Chip's 42 in Minnesota

[david s]

Re: Chip's 42 in Minnesota

My outer arch is separated from the flue gallery by an 8 mm vermicrete layer and you can hold your hand on it when cooking pizzas, although if the oven has been firing for several hours it gets bait hotter. Apart from reducing heat conductivity, it also reduces any thermal expansion stresses on the outer arch which I believe to be the main culprit of outer decorative arch cracking.

[mrchipster]

Re: Chip's 42 in Minnesota

Completed Brick work up to roof on oven area and began to enclose the prep table area.

BTW my daughter and her boyfriend completed the Twin Cities Marathon this last Sunday with a time of 4:37. WOW...

You know why a marathon is only 26.2 miles right... Because 26.3 miles would be Crazy!!!!!...

Chip

[mrchipster]

Re: Chip's 42 in Minnesota

Looks great! Did you mortar your facade arch bricks to the arch fire bricks?

No Mortar just touching contact of 1/2 inch of a brick spacer and a 1/4 inch air gap for the rest of the brick area filled with ceramic blanket.

In the photo you can see the 1/2 X 1/4 inch brick that has been mortared to the flue arch brick, the wide face of the brick was filled with ceramic blanket where indicated on the entire arch (difficult to draw entire area where blanket is) but I think you get the idea.

I will be filling the very thin seam that exists with High Temp Silicone, At that location it should never get to 700 degrees and that is the rating of the silicone I have.

Chip

[ggoose]

Re: Chip's 42 in Minnesota

Looks great! Did you mortar your facade arch bricks to the arch fire bricks?

[mrchipster]

Re: Chip's 42 in Minnesota

Working on exterior and finished the outer arch and wine/beer glass cubby.

Obviously not complete or cleaned up but glass of wine was required for completing another key stone.

Chip

[brickie in oz]

Re: Chip's 42 in Minnesota

Nice.......

[mrchipster]

Re: Chip's 42 in Minnesota

Second firing and all is well. outside of dome got to 160 and inside a little over 240 a couple of times. fired oven for about 4 hours today.

Chip

[mrchipster]

Re: Chip's 42 in Minnesota

I have not posted for a while but I made some progress over the holiday weekend.

I began to work on my roof framing and am building the superstructure out of 1.5X2 inch Wide flange I-beam stock. This requires a considerable amount of welding and steel cutting. My welding skills leave a lot to be desired but it seems to be holding together well. that's me on the ladder doing the welding.

The roof design has a 2 foot overhang on the front right and a large panel of roof that goes over the prep area and up to the peak. This leaves me a peak about 9 feet above the ground and overhanging the front of the oven by about 3 feet. This should provide a nice cover when we have light rain and keep off the sun in summer since the oven faces northeast. Hopefully the roof will provide enough cover for the entrance during heavy downpours. I will be building an outside door to protect the oven from storms as we get heavy thunderstorms here.

I lit my 1st curing fire today, got the top of the dome to about 200?F and moved fire around several times to distribute the heat. The outside got up to 95 with an ambient temp of 80.

I was able to keep a small fire going for about 2 hours. At the end of the 2 hours I put a load of pine into the oven to super-dry for tomorrow's firing. I will be off most of the day and try to keep the fire going for a few hours. The oven seems to be drawing well and the 10 inch flue is working out nicely.

The inner arch was 145 inside the thermal break and the entrance one inch away was 90 so the thermal break seems to be working. The flue gasses at the inner arch were hot enough to try to avoid but at the outer edge of the flue opening I could hold my hand in the flue with not problem. Of course the fire was very small. I am guessing when pizza is being made any attempt to put my hand in the flue will be met with OUCH!!

I started the fire with newspaper and added small amounts of Maple Birch and Oak to keep the fire going. After about the 1st hour I figured why not use pine and that burned well.

No hair line cracks are visible at this time so the 1st firing went well.

Chip

[mrchipster]

Re: Chip's 42 in Minnesota

I started to work on the thermal break between the inner arch and the flue landing.

I decided to reinforce the leading edge of the inner arch with a piece of stainless steel, this will perform three functions.

The first is to protect the leading edge of the inner arch from damage due to logs, tools, and other mishaps; the second function is to provide a smooth positive seal for the insulating door; and a third not so obvious function is to provide a smooth transition between the inner arch and the flue should they decide to expand and contract at differing rates.

There has been some concern in other parts of this forum as to the benefits of a thermal break and then possibly jeopardizing the benefits by putting a piece of metal in between the two thermal areas. I decided that the benefits of protecting the edge of the inner arch and providing a positive thermal seal outweigh the potential thermal loss that would be added by putting in the piece of metal.

Looking at photo number one, you will see that the piece of stainless steel is approximately 2 inches wide and has a 1/4 inch return towards the interior of the dome. I cut the sheet metal with my four-inch angle grinder with an abrasive metal cutting disc. In order to bend the edge of the sheet metal I took a 2 x 6 board and cut the 10 inch radius into the board using that edge to hammer over the sheet metal.

I mounted the stainless steel to the front of the arch using a stove adhesive rated for 2700 degrees. It will also be held in place by the flue landing arch.

As you can see in The other photos, I have cut a 45? by 1 inch deep slice out of the bricks to provide a thermal break, the bricks will be in contact with the stainless steel on the inner arch for about 1 inch.

I will be filling this void with insulation, it will either be blanket material or Vermiculite concrete.

That's all for today.

Chip.

[mrchipster]

Re: Chip's 42 in Minnesota

Why........?

Just thought I should, I guess I am over thinking the situation....

[brickie in oz]

Re: Chip's 42 in Minnesota

so I went in to patch them.

Why........?

[mrchipster]

Re: Chip's 42 in Minnesota

I found a number of pin head sized voids in the mortar after cleaning the inside of the oven so I went in to patch them. Very simple but boy is that opening small for someone my size.

I had to take a flashlight in with me because not enough light came in when my middle (OK beer belly) got in the way.

One nice thing is you can see how well my 3 piece keyway turned out.

I am really happy with it.

Chip

[mrchipster]

Re: Chip's 42 in Minnesota

Chip, thanks for the pictures and explanation.

No problem I hope others can take advantage of this also, the idea came from another similar design presented on this site. So I cannot claim anything unique here.

BTW the angle of the arms is almost always 4-5 degrees but the slope of the plywood boards increases dramaticly as you go up in chains.

Chip.

[garch]

Re: Chip's 42 in Minnesota

Chip, thanks for the pictures and explanation.

[mrchipster]

Re: Chip's 42 in Minnesota

The dome is closed and the 3 piece key is in.

The mortar and bricks are still wet so the photo is not perfect but I will take another picture once it's dry.

Time for a beer.

Chip