Mortar gap.

[Chobbs]

Hey all

Was wandering if I could use your expertise to settle my nerves. I am in the middle of my build, a 36” igloo. I’m on my 3rd course and feel that I am doing something wrong. When lining up my IT (which is pretty shoddy I must admit) for the course and tilting them into position to line up with the IT they seem to have a huge gap at the back. I am bevelling and tapering the bricks in accordance with Deejays dome calc with a take on the chipster jig (using a mitre saw with masonry blade).

I have attached a picture of the gap. Is this usual or have I messed up somewhere?

[UtahBeehiver]

You are really after tight inner joints with mortar filling in the back sides. To confirm that the IT is the correct config, attach a picture of the IT, pivot point etc. Bevels and tapers have not affect on the back horizontal mortar joint but the correct perpendicular angle to the center of the dome does.

[Chobbs]

Here’s a picture of the IT.

The pivot point is level to the floor and the main arm intersects the brick in the middle.

[UtahBeehiver]

Something is out of wack. On this course the bricks on the right side of the pic sit flush with the bricks on the previous course while the brick on the left side of the pic do not. So something is not centered or the IT has slipped. There should not be pronounced steps from one course to the next. Center of pivot to halfway down the brick face appears ok.

[Chobbs]

Okay. I’ll have to look at the IT tomorrow when it’s light again. If it is out should I just readdress this course or look to remove the previous course and start again?

I will say the course being laid, half the bricks are on shims and half aren’t if that’s what your referring too?

The mortar gap will still be quite large. I take it this has to be filled with homebrew?

[UtahBeehiver]

No, the front face of the brick is overlapping the lower course more on the left side of the pic than the right side. Shiming is up to you but home brew will work as well.

[Chobbs]

Cheers Utah. I’ll have a look at the IT and see what’s up and if it needs adjustment.

Thanks for the quick response.

[JRPizza]

When you get your IT sorted out you might want to consider buttering up the bricks before setting them so that the gaps are totally or mostly full of mortar. This will keep you from having to come back and trying to fill those gaps later.

[Chobbs]

Thanks JR. I have been buttering but just getting into the swing of how much mortar to put on. I think I’ve got the hang of it now and have stopped using shimmer.

The IT was checked and seemed to be correct? The rest of the courses are doing better and I don’t k ow what the issue was but I must have misused it somehow?

Started the arch now so fingers crossed for me.

[MarkDLxu]

Hi,
I’m trying with my iT to stack some bricks (without mortar) and I’m having the same issue as Chobbs (overlapping between the courses).
Since the bricks I believe are the same, is it something with the pivot point or the fixed length of the IT?
Look at the difference even on the first three courses

[Chach]

Hi,
I’m trying with my iT to stack some bricks (without mortar) and I’m having the same issue as Chobbs (overlapping between the courses).
Since the bricks I believe are the same, is it something with the pivot point or the fixed length of the IT?
Look at the difference even on the first three courses

how is your length fixed? I see duct tape is that how it is fixed? the pivot point has to be in the center in relation to the center of the brick. It is hard to tell from the picture if the pivot screw is in the center. Also the course looks like it is overlapping less on one side than the other. if this is true is your center staying true or is the it not fastened good to the floor?

[Chobbs]

how is your length fixed? I see duct tape is that how it is fixed? the pivot point has to be in the center in relation to the center of the brick. It is hard to tell from the picture if the pivot screw is in the center. Also the course looks like it is overlapping less on one side than the other. if this is true is your center staying true or is the it not fastened good to the floor?

I’ve completed the dome now. The IT had the duct tape to hold it while I screwed but I just didn’t take it off. It was aligned to the center, no idea how I had them move out of alignment but the rest of the dome went smoothly. Now just waiting for it to cure before I fire it up.