Missing mortar behind lintel

[rick clifford]

Insert is about to in and a final inspection of the firebox indicated a few places between the lintel and the damper where some mortar has fallen out. (I suspect it fell out) In the photo its the lintel at the bottom of the photo and the front of the damper on top. At that right angle there is some mortar missing. I am going to replace but my question is can I use that rutland injection mortar applied with a caulking gun and how much must be injected? OR should I mix up a loose mortar mix and inject it up there with a masons/bakers bag. I don't know what that thing is called. If so what type of mortar should I use and how much should I shoot up there? Thanks

 

[rick clifford]

Insert is about to in and a final inspection of the firebox indicated a few places between the lintel and the damper where some mortar has fallen out. (I suspect it fell out) In the photo its the lintel at the bottom of the photo and the front of the damper on top. At that right angle there is some mortar missing. I am going to replace but my question is can I use that rutland injection mortar applied with a caulking gun and how much must be injected? OR should I mix up a loose mortar mix and inject it up there with a masons/bakers bag. I don't know what that thing is called. If so what type of mortar should I use and how much should I shoot up there? Thanks

...........I forgot to insert the photo

 

[EatenByLimestone]

I never liked the tube mortar. It takes forever to dry. I'd use some Type S mortar mixed with just enough consistency so it's not runny. I'd hold a small scoop with my hand and push it into the cracks with your small trowel.