K79 Oven Build

[K79]

Re: K79 Oven Build

Starting to come up with my decorative arch design. The stone in this picture is what my wife and I picked out. I'm thinking of making the decorative arch out of standard brick with the keystone being a piece of granite with an L engraved in it. Something like this photo.

[stonecutter]

Re: K79 Oven Build

Is the chicken wire used to hold down the fiber blanket just there to keep it in place while the enclosure is built or is it there to keep it tight up against the dome. I'll be burrying my dome and fiber blanket in vermiculite once the enclosure is built.

No biggie if it doesn't contact the dome completely...air space is a good insulator.

[Gulf]

Re: K79 Oven Build

Is the chicken wire used to hold down the fiber blanket just there to keep it in place while the enclosure is built or is it there to keep it tight up against the dome. I'll be burrying my dome and fiber blanket in vermiculite once the enclosure is built.

From my experience the fiber blanket seems to hold firm and stay in place where it is placed. I included chicken wire on my dome in hopes of keeping some of the weight of the vermicrete from compressing the blanket. If you are back filling with dry vermiculite, it may not be needed.

[K79]

Re: K79 Oven Build

Is the chicken wire used to hold down the fiber blanket just there to keep it in place while the enclosure is built or is it there to keep it tight up against the dome. I'll be burrying my dome and fiber blanket in vermiculite once the enclosure is built.

[K79]

Re: K79 Oven Build

Anchor plate is on. Bolted down and mortar on.

[boerwarrior]

Re: K79 Oven Build

You've got us newbies curious now - you're going have to tell us what the curing method is " that shall not be discussed" !!

[Gulf]

Re: K79 Oven Build

Thank's David,
The Heat Bead Method does work great! And to coin a term from my "oil patch" years is "worm proof" (worm is = but not greater than novice )
About the latter mentioned method. I had the equipment and the means to try this. But, not all of the safety features, nor the blls try it

[david s]

Re: K79 Oven Build

Yes, I totally agree Gulf. I've been using heat beads for years because they don't flame up like wood to give you that out of control fire. Use some small wood in addition to the heat beads. For some reason FB state that their warranty is void if owners use coal or charcoal, maybe too hot. The heat beads in Australia are made from brown coal and I think burn a bit more gently. Brickettes is another name for this fuel.
I've built close on 100 ovens so have driven the water out of plenty. Just when the thing starts to dry a bit, so does the fire want to start raging. Be careful this is a danger point. Go slow until that persistent ring of black around the base disappears.

There is another method I sometimes use which is safer for the oven, but potentially more dangerous for the operator, however we are banned from discussing it.

[Gulf]

Re: K79 Oven Build

An alternative, which I don't think is in the curing section would be KD's Heat Bead method. That would be" charcoal" here in the states. I used a blast/smoking door with thermometer and a damper in the flu/U][/B] to help control the temps. I think that partially restricting and adjusting the exit of the flu with some temporary placement of brick or other non combustible would work for those who do not have a damper. It takes a little work, but it keeps the danger of direct flame impingement, uneven heating,and the natural urge to ramp up the fire , to a minimum .

[david s]

Re: K79 Oven Build

Saying maintain a 300F temp is a bit misleading, because it depends on how you are measuring the temp and where you are taking the readings. An IR will only give you the surface temp and the crown of the dome will be way hotter than the walls at base. Likewise an air temp thermometer will read lower at floor level. I prefer to use an air temp thermometer at floor level. Try to avoid flame impingement on the dome for early fires.

[boerwarrior]

Re: K79 Oven Build

The FB Plans (version 2) state this:

Day 1. Maintain a fire temperature of 300?F throughout the
day and as long as possible into the evening. If you cannot
continually run a 300?F for at least six hours, repeat step 1
for a second day before moving on to Day 2.

But I would go with David S's suggestion. I don't think it hurts to be very conservative when curing!

[david s]

Re: K79 Oven Build

only about an hour or two.. i know that is less than recommended but I figured it wouldn't hurt to start drying it out slowly. I'm also lucky because is has rained here only once in the last 3 months and the relative humidity is generally under 40% all summer.

That's way too much for the first few fires IMO. Start the first one for about 15 mins, then increase daily. Allowing the oven to even out in temp between fires reduces the huge temp difference between the top and bottom of the dome each time. The top of the dome dries first and so will heat up again so much faster which exacerbates the temperature difference and hence the uneven expansion.

[boerwarrior]

Re: K79 Oven Build

only about an hour or two.. i know that is less than recommended but I figured it wouldn't hurt to start drying it out slowly. I'm also lucky because is has rained here only once in the last 3 months and the relative humidity is generally under 40% all summer.

[K79]

Re: K79 Oven Build

K79

I found it hard to keep the oven at a particular temperature - so I based it mostly off the amount of wood. For the first few fires I burnt only kindling - then started progressively adding some bigger logs until about Day 12 when I then fired it up all the way and cleared the dome for the first time. I'm not saying this is the best way but it worked for me!

How long did you hold your first few fires?

[boerwarrior]

Re: K79 Oven Build

K79

I found it hard to keep the oven at a particular temperature - so I based it mostly off the amount of wood. For the first few fires I burnt only kindling - then started progressively adding some bigger logs until about Day 12 when I then fired it up all the way and cleared the dome for the first time. I'm not saying this is the best way but it worked for me!