pompeii oven construction began today

[paulages]

well, i couldn't find low duty firebricks, but the medium duty bricks i did find have a fairly low silicon/alumina ratio. the guy ended up giving me a great deal on 2.5" x 9" x 6". he had a palette of 90 that had been sitting around for years, so it worked out well for both of us.
cut in half, this will just mean 6" walls instead of 4.5". and it also means fewer seams in the oven floor.
he also has a great selection of archway firebricks in the same grade, which will make the archway much easier.

[james]

Paul,

I would think about pointing the 41/2" edge out, and the 6" edge in. That would give you a 4 1/2" thick dome, and the possibility to doing a little more cutting to make the 6" inward sides fit better. I'm a little concerned that 6" will impact heat up time.

Most refractory residential ovens are 2"-3" and commercial ovens are about 4"-5" thick, and they are fired 365 days/yr. Heating up a 6" oven from a standing start might take longer than you would like.

Food for thought.

James

[paulages]

i have thought about facing the 6" side in. it makes for less of a graceful curve, and means that the next course would intersect it less smoothly. i'll try laying a few up though, and see.
i was afraid 6" thickness might create too much thermal mass. these bricks were cheap enough that, though it would be extra effort, i could whack 2" off of the back of each one with a brick cutting chisel, and still get both. i won't be using these bricks for the whole oven.

[paulages]

first cut at 7:45 pm


8:13 pm

8:30 pm

45 minutes from start to finish! so much for this taking forever to do. it was incredibly easy! i rented a paver saw from home despot. it did cost $37 for 4 hours, but i used it to cut all of my 9"x6" bricks to size as well.
if anyone is interested, i can post pictures of how to make these cuts, but it's really not so hard to figure out if you haven't done it before.

[paulages]

unfortunately, now i have to take it apart, apply the dry mortar and reassemble.

[james]

Very impressive!

James

[james]

Paul,
This just reminded me a of story. There is a science museum in Florence along the river, where they had to replace the gas lines under the road at the entry. It's too nice a museum for an ordinary poured concrete entry, so they designed a beautiful curb, sidewalk and entry out of locally quarried cut stone. Really nice. I've been watching them put it in, one stone at a time for over a year now. Each piece of stone is cut off site somewhere, then numbered and delivered. The builders look at the plans, then find the right numbered stone, and put it in and tap it to level. Beautiful, and slow.

Don't forget to number your bricks. :-)

James

[paulages]

yeah, actually i just read a book on stonework (to prepare me for the veneering--something i've never done), in which there was much info on restoring old stonework. there were many cases of entire stone structures being deconstructed, mapped, numbered and photographed along the way. this and your story makes my task seem simple.
the only tricky part is that i never really settled on a specific pattern for the brick, but rather aimed for a combination of having no continous seams crossing the direction in which tools will be entering from, and not wasting too much brick on the cut edges. i had very little waste, especially considering that some of the cutoffs were big enough to be dome pieces, and others may be keystone candidates.

[paulages]

amidst the deafening sounds and veil of smoke from all of the 4th of july fireworks last night (you know, it always seems ironic to me how chaotic and warzone-like the fourth of july feels here), i reassembled my floor upon it's fireclay slip pan.
it was harder than i thougth to get all of the seams perfect. i think i made my dry mortar mix a little too stiff. then again, i might have been being to anal. i know how hard it can be to scrape ashes even off of a one or two-piece stone, so i really didn't want anything for my tools to catch on. all of the seams heading into the oven (as in pizza tool direction) are perfect, but there are a few others not quite perfect. i might try taking a grinder to the seams to smooth them out perfect.
off to the brick supplier to get my archway bricks and the rest of the dome bricks...

question:
should the first chain of wall bricks sit upon a slip pan also? i tried this, and it seemed less stable. maybe straight on the hearth, and just fill the bottom 1/2 in. or so of each space between them with the dry mortar mix? or should i just set them on the hearth and proceed with the regular refractory mortar?

[ColonelCorn76]

Just stand them on the hearth bricks and mortar the outside down to the concrete hearth.

Jim