Questions on cladding

[Bec1208]

Hi, I closed my dome yesterday. I had difficulty using commercial refractory mortar, HW Mortar Mix 413, and switched to home brew. I have 2 1/2 bags left and would like to use them to add thermal mass. I could use advice about how to do this. Specifically, what if anything should I add to the mix (such as fire brick sludge, sand, etc). Any help is appreciated.

[david s]

Re: Questions on cladding

Adding extra thermal mass can be counterproductive in that after a few hours of firing the heat may have hardly penetrated through to that layer. If you stop firing then the cooler outer layer will be sucking heat from the inner layer. You will use more fuel to heat the whole oven properly. My own oven has only 50 mm walls and takes at least two hours to get it properly heated. I can clear the dome easily in under an hour, but the heat has not penetrated right through the walls at that point.
If you add sand or aggregate to your mortar you will weaken the mix. I presume your mortar uses calcium aluminate cement, so you would need to add some more of that to bring back the strength if you add any extra aggregates to the mix.
Are you doing the cladding layer for extra strength or for added thermal mass? If the latter then it wouldn't matter if the mix is weak.

[brickie in oz]

Re: Questions on cladding

Specifically, what if anything should I add to the mix

Dead cats are always good, it wont help your oven but it will help the environment.....

[Laurentius]

Re: Questions on cladding

Dead cats are always good, it wont help your oven but it will help the environment.....

Don't mind him, he's my smartass brother. Mom likes me best.

[stonecutter]

Re: Questions on cladding

Hi, I closed my dome yesterday. I had difficulty using commercial refractory mortar, HW Mortar Mix 413, and switched to home brew. I have 2 1/2 bags left and would like to use them to add thermal mass. I could use advice about how to do this. Specifically, what if anything should I add to the mix (such as fire brick sludge, sand, etc). Any help is appreciated.

Nothing need but water for bagged mortar mixes and a couple bags probably won't put more than 3/4" over your dome...IMO, no big deal. Or try and sell it on CL.

[Bec1208]

Re: Questions on cladding

Nothing need but water for bagged mortar mixes and a couple bags probably won't put more than 3/4" over your dome...IMO, no big deal. Or try and sell it on CL.

Everybody, thanks for the feedback. Given there is apparently little benefit, I decided to move directly to insulation and deciding on an entry. I could especially use help on the entry. Here of a pic of the oven showing the inner arch and one with the unfinished door in place.