Gaps, bumps, uneven dome top....how bad can it be?

[deejayoh]

Re: Gaps, bumps, uneven dome top....how bad can it be?

whoa. I don't think there is any way you are going to get a saw or a grinder into those joints to remove them. I guess maybe if you decide to cut an "x" through the middle you might make some progress- but through 4 1/2 inches of brick? Probably not.

Personally, If I really wanted to remove those courses, I'd take a narrow cold chisel and hammer (maybe rubber mallet) and see if I could knock the center bricks out backwards from the inside starting at the very top of the dome. Once you get one out, the next one will go more easily since you have one less side holding it in place. But if it is REALLY that hard to remove them, then they are likely rather well installed and maybe I would stop worrying about what they look like.

[Lburou]

Re: Gaps, bumps, uneven dome top....how bad can it be?

If you decide to redo it, have you reconsidered your strategy for using another (read different, like a pilates ball) form?

[Gulf]

Re: Gaps, bumps, uneven dome top....how bad can it be?

Xene,
If you decide to remove those rows, my advice is to use a side grinder or better yet a skill saw with a masonry blade. A diamond blade is a bit much to pay for in this case since the mortar doesn't go all the way through. Be careful, cut downward along the joint lines. Even if it does not go all the way through it will at least give it a fault line so that your hammering does not break it where you don't want it to .

[Xene]

Re: Gaps, bumps, uneven dome top....how bad can it be?

The overhead tucking sucks part comes out very clear in the post as I read it!

Gulf - fabulous instructions, thank you! Now I'm really torn, as I know I can do a much better job - and I also know that a few of those joints won't take mortar and those little ones will probably bother me once I fix those gapping holes. And we do have a few friends who will be sure to tsk, tsk me over those gaps when they see it, no matter how awesome the outside turns out -oh the shame!

I took my rubber mallot to it tonight and it won't budge...another strike against tearing it apart, but I think I'm going to get a chisel tomorrow and see if I can dislodge parts of it - do a partial pintuck and partial rebuild. I'm still torn. Gulf's instructions give me hope I can salvage it the way it is - ugh.

Was the idea of adding more lime and more sand a good one if I try the brick repointing method? Hope there are a few brick pointing videos on YouTube to check out.

Good grief!

[Gulf]

Re: Gaps, bumps, uneven dome top....how bad can it be?

That needs to be bagged, overhead tucking sucks.

Either I left something out or you misread the post.

IMO it takes a combination of the two.

[Les]

Re: Gaps, bumps, uneven dome top....how bad can it be?

Couple more weeks? I can rebuild that in a few days!

I'm sorry I forgot your awesomeness I still suggest you take your time. If I could go back, I would re-do quite a few things. In regard to people looking inside at your work - trust me , they will. Even if the fires of hell are going on, they will want to look inside.

[Tscarborough]

Re: Gaps, bumps, uneven dome top....how bad can it be?

That needs to be bagged, overhead tucking sucks.

[Gulf]

Re: Gaps, bumps, uneven dome top....how bad can it be?

Xene,
If you do decide to fill the gaps, you will have to keep one thing in mind. That is you will have to fill them from the back of the crevice forward. Or downward in this case. From veiwing the pics I believe that when you were mortaring in the last few rows that you were trying to push the mortar into the joints with a trial or I believe you said with your fingers. Mortar can't be pushed 2 inches into a joint with a tool wider than the joint. It will just bridge over trapping the air or spaces that you see. It has to be "pointed" in. By that I mean that you will have to use tools that are narrower than the joint that you are "tuck pointing". In your case you have many different size joints to fill. So you will have to have several different sizes of tools available. To complicate things you will be pointing vertical. That means that some mortar might just fall in your face. Have at least safety glasses and a bandana over you mouth and nose.

You can use a "mortar bag" to apply the mortar. The bag will keep the mortar from drying as fast but you will still need a tool to point the mortar with. I have three sizes of tuck pointers (1/4" and 3/8" and 1/2"). I dont think that going out and buying masonry tools would be cost efficient for the small amount of work that you need to do though. You can fab a few tools from common every day things, a butter knife, wood rippings, even the flat edge of an unsharpened pencil can be used to point the mortar straight up into the back of a tight joint.

And yes, I do agree with Tscarborough. It would bug me too. But if your pointing is done right it should last many years. At least as long as if it had been filled at the time of placement.

Prior to pointing, clean the joints as good as possible. I have an air compressor, but no more than you will have to do, one can of compressed air like they use for computers would do just fine. Work in small sections. Use a small paint brush and prewet the joints you are pointing. Fill from the back (top) in at least three passes. Apply the mortar about one third of the depth of the joint. Use a tool comparible for that joint to pack or smooth to the back. Work fast on one small section, but don't get in a hurry on the whole project.
If you decide to remove the last few rows, what we call buttering the brick is by far the best route to go. But, for that inevitabe joint or joints that need to be pointed, keep this technique in mind.
I hope this helps.l

[Tscarborough]

Re: Gaps, bumps, uneven dome top....how bad can it be?

If the gaps are pretty big and not triangulated upward, they may well hold the mortar. It is worth a try if the appearance doesn't bother you (and there is no reason it should, it is a cooking appliance after all).

Shuboyje, I have a product that would work for that, the main difference is that it contains a fair amount of perlite. It is sticky and able to be used wet. The Italians are using a volcanic pozzolan mix design, and I have been looking at making a mix with some glassine pozzolans.

[Xene]

Re: Gaps, bumps, uneven dome top....how bad can it be?

whats a couple of more weeks when you get years of good sleep?

Couple more weeks? I can rebuild that in a few days! And enough of you seem to be confirming my gut feeling that I think that is what I'll be starting in the morning. Yucky!

[shuboyje]

Re: Gaps, bumps, uneven dome top....how bad can it be?

I did read in another thread that the builders in Italy fill the gaps with Refractory cement. I think it was Tscarborough who said on the same thread that the gaps aren't a big deal

I just wanted to clarify this point, since I was the one who posted it originally. It is not a solution for this situation, it is instead an alternative method to building the dome that does not require complex cuts.

I made a simple graphic to explain how it works a bit better. Italian builders work on a sand form, and that is critical to this method. The bricks are first laid using the sand form with the mortar joints shown in blue. Once the dome is completed in this manor all the triangular gaps are filled with a castable refractory which is shown in green. The italian builders use a very wet mix and pout it over the dome to fill the holes, but I could not find a refractory product here in the US made for that wet of an application so I simply used a standard fairly dry mix and rodded it into each hole to compact it and eliminate gaps and air pockets.

[Les]

Re: Gaps, bumps, uneven dome top....how bad can it be?

Xene,

I also would not patch it. The lime make the product more "plastic" but it's not a magic bullet to prevent cracks. If the mortar cracks there is always a chance of it falling in chunks or bits and pieces. If it were me, I would remove it, take step back and take your time rebuilding it. The summer is new, whats a couple of more weeks when you get years of good sleep?

[Xene]

Re: Gaps, bumps, uneven dome top....how bad can it be?

Thanks fellas! Those holes are pretty big, I'm not talking a crack here, those are bigger than quarters, I don't think you can tell from the picture. They are really rough and odd shaped (eek, I can sure make my work sound good can't I?) I'm feeling pretty confident that there is enough space and nonuniform surface that mortar would get trapped in those biggest holes and get locked in, just because there would be a significant mass. Some are half the brick deep... Digging my quality-built hole deeper...

I think I could live with the inside as long as I know it won't fall in later in life when I'm too old to fix it. If it is structurally sound this way, I think I'd be happy to give those holes the best fix I can, and hope for the best. If it is not, well that is an entirely different story. I'm going to put so much attention on the finish of this thing that the inside dome will never draw anyone's attention!

Has anyone played with the mortar mix? I've read about lime lately and how it provides more flexibility - in that it allows for more expansion/contraction, and is more breathable, if I increase the sand and lime would that be of any benefit? What advantage is the Portland providing in the mix? Just some ideas I've been tossing about, thought you all might have suggestions?

Deejayoh - Thanks for kudos on burning through this project, we've had such a dry spring that I've been able to work on it every day - it seems like it went really fast - even to me! Even if I knock it out (or up) it still seems like decent progress in a short period of time.

[Tscarborough]

Re: Gaps, bumps, uneven dome top....how bad can it be?

They (mortar repairs) are pretty much going to fall out, no matter what you do, but it doesn't affect the performance. I would probably knock it out just because it would bug me every time I used the oven, but it is up to your preference. If you do knock it out, be sure and knock it UP from inside.

[deejayoh]

Re: Gaps, bumps, uneven dome top....how bad can it be?

With regard to filling those voids after the fact, unless Tscarborough has a fail safe way to do it, I'm not sure the patches will stay. I say that because mine are falling out each time I heat the oven, and its been almost a year!

Uh oh... sounds like I might have some gritty pizza's in my future. I am hoping that filling the voids quickly after setting the brick will make a difference in the mortar bonding- while the mortar is still wet.

I did read in another thread that the builders in Italy fill the gaps with Refractory cement. I think it was Tscarborough who said on the same thread that the gaps aren't a big deal