3:1:1:1

[GIANLUCA]

What type of lime should I use in the home brew mortar recipe also what are some quick pros/cons on refractory vs home brew both are available besides cost of course. One note in my area our local mason supply house said that using a homebrew mix is not code any longer for firplaces and would not recomend it for pizza ovens of course I trust the forum more than him just wanted to get some advice and thoughts.
I will be using the mortar for behind the firebricks on assembly of dome

[Tscarborough]

Re: 3:1:1:1

He is correct for an appliance in the house, only because no one has paid to have homebrew tested.

[vtsteve]

Re: 3:1:1:1

Hydrated Type S lime.

[Tscarborough]

Re: 3:1:1:1

3:1:1:1:1 is not really correct either, it is 3 parts sand by volume of the cementious ingrediants, and lime is considered a cementious ingredient, so the actual ratio is: 6:1:1:1.

[brickie in oz]

Re: 3:1:1:1

3:1:1:1:1 is not really correct either, it is 3 parts sand by volume of the cementious ingrediants, and lime is considered a cementious ingredient, so the actual ratio is: 6:1:1:1.

Ive always thought that the home brew was a very strong brew, but not having used it couldnt say for sure, thanks for clearing that up.

[mrchipster]

Re: 3:1:1:1

3:1:1:1:1 is not really correct either, it is 3 parts sand by volume of the cementious ingrediants, and lime is considered a cementious ingredient, so the actual ratio is: 6:1:1:1.

That is great but the ratios are intended to be a guide for making up the mix and not the actual end result. Lets keep referring to 3/1/1/1 and we will not confuse the issue.

Chip

[Tscarborough]

Re: 3:1:1:1

May as well get it right and not confuse the issue. Use 6:1:1:1 and you will be a lot closer to a good starting point than 3:1:1:1.

[shuboyje]

Re: 3:1:1:1

Lime is considered cementitious, and arguably the fire clay, since it doesn't get fired hot enough, is not. So at this point we might argue the ratio of sand+clay to cement + lime is 2:1 in the homebrew. A very rich mix indeed if you are building a house. If anything moves the bricks might break before the mortar gives.

This is exactly what I found when I demolished my first oven to build a bigger one. When I tried to chip the mortar off the bricks broke before the mortar gave. I finally resorted to cutting the mortar off the bricks I planned to reuse.

[brickie in oz]

Re: 3:1:1:1

I actually dont like to see mortar joints inside an oven its the point of failure.
Some builds on here must think they are building a house the joints are that big.

Id be happy to dry stack the bricks and then slurry around the outside to keep it all together.

I used pre made thin joint refractory bog on my build and you need a feeler gauge to measure the joints.

[stonecutter]

Re: 3:1:1:1

Id be happy to dry stack the bricks and then slurry around the outside to keep it all together.

That's the way many neapolitan domes are professionally built.

[Les]

Re: 3:1:1:1

Id be happy to dry stack the bricks and then slurry around the outside to keep it all together.

That's exactly what I did - and it works!

[Tscarborough]

Re: 3:1:1:1

The reality is that there are very few engineers trained in unitary masonry. They study concrete, and concrete (contains cement) and unitary masonry (contains cement) are not the same thing any more than anti-freeze (contains alcohol) and whiskey (contains alcohol) are the same.

The rule for mortar is to always use the absolute weakest mortar that will suffice, and this is antithetical to a concrete engineer. Mortar should ALWAYS have less compressive strength than the units it is binding together. Mortar is not harmed by excess water or retempering, both of which are opposite to concrete.

Using a 3:1:1:1 will work, but the question remains: Is that the proper or best mix? The answer is no. Just as the shape and dimensions of a Pompeii oven have evolved and been fine tuned over the centuries, so has the art of making mortar. It is only in the last 100 years that the art of mortar has been confused with the science of concrete and therein lies the confusion.

Mortar specifications are broad for a reason, and that reason is that the mortar must be prepared for the conditions, not to a narrow definition such as compressive strength.

If you doubt that this is so, study ASTM C-270 which is the ruling specification for mortar.

[Les]

Re: 3:1:1:1

anti-freeze (contains alcohol) and whiskey (contains alcohol) are the same.

Are you telling me I have been buying whiskey all these years when I could have saved money buying anti-freeze?

[Tscarborough]

Re: 3:1:1:1

No, I am telling you that if you applied whiskey principles to anti-freeze you would be dead.

[Laurentius]

Re: 3:1:1:1

No, I am telling you that if you applied whiskey principles to anti-freeze you would be dead.

Yes, you are! If the first bottle he ever drank had been anti-freeze, he would have never spent a penny on whiskey.