Mortar Choices

[SpringJim]

Originally Posted by e15757

The rest of the story is that I started with one of the premix refractory cements, forget the name at the moment. Was to thin for my liking and I found it difficult to work with...have nearly a full bucket sitting in the garage and not sure what to do with it.

Has anybody added some sand to the thinner premix to fatten it up?

(I think it's best use is for flat firebrick mortar and brick dipping)

Jim

[mannextdoor]

Originally Posted by e15757

I just completed my dome last weekend. Used Heatstop for the whole thing. The best thing I liked about it was the tacky quick-set properties. I didn't use any forms to build my dome. Once two bricks were set in a course they would support themselves in place...vertically. The downside is that I used 2.5 40lb bags at $60 a bag.

The rest of the story is that I started with one of the premix refractory cements, forget the name at the moment. Was to thin for my liking and I found it difficult to work with...have nearly a full bucket sitting in the garage and not sure what to do with it.

The other panic attack I had was that my local distributer only had two bags of Heatstop and I polished that off just as I was at the final 3 courses....yeah the toughest ones. So I bought the fireclay, mortar, and sand and tried that approach. I'm sure it works great but after building with no forms up until that point I didn't want to stop what I was doing and start working on forms, and my fireclay mixture was not going to support those last few courses without a form. So I called my distributer and he luckily had found another bag...so the day was saved.
Summary: of the three I tried; Heatstop, Pre-Mix, and homemade the Heatstop was by far the easiest to work with.

Just getting started on my oven. I would like to know if you cut every brick on a tapper and how thick you joints were?

[e15757]

Hi yes I did cut every brick on taper.. Not sure I'd do that again. I also oriented the bricks vertically in the long direction rather than horizontally. I started by creating an arch on a flat surface to get my measurements. What I totally forgot to account for is the three dimensional aspect of a dome and the fact that a double angle cut is needed on each brick...actually three cuts on most bricks (angle on vertical top and vertical bottom to form the dome and a taper on horizontal either left or right side to account for curvature going around the dome. Most of the inward facing joints have small joint, only where I squeezed the mortar through. Back side still has the gaps most in the 1/2" to 3/4" range. Hope that helps, if you have more questions let me know.

[mannextdoor]

Thanks. That is a big help. Did you use the heat stop 50 to cover the dome as well when finished? Some ovens have 2" or more of a cap put over it. Did you do this and how thick of a cap did you use? I am trying to find out what kind of coverage you were able to get out of you 2.5 bags of heat stop, and where it went.

[e15757]

For refernece purposes the dome I created is 39". Two bags of Heat Stop got me up to about the final 15-20 bricks, including a very light skim coat of mortar on the outside of the dome I probably only used 1/4 or less of the third bag. I prob actually have close to 3/4 or more of the final bag remaining. As it stands now I have 1/2-3/4" of cladding on the outside that was made with the fireclay-mortar homebrew. I guess that's my question to the board as well. Am I good with this cladding or should I put something thicker?

[Dutchoven]

Originally Posted by e15757

As it stands now I have 1/2-3/4" of cladding on the outside that was made with the fireclay-mortar homebrew. I guess that's my question to the board as well. Am I good with this cladding or should I put something thicker?

With cuts on each side of the brick or otherwise that amount of cladding should be fine...in truth a cladding is really not necessary unless you want to increase the thermal mass of your oven!
Best
Dutch

[Kemo]

My oven used a mix of mortars depending on the availability and my pocket book.

I started with some heatstop 50, then to fireclay because I ran out real quick. Then tried some Refmix and then back to Heatstop 50. So my oven has different mortars at different stages.

when I build my next oven...I will use Heatstop 50 for the main build and Refmix for the arch ways and landing areas. The RefMix is really strong IMO but it comes at a price. I also will NOT be adding any cladding at all, just filling the gaps with Heatstop 50 and straight to blanket insulation and vermiculite.

I have a 42" oven with about 1" of cladding atop the dome and its a good 2-2.5hrs to come up to 900, with the best cooking after heatsoaking the oven over a 4-5hr period.

I made alot of mistakes in my first oven build, but I learned alot too. I also love my oven, but I also look forward to building another one. Lots of things run thru your head during the build...and certainly afterwards


After looking over my rant, I never really answered the original question. I used Heatstop 50 for a 1" cladding on mine with plenty of gaps on the outside bricks up to 3/4 of an inch and possibly larger in some areas. I was just trying to get rid of what I had left over. I havent had a brick fall or any major cracks aside from a loose brick in the arch area thats currently giving me grief. I dont have a way of looking at my external dome since mine is enclosed in a structure of sorts. As mentioned earlier, I wouldnt even clad at all if I were building now.