|
Post by downunderdave on Mar 28, 2016 21:24:20 GMT
Yes, Stuart but cover it if it looks like raining.
|
|
|
Post by lovepizza on Apr 7, 2016 4:31:09 GMT
Hi all, Heres an update form Cambridge. Yesterday, the weather was shall we say, changeable! However I have made some good progress since the vermiculite base layer went down so I thought I would share...
Here is the first pic with board on. I layed it on a 6mm bed of builders sand over a 75mm layer of vermicrete to ensure level and solid.
|
|
|
Post by lovepizza on Apr 7, 2016 4:34:24 GMT
Hi all, Heres an update form Cambridge. Yesterday, the weather was shall we say, changeable! However I have made some good progress since the vermiculite base layer went down so I thought I would share... Here is the first pic with board on. I layed it on a 6mm bed of builders sand over the 75mmm vermicrete layer to ensure level and solid. Sorry, all of my photos are on their side....don't know what s going on..
|
|
|
Post by lovepizza on Apr 7, 2016 4:52:20 GMT
Here is the next pic with the fire brick installed, very snugly!! Bricks at the back will not be subject to intense heat, they will hold the insulation layer only.
|
|
|
Post by lovepizza on Apr 7, 2016 4:59:28 GMT
1/2 brick Inner arch (for door to butt up against) and sand former ready to go. It was far too windy to attach the paper, so will keep it moist under tarpaulin and start again at weekend with newspaper on inner clay layer.. A quick question...When I do the clay layer, should I leave a small gap between the oven layer and the inner arch to allow for expansion/avoid cracks ? Some cardboard that will burn out or when fired then fill with something perhaps or is this not necessary?
|
|
|
Post by downunderdave on Apr 7, 2016 7:26:09 GMT
If I were doing it your way i'd use two layers (around 8 mm) of corrugated cardboard between the cob and the bricks, remove it as soon as the dome is built, then fill the gap with 7:1 vermiculite, cement mix. Then remove all of the sand so the dome can shrink without too much cracking.
|
|
|
Post by lovepizza on Apr 8, 2016 4:59:38 GMT
Thanks for the response Dave.
Would you have done this differently? I know the traditional way is to form the dome, cut the door then butt up the arch and cover in the gaps. I thought by making the inner oven a single piece would improve overall strength.
So will the 7:1 Vermiculte mix stay flexible to cater for expansion and contraction when getting hot and cooling down?
Regards
Stuart
|
|
|
Post by downunderdave on Apr 8, 2016 6:28:58 GMT
Thanks for the response Dave. Would you have done this differently? I know the traditional way is to form the dome, cut the door then butt up the arch and cover in the gaps. I thought by making the inner oven a single piece would improve overall strength. So will the 7:1 Vermiculte mix stay flexible to cater for expansion and contraction when getting hot and cooling down? Regards Stuart Your plan is ok it's just easier to plug the gap with the vermicrete before removing the sand because it won't fall right through the gap so easily. 7:1 vermicrete should stay somewhat flexible enough.
|
|
|
Post by downunderdave on Apr 8, 2016 6:33:45 GMT
Downunderdave...I have managed to reduce my vermiculite bed to 75mm by putting another brick course on the inner plinth. Concrete slab now on, will be putting the vermiculite bed on tomorrow evening......Progress! This will now reduce the drying time. Would you say 2 weeks to dry prior to laying the board and fire bricks (weather dependent)? Stuart Stuart, here on attachment is an experiment I did with drying a vermicrete slab. It may help you. You do not have to wait until the vermicrete is totally dry before building over it, but it takes way longer and more fuel to eliminate the water if you don't. Two weeks sounds reasonable. Vermicrete insulating slab copy.doc.zip (73.2 KB)
|
|
|
Post by lovepizza on Apr 10, 2016 19:51:16 GMT
looks good doesn't it........2 hours later I ripped it down as the doorway dropped and cracked badly. I suspect I didn't leave enough drying time before removing the sand former. Lesson learned....be patient!!! Can the sand stay in overnight (covered with a tarpaulin) without causing issues? I have now out the clay in polythene bags. Will it stay moist for a couple of days whilst I work up the enthusiasm to again??
|
|
|
Post by lovepizza on Apr 13, 2016 7:31:23 GMT
Ok, an update.. Rebuilt the sand former and inner clay oven...This time I kept it under a tarp all night. Today should be a good drying day so will probably start to excavate the sand during lunch break. I might even dig out a little sand at the front and light a small fire to putt a crust on the opening wall....Wish me luck! Photo below (I have also keyed up the exterior to accept the vermiculite insulation coat once totally dry and fired)
|
|
|
Post by lovepizza on Apr 13, 2016 16:39:46 GMT
Success!!!!!!!!!!! Little tea lights inside just to give it a little gentle encouragement!
|
|
|
Post by lovepizza on Apr 18, 2016 18:52:11 GMT
Did the first firing. I think I overdid it because I got a big crack in the opening where the smoke was pouring out. I scraped it out a bit and filled it whilst it was still warm. i will give it another firing tomorrow. The top of the dome I think Is dry now, just the bottom third to go!
|
|
|
Post by lovepizza on Apr 18, 2016 18:55:53 GMT
..........One thing I forgot to mention, the inner arch (pictured in last post) did not last the firing. It stayed in one piece but didn't stay fixed to the hearth. I am using home brew for this 4:1:1:1. Is that right? The arch is being fixed to fire bricks, should I key the fire bricks up first or something? Any advice guys & girls?
|
|
|
Post by lovepizza on Apr 25, 2016 19:05:27 GMT
Bump..
|
|