Making a mold for the core

I want to make a mold for making rocket oven cores with air crete for Peter's  Van design.


I am curious where I can find more information about the molds made that have been tested.


I am trying to think thru the best way of making this, as a plywood form or if there is a better material / method.

Mart

Hi Mart;   I used 1/2" plywood on my core. I have seen plenty of photos of people using osb  board.  Its removable, so what ever you have on hand that is strong enough should be fine.

Thanks for the reply.

I think then starting with a rectangular box then cutting a foam filler to go inside would do the trick?

As I look at this, I am wondering about doing multiple pours to get the shape.     Hmm perhaps putting the rectangular box on end might be better.

Hi Mart,

I am just curious what you are going to do to the aircrete so that it will survive the 2000+ deg F temperatures in parts of the stove.  I have looked at using aircrete in some concetual designs but have not yet overcome that obstacle.  Thanks.

Ralph Kettell wrote:Hi Mart,

I am just curious what you are going to do to the aircrete so that it will survive the 2000+ deg F temperatures in parts of the stove.  I have looked at using aircrete in some concetual designs but have not yet overcome that obstacle.  Thanks.

I have 3 options as I look at, my first is to use ceramic fiber for both the chimney and the interior, I have found I can mold the ceramic fiber when combined with sodium silicate and water and it holds its form.

The second is to make the form to use firebrick inside the mold, using the mold so that the interior is firebrick the outer shell is aircrete.


The third is I have bought a refractory mix from "The Honey Do carpenter" off Etsy that he has found to work with his rocket stoves.


I have bought extra material, and my initial results with the ceramic fiber shows me that  my first plan should work just fine,     I do not plan on putting this in my home, but for an outside oven use so  I am prepared if this does not work, but all of my research tells me that I am moving in the right direction.      

I think I will make a few chimneys with the different mixtures and test them, I let the results direct my path.


Cheers,

Mart

Hi Mart,

Did you buy a foam mate from him? Are you going to support his kickstarter?  We should probably take this private.  I had some ideas and I wanted to run something pay him as an additional business op and he never even emailed me back.

Mart Hale wrote:
I want to make a mold for making rocket oven cores with air crete for Peter's  Van design.
I am curious where I can find more information about the molds made that have been tested.

Hi Mart,
All my casted experiments were done in a coated plywood or white melamine MDF box. All the sculpting was done with extruded polystyrene foam, made to size and shape with a table saw and smoothed by hand.

The foam parts were glued into place using double-sided adhesive tape, the kind that is used for fixing carpet edges to the floor. Any crack was sealed using acrylate sealant so no cement water leaked behind the foam parts. In fact, the pictured core is done like that.

Peter van den Berg wrote:

Mart Hale wrote:
I want to make a mold for making rocket oven cores with air crete for Peter's  Van design.
I am curious where I can find more information about the molds made that have been tested.

Hi Mart,
All my casted experiments were done in a coated plywood or white melamine MDF box. All the sculpting was done with extruded polystyrene foam, made to size and shape with a table saw and smoothed by hand.

The foam parts were glued into place using double-sided adhesive tape, the kind that is used for fixing carpet edges to the floor. Any crack was sealed using acrylate sealant so no cement water leaked behind the foam parts. In fact, the pictured core is done like that.

Thank you Peter!

Ralph Kettell wrote:Hi Mart,

Did you buy a foam mate from him? Are you going to support his kickstarter?  We should probably take this private.  I had some ideas and I wanted to run something pay him as an additional business op and he never even emailed me back.

I bought his plans for his small foam mate which I am up-scaling to be a larger one.

Feel free to private message me.

What I am doing is highly experimental, so I hate anyone to follow in my untested footsteps ;-)       In the tech industry we called this bleeding edge technology as you often made mistakes
along the way.