The plan was to use clay, I started using brick today. Paul's 36"er

[Paul150]

Re: The plan was to use clay, I started using brick today. Paul's 36"er

I started my third fire and as I was pondering my next move I noticed cracks. Once the dome got up to 500 inside, I checked the heat over the cracks and it was no different than the rest of the outside, around 130.

Is there anything I could or should do?

[david s]

Re: The plan was to use clay, I started using brick today. Paul's 36"er

Well I got a break in the rain and was able to fire it up for another fire. 350- 400 on the dome and 200 - 250 on the sides. I know I have some clean up and filling to do. However I just ordered from amazon tipo 00. It is hard to wait.

The huge difference in dome and side temperature means different expansion rates. you have double the temperature difference, you're going at it too hard. As the dome gets hotter (heat rising) it dries the top of the dome out and the temperature rockets away there leaving the sides and base still cool and wet. Try to keep the fires low with no flame impingement on the dome. Reading the curing thread will help you. If you don't mind cracks through the dome ignore this advice and forge ahead the oven will still work. ok.

[Paul150]

Re: The plan was to use clay, I started using brick today. Paul's 36"er

I have been looking for the curing thread for a few days now and cannot find it. Is there somthing else I should use to search with besides curing or can someone provide a link please?

[david s]

Re: The plan was to use clay, I started using brick today. Paul's 36"er

Start here.

http://www.fornobravo.com/forum/f16/....html#post3869

[Paul150]

Re: The plan was to use clay, I started using brick today. Paul's 36"er

Thanks David. The word curing shows up in just about every thread.

[Paul150]

Re: The plan was to use clay, I started using brick today. Paul's 36"er

Hey, when the time comes for me to insulate (blankets and vermicrete) can I continue to use it, like the next day? Or do I need to wait or ?

[david s]

Re: The plan was to use clay, I started using brick today. Paul's 36"er

The vermicrete layer only serves to get a firm substrate to render against, it also evens out the bumps and lumps left by the blanket and provides additional insulation. Therefore it's not strength you're after. Let it set for 24 hrs and then start your gentle fires. I use 10:1 over the dome as I find that's about as lean as you can go without making application really difficult. I also add a handful of powdered clay for every litre of cement, it helps make the mix stick together better.

[Paul150]

Re: The plan was to use clay, I started using brick today. Paul's 36"er

It has been a while since I posted. Honey do lists again. I put on my 8lb fire blanket 2 - 3" then vermicrete, 8/1. Did it in layers using a thin board and cardboard with bungies as forms. 3" to 6". so I have insulation from 5" around the bottom, 6 inches up, up to 9 inches the rest of the way. At positions 10 and 2, I am sure it is thicker than that. Tomorrow I am back to applying rock. Used a 11 foot umbrella from Sam's to cover it from the rain and let it breath at the same time.

Comments please?

[david s]

Re: The plan was to use clay, I started using brick today. Paul's 36"er

A 6" thick layer of vermicrete is very thick and you can calculate how much water is in there because a third of the vermiculite volume will be water. The outside will go white after about a week, but underneath it will still be quite wet. You don't say how long ago it was applied, but the water is best removed before covering it over. Sun and wind will do a good job of drying the stuff, dependent on weather conditions, but I like to start firing and drying it out completely before adding the outer shell. Are you doing an igloo or enclosure? Attached doc shows how slow vermicrete is to dry, it refers to underfloor vermicrete but also applies to over the dome too.