I've always been unsure about when to use the different types of sand.
Obviously it's sharp sand for screed and builders sand for bricklaying
mortar but can someone tell me why? I'm about to bed a shower tray with
mortar (per manufacturers instructions) but can't decide whether to use
sharp sand or builders sand - ?
I think it's to do with workability: soft sand has many grades of rounded
particles, right down to clay. This makes it handle well and you can adjust
bricks easily, the mortar made with soft sand supports the bricks but allows
plenty of movement if you need it.
Sharp sand has angular grains, less gradation, and I believe makes a
mortar, but it won't handle well or have the range of adjustment that
mortar does. My experience with soft-sand is very limited, but I have a fair
with sharp sand, and found that if you didn't get the thickness off mortar
first time when bricklaying or laying paving stones on a solid bed of
then if you tap the brick/paving down only a limited amount of adjustment
before it locks up solid, then it's take the brick/slab up and start again.
allegedly doesn't handle well on a trowel. I built a wall using sharp sand
as I wanted
white mortar, and the local sharp sand is silver, but it wasn't easy.
Supposedly mortar can be made to handle better by using a plasticiser, which
either lime, or a proprietary plasticiser, like PVA or Febmix ( or squeezy
a cheapo! ).
I'm not an expert, but bedding something like a shower tray makes me think a
mortar that allows a goodly amount of adjustment is best, so I'd try the
There is a special cement for bricklaying, masonry cement, that does not
additional plasticiser, but if you're using ordinary Portland cement, I
lime or plasticiser added to the mix will be beneficial ( e.g. 1:1:6
PS: I defer to anyone else who's had years of experience in the trade and
I thought that essentially that is what sand actually is.
Why on earth we dont just throw bottles into a smasher and then into the
sea and let that do the job of reducing them to coloured pebbles and
sand I don't know...
Sand and glass are not really the same thing, though sand is used in
the manufacture of glass. Sand is mostly the crystalline form of
silicon dioxide known as quartz. The yellow/brown colouring comes
mostly from iron oxides. Glass is made by melting sand with sodium and
other metallic compounds and then supercooling it to form a
non-crystalline solid. Glass is not nearly as hard as quartz but the
main reason for not using it as an aggregate is that it is much more
valuable than sand.
Unless you are being paid for how many zillion bricks per hour you can
lay, sharp sand is perfectly good enough for building and the mortar
will indeed be stronger than with soft sand. More importantly, if you
want to be on the side of the angels, don't use Ordinary Portland
Cement at all. Build with lime mortar, a 3:1 sand : lime mix. The
best lime to use comes wet in a plastic tub and is called lime putty
but a cheaper alternative is the bagged hydrated lime available from
all buildres' merchants. Buy it from a merchant with a rapid turnover
and empty the bag into a plastic dustbin of water as soon as possible
and then use it wet because the lime cabonates on contact with the air.
And keep your work covered for how long to protect it from the rain?
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On 28 May 2005 05:11:18 -0700, firstname.lastname@example.org wrote:
OK so the silica in glass is in mixture with other chemicals which
lower its fusion temperature and prevent it forming back to small
particles on cooling? It is not strong as silica grains in sand.
Is the strength of silica grains a limiting factor in the properties
of the sand?
I continue to ask as my local council has a problem disposing of
coloured glass, it going to landfill. There is a market for clear
glass but even this does not cover collection costs if my local
authority is correct.
Glass really wasn't worth recycling at all until the landfill
tax came in. If you have to start your car engine in order to
participate in glass recycling, then it's almost certainly still
not worth it. "Driving to the bottle bank" is an expression which
is sometimes used to refer to pointless recycling. People are
looking around for uses for coloured glass, and new road surfaces
is something they are being used on, but I think that's still
experimental. Manufacturing and using less coloured glass in the
first place is probably a better bet, but people seem to like
trying to solve problems at the wrong end of the supply chain.
Paper is another questionable one. The cost (in particular the
energy use) of processing recycled paper often exceededs the
cost of creating new paper. It has always seemed to me that
paper should be buried in landfill as this is exactly the reverse
process of burning fossil fuels, i.e. it's taking CO2 out of the
atmosphere and burying it back underground. Actually, planting
fast growing plants, harvesting them, and burying them down old
coal mines could be quite a good thing to do from this perspective.
On 05 Jun 2005 15:55:09 GMT, email@example.com (Andrew
I'll not disagree but given the "need" to avoid landfill and ongoing
quarrying/dredging for sand it just struck me as a possible use
without too much recycling cost.
I'll agree this with the possible exception of glossy papers which
have lots of china clay in them, I wonder if this filler can be washed
out and reclaimed?
This is a bit of my hobby horse because use of recycled fiber impacted
on my erstwhile trade. In the 70s we harvested the portion of the crop
that was "pulpwood" at a profit. As GATT and recycling bit we needed
to cross subsidise harvesting this with the better grades, now with
mechanised harvesting a lot gets left in the wood.
I disagree about burying it though, if anaerobic conditions occur
biogas is given off and this has implications for damaging the ozone
layer as well as being a worse climate changing gas than the CO2 that
would be generated by burning it.
Now if you consider pyrolysing it to >85% fixed carbon and then
I also cannot see the benefit in recycling simple (non halogenated)
plastics over burning them for power, more a topic for the environment
Eh? either he nitrate has gone into teh plantst or it hasn't. If its
gone in it won't be in the water.
Its perfectly possible to grow willows with very little nitrate. Or
ghrow a crop of field beans one yaer and then plant the willow.
replying to biff, chris wrote:
silica sand is glass, used for ashlar . sharp sand contains glass but a not as
much. 3:1 ratio is okay for walls and low level renders/pointing. exposed areas
need something stronger. 2.2:1 lime to sand ( add a tiny wee bit cement to the
mix ) any st astiars nhl (except 5) will work greatly. you can buy pre mix 25 kg
for £12.50. fine sand or coarse ( fine for pointing/rendering less than 5mm) .
just add water. adhesion is exceptional and it sets very quickly. its
bombproof!!! otherwise general building ...... sharp, sand, tradiblanc nhl (35
kg) but be aware, tradi sets very light so use a dark sand or add pigment and
defiantly carry out a wee trial.patch
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