Pdx 42" update

[Macrinehart]

Today I rebuilt the opening arch. While I usually with I would have followed UtahBeehiver's advice, today I decided not to adjust the height of the arch form as that task seemed like a fairly unsafe use of the tablesaw, and I figured safety first. I also measured the height of my lath strips and they are 3/8" total with 2 strips. Hopefully it is enough.

I built the entire arch in one go with slightly higher hydration on the mortar to make minor adjustments easier. The entire process was smooth, but I'm leaving the arch support in place to allow the mortar to setup some more. I used a level to check things throughout and the front face is now smooth and perpendicular. (The picture is crooked, not the arch. )

I did have to pull it forward a little, and there is now about 5/8" gap to the inside radius of the dome. I imagine that means I'll have a little offset between the back face of the arch and dome bricks. I'm not too concerned about it.

[UtahBeehiver]

Before you start the rebuild, check how much release you have under the form, one of the pic show small wood shims (1/4"??) this "may" not enough release to drop the form after the arch is completed. In my build I started like this but soon found out 1/4" was not enough and redid form and had a release of about a 1/2".

[Macrinehart]

Today was a day of prep work for rebuilding the opening arch. I started with cleaning mortar off the arch bricks, using a hammer and cold chisel. I found the process worked best if bricks are soaked thoroughly before cleanup. It keeps the dust down and I think the mortar comes off more easily.

After that I started improvements on the arch support. My brother brought over a custom tool for bending wood, and we cut some thin mahogany plywood down to size and bent it befor attaching to the arch support. I also used some scrap wood to add a faceplate to the front of the arch support, ensuring all bricks are plumb. Borrowed this idea from one od the pros on the forum, can't remember who but I'm sure you'll recognize it - thank you!

The inside arch now ihas an extra 1/8" radius, so after dryfitting and checking measurements I went to work on the dome removing mortar and a few filler bricks to expand my opening a bit. The arch will be a little forward of it's planned position, but much better than the out of true build I had on the first pass.

As dinnertime approached, I decided rather than starting to build the arch I'd do some cleanup instead. Got out the shop vac, removed Ll the spilled mortar and dust from inside the oven, and then took out my floor protector and cleaned up around the edges. Things are looking pretty tidy and I'm ready to rebuild the arch tomorrow.

[MarkJerling]

I don't think the dome is high enough yet for you to worry about collapsing, but, of course, I'll deny all liability if it does! LOL.
No, I really don't think it should be a problem. I've seen many builds here where people get stuck into their domes before doing their door arch, while I've always considered it better to build the arch first, as you have done. Worse case scenario, a few of the closest dome bricks may loosen, but if the mortar is well set already, it should be fine.

Of course, if the first few courses are fine, then leave them be, but it is nice to have a good, straight door opening for a nice door seal, so review that as you go.

[Macrinehart]

Thanks MarkJerling! That didn't occur to me. I think the first 2 or 3 bricks are ok. Maybe just rebuild the top of the arch? Do I have to worry about the dome colapsing if I take the full arch out to rebuild it?

[MarkJerling]

While you can certainly cut it straight, considering how little it is attached to the dome, what's to stop you simply removing the arch and rebuilding it? (Making sure to keep the brick numbering and joins the same, but working over a better temporary former this time, with support wedges under, so that you can drop the former before pulling it out.)

I'd think the vibration from the cutting will loosen the mortar joints anyway, so might as well dismantle it, clean the bricks and rebuild the arch in my view.

[Macrinehart]

Hi Gang - I could use a little problem solving help with this post.

The inner arch on my oven is about 1/2" (~13mm) out of plumb, leaning forward and roughly symetrical (keystone is furthest point forward). This happenes when I was removing the arch support.

So a few lessons learned on that, first I propped the arch support on 1/8" lathe, and removed the lathe to drop the support. Right idea, but 1/8" was not enough to clear obstructions. Second, My arch support was open in the center, I just used som thing plastic binders to cover the gap but when I set my bricks the mortar pressed through the inner joint and that plastic just warped so the mortar hardened and bound between the inside and outside faces of my arch support. If I was thinking, I would have disassembed the arch support to remove it. But I was not thinking so I just horsed it out and that's that.

So, I am trying to decide how best to correct this issue, inside the dome and out. I have a couple ideas and wanted to run them past the thread.

Inside the dome, I was thinking of mortaring some excess brick material around the top inside arch to restore it to plumb before I continue with the dome. I feel like that is the right answer to prevent "the dreaded droop" form deforming my dome

Outside, I have a couple thoughts. First, I could cast a door that fits flush against the out of plumb surface, and then build the outer arch plumb and fill the gap with ceramic fiber rope. Or, I could use mortar to bring it to plumb on the front face of the arch. Or I could use my angle cutter to cut it to plumb. On this I have seen too many storys of folks injurying themselves with the angle cutter to feel comfortable with this much cutting. But with caution and a lot of blades I think it would work. The mortar solution seems a little like something that would not stand the test of time. Welcome all input!

Here are some photos of the plumb issue and outer arch prep. I paused the dome build, but there is still plenty to do!

[MarkJerling]

That's coming along nicely Mac. At this rate you'll be able to bake pizzas before the year is out!

[Macrinehart]

Hello All - It's been a while, and if it weren't for working full time and running a business on the side my excuse would simply be laziness. But last weekend my wife managed to get me back out by suddle suggesting that she needed some special tools to clean out the overgrown jungle of weeds around our oven project. And, I couldn't just let her work on that while I neglected the project so I got started again!

Today I'm happy to anounce that I'm on course 6 of the dome and I closed the opening arch to boot. Removing the arch support was a challenge, luckly I decided to do that while the mortar was still a little pliable. The arch support was poorly built, and mortar sqeezed out inside the opening an obstructed removal of the form. I did have it propped up on 1/8" slats, and removing those dropped the form a bit but it was still stuck. I has to knock it out with a mallet, which caused some cracking and deformed the arch a little. But, mortar still a little wet so I was able to make some adjustments and reset the bricks.

For the outside arch I plan to use a 1/8" plywood scrap to wrap the arch, and I'm going to prop it on 1/4" slats.

Photos attached. I think I could be closing the dome with 2 to 3 more weekends!

Cheers, Mac

[Giovanni Rossi]

Mac, Maybe you're already doing this, but I found if I gently worked each brick left and right while it was fixed in the IT until I could feel/hear it rubbing the lower course I was able to stay level through the build...as long as your bricks are uniform. This kept the joints on the inside of the dome tight course-to-course.

[UtahBeehiver]

The area near the arch is where you need to pay attention or you get what is called the dreaded droop. Make adjustments over several courses.

[Macrinehart]

Hi Pizza Oven Officianados! It's been a minute but I haven't entirely passed this time idlly. Here in Portland, OR we've transitioned from a lingering, cold, wet winter to a record-breaking heat wave! Since my last update a month ago I've put in some work at both extremes of the temperature guage. Currently I am working on the 4th course of bricks in my dome. Things seem to be going pretty well.

I was joined in my build by my friend Gus yesterday, and we laid most of the latest course, knocking off in the afternoon as the temp soared past 90-F. I told Guy there's a policy against having his likeness in photos until the second day of help. He has the link to this thread, so hopefully Gus, I'll see you again!

The only Issue I have at this point is that I am starting to get slightly out of level on one side were the dome connects to the opening arch. The bubble is still between the lines on my level, but is touching a line on one side. So I figure the answere is a little estra mortar on the next course to bring it back into level.

[Giovanni Rossi]

Mac , Looks like you're working through it but UtahBeehiver always says, "The last brick of the day, place one on back center of the new course so it can set and gives you an anchor to work from." It was one of the quotes that made it into my research notes!

It certainly made my life easier.

[Macrinehart]

Today I could only get in a half day, as the morning was spent supervising my son's driving practice. His driver's test is coming up on Tuesday, so we spent a couple hours cruising around town. No accidents, but I did get an elevated heart rate a couple times. It's amazing how much energy it takes for new drivers to stay focused on the road. After two hours of driving we got home and my son was ready for a nap.

As for the oven, I finished cutting all the bricks for the second course. Then I had to refresh myself on the home brew formula. I doubled my batch to have extrat mortar for the tilt, but only had enough for 2/3rds of the course. It was fine though, as my morter was getting a little difficult to work in the end.

I was a little intimidated with the mortar work to start, but things went pretty smoothly. I think setting the first 2 - 3 bricks in the course is the most challenging bit as they all want to move a little. But after I had 3 bricks down the course was pretty stable. From that point I just started alternating between each end - place a brick, tap it in place, and the let it stabilize while I worked on the other side.

I finished the day by covering all the work in process with wet terricloth towels and a tarp. Here's the latest pics. You can see that I'm about ready to do some 1/2 width bricks to get my joints staggered.

One thing that started to become clear today - this oven is going to be really tall! I think I can do 2 - 3 more courses from the ground. I'm also starting to think that maybe a 36" diameter would have been fine. I image that I could be making more progress at this stage if I didn't have so many brick to lay for each course. But no regrets - This oven is going to be great for back yard parties!

[Macrinehart]

Good tip. I manage to do the first side cut by setting saw once and then processing all bricks. The second side-cut I couldn't just setup once for a couple reasons:

1. Minor variations in brick width requires adjusting the miter gauge. This is where having the bricks marked on the second side is pretty helpful.
2. The tilt angle is only 1.5 degrees, which is pretty hard to visually oberve, which increases risk of setting the brick upsidedown on the second cut.

One weird thing I haven't explained, I ended up with three bricks where the first cut appears to be on the opposite side from all the other bricks. I don't know how that happens when the blade and miter guage were in the same position for all the bricks on the first cut. The only theory I have is maybe I didn't get those bricks set correctly, or maybe they moved while being cut.

In any event, measure twice, cut once, and measure again!

Another shortcut, I have my hose with a garden sprayer on it a little loose so water is constantly dripping into my bucked with the water pump. The rate of flow is about the same in and out so I don't have to pause to refill the bucket.

Between each cut I also clean the debris off the wet saw table.