Filling the gaps with mortar

[scottsummers]

Ok some I'm a newbie and have just finished the dome (see my build Scotty 36 sunshine coast, Australia) I'm not a master brick layer, I'm a helicopter pilot. Some of my joins on the oven side are not ideal, not terrible maybe 5mm gap here and there, can I just climb inside and use the same mortar to fill the gaps from the inside? I'm using a mix of fire clay/cement/lime/sand so far to stick the dome together. I have heard that cement can break down under xtreame heat, so would my planed mix work?!?
The mix is 10 sand/6 fire clay/3 lime/2 cement.
Thanks
Scotty

[david s]

Re: Filling the gaps with mortar

The consensus seems to be that any breakdown of the Portland cement is compensated for by the lime.
The usual mix is sand, fireclay, lime, cement 3:1:1:1 Your brew is pretty close, but has more fireclay. Too much clay can create excessive shrinkage, but you should be ok.

[doctorphreak]

Re: Filling the gaps with mortar

question about the heat could a person add more lime to the mix maybe like
3:1:2:1 to help with the heat more ?????

[robinwham]

Re: Filling the gaps with mortar

Hi, I have just closed the dome on my 37-in Pompeii, and notice some mighty large gaps in the inside joints. Did you end up filling them, (I'm using refractory mortar), and if so, how? Did it work out well? Appreciate any responses!

[cobblerdave]

Re: Filling the gaps with mortar

Gudday
I had the same and couldn't help myself and disregarded good advice and crawled in and patch a small section. They were right it didn't work and fell out.
Just live with it,its a dome and is strong for that reason not pretty brickwork.
Regards dave

[robinwham]

Re: Filling the gaps with mortar

Thanks Dave...are you sure?? I don't know if I can stand it. These are some pretty big gaps. Thought I'd use a pastry bag or a huge syringe to squish some mortar in...sigh...

[boerwarrior]

Re: Filling the gaps with mortar

So Scotty,

I have to ask! What's harder?

Flying a helicopter or building a wood fired oven?

[cobblerdave]

Re: Filling the gaps with mortar

Thanks Dave...are you sure?? I don't know if I can stand it. These are some pretty big gaps. Thought I'd use a pastry bag or a huge syringe to squish some mortar in...sigh...

Gudday



No one sees it anyway so you will learn to live with it. And because you introduced some some stress relief points you shouldn't get any cracks!
Only the real tight builds seem to gets visible cracks
Regards dave

[robinwham]

Re: Filling the gaps with mortar

OK Dave, I don't feel so bad (although I think your "inside" looks better than mine). My concern was heat retention without all the gaps full of mortar. But clearly, you're the boss here...nice "white" dome! I can't wait to fire the oven up (not quite there yet...)!

[wotavidone]

Re: Filling the gaps with mortar

I'm a little bemused by gaps, especially when using the homebrew.
Why don't people just butter the brick with so much mortar that when they set it in place the excess squeezes out through the gaps, then scrape the excess off with the trowel as they go? Worked for me.
Only time I see this not working is if the dome is built on a sand form instead of using an IT

[cobblerdave]

Re: Filling the gaps with mortar

I'm a little bemused by gaps, especially when using the homebrew.
Why don't people just butter the brick with so much mortar that when they set it in place the excess squeezes out through the gaps, then scrape the excess off with the trowel as they go? Worked for me.
Only time I see this not working is if the dome is built on a sand form instead of using an IT

Gudday Mick
You missed two.... Ply form like I used and styrofoam form. There all in the plans. Which are unchanged from when I built I might add.
I have also been involved with a sand mold. One day for arch and 4 or 5 levels up. Next day sand mold, brick over, keystone in remove sand after a beer and clean up the inside. No gapes either. But I might add it was a paver dome as well so the thinness of the pavers contributed to the smallness of the gapes till high in the dome the mortar space was bigger.
Regards dave
Regards dave

[robinwham]

Re: Filling the gaps with mortar

Hi, w,

So, true confession, I AM TERRIBLE WITH MORTAR! No matter how I tried, I could never get the right amount on the brick...coupled with the decreasing visibiity and increasing bevel of the bricks as I neared the top of the dome. I did use an IT, but that did not help my mortar skills. Thanks for writing.

[Tscarborough]

Re: Filling the gaps with mortar

You should fill all the gaps. Some may fall out, but most will stay, and if it is a big gap you should fill it again.

[stonecutter]

Re: Filling the gaps with mortar

For larger open joints it is better to use larger sieve sand in the mortar mix.

[cobblerdave]

Re: Filling the gaps with mortar

Gudday
Sorry guys ,but I have to disagree on the one . I've tried it the mortar wants to fall out. I can live with it now that I have cooked so much in my oven, and it didnt fall down
Regards dave