Canberra - my first oven, help

[brickie in oz]

Re: Canberra - my first oven, help

Al, do you also regularly use plasticiser?

Always, its just a surface tension breaker and helps keep the water in solution with the sand and cement, without it the water starts to bleed out after a few minutes and rise to the surface resulting in the top portion of mortar being wet and the bottom being dry.

I have worked with lots of other brickies who refuse to use it for some reason, they all quote the AS 3700 for Brickwork as being the reason, they obviously dont own a copy (at $200 per copy Im not surprised) as Ive re-read it time and time again but have failed to find the reference to where you cant use it.

Without plasticizer, or a drop of detergent the mortar with require constant knocking up, even more so if it is hot or a wind is blowing, why the other brickies insist on making extra work for themselves has me baffled (which isnt hard ).

Excess palsticizer will kill mortar in that it will over aerate it, this also makes it go off much quicker.

I havent seen any results if over aeration weakens the mortar, again lots of brickies pull figures out of a hat about it being weaker without any proof to back it up.

Edit:-
I have found a reference on page 89 of the standards that permit the use of plasticizer and workability agents.

[david s]

Re: Canberra - my first oven, help

Thanks, that's most illuminating. I did a short course in bricklaying years ago and we were taught to add a few drops of detergent to the mortar to improve workability, but I have since read that other chemicals in detergent have a damaging effect on the mortar and should not be used, only mortar plasticiser.

[brickie in oz]

Re: Canberra - my first oven, help

I have since read that other chemicals in detergent have a damaging effect on the mortar and should not be used, only mortar plasticiser.

I would love to see the reference and the data.

Im sure plasticizer and household detergent come from the same tap but with a different label and price tag, plasticizer being 4 times the price.

[david s]

Re: Canberra - my first oven, help

Yes, that's exactly what I thought, but I've seen a few references to its use as being damaging to the mortar, so now no longer use it. Dish washing detergent for instance contains lots of other chemicals.

[brickie in oz]

Re: Canberra - my first oven, help

I've seen a few references to its use as being damaging to the mortar,

But nothing written to prove it?
Ive been hearing the same all my life but have failed to find the evidence, so until I do I will continue to use a drop of detergent.

The building trade has more myths than actual workers.

[brickie in oz]

Re: Canberra - my first oven, help

Just found this.
http://www.cementaustralia.com.au/wp...Own+TDS+v2.pdf

Brickies Own effectively replaces the need for lime in a mortar mix where the lime is added
as a plasticiser.

WRONG......

And this.

is a concentrated blend of petroleum based surfactants

Just like detergent.

[david s]

Re: Canberra - my first oven, help

Yeah, that's the stuff I've got, it is so concentrated I've got enough to last me a few reincarnations.