Mortar thickness

[dbhansen]

What's the approximate minimum thickness of the mortar used in the soldier course? I tapered my soldiers (full bricks, standing on end), but I'm not sure how much space to allow for mortar. Zero at the inside edge and ... maybe 1/8" at the outside? Is 1/16th better? Or 1/4"? I assume there will be some outward force from the dome and that some amount of mortar is necessary, but I have no idea how much to plan for.

[dmun]

Commercial refractory mortars like heat-stop and refmix are designed for minimal mortar joints, from 1/16 - 3/16 inch. They can be used thicker, but the joints are best when thin. Some makers have used the refractory mortar on the inside joints, and filled the big outside joints with the homebrew stuff after the dome is up.

If you are planning to cut every brick, plan for minimal mortar joints.

[SpringJim]

If you do a soldier course, with no cutting, your external mortar joint width is controlled by the brick spacing....virtually no mortar is present on the inner oven joint as the two brick faces should be touching!

[dbhansen]

Thanks for the replies! I have already cut a taper on each brick; I just didn't plan ahead for the mortar joint and wasn't sure how much space I'll need on the outside edge, using HeatStop50. If 1/16" is enough, then I might not have to do any additional cuts. Thanks again.