Post by mintcake on May 22, 2014 12:35:25 GMT -8
Hi all,
I know it's been said that it can't be done, but I'm having another go anyway.
I really don't want my curious 3 year old poking fingers/sticks into the fire through the front air opening, and nor do I want ash falling out of it when I add extra wood. Maybe I'm just not being careful enough, but it's happened too many times.
To make version 1, I partly cut the front and rear half of the side out of 2 pieces of rectangular pipe, These partly detatched portions I then bent up cut, twisted to 45° and welded to the other piece of pipe. Hey presto: lots of louvres, giving up-and-back airflow.
The left hand pipe sent air (mainly) to the back of the fire, the right hand to the front of the fire. Each side was 10% CSA, so I had 20% in total for primary air. I didn't segregate the air supplies, hoping that way that ash build-up wouldn't cut the air too much.
This Mk1 grate worked for a while on my test stove, but the louvres were too close and there wasn't enough space for the ash to drop out of the way, so eventually it started smoking until I let more air in. It was certainly easier to light than in the normal front-air configuration, and there was no path for the ash to drop out at the front at all.
I've just about finished building my mk2 grate. It has proved a lot harder to make, because
I've chosen a different technique to make the grill and I can't weld very well. I've increased the louvre spacing, I now have added vertical divisions so the air goes exactly where I want now. The left hand pipe (10% CSA) supplies the rear 2/5 of the fire from below, the right the front 2/5 from below, and I have a central gap of 20% CSA which is directed to provide front air above the grate. I thus have an over-supply of air ( theoretically 40%CSA before I get blockages), just in case it's needed, but I expect that I'll not need to ever have all 3 ports fully. (I've made sliding doors to select the air flow).
The divisions in the grate are matched by divisions in the ash-tray, and I hope I've made it
precisely enough that there are only a few mm2 of gap for air to go through another route.
I'll let you know how it works. My hope is that with the ability to choose from bottom or front air or a mixture of both then I'll have a good way to get it lit and stay lit, burn beautifully and not have ash falling out either.
Test burn tomorrow or Saturday if all goes to plan.
Sorry, no instrumentation so all I'll be able to tell you is how much smoke there is.
I know it's been said that it can't be done, but I'm having another go anyway.
I really don't want my curious 3 year old poking fingers/sticks into the fire through the front air opening, and nor do I want ash falling out of it when I add extra wood. Maybe I'm just not being careful enough, but it's happened too many times.
To make version 1, I partly cut the front and rear half of the side out of 2 pieces of rectangular pipe, These partly detatched portions I then bent up cut, twisted to 45° and welded to the other piece of pipe. Hey presto: lots of louvres, giving up-and-back airflow.
The left hand pipe sent air (mainly) to the back of the fire, the right hand to the front of the fire. Each side was 10% CSA, so I had 20% in total for primary air. I didn't segregate the air supplies, hoping that way that ash build-up wouldn't cut the air too much.
This Mk1 grate worked for a while on my test stove, but the louvres were too close and there wasn't enough space for the ash to drop out of the way, so eventually it started smoking until I let more air in. It was certainly easier to light than in the normal front-air configuration, and there was no path for the ash to drop out at the front at all.
I've just about finished building my mk2 grate. It has proved a lot harder to make, because
I've chosen a different technique to make the grill and I can't weld very well. I've increased the louvre spacing, I now have added vertical divisions so the air goes exactly where I want now. The left hand pipe (10% CSA) supplies the rear 2/5 of the fire from below, the right the front 2/5 from below, and I have a central gap of 20% CSA which is directed to provide front air above the grate. I thus have an over-supply of air ( theoretically 40%CSA before I get blockages), just in case it's needed, but I expect that I'll not need to ever have all 3 ports fully. (I've made sliding doors to select the air flow).
The divisions in the grate are matched by divisions in the ash-tray, and I hope I've made it
precisely enough that there are only a few mm2 of gap for air to go through another route.
I'll let you know how it works. My hope is that with the ability to choose from bottom or front air or a mixture of both then I'll have a good way to get it lit and stay lit, burn beautifully and not have ash falling out either.
Test burn tomorrow or Saturday if all goes to plan.
Sorry, no instrumentation so all I'll be able to tell you is how much smoke there is.
