Firebrick Hearth Recovery Time Slow

[Oven_Man]

Hello Everyone
I built my Pompeii Oven many years ago - my thread is on the forum.

I'm starting to use it more often these days and found that making more than a couple pizza's is a challenge when you have hungry people standing over you. Once the oven floor hits around 675F to 700F,
I bake my first pie then it's all downhill from there. The oven floor looses heat rapidly after the first pie is done - first pie bakes in +-3 mins and the bottom is perfect but the floor then goes as low as 450F - it can take anywhere from 10 to 20 mins before if comes back up to 650F to 700F and hungry people are angry people when you make them wait especially after enjoying the slice of the first pizza.
The radiant heat in the oven for the top of the pizza doesn't reduce much so I don't think I'm loosing heat out the vent. The outside of the oven is warm to the touch so think insulation is fine. I also make sure I have a small fire going to keep the oven hot and at it's optimum.


My Hearth Floor is made from 75mm Medium Duty (38% Alumina) firebrick and I'm thinking of cutting my bricks in half and bring down the thickness to 38mm - will that make any difference to recovery time for the bricks? I'm also considering placing more insulation underneath the bricks to cover the gap that will be left after cutting bricks in half.

Thanks

[Baza]

Hi Oven_Man wondering what you have under the cooking floor in terms of insulation? ie/ between the hearth and the bricks of the oven floor?

[Oven_Man]

Baza I've got Ceramic Fiber Board - 50mm thick. By the way, my oven is build on a steel trolley so there's no heart as such - I just have a steel sheeting underneath, then it's the Ceramic Fiber Board and then the firebrick.

[fox]

75mm brick base is pretty standard and undoubtably works extremely well in most cases.
it may be the steel below your insulation is shedding the heat especially if it is exposed to the air.
50mm of ceramic board will slow down the heat lost but it will still penetrate through and without any backing mass i wonder if this is the main issue?
Is it possible to measure the heat of the steel plate under the insulation?

[Oven_Man]

fox , I think you may be right sir. I will take a measurement of the steel the next time I fire up the oven and report back.
If it is the case, maybe I should add some insulation underneath the steel plating?

[Baza]

Oven_Man - hey! Yeah - when I read your reply to my question - I started thinking like Fox as well - could be the concrete a lot of folk build as the hearth provides more thermal support than the metal and this is where the sinking is happening. Good news is - looks like you are thinking to a great solution! I bet rigging another layer of ceramic board under the steel hearth will add the heat stopping effect you are looking for ... worth a try anyway!

Best of luck sir!
Barry