Chip's 42 in Minnesota

[mrchipster]

Re: Chip's 42 in Minnesota

Yes I used the fixed length IT to mark the brick insides to match the dome inside and the string was used to mark the angle of the sides I'd the brick. I marked the string where the outer dimension of the dome came to and was able to mark the back sloping angle quite easily.

I hope this makes sense.

Before laying the next brick up I would transfer the dimensions of the lower brick's top side to the bottom of the upper brick and that seemed to work quite well.

Thank you for your kind words.

Chip

[garch]

Re: Chip's 42 in Minnesota

Chip

I really like your build and your innovation. Do you have any pics of the jig for your saw? It sounds like what I am looking for as i begin to start cutting.

Gregg

[mrchipster]

Re: Chip's 42 in Minnesota

Chip

I really like your build and your innovation. Do you have any pics of the jig for your saw? It sounds like what I am looking for as i begin to start cutting.

Gregg

I will post photos of the jig tomorrow as it is to late tonight to drag it out.

Chip

[mrchipster]

Re: Chip's 42 in Minnesota

Here are the Jig photos I promised.

The jig is Built on a 2 x 8 piece of lumber. I cut a groove about 1 inch wide in the center of the board to allow clearance for the blade and also allowing the angled tables to swing up without hitting each other. Each table has two hinges placed along the groove.

On the inside corner nearest the saw, I drilled a hole for the angle bars that are attached to the top of each table. The bolt that goes through the hole is snugged up tight so that the arms do not move freely. Because they are tight they stay in position easily. You may want to add a clamp at the end of the the angle bar to more firmly hold it in position.

I screwed shims to the 2 x 8 to position the table in a horizontal. To make up for the thickness of the hinges.

I put pieces of brick underneath the table on each side to elevate the table into the angle I want.

The last photo shows how I make the table the same angle on both sides, I just measure up from the board equidistant from the saw blade in my case 9 inches away and if the left side is elevated 2 inches, then I just make the right side elevated 2 inches at the same 9 inch distance from the saw blade.

It took less than an hour to make this table and it has saved me a great deal of time.

BTW the hinges look strange because they are from a folding door and not real standard. They were just something I had lying around.

I hope this helps.

Chip

[mrchipster]

Re: Chip's 42 in Minnesota

I was having a difficult time deciding how to tackle the last few chains and decided I would go all in...

The sharp V shapes were driving me crazy. So I decided that at chain 15 I would grind the bricks into a circular shape. That way bricks placed on top could be easily ground into an arc on both the top and the bottom.

This worked out extremely well as you can see from the photos.

The real beauty of this method is that I could use larger bricks. And not have as many lined up seams.

It wasn't that difficult with an abrasive grinding wheel on my 4 inch hand grinder to create the arcs. I was able to place the bricks side-by-side to get a nice continuous arc I think you'll agree.

Chip

[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

[garch]

Re: Chip's 42 in Minnesota

Chip, thanks for the pictures and explanation.

[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.

[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

[brickie in oz]

Re: Chip's 42 in Minnesota

so I went in to patch them.

Why........?

[mrchipster]

Re: Chip's 42 in Minnesota

Why........?

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

[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

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

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

[brickie in oz]

Re: Chip's 42 in Minnesota

Nice.......