Build started in Mountain Top NSW

[Gretsch]

G’Day all,

I started my build couple months ago, wasn’t going to start a thread on my build because there’s so many really good builds already that I’ve referenced but I figure it’s a good opportunity to catalog the build and get some feedback from this great community forum.

Have been planning this since retirement 6 years ago when we moved here from Darwin but there’s been renovations to do and other projects that’s slowed me down. (Well, truth is, my bro in law had one installed and I couldn't live with that !!!)

Our property is as the title suggests, in a mountainous area, beautiful views over the valley we can see Mount Warning from our window. We excavated a flat area to one side of the house and still not completely finished but enough so I could plop my WFO base down. Should be pretty spectacular where it’s set to take advantage of the background views.

All my neighbours are egging me on to get it done, they’re busting to eat pizza and I hope I don’t disappoint them.

So anyhow, my base was laid in a 150mm deep red soil, reckon I put enough rod and cement in the mix to be plenty strong enough, took 2 of us a few hours let it set under a tarp for a week to get maximum strength before I put the blocks on top.

I bought a stack of seconds from ABC bricks that I’m using in my landscaping they’re 140 x 200 x 100 so decided they’ll do.

will post pictures soon.

[Gretsch]

Have to say our internet speeds are atrocious! Dial up was faster. It takes several attempts to upload photos they bomb out and I have to try again. The exchange is 8km away which is partly the reason.

Finally got some piccies uploaded, paving job under way, formwork down, concrete down, blocks down, frame finished. It came up pretty good and I’’m happy with the result.

[Gretsch]

I put down a 100mm layer of Perlite, it took a while to set but then I felt it was a bit fragile. I looked around for alternatives and Claypave had a load of kiln insulation bricks they pulled out of a kiln, light weight and cheap so I put them in. They just seem like they won’t break down too easily.

Sat them on their edge for maximum insulation, a layer of sand and fireclay and then the hearth bricks. I’m not going to put a soldier course down I don’t the need for it. I used a plastic fluted material to prevent mortar filling the gap, should be able to pull it out when the time comes.

[Gretsch]

Now I'm at the stage where I'm building the dome. After I assembled the arch and glued it together it occurred to me that night I didn't cut the inside downward face as everyone else has done. I didn't want to pull it apart in case I broke a brick. Claypave are the closest refractory supplier and it's over 2 hours drive from here.

So it's a painful process cutting them bricks around the curve, at least I've got a brick saw so it's easy to cut but time consuming. Then there's a fair gap as you can see in the picture which takes a bit of mortar to fill, I'm having to push the brick upwards and stuff the corner with mortar to keep the dreaded droop at bay. If anyone can provide some feedback on this it would be helpful.

Otherwise, I think it's looking good, gaps on the bricks are nice and tight, it's staying level.

[david s]

What kind of mortar are you using? The reason I ask is that you mentioned glue. Refractory glue is not suitable for large gaps. You are better to fill large gaps with homebrew mortar, which by the way is far cheaper and has proved quite adequate for the temps we fire to.

[Gretsch]

David I used Rylbond refractory glue on the arch bricks and home brew mortar on large gaps. Yes I know the glue should only be used up to 2mm thick otherwise it doesn’t set.

The home brew I’m using is 3 parts fine sand to 1 part cement, lime and fireclay. Sure is sticky and hard on the hands, had to put on disposable gloves under leather gloves to keep it off my skin!

[Gulf]

Mineral or baby oil will also help keep the lime out of the pores of the skin.

[SableSprings]

Another thing that works well to help recover after working with anything containing lime & caustics, is to rinse your hands with plain white vinegar. The gloves certainly help, and as Joe mentioned, the mineral/baby oil hand pre-coat is worthwhile.

For me, I just always ended up with bare hands doing some "little mortar patch or fix" that resulted in itchy & irritated skin. The vinegar rinse neutralized the lime on my hands from my "unprotected mortaring" and soon became S.O.P. for any cement or mortar work on my oven. (...and vinegar is really cheap )

[Gretsch]

Thanks for the handy tips (pardon the pun) have been using hand cream morning and night to try and keep my hands from cracking and the gloves are working well. I was just getting lazy and decided to tackle some mortaring without gloves and was I sorry! Took some skin off.

Making progress, I've laid 5 courses, the cuts around the arch are taking forever and the gaps are getting bigger further up and they're doing my head in.

Decided to make a downward cut on the remaining arch bricks with an angle grinder to eliminate all those ridiculous angles. Still getting a droop on the brick that faces the arches, I can't figure out how it's happening. I'm having to push the end along the arch up about 3-5mm higher to stay level, hope the mortar fill doesn't fall out.

[Gretsch]

Laid row 6 today, 3 or 4 more to go.

I’m seeing that droop around the arch so think I’ll place this brick now that the row is done. I should be able to make a cut that will sit nicely in this corner and angle it to bring it back up level again.

My arch opening height is 325mm, inner dome width is 1070mm so my IT is set to 535mm. Ideally 63% of arch opening is 510mm. So if I start to reduce the IT length down gradually for the next 3 or so rows say around 8mm per row am I going to run into difficulty?

The green tinge in the photo is from the tent I bought to keep the hot sun off me and the bricks.

[SableSprings]

I think you should just tell people, the oven's tinged green cause it isn't ready yet...sorry, poor joke

The build looks great! The droop is not a structural problem...it's just annoying (IMHO). Lots of builds have had the "problem" and easily resolved it in lots of ways to bring things back to level. Your brick joints look good...no alignment issues and the arch is very nice!

The 63% door height to inner dome height ratio is merely a goal that you want to aim for...my ratio is below 60% and the oven breathes just fine. Reducing your IT length to lower the dome height should not be an issue but neither will your projected ratio of 60.7% (325/535) without the adjustment (lower ceiling 8 mm, 325/527=61.67%).

[Gretsch]

Thanks for that Mike, I feel a bit more confident in my work. I would think others would be green with envy (sick I know)

That’s 8mm over 3 courses = 24mm. 325/510 = 63.7% approx.
Dunno wether that bit lower ceiling height is really going to give it any advantage to bread baking but hey what the heck !

[Gretsch]

Well I'm over the arch, it was a hell of a job juggling the cuts, it's a bit ugly in the front but some off cuts stuffed in the gaps should hold up, looking from inside there's no big gaps to speak of can't see them yet until I finish the dome and remove the timbers.

One thing... I forgot to shim the supports so I think I'll have to cut them rather than knocking them out and risk breaking the dome

Got a question regarding the landing. I'm going to leave a 10mm gap between the chimney arch and dome arch for a fire break and stuff the gap with some insulation rope (anyone know where I can get some) so I've got some old house bricks I want to use up. Can I use them for the chimney and arch and also the floor landing in front of the dome ? Do I need to extend the hearth insulation layer beyond the dome arch ?

[SableSprings]

Bummer about the "shim-less supports" but hopefully you've got (or have access to) a sawzall. It'll make the cuts pretty quickly. Make the cuts on the back supports first so the sand/top piece(s) slides (or falls ) away from you. If you used a lot of sand on top, a big spade bit from underneath the supported platform will help "drain" the sand via some holes before you go at the supports.

Check a local dealer that handles stoves & fireplaces for the gasket rope. Here's a link to our (USA) Amazon web site and a fiberglass gasket kit

https://www.amazon.com/inch-Woodstov.../dp/B01ETURR0M

and a graphite/glass variation.

https://www.amazon.com/Rutland-96N-6...8YABEDQCTMHJ27

You should be able to find some very similar materials next time you get into town.

If you are going to make a heat break, don't forget to continue the break across the front of the landing. The purpose is to try to isolate the oven and leaving the floor/landing just leaves an avenue for heat to escape. That said, I think the heat loss here is going to be minimal and you've got to ask yourself...Am I really needing to extend my baking over 3-4 days after a firing? I have poor floor insulation and no heat break and I can cook a chicken the day after I bake bread...

I used firebricks in the lower smoke collection area (I've had flames shooting out the oven and up into the collection hood). But my outer arch doesn't get that direct flame/heat hit, so it's house brick as is the outer facade. Just think where will bricks experience fast (and big) temperature changes...those areas should be firebricks (IMHO). Firebricks can withstand that heat stress where house bricks may not . My front landing bricks are bullnose (house bricks) but they are in front of my ash dump and the bricks extending out of the oven to the ash dump are firebricks (I guess my ash dump is a primitive (and partial) heat break for my cooking floor.

You do not need to extend the hearth insulation beyond the dome arch (here's where some folks add the thermal break to isolate the oven). Just make sure to give yourself an adequate reveal to seat your door properly. Having 2-3 cm reveal all around gives you plenty of wiggle room when placing the door.

Sorry to be so long winded...hope this helps. By the way, I think your inner arch looks great and remember all that "ugly stuff" is going to be hidden with the insulation blanket and final render or cover you end up doing. Relax...your oven is going to produce great pizza and good memories!

p.s If you haven't been following this thread on heat breaks, you might want to take a look...
https://community.fornobravo.com/for...o-or-not-to-do

[Gretsch]

Mike, thanks for the info, long wind is good

Great tip drilling a big hole to let the sand out, I wasn't looking forward to cleaning up all that sand! Unfortunately Amazon won't ship to Australia, but a quick google came up with several sources and I know a few wood heater manufacturers in town so I'll see them next time I go. I don't have a sawzall (we call it a reciprocating saw) but I do have a multi tool that'll do the job no worries. The heat breaks thread was quite informative and I've now formulated a solution in my mind which I'll put into motion when the time comes.

Yes I do want to preserve as much heat as possible so I can do lots of different things as it slowly cools down. I usually have buckets of fruit and veggies to dehydrate each year and my poor little electric dehydrator just can't keep up.

Another thing I learnt somewhere in this forum was how lime in mortar makes concrete more water tight and less brittle. If I had known that when I poured my slabs I would have thrown some in the mix. Probably doesn't really matter as I've used insulating fire bricks on my floor and I think they're a glass product and if what I've read is right they don't wick water up. (here's hoping)!

BTW: I took a look at your build I have to say you did an amazing job, not only does it look bloody good but I don't think I would have attempted the teardrop shape!