Our Earth Oven Progresses Slowly

The next steps in our earth oven construction were to make the door (out of a beautiful old plank), repair a bit of damage caused by dampness, and then create a layer of insulation with bottles and cob mixed with straw. The bottles I picked up at the Stater Bros market recycling center (let's just say, 29 is not a wine drinking town). 
My 17 year old was enlisted to help, and it was a miserable job because the winds were gale strength, not kidding. We could barely get they hay mixed in, and had to hold the tarp down with large rocks. The weather is just crazy out here.
Now we have to put another layer of insulation on top. I'm hoping to use local clay for the last layer of cob.