Slacked lime is hydrated lime only once it has soaked in water usually recommended time of at least 3 days but can be much longer. The slacking process is the stirring of the dry powder into the water and getting all the lumps out.
Nick
From:
Sent: Tuesday, May 04, 2010 6:49 PM
To:
Subject: [papercreters] Re: fire-proofing, etc.
Hi don;
Well I'm sure you know that slaked lime and hydrated lime are the
same. But I believe it may have been unslaked lime mixed with boiled
oil that medieval castle builders used. Anyway so long as the calcium
hasn't bonded with carbon, either from the air, or another source its
in contact with, then it should work.
Ammonium sulfate I've purchased from chemical and garden supply houses
(as a fertilizer); also you could make it yourself from ammonia and
sulfuric acid. It's not so cost effective though.
Oil and portland cement, that is interesting because heavy oil can be
used for coating molds to remove cement castings, I wouldn't think of
using it in the cement; but cement does contain some gypsum and
calcium so the hydrocarbons and lime probably does initiate a
chemical exchange, from sulfate to carbonate. Also silica and carbon
could form carbonates, etc. That's a great idea for a coating and
sealer. Last time I checked,
dust sold by landscapers is already carbonated, although that could
be driven off by heat, which is how the cement-making process is done.
------------
--- In papercreters@
>
> Interesting observations. A couple of dumb questions. First, what is the difference between slaked lime and regular hydrated lime? Where is ammonium sulfate available? I am currently making blocks with cardboard pulp and clay with no cement and I bought some boric acid to spray the walls with (when they're finished, of course) for fireproofing as I talked to some straw pale people who do that for fire retardancy and also to repel insects. I haven't tried it yet so don't know if it will work or how well.
> Â
> As for used vegetable oil, I have been collecting that for some time now to power my pickup with and last winter after noticing how the oil that spilled on the top and the sides of my barrels interacted with the fine clay dust to make a hard rubbery coating, I made a mixture or oil and portland cement with a small amount of fine sand and coated some of my walls I had put up for a windbreak. It dried into a hard cementous surface with the ability to shed water which is great because all papercrete regardless of the amount of cement uses will absorb water. I did not do this very scientifically as to the proportions of the mix but was very pleased with the results. I also coated part of a wooden structure and it stuck very well to that and also an adobe shed and once again it coated that well. It makes kind of a greenish color to the blocks but perhaps in the summer sun will bleach out. I plan on doing more with this when I get my house walls up. I
> applied this with a paint brush and not very thick but one could use a roller to speed up the process. The beauty part is that it doesn't take a lot of the mix and with the oil in mixture it absorbs readily into the papercrete./
>
>
> --- On Tue, 5/4/10, germeten <germeten@..
>
>
> From: germeten <germeten@..
> Subject: [papercreters] fire-proofing, etc.
> To: papercreters@
> Date: Tuesday, May 4, 2010, 12:28 AM
>
>
> Â
>
>
>
> Hi all, this is my first post, be gentle!
>
> Several observations made before joining this forum.
>
> "Paper is rendered fireproof by saturating with a solution of:
>
> Ammonium sulfate 8 parts
> Boric acid 3 parts
> Borax 2 parts
> Water 100 parts
>
> This is very similar to the formula for hardening gypsum:
>
> "Dissolve boric acid in hot water and add sufficient ammonia water to
> the solution that the borate at first separated is redissolved. The
> gypsum to be cast is stirred with this liquid or the gypsum once dried
> is painted with the solution which is quickly absorbed. Articles
> treated this way are as hard as stone."
>
> So maybe adding gypsum to paper-crete is the way to go.
>
> I experimented making paper-crete molds and found that by adding
> slaked lime, the paper (which is mostly carbon) bonds with the
> lime over time to form calcium-carbonate (rock) which doesn't
> support combustion. I used about a third lime to
> to treat with borates afterwards, if still found necessary.
>
>
>
> And lastly, during the middle ages, mortar for cementing stones was made with a combination of unslaked lime and boiled oil which held
> the stone. Chemistry is similar: Hungry lime + hungry hydrocarbon =
> calcium-carbonate stone. This would make a fine coating for exterior
> and inside plaster for papercrete structures, and I'll bet deep-fry
> grease from restaurants could serve as the boiled oil.
>
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