Vegas Pompeii getting off the ground

[cvcrash]

First of all thanks to all for the great inspiration throughout this forum.

Finally got started and really happy to be so close to playing with some bricks. This is going to be about a 42" diameter oven. All of the planning and measurements have come from the forum so please prep me with some questions.

Anyone have an indispensible tool for sale?

[Lburou]

Re: Vegas Pompeii getting off the ground

Your stand and hearth look real good. I like your thinking outside the box with the oven on a 45 degree angle too.

[exceloven]

Re: Vegas Pompeii getting off the ground

Crash,
Congrats on the start. I can tell by your hearth that yours will be a very clean build. I did the same as you careful planning before starting. Keep up the good work and enjoy the results!

Mark

[brickie in oz]

Re: Vegas Pompeii getting off the ground

I was expecting flashing lights and dancing girls....

[azatty]

Re: Vegas Pompeii getting off the ground

I was expecting flashing lights and dancing girls....

Wait until the first pizza bake....

[C5dad]

Re: Vegas Pompeii getting off the ground

CVCrash,

I do not have an indespenible tool. Best thing to do is to just build one - cut and paste this into google

site:Forno Bravo Forum: The Wood-Fired Oven Community - The Pizza Oven Installation and Cooking Community "indespsnsible tool"

and that will bring up links.

Keep up the brickin!

[azpizzanut]

Re: Vegas Pompeii getting off the ground

Hi CVCrash,

An indispensable tool is easy to make after you've seen a photo or diagram of one and understand how it works. I made mine from a door hinge, a length of 1" square oak, some 1/4" x 20 all-thread rod, a piece of aluminum sheet from a sign and a second piece of oak board for the lip of the device. You may already have 1/4" x 20 nuts and a couple suitable screws for assembly. It's nothing more than a gauge to keep the inner measurement of the dome bricks consistent. It doesn't have to be fancy, no welding or clamps or mystery to it. Mine does adjust longer or shorter because of the threaded rod but it isn't necessary. It is set at 18" which is the size it needed to be.

You will need to mount the tool in the center of a board placed in the center of the oven. My "board" is a piece of 1" styrofoam insulation with a 4" block of wood glued into the center. I used a wooden yardstick with a nail in one end and a hole at the 18" mark and drew a 36" circle. The block of wood provided a place to hold a pivot bolt for the hinge. I put a matching piece of corrugated cardboard over the styrofoam. I just used the materials at hand for both the indispensable tool and the center mount and didn't have to buy anything. Other folks use plywood pieces. Whatever you choose, just be sure you can remove it from inside the oven when construction is done.

Credit goes to a former member for sharing this "indispensable" device with us. He's gone now but his legacy lives on. Search for posts by "Hendo".

Cheers,

[cvcrash]

Re: Vegas Pompeii getting off the ground

thanks Bob and all... i see what your saying about the tool and a door hinge it will be. i also have a piece of plywood that i used for a floor template that i plan on cutting to protect the oven floor durring construction.

got the bricks this weekend and a saw.

Did not worry too much about cutting the bricks for the oven floor, I plan on laying the forst course on top of the floor.

Any reccomendations on cutting the bricks for the first course? i plan on laying half bricks down on their side with the factory edge facing in the dome. I have seen some cut the bricks on an angle for this course and was wondering if that would be worth it to reduce the amount of mortar used.

would like to get the first course and first couple bricks on the inner arch done next.

[azpizzanut]

Re: Vegas Pompeii getting off the ground

Hello CVCrash,

You can start the first course in several different ways according to the Pompeii plans. Mine is half bricks standing on the narrow edge, soldier style, 4 1/2" tall. The next course is flat against the top of that row and the third row begins the taper. Some lay half bricks flat for a couple rows and others stand full size bricks on the narrow edge, same as mine, except 9" tall. You may want the first couple rows without inward taper so you can fit cooking pots close to the side without contacting the tapered side of the dome. There is no right or wrong way to start. The joints on the first course are narrow compared to the other courses. Taper the bricks if you want but if you stand the bricks on the narrow edge then you won't have big gaps to fill.

You will have fun planning the bricks so you don't get joints lining up. You have the saw close by so if you find your brick lines up with the joint below it then you can trim an inch or so and then mortar it in place. The joint lines don't matter so much on the first and second courses but you will want to stagger the joints in the remaining courses to help prevent long cracks and promote strength. I cut a few bricks into thirds so I would have some handy. Eventually you will find you need to custom cut a brick to fit and to make a key. Your big saw will make quick work if it.

I'm using the "Poor Mans Mortar" recipe and bought enough Portland cement, fire clay, fine sand and lime to build a couple of ovens. If you buy bags of refractory mortar then I can understand why you might want to taper your bricks to save mortar and $ but since I mix small batches and have lots of materials at hand I don't worry about it. One thing for sure, there is lots of mortar in my oven.

I soak my bricks pretty good before putting them in place. Since you also live in a dry desert region you may find the mortar begins to set too fast and you aren't quite ready to move on to another brick. Be sure to wet the bricks below the one you are working with since they always seem thirsty and will suck water from the mortar. If that happens, just remove the brick, wash it off, remove the dead mortar, put on some fresh and continue.

Cheers,

[cvcrash]

Re: Vegas Pompeii getting off the ground

Thanks Bob...

what is the ratio for mixing your own high temp mortar?

the places im calling locally only sell fire clay.

[azpizzanut]

Re: Vegas Pompeii getting off the ground

Hi CVCrash,

There are a variety of recipes and opinions on what is best. I'm using:

1 part fire clay
1 part Portland cement
1 part hydrated lime
3 part 120 mesh silica sand. (or 60 mesh or anything in between it and 120)

Recent forum comments suggest an additional amount of sand and also less lime. Some even suggest no lime at all, because it is what starts the hardening process. You can try using less lime if you if you find the mortar sets-up too quickly for your building style. I've tried less lime and more sand but apparently it wasn't enough deviation to notice a difference. These ingredients are fairly forgiving as to proportions.

Mix up small batches of mortar, say one or two, one pound, coffee cans, of dry mix. See how many bricks you can do with that amount and if the mortar thickens too much before you are finished with a few bricks. That routine should give you an idea how much mortar to mix at a time. You may also hear from others about their preferred recipes and mixing methods. Somewhere in the Pompeii directions or on a thread you will find mortar recipes too.

Here is a tip on how to combine the various ingredients for a consistent distribution. Locate a 1/8" to 1/4" screen or a prospectors sieve or a bonsai soil sieve and pour your ingredients through it. It breaks up the lumps and mixes much of the ingredients as they pass through. Work over a 5 gal bucket or large tub. Next you can pour or scoop the nearly mixed dry ingredients a second time into another bucket or tub, use the sieve. This second sifting blends the dry mix consistently. Of course, you can do it the old fashioned way by tossing all the ingredients together and mix, and mix, and mix, etc.

If you decide to mix larger batches of dry ingredients you can do what is called "circle mixing". You will need three five gallon buckets. Toss the dry ingredients into two buckets, don't bother stirring them. A five gallon bucket will hold several recipes of ingredients if scooped with a one pound coffee can. This makes layers of raw ingredients. Pour a partly filled bucket into the empty bucket, then the other partly filled bucket into that one, then pour out half the filled bucket into the two empty ones. Blend this way until all the ingredients are mixed. It seems labor intensive but it works. Wear a dust mask. I like using the sieve method and making small amounts at a time.

The mortar should be mixed smoothly and I have good luck with mortar that is like thick pudding but not as stiff as cold peanut butter. A stiff mix won't let you lay as many bricks before setting up. If it is too thin then it runs off the brick. Somewhere in between is the right mix. Use cool water.

You will find out what hand lotion is all about after awhile too.

Cheers,

[GianniFocaccia]

Re: Vegas Pompeii getting off the ground

Hey Bob!

I thought I read that lime extends the set-up time of portland cement. Do I have it backwards?

John

[azpizzanut]

Re: Vegas Pompeii getting off the ground

Hi John,

I repeated what I read from other forum members about the addition of lime to our oven mortar and took it as reliable. However, I did a Google search on lime, Portland mortar mixes to verify what others were saying. Here is something that might clarify: "The speed of set can be increased by using impure limestones in the kiln, to form a hydraulic lime that will set on contact with water. Such a lime must be stored as a dry powder. Alternatively, a pozzolanic material such as calcined clay or brick dust may be added to the mortar mix. This will have a similar effect of making the mortar set reasonably quickly by reaction with the water in the mortar". Maybe not quite on point but pretty close. Apparently, there are several different types of lime that can be used for various types of mortar. I think any brickie will acknowledge that the addition of a little lime to Portland mortar for common brick construction enhances workability and makes the "mud' sticky. The temperature of the water and its chemical content also affect the mortar set time. There are other forum members who can provide a better explanation.

To contrast with the above, many historic and ancient buildings were constructed with mortar made of lime/sand in various proportions: no Portland at all (It wasn't invented until 1824). I couldn't find anything on the set time or workability of lime mortars.

Cheers,

[azpizzanut]

Re: Vegas Pompeii getting off the ground

Hi John,

Aw, drats. I had a nice long explanation all ready to send but it wouldn't go, then the entire page disappeared. So, here is the short version. Lime adds to the workability and plasticity of Portland mortar. You can add varying amounts of lime but too much will set-off the mortar making it too stiff to use.

Cheers,

[GianniFocaccia]

Re: Vegas Pompeii getting off the ground

Lime adds to the workability and plasticity of Portland mortar

Thanks, Bob. This is exactly what I think I've observed. I do notice a stickiness to the mortar that is becoming more beneficial the steeper the courses become. I am curious though, apart from the lime's contribution to the mortar consistency and ease of application, what long-term attributes does it provide? Is it truly a refractory product? As my courses progress (I'm up to the sixth course now) I 've been fudging on the classic 1:3:1:1 homebrew mix: portland/lime percentage (a little less) and fireclay/sand (a little more).

John