42" build in McPherson KS

[slschoming]

UtahBeehiver Thanks, that's exactly what I needed to hear.. I will plan on building with firebricks.

I have read many comments on here that refer to buttressing and I have looked it up but I'm not sure I fully understand.. If I build straight vent walls and match the arch of my inner arch (adding enough width/height to allow for a reveal) all with firebrick and build walls outside of the firebrick walls using regular house bricks would that be sufficient buttressing? This is my first masonry project and I am trying to learn as much as I can as I go.

I am also not opposed to putting a duravent on top of a simple arch with minimal weight on top if necessary, just thought I could save a little cash by doing a brick chimney.

I like the look of a shorter brick chimney, but I also want it to work properly. What is the minimum recommended chimney height?

[UtahBeehiver]

I would not recommend regular bricks on the vent area or interior of the chimney, too hot. A chimney vent on a fireplace will have a clay liner. Speaking of chimney vents, the existing shape of the arch does not lend itself to a heavy chimney load without buttressing the side walls. So if you build a brick chimney of any height you will need to buttress the side walls.

[slschoming]

I like the idea of the L shaped vent arch. I assume if I go that route I'll need to fill in this gap (circled in red) with a little wedge so my inner arch is a consistent distance from the vent arch all the way around?

Also, can the vent arch and chimney be built with regular brick? I plan to finish the outside of my dome similar to cobblerdave's oven and I have been accumulating old house bricks for this purpose. It might be nice to do the vent arch with house brick from the start so there is no extra layer required around it when I'm done. Does that make sense?

[JRPizza]

Gulf's build was one of the ones I copied when I did the L shaped brick trick for my vent arch. It not only provides a nice way to get a door reveal around your inner arch but also provides a horizontal surface to put a length of insulating rope to seal off your heat break.

[slschoming]

I lucked out and my arch template came out very easily but I will have some cleanup to do, followed by a little pointing.. Any advice on removing excess mortar that has already hardened? Grinder?

[slschoming]

The release is a little small,so you have to be really careful because the form will be tight and you risk disturbing the arch joints.

For all you builders out there, make sure you have at least a 1/2" so the template will come out easier.

Yes, I worried about it being too tight, but not until I had already set some of the bricks and was stuck with my mistake..

Fortunately, my template is some 2x4 framing that is smaller than the arch sandwiched between two pieces of plywood and all screws are accessible. If I have to, I can unscrew it all and get the front piece of plywood out with a little patience and preserve that for a door template. Then the rest of the wood can be sacrificed if it's too tight... I might also be able to pull the floor bricks out from the front as well once I remove the shims..

I will check out Gulf's thermal break. Thanks for the tips as always!

[UtahBeehiver]

That is correct, this was to minimize thermal transfer between inner arch and vent area. But I do like how Gulf did a "L" shape brick for vent area for his thermal brake as well. Look at his build.

You should be able to drop arch as soon as mortar sets up. Save you template since you can use it for laying your door. The release is a little small,so you have to be really careful because the form will be tight and you risk disturbing the arch joints.

For all you builders out there, make sure you have at least a 1/2" so the template will come out easier.

[slschoming]

I saw on another page that I could probably remove my arch template now, so I will try it today. Hoping I don't have too much sloppy looking mortar mess under there..

UtahBeehiver it looks like your bricks are cut at an angle and are just barely touching on the inside of your outer arch? Is that homebrew circled in red? Then you stuffed in the ceramic rope and sealed with the high heat caulk?

[slschoming]

I finished the inner arch and ordered a tube of inswool pumpable caulk last night.

How soon can I remove the shims and pop out the arch template?

[UtahBeehiver]

Not even a tube, but depends on how wide, deep, and long the joints are. Also used under my adapter plate for the chimney.

[slschoming]

I have been google searching Kawool moldable caulk and uni-extreme for the past week and found inswool pumpable to be comparable, but more reasonably priced. UtahBeehiver How much of this did you go through? I am wondering if I can get by on one 10 oz tube.

https://www.theceramicshop.com/produ...e-10-oz-caulk/

Thanks in advance

[slschoming]

UtahBeehiver and JRPizza Thank you for the responses. I will try some of these and see which work well for me. Russell, your advice (from a few weeks back) about leaving an "anchor" brick on the next course has been very helpful. I am always thankful to have a solid brick to join to when I start a new course.

[JRPizza]

I had good luck with a combination of dry bricks and sloppy mortar (homebrew). I'd just wipe the edges of the dry bricks with a damp sponge to remove anything loose and get some color on the edge, then butter the bricks with the wet mortar. It starts to suck into the brick really fast. I'd press and hold in place for about 20 seconds and the bricks would adhere enough to proceed to the next one. Get a row in and let the cure overnight. I'd hit the inside with the wet sponge to knock off any excess. Nothing wrong with using some kind of support but once I got the mortar consistency and brick dryness dialed in I was really able to speed up the build.

[UtahBeehiver]

I just used some notched sticks. There is a build that made something used by old time "eastern Indian" masons the resemble a claw, string and brick just recent on the forum. I tried the jack and plywood platform but did not like it due to not being able to see or clean up the inside of the dome.

[slschoming]

It started raining on me yesterday so I had to bust out the pop up. I am getting close to the point where I will need some kind of support under my bricks so they don't fall into the oven as the mortar solidifies. I get a lot of mortar on the inside of the oven when I am laying bricks so I don't really trust myself to use a support that prevents access from below. I like to be able to wipe my brick faces clean after each batch of mortar. Any ideas?