Nathan's 36" SoCal WFO build

[n8huntsman]

Tying the arch in with the dome

I completed another course and tied the dome into the arch this week. It’s getting exciting… starting to look like something.

[n8huntsman]

Entry Arch is Complete

I’ve got a backlog of pics to post. I finished the entry arch last weekend. This took me quite a while to get all the bricks cut. Not easy cuts. I tapered each brick to maintain a constant mortar joint. Like the previous courses, I cut each and every brick to a drawing, as opposed to putting the brick in place and marking with my IT, then cutting. They all ended up lining up with each other pretty good and it appears that it maintained the dome curvature. I’ll be able to see better as I complete additional courses.

[n8huntsman]

Got a couple courses finished

Starting to get the hang of it.?* I think it’s about time to start the entry arch. So far I have cut everything straight from my model and drawings. I’ve only used the IT to maintain the proper inward tilt of the brick. I have been using an adjustable square to measure the height from the floor to the top inside edge of each brick to maintain my mortar joint per my drawing. This will insure that I finish where I expect and keep my final keystone plug predictable.

[DavidApp]

Re: Nathan's 36" SoCal WFO build

Hello Nathan

Very nice stand. I have never seen curved blocks before great idea.

Your software rendering of the dome and vent connection makes it much easier to see what you are doing and need to do. I did mine old style pencil and paper full scale.

I think you will find that wetting the bricks will help. I would put some bricks in a pan of water for a few minutes then remove them and let the surface dry off before mortaring them into place. I did use HS50 because I could not find the "S" type lime anywhere locally otherwise I would have gone the home brew route.

You mentioned the brick size as you go up the dome. I cut them in half then in thirds finally in quarters to try to keep the gap that starts to form under the brick to the minimum. In fact I chamfered the corners of the brick so that it fit the course below better.

David

[n8huntsman]

IT tool

I completed my IT tool. It’s pretty much like Jims (http://www.fornobravo.com/forum/f28/...heme-2985.html) except with a few modifications. Welds aren’t the prettiest but I was welding to cast iron and galvanized. It’ll stick though. I really wanted to make the pivot axis on the same plane as the floor because this is how my model was created. This required me to have to dish out a brick to insert into the floor. I got it pretty much dead on with zero offset so I wont have to adjust my IT length as I go up.

[n8huntsman]

Re: Nathan's 36" SoCal WFO build

The homebrew mortar (3:1:1:1) didn't seem to be very sticky. I had read differing opinions on pre-wetting the bricks so I opted to try it without doing that. I think on the next course I will wet the bricks first. The next day after mortaring it appears that at least two of the joints have separated. I'll fix these but should I worry about the rest? My instinct is that if I do the next course better, it will lock in the first course a little better than it is already.

[n8huntsman]

First course

[deejayoh]

Re: Nathan's 36" SoCal WFO build

Nice progress. Very neat and tidy. I wouldn't worry about the peel catching until it becomes a problem. I think it's a concern most of us have when we first start our ovens that is probably overblown.

Things start to get messy from here

[n8huntsman]

Started and finished the floor of the oven tonight

They aren't the flattest but it's mostly just the edges that stick up a bit. I think I could easily go over it with a diamond grinding wheel and get it perfectly flat to prevent the peel from hanging up.

[n8huntsman]

Got the insulation down

I put down my 3″ of Thermo-12 Gold Calcium Silicate board the other day.

[n8huntsman]

Re: Nathan's 36" SoCal WFO build

Well, I think I'm convinced to just go with the Portland homebrew. Thanks for the explanation regarding the Portland.
I've been keeping my hearth covered and wet. There's actually standing water on it right now. Tomorrow will be day 7 but I'm worried that if I dry it off and remove the tarp then try to place my calcium silicate board it might wick moisture and ruin the insulation. Is this a concern? If so, I can put it off for a few days I suppose.

[deejayoh]

Re: Nathan's 36" SoCal WFO build

Nah, I was just a little confused about the term "home brew." It's a little ambiguous as there are two recipes in the mortar primer; one with Portland and one with Calcium aluminate instead. I kinda assumed the calcium aluminate variant was preferred but in your last post you specified Portland so it's a little more clear now. I guess I could have just asked for clarification.

My apologies then. Homebrew commonly uses portland. Works fine. As David suggests - apparently the temps aren't hot enough to be a problem. Hundreds of successful ovens out there on this forum built using it. I wouldn't worry about it for a millisecond.

[david s]

Re: Nathan's 36" SoCal WFO build

The calcium aluminate based mortar is more refractory (fire resistant) than the Portland Homebrew. For the temperatures we fire to <500C the homebrew is perfectly adequate. Where the portland may break down for those areas where it gets really hot, the lime in the brew takes over. But, the four big drawbacks with calcium aluminate are cost (it is far more expensive), accessibility, poor shelf life and working time. The stuff goes off very quickly, necessitating mixing small batches all the time. If you add lime to it as suggested in the Pompeii plans, it will accelerate the reaction giving you even less working time.I believe this is a failing in the plans, or the authors have not tried it before recommending it.

[n8huntsman]

Re: Nathan's 36&quot; SoCal WFO build

It feels like you are going to ask the question until you get the answer you want...

Nah, I was just a little confused about the term "home brew." It's a little ambiguous as there are two recipes in the mortar primer; one with Portland and one with Calcium aluminate instead. I kinda assumed the calcium aluminate variant was preferred but in your last post you specified Portland so it's a little more clear now. I guess I could have just asked for clarification.

[deejayoh]

Re: Nathan's 36&quot; SoCal WFO build

9 out of 10 people on this site use homebrew. Even those that start with something else generally finish with homebrew. Portland + sand + Lime + fireclay

It feels like you are going to ask the question until you get the answer you want...