Agricultural lime in home brew

[skywalker]

What will happen if I used Agricultural lime in my home brew mortar? I'm way past the disturbing mistake where I just realized I used the wrong Lime.

I've already finished the oven and I've been cooking already. I have a few "normal" hairline cracks, which I'm not too worried about, but now I'm starting to lose sleep after finding out I've used the wrong lime... will it collapse? Did I severely shorten my oven's lifespan? or what?

I obviously did not do enough research on lime...

[brickie in oz]

Re: Agricultural lime in home brew

What will happen if I used Agricultural lime in my home brew mortar? I'm way past the disturbing mistake where I just realized I used the wrong Lime.

I've already finished the oven and I've been cooking already. I have a few "normal" hairline cracks, which I'm not too worried about, but now I'm starting to lose sleep after finding out I've used the wrong lime... will it collapse? Did I severely shorten my oven's lifespan? or what?

I obviously did not do enough research on lime...

I thought slaked lime was lime was lime?

[skywalker]

Re: Agricultural lime in home brew

I found out that slaked lime (Type S) is what you want to use. Not agricultural lime, which is what I used... I really would like to know what it'll do to the oven.

[Tscarborough]

Re: Agricultural lime in home brew

It is, but you have to actually slake ag lime, while Type S is already once hydrated, so simply adding water will slake it.

You should be alright anyway.

[Greenman]

Re: Agricultural lime in home brew

You will probably find that agricultural lime is hydrated. Like many things destined for agricultural use it is only processed to the form that meets the need of the industry. The lime bagged for domestic and construction use is likely to contain less by way of impurities but I don't believe that the different specification would make any difference in your application. Like Brickie said - lime is lime.

I am sure that your oven will be OK.

[skywalker]

Re: Agricultural lime in home brew

Thanks guys! Feeling a LOT better already!

[Tscarborough]

Re: Agricultural lime in home brew

Ag lime is hydrated, Greenman, Type S is double hydrated, meaning 2 different methods to involve more of the chemicals in lime.

The difference is small but not insignificant, and Type S can be considered to be dry slaked lime, while ag lime should be slaked by immersion and time.

[skywalker]

Re: Agricultural lime in home brew

So I guess that just by adding water to make the 3-1-1-1 homebrew mix wouldnt be considered slaking wouldn't it?

[wotavidone]

Re: Agricultural lime in home brew

I thought about it for a while before posting this reply, because I did not want to dishearten you.
However, in the interests of making sure others don't have the same issue, I gotta say, lime ain't necessarily lime. I suspect it probably depends where on the planet you are.

I thought slaked lime was lime was lime?

"Lime" is a catch all term for the common calcium compounds.
The trouble is, there are many traditional names, that vary wherever you are in the world.
In the game of extracting lead, zinc copper and silver from ore by the process of sintering and smelting, we take care to distinguish the different types. The old nomenclature has potential to derail the process if the wrong lime is used in the wrong place. (It's not helped by the fact we tend to use all three common types in different parts of the process.)

In Australia:
There's quicklime, soft burnt lime, or burnt lime = Calcium Oxide.
There's slaked or hydrated lime = Calcium Hydroxide.
There's Lime stone, Lime Rock, lime sand, or Lime rock sand (lime stone crushed to our required particle size) = Calcium Carbonate.
The last one tends to confuse our new graduate Metallurgists the most, for reasons which escape me.

I found out that slaked lime (Type S) is what you want to use. Not agricultural lime, which is what I used... I really would like to know what it'll do to the oven.

This will depend on what they use for agricultural lime in your part of the world. The point of using lime in mortars is to use either burnt lime which will convert to slaked lime when you mix it with water, or slaked lime calcium hydroxide.
Either of those will, on exposure to the carbon dioxide in the atmosphere, slowly turn to limestone, calcium carbonate, as the mortar ages, adding strength as the process goes on.

If they use calcium carbonate for agricultural lime in you part of the world, like we do in Australia, no chemical reaction is going to take place and no extra strength is going to develop.

If, as Tscarborough says, agricultural lime in you part of the world is hydrated, you should see some contribution of strength from the lime.

However, don't forget you have used two other agents in your mortar that help harden the mortar - clay and cement.
If you used Portland cement, it's possible that we are going to find out if
there is any truth to the oft repeated assertion that pizza ovens get hot enough to break down the Portland cement over time.
Also, possibly not, as I expect you used clay as well. There must have been plenty of ovens assembled with clay as the only binder in the mortar.

You will probably find that agricultural lime is hydrated. Like many things destined for agricultural use it is only processed to the form that meets the need of the industry. The lime bagged for domestic and construction use is likely to contain less by way of impurities but I don't believe that the different specification would make any difference in your application. Like Brickie said - lime is lime.

I am sure that your oven will be OK.

As I explained above, slaked lime is lime, but lime ain't lime, and according to this explanation from the NSW department of primary industries, agricultural lime in Oz is limestone, not burnt or slaked lime. As you rightly assert, that used for agriculture has the least amount of processing they can get away with. I've used a lot of finely crushed lime stone, 3000t per month of minus 2.5mm at one stage, and when it's wetted it does not develop any strength at all.

Which liming material is best? | NSW Department of Primary Industries

Thanks guys! Feeling a LOT better already!

I apologise for disturbing you mood, but I really felt the issue needed to be explored further. I reckon your oven won't fall down anytime soon, regardless of what lime you used.

[skywalker]

Re: Agricultural lime in home brew

Thank you wotavidone for that thorough answer. Its ok I can take the honest answer and I did want to hear an answer like yours so we can make a useful thread for others that might do the same (gosh I can't be the only one, right?... right?).

I've searched a lot after I realized my mistake and nowhere did I find what happens if you do use Agricultural lime in the homebrew. I did find a lot of warnings agains doing just that (I should have done the lime research before). But no explanation of what would be the consequence.

What you say makes a LOT of sense. I have noticed a that my homebrew is not very strong. When I installed the chimney on the anchor plate, the bricks that the anchor is screwed onto came loose. So I had to glue them back together with high heat cement. Hopefully I did a good enough job with the brick work in the dome and it truly is self supporting.

I swear when, and if, it collapses or something, I will come back and update the thread for the greater good of having a record of it.

By the way, I got the Agricultural Lime at HD and the construction guy told me to look for lime in the garden section, so I went to the garden section. The garden guy told me, "oh yeah! lime, we have it pulverized and in pellets, I asked him if I can use this lime for masonry and he said "lime is lime", ironically, so I went with the pulverized lime (Agricultural lime, which is pulverized limestone).

Live and learn.

Lucas

[wotavidone]

Re: Agricultural lime in home brew

Here comes another long winded reply.

I have noticed a that my homebrew is not very strong. When I installed the chimney on the anchor plate, the bricks that the anchor is screwed onto came loose. So I had to glue them back together with high heat cement. Hopefully I did a good enough job with the brick work in the dome and it truly is self supporting.

That's interesting. One of the guys on this forum (TXCraig? Tscarborough? can't remember) pointed out that the stronger the mortar, the weaker the bond between the mortar and the brick. So, if your bricks pulled away, either the mortar is strong or it was still "green" maybe.
Anyway, lots of bricklayers will tell you that the real job of the mortar is to keep the bricks apart and allow for minor differences in size and shape.
So, if you can imagine, in your oven, as long as the mortar is strong enough to not crumble and collapse, it is just another masonry unit, that is perfectly fitted to fill the gap between the bricks , if that makes sense. So if your mortar doesn't crumble back to dust, the oven consists of a heap of blocks, some brick, some mortar, that fit together perfectly. So well, it doesn't matter much if they aren't actually glued together.
Also, I'm assuming you have vermicrete over the outside? So the whole thing is encased in a block of concrete foam and the bricks can't slide anywhere?
It's gunna take a lot for this thing to fall down, bro.

[skywalker]

Re: Agricultural lime in home brew

That makes a lot of sense. I wouldnt glue bricks on the inside. But the ones that came loose (because of me over -tightening the chimney to the anchor plate) are holding the chimney in place so those have to stay put.

No vermicrete, just 3" of ceramic fiber, 1" of stucco and a layer of acrylic reinforced surface bonding cement. I guess the bricks have a little bit of wiggle room in there because of the blanket, but man I think it would take an earthquake to move them...

[dakzaag]

Re: Agricultural lime in home brew

Just so anyone reading this thread knows what Ag lime is, it is finely crushed limestone.

It is not intended to be any portion of the binder of a mortar. Regardless of your intention to use Lime in your mixture, Ag lime is not hydrated, collated or related to building lime except that it's origin is Calcium Carbonate. Please do not make the same mistake as Skywalker made, because you are simply adding aggregate instead of binder.

The only possible use in a mortar mix for Ag Lime would be to replace sand as it is similar in consistency and size to fine sand. I have been tempted to try Ag Lime because there are two limestone quarries within 1 mile of my house and I have to go 30 miles for mason sand.

The purpose of refractory mortar or refractory cement is to give strength to the whole construction throughout the heat cycle. Portland is very strong as a binder until it heats up past 600 F then it fails. (actually it fails as it cools down below 600 F so if you intend to keep your oven hot, it will work fine.

Building lime is added to give strength when the Portland fails, but Lime mortar sets up really slow. The combination of Portland and building Lime is excellent for an oven because each ingredient compliments the weakness of the other, thus contributing to the overall strength.

[Tscarborough]

Re: Agricultural lime in home brew

Ag lime is, as stated, not "lime" per se, it is finely ground calcium carbonate, which is what you want your real lime to turn into as a part of the mortar. It is used to add alkalinity to acid soils.

[Ganlet]

Have the same problem I Sweden, hours and hours to research this... Fortunately before starting the project though. I'm all on board the Ag lime vs slacked lime, but within slacked lime there still seems to be quite the wiggel room for various sorts. Typically discussed here as S-type (wiki: Type S lime is almost always dolomitic lime, hydrated under heat and pressure in an autoclave) and N-type. In Sweden however there seems to be no distinguishing here.

Excluding the hydraulic sort which is a struggle to find on its own, there are two sorts readily available. Slacked lime sold as a pure binder (referred to as type E here) for masonry work and pure slacked "technical" lime referred to as "for many uses, but the main use is for neutralization (Nordkalk SL is also suitable for manufacturing lime-based paint)" .

Both calcium hydroxide, the latter found at agricultural product stores for a fraction of the cost. Just go with that one and never look back?