Oven Building Course

The Oven at the Sustainability Centre

You'll be making one of these.

Last year I ran a one day clay oven building course at the Petersfield Sustainability Centre which is near my home in Hampshire, UK.  About 20 people turned-up on a beautiful, sunny, summers day and, under my supervision, constructed a clay oven like the one featured on this blog. The Sustainability Centre have their own, permanent oven on site, so for lunch all the participants made and cooked their own pizzas.  A fabulous day was had by all (even though I do say so myself!).

 

I’m pleased to say that I am running the course again this year on Saturday 18th June (2011).  If you’d like to come along, you can find more details on the Sustainability Centre’s website.  Here’s the link:

http://www.sustainability-centre.org/courses_adult_detail.php?id=30

Maybe I’ll see you in June?

Simon

Sticky or dry?

Clay Powder*

A question that I commonly get asked on the clay oven blog relates to the process of mixing the clay:sand mixture used to build these ovens.  I learnt how to prepare this mixture by using wet clay and mixing it into the sand using an old fashioned technique called puddling (I believe the Roman’s used this same technique for mixing material for their villa floors – they used things like dung, soil and cows blood though!!).

You will find a post on how this is done here:

https://clayoven.wordpress.com/2008/09/04/3-the-clay-sand-mixture-and-puddling-technique/

Puddling is effective but rather laborious and time consuming. Many suggestions have been made by visitors to this blog from using cement mixers to industrial hand “blenders”.  The problem is that clay and sand don’t really like to mix unless they are ground together using the puddling technique.

One commenter suggested drying out the clay first, grinding it and then adding it to dry sand and water in a cement mixer.  Technically a potentially useful solution but in practice, drying and grinding clay to powder would be a nightmare and would likely take much longer than getting your feet dirty, puddling.

This week I have had a few conversations with blog visitors Steve O’Conner and Dori who inform me that one can purchase bags of dry, powdered clay.  Dori said:

“Ive actually used the powdered stuff to build my oven – bags of FireClay (which was also called mortar clay in my store). We first did the tarp and dance method where we poured all of our ingredients on a tarp and stomped on them, but eventually used a cement mixer which was much faster. What ive learned from the powdered stuff is that you need a MUCH higher ratio of sand:clay then the lumpy stuff. Pure clay in powdered form shrinks quite a bit. Other then that, it has worked just fine for me.”

Well I never knew this but it sounds like a great alternative to puddling to me!  I will try some experiments later in the year to see what ratios one needs exactly.

In the mean time, if you try it out, please be sure to share the details on here.  Thanks for the info chaps!

Simon

*Image taken from http://www.starwest-botanicals.com/images/D/210106-51.jpg