Dome spreadsheet calculator

[oasiscdm]

Re: Dome spreadsheet calculator

Looking at the first picture in post #112 on your thread, yes, I think that is correct
TILT = the angle of the plate
SIDE = the angle of the Angle Iron



Yep. You'll need to decrease the angles by the amount of taper on the brick. But why are you using tapered bricks if you've gone to all the trouble of setting up the jig? Seems like a lot of extra cost when you are going to cut them yourself.

That is one nice jig, btw - wish I had one like that!

Thanks for that very clear now. I am using tapered bricks as over here in Australia, they are the same price as straights. I got mine at a good price from trickle in Oz.

Any idea of the angle decrease considering the tapper.?

[deejayoh]

Re: Dome spreadsheet calculator

So if you look at my jig [same as Utahbeehiver] if i lift the half brick from flat that will give the tilt adjusting the stop angle will give the side angle.

Have i got this right? If you could confirm that would be great.

Looking at the first picture in post #112 on your thread, yes, I think that is correct
TILT = the angle of the plate
SIDE = the angle of the Angle Iron

The other thing i have to ask, I'm using tapered bricks. If sitting on the tray they obviously will sit flat placing the brick on that angle, will that alter the figures in the spreadsheet as i can clamp the brick to the brick stop which will have it sitting as a full brick would sit.

Will this have an impact on the cuts and angles?

Yep. You'll need to decrease the angles by the amount of taper on the brick. But why are you using tapered bricks if you've gone to all the trouble of setting up the jig? Seems like a lot of extra cost when you are going to cut them yourself.

That is one nice jig, btw - wish I had one like that!

[oasiscdm]

Re: Dome spreadsheet calculator

Thanks Deejayoh

that makes it much clearer, and a great idea to put it in the spread sheet.

I get completely confused with nonclemature bevels, tapers, side angle, tilt it is very confusing.

So if you look at my jig [same as Utahbeehiver] if i lift the half brick from flat that will give the tilt adjusting the stop angle will give the side angle.

Have i got this right? If you could confirm that would be great.

The other thing i have to ask, I'm using tapered bricks. If sitting on the tray they obviously will sit flat placing the brick on that angle, will that alter the figures in the spreadsheet as i can clamp the brick to the brick stop which will have it sitting as a full brick would sit.

Will this have an impact on the cuts and angles?

[deejayoh]

Re: Dome spreadsheet calculator

Hi Deejayoh

I have checked Hendo's Twist and Tilt thread you referenced, but still dont understand the tilt and side angle values you mention.

Was wondering if you could look at my build last page and look at the pictures of the brick saw jig i have had made to clarify my thinking.

I am using 75/63 3/2.5" tapered bricks.

Hopefully this will help explain it, it is a graphic of a half brick viewed from the back with labels for the angles. Let me know if it helps. If it does, I will probably paste into the spreadsheet.

[oasiscdm]

Re: Dome spreadsheet calculator

Hi Deejayoh

I have checked Hendo's Twist and Tilt thread you referenced, but still dont understand the tilt and side angle values you mention.

Was wondering if you could look at my build last page and look at the pictures of the brick saw jig i have had made to clarify my thinking.

I am using 75/63 3/2.5" tapered bricks.

[deejayoh]

Re: Dome spreadsheet calculator

What AT said .

Even for builders obsessed with having a neat build, I don't think many (if any) cut the top/bottom. The reason for the tapers on the sides is to minimize the mortar gaps inside the dome. For the top/bottom there's not a mortar gap to worry about inside the oven.

The exception I would call out is cutting the top of the soldier/sailor course. Depending on the dome shape, that may be necessary to get the arch started correctly.

[ATK406]

Re: Dome spreadsheet calculator

Miles,
The taper cut you are referring to would minimize the mortar gap on the outside of the dome but adds a lot of extra brick cutting (more than doubling the wear and tear on your saw and blade). Furthermore, most saws will not make a 4.5" cut in one pass, I'm sure there are some that do. Everybody likes to do things differently (I know I do) but I think you'll find that this cut is really unnecessary.

Regards,
AT

[miles_hot]

Re: Dome spreadsheet calculator

Thanks for that Deejayoh - I sort of thought that this was what you'd done (hence the edit) but it's great to have the confirmation.

About the second point - am I right in thinking that your sheet assumes that you're only cutting the left and right faces of the brick and not the top and bottom ones as well?

Have I got the right terminology in my picture (in terms of the angles)?

[deejayoh]

Re: Dome spreadsheet calculator

Miles -
Check the dimensions in the far right columns. I assumed you're cutting a full brick into what basically amounts to half pieces. Generally you start with full bricks, and if your saw allows, you can get two tapered bricks with 3 cuts. The cut in the middle can give you the correct angle for both sides.

[miles_hot]

Re: Dome spreadsheet calculator

Thanks for this brilliant resource!

I think that this spreadsheet assumes that you're using a full brick prior to cutting the tapers - is that right? What if you decide that you want to cut each in half to give a smoother curve? Or is this a daft idea??

Edited to add: I fear I've been stupid - you've already cut the brick in half haven't you? I have a follow on question though - does this spreadsheet assume that you're only cutting the ends of the brick and have not cut angles to form the arch element (i.e. you're spacing the bricks with mortar rather than cutting an additional angle on the brick)?

Thanks

Miles

[h12rpo]

Re: Dome spreadsheet calculator

Fantastic! Thanks for the clarification....youve really helped me crystalise my thoughts

I was going on the assumption of my first sailor/soldier course of full bricks being laid standing upright outside the hearth with the 3 inch side facing inwards and then all the following chains laid on the flat using 1/2 bricks.

I get it now and the spreadsheet makes sense.....thanks again!

[deejayoh]

Re: Dome spreadsheet calculator

Thanks thats as bit clearer now.
When I said 29 1/2 bricks......I wasnt pointing out the difference between 29.5 and 29.2 but rather suggesting it would 1/2 bricks, 29 in number so in total 15.5 whole bricks to get the course laid if that makes sense ?

Ah - I get it. The count for each course is the number of half bricks. So half that for whole bricks.

A couple of other points .....The soldier course is laid with the short edge (3ins) facing the circumference isnt it? If thats right then the number of bricks required ( for my 34incher) would be 107 divided by 3 ins = 35.6 whole bricks ( less the opening)

I created the spreadsheet to help with calculations for a dome with tapered bricks. Most builders going that way lay the bricks on the flat edge - I think it is called a "sailor" course rather than a "soldier" course. You can build either way, but the spreadsheet doesn't assume soldiers. I kind of built it for the way I built my dome. So many of the builders who were completing their domes at that time used sailors that I didn't even think about including an option for vertical soldier bricks. Probably an oversight, but as I said - the spreadsheet is mostly about calculating tapers, which most builders using soldiers don't bother with.

How do I calculate the decreasing circumference as you go up the chains ?

Column H

[h12rpo]

Re: Dome spreadsheet calculator

Thanks thats as bit clearer now.
When I said 29 1/2 bricks......I wasnt pointing out the difference between 29.5 and 29.2 but rather suggesting it would 1/2 bricks, 29 in number so in total 15.5 whole bricks to get the course laid if that makes sense ?

A couple of other points .....The soldier course is laid with the short edge (3ins) facing the circumference isnt it? If thats right then the number of bricks required ( for my 34incher) would be 107 divided by 3 ins = 35.6 whole bricks ( less the opening)

How do I calculate the decreasing circumference as you go up the chains ?

[deejayoh]

Re: Dome spreadsheet calculator

H12rpo -

The spreadsheet is giving you the right numbers -
- The soldier course and the first course have the same radius (always measured at the bottom of the course) so they require the same number of bricks.
- It's 29 bricks instead of 24 because it assumes you are tapering your bricks. Look at column "P" - the inner width is 3.53". that's how you get to 29 bricks. I probably wasn't clear about this in the assumptions
- To the question about 29.2 vs. 29 1/2 bricks - the way I set it up, it gives you the bricks needed to the 10th of a brick. So realistically, if it says you need 29.2 bricks, you might use 29 bricks with a little thicker mortar gap. Or, you could (quite painfully) cut every brick a bit narrower to use an even number.
- Your comment about using half bricks - yes, but with tapering. The spreadsheet assumes the bricks are all standard width (usually 4.5 inches) at the back unless the builder enters a narrower width in column "R". I built in the ability to change this because I at some point almost every builder starts cutting the bricks into thirds or even smaller in order to make them easier to work with.

In the end, It's really up to the builder - but your questions are good ones to help understand how to interpret the calculations. I set the spreadsheet up to make the taper calculations really easy to do and very accurate. The brick counts were a by-product of that. But if you want to build an oven without tapering the bricks - then I'd look at the calculated radius for each course and use the math you propose to get to the brick count. It shoudl be quite easy for you to add a column to your own version of the spreadsheet that will give you this.
Does that all make sense?

[h12rpo]

Re: Dome spreadsheet calculator

Just looking at the spreadsheet and the number of bricks needed for the soldier course for 34 inch oven are 29.2
The sheet says that course 1 is also 29.2 bricks??? that can't be right can it? The courses are constructed of 1/2 bricks past the soldier course arent they? surely that would make course 1 around 29 x 1/2 bricks wouldnt it?

heres an extract
Soldier 29.2
1 29.2
2 28.9
3 27.9
4 29.5
5 27.1
6 24.1
7 20.6
8 16.6
9 12.3
10 7.7
My rough calc goes like this: circumference for 34 inch oven is 107 ins....divide that by 4.5 inches ( brick layed flat) = 24 x 1/2 bricks !
It would actually be a few less because of the oven entrance
Or am I missing something ?