Filling the gaps with mortar

[robinwham]

Re: Filling the gaps with mortar

Hey Dave, Stonecutter and TScarborough, you guys are great! I did what my control-freak dictated. Against the majority opinion, I hunkered into that oven and filled those gaps! I feel good about it, and did a darn good job, but only time will tell how my patch went. I can just see it now...all those guests biting into chunks of fallen mortar. More garlic, I say! They'll never notice. Thanks, you guys, for helping me out.

[stonecutter]

Re: Filling the gaps with mortar

Reckon you are right, that is probably where I saw it, I think.
Am I right in thinking the bricks go in completely mortarless?
Wonder if it could be done with homebrew?

Almost all the build pictures I saw show the courses being mortared in....at least, they had bed mortar, which would keep the brick face aligned with the sand form. Some appeared to have an open head joint, to be filled when the pourable is applied.

One oven looked like it was dry set (hard to tell by the picture angle), maybe the brick were held by wedges until the pourable was applied.


I don't see why you couldn't use the 3:1:1:1 or something similar, as long as you know that it isn't the same as refractory.

Maybe consider reducing the portland content while increasing the lime and clay. Also, you should use larger aggregate for the pourable mix, as the bigger gaps would require it. You could actually make a good grog mix from when you cut the firebrick, and leave the small bits that are normally sieved out.

[wotavidone]

Re: Filling the gaps with mortar

I don't know if there is a thread like that on here, but there is one over at Pizza Making that documents a number of Neapolitan oven builds. The material poured into the brick work is a type of refractory.

Reckon you are right, that is probably where I saw it, I think.
Am I right in thinking the bricks go in completely mortarless?
Wonder if it could be done with homebrew?

[stonecutter]

Re: Filling the gaps with mortar

I'm tempted to try the sand form on the dome my mate wants me to build for him. Somewhere, on this forum I think, there was a link to an Italian professional build. It looked like they did a soldier course, then laid the rest of their bricks dry on top of a sand mould, just dropped them in place with some gaps, then just poured some sort of mortar over it. It'd be one technique where it would actually be beneficial if the gaps were pretty big, so it was easy to work the mortar in.
It would certainly be a lot quicker. With the IT, I was always reluctant to start a new course of bricks until the course below had set up.

I don't know if there is a thread like that on here, but there is one over at Pizza Making that documents a number of Neapolitan oven builds. The material poured into the brick work is a type of refractory.

A sand form is arguably the oldest method used for oven building. It works great, give it a try.

[cobblerdave]

Re: Filling the gaps with mortar

Gudday mick
Yes the watery mortar was used but only on the last bricks at the dome apex.
The thing was it was very fast to build and the main thing apart from the way it was built was there was 2 of us. I was there for moral support rather than my bricklaying skills . All I did was to shape pavers in 1/2 and pass them over and mix mortar. A stack of empty pet bottles was included in the sand so removing it was easy. It has to removed early so the mortar doesn't set for a good clean up.
It turned out to be a great little oven, my mates patient and let the bits dry and cure correctly so it has no cracks to speak of.
If I was to build again I would use this method and pavers as well . It was efficient and cheap to build.
Regards dave

[wotavidone]

Re: Filling the gaps with mortar

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

I'm tempted to try the sand form on the dome my mate wants me to build for him. Somewhere, on this forum I think, there was a link to an Italian professional build. It looked like they did a soldier course, then laid the rest of their bricks dry on top of a sand mould, just dropped them in place with some gaps, then just poured some sort of mortar over it. It'd be one technique where it would actually be beneficial if the gaps were pretty big, so it was easy to work the mortar in.
It would certainly be a lot quicker. With the IT, I was always reluctant to start a new course of bricks until the course below had set up.

[cobblerdave]

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.

Gudday
Yes I agree it would be best practice but better practice would be not to get into that situation in the first place. I'm thankfully that these ovens are so forgiving in design and works regardless of my poor masonry skills
Regards dave

[Tscarborough]

Re: Filling the gaps with mortar

It is somewhat important to have a relatively smooth surface without exposed edges and corners. They (edges and corners) will concentrate the heat and will fail sooner than the rest of the oven. A small thing and not one to worry about, it is just best practice to fill them.

[cobblerdave]

Re: Filling the gaps with mortar

Gudday
Yes Im pretty sure I did that. I was conscious of having clean joints and also used a paintbrush and water . I only did a small section in a corner as I didn't want to have anything in my food
Regards dave

[stonecutter]

Re: Filling the gaps with mortar

Gudday
That's the question was I able to clean the joints enough, hard to remember now, but the mortar certainly didnt take.
Regards dave

One way to clean it would be a looong hot clearing fire, and then brush the joints out well. Any particles that are on the masonry will hinder the bond, as you have experienced.

[cobblerdave]

Re: Filling the gaps with mortar

That's what I thought...the mortar wouldn't stay because the joints were dirty.

Gudday
That's the question was I able to clean the joints enough, hard to remember now, but the mortar certainly didnt take.
Regards dave

[Tscarborough]

Re: Filling the gaps with mortar

Best practice and common sense says tuck all joints. If it falls out, try again.

[stonecutter]

Re: Filling the gaps with mortar

That's what I thought...the mortar wouldn't stay because the joints were dirty.

[cobblerdave]

Re: Filling the gaps with mortar

Gudday
The ovens was definitely fired ... I burned the ply form out
Regards dave

[stonecutter]

Re: Filling the gaps with mortar

Did you try to point it up after you fired the oven ( to dry it out) or right after you closed the dome?