Point Gaps Inside Dome? Skim Mortar Coat?

[mpholland]

I've just finished the Pompeii dome and am looking for some perspective:

1. The inside brick joints on the last 2 - 3 courses are not as elegant as they probably should be. There are a number of gaps between bricks that are probably in the 0.5" - 0.75" range. Is it best to fill these gaps by pointing them with mortar from the inside or just let them be?

2. Once completed, is it helpful to cover the exterior of the dome with a 0.25" - 0.5" skim coat of refractory mortar to ensure that all the joints are filled from the outside? Additionally, I have many small pieces of firebrick remaining, is there any advantage to embedding them in the final mortar coat to provide a little more mass prior to wrapping it with the ceramic blanket.

As always, thanks in advance for your input.

Mark

[Les]

Re: Point Gaps Inside Dome? Skim Mortar Coat?

Mark,

1. Those are pretty large. It?s think it?s been agreed upon that it is best to fill them. I have some gaps but they are no larger than 1/8 inch (I used no mortar on the inside).
2. I covered the outside with the amount you are considering. I don?t think you need more mass, ? brick thickness appears to be fine.
Les?

[dusty]

Re: Point Gaps Inside Dome? Skim Mortar Coat?

Hi Mark,

Here is what I think:
1- If I had 1/2 to 3/4 inch gaps on the inside, and had some pieces of firebrick left over, I would cut some wedge shaped pieces and mortar them into the gaps. I would put some mortar in a gap and then lightly tap the wedge in.

2- I did not skim my dome with mortar when I was done, but some here did. By increasing the mass, you also increase the time and amount of fuel it takes to heat the oven up. If you are not sure all the outside gaps are filled, check them by looking at them. If you see some air gaps on the outside, fill them with mortar. If they are large, try the wedge thing. Just don't tap too hard as to not crack the dome.

Just my opinion, but I hope this helps.

dusty

[egalecki]

Re: Point Gaps Inside Dome? Skim Mortar Coat?

I would do as Dusty suggests on the bigger gaps. Use a mortar bag, mix your mortar a little on the loose side so you can squeeze it out.

I would only fill gaps on the outside to even the mass out, not add mass. I did a layer over mine, but it was because of my construction technique, not to add mass. Unless you want extra retained heat, I wouldn't bother.