »
Hi Fran,

The oven looks fantastic and so do the pizza. Keep the pictures coming.

WFO cooking is about passion.