Top lessons learned

[Yahoo-Archive]

We have a had a number of new members sign up for the group recently,
and I was hoping that the experienced builders could share their top
two or three lessons learned from their experience. It could prove
helpful to both prefabricated oven builders and Pompeii builders.

Thanks.
James

[Yahoo-Archive]

1) We aren't building spaceships, so relax.
2) Reduce the thermal mass in the hearth (see my previous posts on the
most efficient thickness/volume).
3) Thermocouples are nice for research but near useless for cooking.
4) Plan to take as long to finish it (housing, etc) as you do for the
entire foundation-thru-oven-proper section (you can cook in it when
you've only gotten 1/2 the work done...sometimes this will encourage
you to defer the 2nd half of the work - I've a friend who hasn't done
anything on his after he was able to cook...no housing, no insulation,
no nothing...just cooking every week)
5) Cook more than pizza & bread...this is very versatile so branch out.
6) See #1

Jim

[Yahoo-Archive]

Hello, just responding to Jim's top lessons learned
with a few additional questions.

For the Pompeii oven:

Is the thermal mass in the plans what you used or are
you saying reduce the amount specified, if so, by how
much?

Is the housing and insulation necessary if you don't
need it to cook? Is it just for looks or a must?
Remember I'm in Ohio, it's frickin cold and snowy all
winter.

My husband, who is an engineer, was wondering if there
are more specific plans and drawings anywhere. He's
going to take a closer look at the plans but is
looking for more details. I reminded him about the
spaceships but he's more comfortable with a new
project with detailed plans.

Thanks, we are to begin when the weather breaks, can't
wait!

Elizabeth

[Yahoo-Archive]

things i am absolutely certain of:

1. forget the ash slot.
2.*circular is better for pizza and roasting. bigger is better too*(mine is 42 inches in diameter).
3. buy a tile saw (under $100 at home depot) and an angle grinder (under $100 at costco).
4. don't try to mix*vast amounts of concrete in a wheelbarrow; rent a mixer.
5. use perlite and not vermiculite. it seems to hold together better and its real easy to tell when the cement is mixed in (perlite is white. vermiculite is the same color as cement).*

things i'm pretty sure about:

1. for insulation, increase the amount of cement used in the perlite. using the "published" ratios seems to create a material with the strength and consistancy of an oatmeal cookie. run some test batches with different ratios to see.
2. plan on leaving the plywood*support under the perlite layer in place. it holds up the perlite layer and you don't have to worry about the perlite crumbling away. by the way, you can get a little over 1/12th of a cord under the oven.*
3. use the angle grinder to remove any uneven brick edges on the hearth that might catch the edge of the peel.
4. the best mortar seems to be the mortar i mixed myself (instead of sacked pre-mixed).

things i think, but i'm not too sure about:

1. (if you have courage and faith) when finishing the very top rows of the oven, instead of driving yourself nuts making a gazillion cuts in firebrick, simply stack up some bricks and wood in the center of the oven, until they reach the bottom of the opening (at the top of the oven) and then place cardboard or wood on top of that stack of materials. then use modeling clay to seal any*gaps. then*pour a "plug"*as the final "cap". for my plug i used repair mortar mixed with crushed firebrick to create a concrete like mixture. my plug was about 6 inches in diameter. i've done 4 months*of cooking now at the rate of 3 to*4 fires per week and the plug seems to be holding up with no problems but i can't guarantee*how long it will last. i used repair mortar because it had alumina (in addition to silica) in it and i read somewhere that alumina based cements*retained strength better under heat.*

things i did which were a matter of personal taste.

1. i have a "removable chimney". i have an 8 " duct pipe that i slip into a slot on the top of the vent. this renders the need for a door moot. when i want to seal the oven, i just take the chimney off and seal off the top with a big*aluminum dustpan and a brick for weight. i then rest a piece of backerboard against the front opening of the oven and hold*the backerboard*up with another brick, viola... both holes sealed. downside is that the chimney blows off in high winds (onto my head in one case) but i plan to fix this by making my chimney slot deeper (and perhaps putting a fastening device in).

Robert

[Yahoo-Archive]

let me add one more to my absolutely certain list:

do not mortar the walls (mortar only*the bed) of the oven stand base. dry stack the walls and use "quikrete" quikwall surface bonding cement instead. (available at lowes in my area). <http://www.quikrete.com/catalog/QUIKWALLSurface-BondingCement.html>http://www.quikrete.com/catalog/QUIK...ingCement.html

[Yahoo-Archive]

I definitely agree with this one. I think back to my first oven, and how much time and mental energy went into just the stand. On my last oven, I dry-stacked the blocks, and flew through it. Your oven will never know the difference.
James

[DavidK]

I'll add one; Laying the hearth.

Make sure to sift the fire clay when making the hearth bedding, and use fine sand (play sand works great). A kitchen sifter works great to remove the larger clumps that keep you from getting the floor level and even. Also, soak the bricks for a few minutes, then allow them to dry slightly before setting them. That will keep them from wicking all the moisture from the bedding before you've had a chance to beat them down evenly... Oh, and instead of leaving wood underneath to keep the pearlcrete together, just apply a skim coat of surface bonding mortar. That stuff is GREAT!

[Fio]

Do not rent a brick saw, BUY one

I coud have rented a wet cut diamond saw for $80 for ONE DAY.

Instead, I bought a cheap 14" abrasive chop saw from Harbor Freight. It was half price at $50, with five abrasive wheels, the cost was about $75.

It would have been a bargain at twice the price. It held out through the entire process, and is STILL WORKING.