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Hey Everybody,
I have a need to build 2x 1200 high non structrual decorative peirs around steel posts at the front of my house.
I was planning to form up a mould out of timber and fill it with cement, then put a skim coat of acrylic render over the concrete.
My question is, would it be OK to use plasterer's sand, mixed with cement and bluemetal for the concrete, as I have around 2 cubic meters of it left over from the renderer guys
Or should I be buying some brickies sand..
Plasterer's sand is the type you want, because the clay content of brickies' sand may possibly cause light cracking.
Excellent! thanks for that!
Also, I would urge you to panel the formwork in foot-high increments to one side - the three other sides can be continuous. As you fill, tap the boards evenly and rhythmically with a hammer to settle the concrete and expel air.
When the top of a section is aproached, screw in the following panel or "shutter" (pre-prepared) and continue. With the next load shovelled in, a vigorous poking with some offcut reo into the already-placed/settled concrete will meld the two together.
Be aware of the substantial pressure a pillar of wet concrete can exert near its base, and brace the formwork adequately. Sealing all inside faces of your forms the day before with Danish Oil, Penetrol or other similar product will not affect the acrylic render process, but will aid curing by not allowing moisture to leave via absorption. I personally use vege oil, but if you're too generous it can get into the new concrete.
One question for the greybeards might be whether there needs to be any thin foam (2mm or so) wrapped around the steel for thermal expansion issues.
Cheers, Adam.
In Perth, plasterer's sand contains clay but the clay content is less than brickies sand (I don't know the relative difference) - similarly, I don't know what effect that difference has on making concrete. I strongly suggest that you speak to a few Perth sand suppliers before you make a decision as to whether plasterer's sand is suitable for concreting. Better still, speak to someone who is experienced in concreting.
North of the Swan River:
http://www.midlandsandsoilsupplies.com.au/sands.htm
South of the River:
http://www.landscapeyard.com.au/sand.html
Plasterers sand will be fine. It is important that you don't go overboard on water.
Use 5 - 10mm aggregate Guage 4 blue metal, 2 sand and 1.5 cement as a ratio.
Do not use very runny concrete or it will crack when the water volume evaporates or leaves the concrete.
Use enough water so the concrete is just usable into the form and tamper to remove any air pockets.
Use general purpose cement only.(GP) Strictly no lime.
Are you going for a record Genious? :?Quote:
Originally Posted by autogenous
Your answers wrong btw..
Autogenous. :) No genius in there.Quote:
Are you going for a record Genious? :?
Your answers wrong btw
I welcome criticism. Im not always right.
Ref: www.swancement.com.au/<wbr>technical/images/READYRECKONER.pdf
Sorry I read the title about plasters sand and didnt read the rest..My mistake, you are correct, although a bit late....:roll:Quote:
Originally Posted by Brickie
Not a problem. Its easy done.Quote:
Sorry I read the title about plasters sand and didnt read the rest..My mistake, you are correct, although a bit late.
Yeah I did rip through the posts without realising they were so old. Not to worry. When people search for these things anything unanswered will turn up with an a answer.
Old questions still provide answers to many people, not just the immediate query user.
Its good for Neils sponsors too. :)