What to use for filling gaps between the bricks?

[vincentvintris]

What is the best material to fill the gaps between the fire bricks when building the dome? I'm looking at the brick structure built as per the Pompeji plans and wonder about the very thin wall where the half bricks come together.
It seems to me that the gaps must be filled to create a solid oven wall.
(Or alternatively cut the bricks to fit better)

I'm using heatstop 50 for mortar. Given the recommended max joint width I'm not sure I should use it to bridge a 1/2 inch+ gap.

Any advice would be great.
Thanks

VV

[DrakeRemoray]

Re: What to use for filling gaps between the bricks?

Well, I used Heat Stop 50 and bridged large gaps...



Well over the reccomended joint width...

Drake

[oventhusiast]

Re: What to use for filling gaps between the bricks?

I'm starting my dome (42") this week and I'm also using Heatstop 50, and I was wondering the same thing. The bag says 1/16" to 1/8" is the normal joint width but 3/8" is acceptable. I'm thinking if the joint starts small (on the inside of the dome) it will hold fine, but I'd also like to hear from others who used the Heatstop 50 for their dome. Any cracks? Did you soak or wet the firebricks before laying them? Anymortar cracks? How many bags did you use? Anyone use firebrick shims cut on a bricksaw to fill those outer voids?
HELP!!!!!
Thanx!
Rick M.

[dmun]

Re: What to use for filling gaps between the bricks?

Here's what i'd do: I'd build the pompeii dome with heat-stop, only mortaring to about 1/3 or 1/2 of the wall thickness, and leave the wedges in. Then when I'd gotten about half way up, i'd pull the spacers and overcoat the oven with something cheaper, like the fireclay-sand-portland mixture.

Bear in mind: I'm not speaking from experience. I gave a lot of thought to building a pompeii, but I didn't actually build one. I finally did a cut-every-brick plan so i'd have uniform thin heat-stop joints.

[dmun]

Re: What to use for filling gaps between the bricks?

Did you soak or wet the firebricks before laying them?

The firebricks MUST be wet but not sopping wet. Masons let a hose run over the pile of bricks for an hour or so before starting with that pallet.

Anyone use firebrick shims cut on a bricksaw to fill those outer voids?

If you are going to cut firebrick shims, why not just cut the bricks to fit? same amount of work. Think about my cut-every-other-brick plan:

This is a modified trapezoidal construction method where every other brick is cut. The flat, lowest ring is the easiest to cut. As you go up the dome, each spacer brick would need to be cut at an angle to get a tight fit. Every ring would be different.

[wlively]

Re: What to use for filling gaps between the bricks?

I took all the extra pieces from my brick cuttings and if they were the right size wedge, I mortared and wedged it in the gaps. For the rest I smashed the left over pieces up and mixed it into a bucket of Heatstop. Worked well to fill the gaps. Agree with Dmun that Heatstop may be too pricey, but I was fortunate enough to have a local supplier sell me mine at $34 a bag.

I just finished using my left over Heatstop to clad the dome.

I have not fired mine yet so we'll see how it does, but I think it will do fine.

[vincentvintris]

Re: What to use for filling gaps between the bricks?

Hello Dmun,
thanks for the info.
Can you provide some more detail on how you mark, cut the bricks using your (cut-every-other-brick) plan?

I'm using the same saw I saw in your pictures. Works great so far. It was on sale. Thanks for the hint...
VV

[welshpizzaman]

Hi I've got the same problem re gaps (see photo) as my builder didn't cut bricks to size Can I use fireproof mortar to plug the gaps and will generate the required thermal mass?

thanks for any advice

Paul

[DavidApp]

Hello Weishpizzaman

I presume there is mortar between the sides of the bricks and it just did not make it to the inside of the oven. What mortar did you use home brew or Heat Stop 50? You could try to force some mortar into the gaps but it may not stay in place when the oven gets up to temperature.
David