For firebox and flue you would be safer to use refractory mortar instead of lime mortar, due to the high temperatures that will convert the lime to quicklime and in the end lead to mortar failure. By the same reasoning, avoid limestone in firebox construction.

Normally true, but this is a special case

The flue itself will be a stovepipe, and the actual fire does not get very hot -the rocks will never reach the 900 degrees necessary to burn lime. The fire for cooking cheese has to be very slow and controlled, and nearly all of its heat will go directly into the copper vat (this is the chief advantage of using copper)
In fact, in the Swiss Alps traditionally the cheese making huts are highly sealed, more so than any other building, because all heat needs to be retained for the cheese.

And furthermore, I will probably give the inside a thorough coating of mud with wood ash mixed in to serve as both a fire shield and to bring the casing itself to near proximity with the vat -almost touching. The vat has bulging sides, allowing it to fit snugly into such a box and retain as much heat as possible.

Hello Roger,

By that reasoning it should be possible to recharge, let's call it, opened yet unused sacks of NHL that have been sitting around for a long time by heating the powder to the required temperature. Is that so?

Greetings,

Don Wagstaff

Hi Don

I suppose so but not efficiently, if the bag spoils why not use it on acid soil?

DL

I think the brown & skim coats of lime plaster will be too much for the basement aging area. I'd suggest 2-3 coats of limewash over a clean block surface. Brush the first coat in thoroughly. Adjust the consistency of the wash coats to meet your needs. That should do it!

Your description of the firebox and how it is used leads me to believe that you will be better off with a clay/sand mortar without any straw. Just use a coarse sand aggregate with a fairly even gradation from 1/4" - down to very fine for the strength it provides. No lime or cement will be needed.