30"/760mm Scotland Pompeii

[Bookemdanno]

Re: 30"/760mm Scotland Pompeii

Your readymix will not harden up at joints larger than 5mm, and the aggregate is too fine to hold together and will slump and pull away from the bricks JMS. Don't use it!

You have two options really, more cuts or get some fireclay to make a batch of homebrew for the outer edge of your joints. Use a sliver of brick to support the dome bricks but leave the joint open at the outer edge. When the mortar has set up a bit, you can point/pack the outer joint with a homebrew mix.
If the joints get larger than 10mm, which they can as you get higher up the chains, i'd even be adding some washed sharp sand to the mix to strengthen the mortar and allow it to hold together in place.

Are this lot near you?

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[jms]

Re: 30"/760mm Scotland Pompeii

I have a bag of fireclay which I got for the floor. To make homebrew all I would need is lime. Do you know where I can get some?

[jms]

Re: 30"/760mm Scotland Pompeii

I'm not very happy with the way the arch has turned out. I cut the bricks to be less than full thickness, but I didn't realise until today that it would mean that there would be an overhang above them when they get linked to the top of the dome. My lack of skill with the saw means that the lengths, taper angles and cut faces are all uneven (in the third picture all of the bricks are aligned at the front to show the length variation). I probably have enough bricks to redo the arch, but it doesn't leave me with many if I muck up anything else.

The closer I look at what I've done so far the more things I find to be annoyed about. I'm entertaining bad thoughts about ripping it up, cleaning the bricks I've already cut and starting again with homebrew mortar.

[texman]

Re: 30"/760mm Scotland Pompeii

I don't see anything that would require a restart. IMO-it looks good to go.
Remember, all of this is concealed inside the oven. Only us brickheads will see it. Structurally it looks fine.

I would decide which mortar you are going to use now and stick with it. I would choose the homebrew and get your mix right before you proceed. (see DJ) If you have to waste/return/donate that other stuff that is a small price to get the oven you want.

I would suggest a tapered arch though. easier tie in and structurally stronger IMO. See Octoforno,DJ,Utah BH, stargate or me.

That first course is held in place by weight of dome more than any mortar.

Texman

[mrchipster]

Re: 30"/760mm Scotland Pompeii

Make sure the outside of the inner arch is flat and square, as tex says no one will see the inside
I double down on his suggestion to a reaching arch, sharkey and I also used that method and it works great, you should still be able to recut your arch bricks into that shape you just might need to move the arch further into the oven slightly, 1-2 inches.

[jms]

Re: 30"/760mm Scotland Pompeii

Thanks for the input. I was just getting frustrated earlier and probably a bit melodramatic. I'm going to pick up some hydrated lime tomorrow and continue on with homebrew mortar and a fresh mind.

[texman]

Re: 30"/760mm Scotland Pompeii

JMS

Glad to hear that.

do you have your IT put together yet? the tool is great for setting the arch placement and for the taper of the inner arch bricks. If you can get the tool set, i think it wall all start to make better sense at this point of your build.

Enjoy the build. It is hard work, but very satisfying. If you are like me, this was the first time i ever built a round oven out of square brick. not the easiest thing at all. I remember staring at the oven trying to picture what i was doing and if it was correct. It will all work out, just enjoy the whole process. (adult beverages are recommended as well.

Tex

[jms]

Re: 30"/760mm Scotland Pompeii

Yeah, after I picked up a bag of hydrated lime I spent this afternoon fitting a IT. I can't weld so it was a wood only deal. I also had to harvest a bearing from a spinning table.

I regret not having this together when I was placing the soldiers. I made sure the IT was centered and flush with the middle of the brick at the back of the oven, and it turns out the rest of the soldiers aren't in the best circle. Oh well the next course is going to not be perfectly aligned with the soldiers at the front, but nobody will ever see it

[texman]

Re: 30"/760mm Scotland Pompeii

JM

Something is not making sense in your last two pics. I dont think that you are that far off of round in your second pic. your oven looks about perfectly round. An error of that much would be visible in the pic. My guess is with all of the moving around of the floor that what you thought was the center is not any more. I would check the placement of your IT at the center. Use a tape measure and find the center.

Also, you will want to make some slight mods to the IT you have. You want the shaft to be in the center of the brick vertically and horizontally. add some more spacer above the shaft to move the top piece up and maybe taper the end of the shaft some so you will be on center. Also, get a cheap clamp to hold the brick if you can.

Texman

[jms]

Re: 30"/760mm Scotland Pompeii

JM

Something is not making sense in your last two pics. I dont think that you are that far off of round in your second pic. your oven looks about perfectly round. An error of that much would be visible in the pic. My guess is with all of the moving around of the floor that what you thought was the center is not any more. I would check the placement of your IT at the center. Use a tape measure and find the center.

Also, you will want to make some slight mods to the IT you have. You want the shaft to be in the center of the brick vertically and horizontally. add some more spacer above the shaft to move the top piece up and maybe taper the end of the shaft some so you will be on center. Also, get a cheap clamp to hold the brick if you can.

Texman

I found the new center of the oven today when I was putting the IT together. I've just gone out and checked it, the rest of the soldiers aren't bad - 1/8th" out at most, and both sides are equal distance from the center. It just seems that the front left hand corner is out of line with the rest by ~1".

[deejayoh]

Re: 30"/760mm Scotland Pompeii

I found the new center of the oven today when I was putting the IT together. I've just gone out and checked it, the rest of the soldiers aren't bad - 1/8th" out at most, and both sides are equal distance from the center. It just seems that the front left hand corner is out of line with the rest by ~1".

That doesn't sound too bad. If you haven't mortared your arch yet, you might just knock loose a couple bricks at the front left to get it back in round. It is still easy to do that now.

[jms]

Re: 30"/760mm Scotland Pompeii

I've got my first course cut to size. I was wondering about the brick staggering and the best way to do it. I've seen builds do their bricks staggered at 1" intervals, and I've seen builds do bricks staggered at half-brick intervals, is there any benefit to doing one over the other?

[deejayoh]

Re: 30"/760mm Scotland Pompeii

half brick intervals is the ideal. Staggering as much as possible makes the strongest dome. In practice, you will find that it's tough to maintain and that you have to be super mindful not to line up joints between courses.

[UtahBeehiver]

Re: 30"/760mm Scotland Pompeii

Just a tip from what I found during my build. As you move up in courses, consider only cutting a portion of the course then mortar in. Both taper and bevel angles have a way of changing slightly not matter how precise you cut the bricks. This way you can make adjustments to the angles as needed rather than having to adjust the whole "precut" brick course. The goal is to stagger the joints, whether it be 1/2 or 1/4 does not matter. Do your best work on the back half of the oven, this is the only area that is really seen after everything is all said and done.

[jms]

Re: 30"/760mm Scotland Pompeii

Just a tip from what I found during my build. As you move up in courses, consider only cutting a portion of the course then mortar in. Both taper and bevel angles have a way of changing slightly not matter how precise you cut the bricks. This way you can make adjustments to the angles as needed rather than having to adjust the whole "precut" brick course. The goal is to stagger the joints, whether it be 1/2 or 1/4 does not matter. Do your best work on the back half of the oven, this is the only area that is really seen after everything is all said and done.

I'll definitely consider that for the next course.

I got the inner arch up and mortared. 3:1:1:1 is much nicer to work with than the premix. It got dark before I could take a picture. I'm happy with it, but its not particularly seamless compared to many on the forum. I'm more concerned with getting the oven finished before 2059 than complete perfection now