Starting new 36" build

[deejayoh]

Re: Starting new 36" build

Great job Dennis!
I am starting row 4.

Tracy

Thanks Tracy. I've been watching your build. Looking good. I love the covered location. Call me jealous! You may pass me if I don't get on this weekend (not that it's a race)

I got a Living Social deal on a two-hour intro to metalworking class in my email today. A little bit of welding knowledge should come in handy for building the door. Plus I've always wanted to know how to weld.

[texman]

Re: Starting new 36" build

Great job Dennis!
I am starting row 4.

Tracy

[deejayoh]

Re: Starting new 36" build

Does that block on the form board slide up? If so good idea. One drawback of the IT is it doesn't keep the height consistent along the row - and a level is needed at least now and then. I tried to think of some attachment but gave up on it. Some hybrid IT and formboard would solve it.

Thanks for the comments and reassurance

to your question, yes - the block slides up. Well, actually I slide it up and screw it to the board for each chain. But it does work to keep things level and at the same angle. I had to go this way because my dome doesn't have a constant radius - but now that I have it set up, I think it works pretty well. I don't know that I would have wanted to use an IT for each brick. Too much jiggling and scraping of mortar going on. I set each one, and then swing the form by to check the angle and position. Works pretty well.

I'll try to post a close up picture later.

[Amac]

Re: Starting new 36" build

I used a half brick in the middle of my 6th chain

You are bing much more precise than I was. It wasn't until the top 3 or 4 rows that I got the side angles and bevels figured more or less right. I ended up turning bricks inside out (wider on the inside than the outside) on a couple of occasions just to recover mistakes.

You should check out Laku's system for cutting 2 indentical bricks from one for the last few rows. The cuts are straight and include angles and bevels in 3 single cuts and just small ends wasted.
http://www.fornobravo.com/forum/28/m...tml#post102532
The same system can get you 3 bricks from 4 cuts.. Unless my memory is tricking me I think I did that for the last two full rows.
Maybe it works better (for a change) with the angle grinder since jcg31 had trouble with it on the HF saw.
Also on aligning the joints - now that I see the hairline cracks I can see one or two that have descended on those joints - but also on others, and on one almost complete circular horizontal joint. I have mixed feelings on them - on the one hand I prefer that the joints are not so strong that the brick splits. On the other I would prefer to see none - but is that possible at all?

Gulf had a good system for preventing the droop of the bricks joining the arch. He used a laser level set up at the back. It's hard to see with the naked eye because when you stand back and look at any row it seems to wave up and down even though it is perfectly level.

In the end it just meant I had a slightly egg shaped plug rather than circular.

Does that block on the form board slide up? If so good idea. One drawback of the IT is it doesn't keep the height consistent along the row - and a level is needed at least now and then. I tried to think of some attachment but gave up on it. Some hybrid IT and formboard would solve it.

Keep it up - nearly there - it looks brilliant.
I recommend Sharkeys vent (btw also used by Aceves) when you get there, although I spent a while after finishing the dome before I could work myself up to any more building. It seems to work very well even though I made the opening a bit narrow.. front to back

[deejayoh]

Re: Starting new 36" build

Looks brilliant Dennis - I looked in vain to see had you made any of the building mistakes I made.
- you have staggered the vertical joints
- it looks like you didn't allow the brick which joins to the arch to dip ever so slightly.
- no inverted Vs - only other dome builders will appreciate the work that goes in to minimise those. I saw even "Brickie from Oz" was hard to convince that they were a problem ( at that time he had built just vaulted ovens)

Update - I'm about halfway through my 8th chain of bricks.

Aidan -

It seems that on the next chain after taking this pic, I endeavored to make as many of these mistakes as I could!

- On the joint spacing, I used a half brick in the middle of my 6th chain, and now that is screwing up the spacing in the 7th and 8th. I guess one learns quickly how any changes to the pattern are compounded in the next chain(s) as you move forward! I am trying to decide if I should just take the pain and allow some joints to line up in the 8th chain (and have even spacing) or keep trying to cut around the different sized bricks.

- I lost the curve on the brick that attached to the right side of the arch on the seventh chain. I had to go back and add a shim on top of it to get the level and radius where it should be.


- at least the "V"s are still working out. So that is good


The good thing that I have realized is that I don't need to angle the bottoms of the bricks any longer. On the 6th and 7th chains, I had cut 1/4 inch angle to the bottom of the brick to get the radius of the dome right. But I mocked up the dome to the top and realized from the 8th on, I can use full height bricks and get the correct radius by tilting each brick up about a quarter inch in the back. That should help me close this thing in faster. One less cut, and a quarter inch more brick in each chain. I think I have 5 more chains + the plug to go

[Amac]

Re: Starting new 36" build

Looks brilliant Dennis - I looked in vain to see had you made any of the building mistakes I made.
- you have staggered the vertical joints
- it looks like you didn't allow the brick which joins to the arch to dip ever so slightly.
- no inverted Vs - only other dome builders will appreciate the work that goes in to minimise those. I saw even "Brickie from Oz" was hard to convince that they were a problem ( at that time he had built just vaulted ovens)

I found the homebrew sometimes really sticky and sometimes not so. I don't think it is so much the wetness but rather maybe use a little more than 1 of the fireclay - as Gianni suggested.
I also found that when I used some brick dust which I scraped up from my "workbench" and a "tray" which I put underneath - that it wasn't as sticky as the coarser clay which I bought. Not sure what advantage superfine sand would give - my sand is just labelled "builders sand".

Looks like the arch and dome are tying together nicely. I found that the IT was useful during the arch building as it gave reassurance that the dome would not drift off unexpectedly. It was worth giving it some attention in advance.
Well done
Aidan

[deejayoh]

Re: Starting new 36" build

Got some unexpected good weather this afternoon, so I was able to start working with the homebrew mortar. My first reaction was that it wasn't at all sticky. Then I figured out it needs to be a bit looser/wetter than the HeatStop and it was ok. I do think the sand I have may be a little coarse - but I can't seem to find the superfine sand. I got it at the local cement and masonry supplier.

I got about half a course in using the homebrew. Seems to work, and what a cost savings!

Happy to report that I seem to have done ok on the arch to dome transition using my high school geometry skills. I am pretty happy with how well it seems to be lining up.

Here are some progress shots. I am off work this week and hoping to get the dome closed in!

[deejayoh]

Re: Starting new 36" build

Had some good weather this weekend, so got one day of work in. I finished up the 5th course and got most of the cuts done on 6th. Then I ran out of HS50 mortar. Grr..

I think instead of ponying up another $100 for a bag of mortar, I am going to go with homebrew. Does anyone see any issues with changing mortar type halfway through the build?

Planning to pick up the sand/cement/lime today. I already have a bag of fireclay

[gmchm]

Re: Starting new 36" build

Your good-looking build, and the improvement in the weather, is inspiring me to get going again on my own project.

[Amac]

Re: Starting new 36" build

Well done Dennis looking good now. You won't have to worry about those angled cuts when you are doing the front (vent area?) arch. Very good tapers and you managed to get a decent size keystone.
Couldn't open the first pic for some reason btw?
Aidan

[deejayoh]

Re: Starting new 36" build

Finally had some decent weather, and I got the Arch done this weekend. Man, that thing caused me some headaches. I figured out that since my dome was not a constant radius, I had to reflect that in the transition.

I knew that the arch stuck out 1.5 inches at the bottom, and from my sketchup, I knew the same measure was 3 inches for the keystone. so I laid all the bricks out side by side on a table, and drew a line from the keystone to the bottom brick - and cut all them according to that line. Seems to have worked out ok.

I had to hack at the back of the bricks with a grinder blade after I got them in, because I had that measurement wrong. But no one will ever see that...

This was the first sunny weekend we've had since I started this thing. Hoping the pace will pick up a bit now.

My new mantra: When I get something wrong, if fixing it won't make the pizza any better (or get here any faster), forget about it!


The picture is from saturday. I pulled the form this morning and finished off the transition row. The arch is still standing...

Edit: it was still light enough out that I snapped a new pic showing the arch standing on it's own.
Also, check out the little stool I snagged at the Harbor Freight sale today!

[deejayoh]

Re: Starting new 36" build

When you say "the angle of the bricks around the arch" you don't mean the arch bricks? The way I see it is that will allow you only to get the correct angle on the arch keystone brick, and the only reason for removing the added section is so it can rotate without disturbing the arch form - no?
I actually used the IT to help build the arch in advance - without needing to change the radius.

Yeah, I probably wasn't exactly clear. I was referring to using it to set the bottom/back angle of the brick - which I want to contour so it matches the dome. The top angle will be set on the keystone brick to match the course of bricks to which it aligns. And yes, removing the added section lets the guide clear the arch form

[Amac]

Re: Starting new 36" build

Of course Dennis - my bad - I see what it is now.

if I remove the part that is screwed on with the block, I can use it to gauge the angle of the bricks around the arch too.

When you say "the angle of the bricks around the arch" you don't mean the arch bricks? The way I see it is that will allow you only to get the correct angle on the arch keystone brick, and the only reason for removing the added section is so it can rotate without disturbing the arch form - no?
I actually used the IT to help build the arch in advance - without needing to change the radius.

[deejayoh]

Re: Starting new 36" build

Yeah, the idea is that the edge won't show inside the oven at all - so there should be no opportunity for spalling. I agree that the straight forward dome is probably a lot easier, but I guess I just have to things difficult for myself

As for the arch - actually that is my "IT", not my arch form. I had to use a plywood form because the shape of the dome precludes a lever-type tool. So I am going to be shimming that with cardboard or something as I lay up the dome so that there will be room for it to spin inside the dome.

One thing I did with the form for the dome which may be of interest to others is that I made the radius adjustable. As shown it works all the way to the edge, but if I remove the part that is screwed on with the block, I can use it to gauge the angle of the bricks around the arch too.

The arch is sitting on a couple of pieces of 2X6 that I can easily knock sideways to get them out once the arch is in place

[Amac]

Re: Starting new 36" build

I would think that the thin edge will spall easier.

I think the thin edge dennis is making will be invisible to the inside of the dome - so maybe spalling shouldn't be a problem.
On the other hand if he used the full brick and the same angle it would show a very narrow edge to the inside, which could be problematic.
So I think it will be OK.
I have seen builds where some people fill what would be large mortar joints with wedges of brick, and haven't seen problems reported.

There's a lot to be said though for the straightforward hemispherical dome.
BTW dennis it looks like there are no wedges under the arch form. Make sure it is removable easily after the arch is complete.
Aidan