Is more insulation required???

[scottz]

Hi guys,
Just thought I would get some peoples ideas in regards to my WFO. I bought a kit oven, as has been told in other threads.....and put it together myself. The WFO works really good and is great at getting 'Pizza Hot' and also slow cooking. Bit I find that after about 40 mins of the oven being 'Pizza Hot', the centre top of the outside does get a fair bit warm...not scolding hot (have no problems letting the kids touch the outhside of the render!) but you can feel the warmth through the render. I havent had any problems when slow cooking for 7 to 9 hours...the oven retains alot of heat. I emailed my supplier about the problem I was having and he said that if the oven still cooked well...he would be inclinded to leave it. He also said that you will get the top of the oven warm when cooking. He did offer to give me (for free mind you...really nice family business!!!) another ceramic blanket and enough render to do another coat.

The question I guess Im asking is do I really need to get more insulation if my oven is doing what I want it to??? I know I have seen pics on here of peoples WFO fully fired with snow not even melting off it...but one side of getting abit of warmth out of it is in winter with my patio enclosed, it would add some great warmth to the area. If I am going to do another blanket and render..I need to do it soon as I want to get the worktop tiled before the weather turns over here. So...what should I do??? I have attacthed a couple of pics to show what insulation was used.

Thanks....

Scott

[Les]

Re: Is more insulation required???

Hey Scott - more is always better. BUT, if the oven is doing what you want, sounds like you are golden. It's hard to tell from the pic's how thick the insulation is. What are you cooking?

Les...

[scottz]

Re: Is more insulation required???

Hi Les,
The blanket was a good 4 inches thick and also has 2 coats of render over it. We cook pizzas, roasts, slow cooked meals and have just started bread....and everything works the way it should.

[scottz]

Re: Is more insulation required???

Hi guys,
I have found the top of my oven to be way to hot for myself to be happy with it...so the people who made my kit rang me today to discuss options. I know it is in some other thread, but can anyone give me any advise on what the ratio is with a render mix with perlite through it as I think I am going to do one more coat to do the job. I will be adding Boncrete to the exsitising render and then doing a riversand render over the top. Just unsure what ratio render to perlite I should be using.

Thanks....

Scott Z

[lwood]

Re: Is more insulation required???

Can you estimate the temperature, on the hottest part, of the outside of your oven?

[scottz]

Re: Is more insulation required???

The hottest part would have to be the very centre/top of the oven. Its good for a while, then gets warm and after about 2 hours of constant Pizza Hot, you can leave you hand on for a max 1 - 2 seconds. The company that I bought the kit of have been fantastic, he is going to find out the best way to fix Perlite in with a final Render mix to add one last layer of insulation, thats why I was asking if anyone had any idea as to a ratio mix. The oven still cooks everything fine, even slow cooking...its just after a while it gets quite hot.

[texassourdough]

Re: Is more insulation required???

Hi Scott!

I put the blankets on mine, then three inches of pearlite/cement, then the render and I rarely see 110 except in the hot sun!. Only time I exceed that much is if the oven is wet (steam escaping heats it) and where the dome and chimney meet. I am suspicious that you have a small crack that is letting hot gases into the dome. This is not unusual (I think especially for kit ovens and mine is too) and seems to not be a problem. I wouldn't worry about it but would guess that a couple more inches of cement/perlite would resolve any concerns.

Good Luck!
Jay

[david s]

Re: Is more insulation required???

It takes a long time to purge the oven of moisture. New ovens perform better and better as this moisture is gradually expelled. Faster heat up and better heat retention. Moist insulation does not insulate well. hen the oven is dry it won't be as hot to touch on the outside. Maybe you just need to fire it lots to improve its performance.

[Neil2]

Re: Is more insulation required???

Put a small (1 inch diameter) vent thru the render in the top. The kind of thing you see in some soffits. You may be getting a steam build up.

[scottz]

Re: Is more insulation required???

Cheers David, and you may be right with what you have said and to be honest...I have never really thought about the fact that the oven may not be fully cured yet. I have used the oven maybe a dozen times since I put it together, and I know when I used it the other day...it was the longest I have had the WFO at 'Pizza Hot' temps, just over 2 1/2 hours straight! It just may be more hot moisture coming out. Will have to keep an eye on it before I go ahead and add anymore render or insulation. The oven is performing really well in terms of cooking. But thanks for that suggestion mate...will watch how it goes the next couple of times.

Scott

[david s]

Re: Is more insulation required???

Scott,
I notice that from your pics that you used a foil layer. From my experience I tried this also and found that it has the effect of locking moisture in and making it harder and slower to remove the water. Your oven also looks like it has no insulation under the floor. Is the concrete slab hot to touch underneath?

[scottz]

Re: Is more insulation required???

Hi David,
It has insulation board under the fire bricks, so there is no issue there. I fired up the oven last night and cooked some beer can chicken...also kept the fire going hard for a good couple of hours after I finshed to see if I can get some moisture out. But I think you guys just might be on the money with the whole not yet cured and trapped moisture idea. The foil blanket I used was part of the kit and needed to be installed prior to the insulation blanket. I am just going to have to keep firing it for another 12 times or so and see if it gets any better.....but like I have been saying, it still cooks very, very well!

[lwood]

Re: Is more insulation required???

Funny, I just went through the same thing. I have fired it maybe 12 times now and I think I finally got all the water out. The last time was the hottest and the outside dome was almost cool to the touch. Previously it would get very warm as you described.