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Posted: Wed Jan 20, 2010 12:52 pm
by dr benway
thanks all, for the replies
the slabs arent rocking, so as Tony suggests, I'll wait and see.
thanks
Posted: Wed Jan 20, 2010 4:50 pm
by lutonlagerlout
cookiewales wrote:lutonlagerlout wrote:i thought unibond was PVA?
definitely wouldn't use any additives in the pointing,even the dyes leach out fast
LLL
unibond is a sbr in most cases take a look on the tin :p ??? ???
in that case I am ok as i have always used unibond 
LLL
Posted: Wed Jan 20, 2010 4:58 pm
by lutonlagerlout
bah just checked and they make PVA too
IME I have never had a problem with unibond PVA in the mix
maybe i have been lucky
LLL
Posted: Thu Jan 21, 2010 1:49 pm
by Tony McC
Plastering sand is a little bit sharper than building sand but nowhere near as coarse as sharp/grit/concreting sand. It is normally used to create a scratch coat.
You have to be careful with it when laying the Indian sandstone as it can contain a lot of iron that gets carried through the stone causing discolouration.
Nice of you to ask about the Boddies, Craig: didn't you owe me a pint or three? 
Posted: Thu Jan 21, 2010 9:19 pm
by Craig2
I guess I am not alone in owing you a pint or two...
I have had some discolouration issues but only with the Grey/blue and not consistantly but with the occasional job, gotta admit It had me stumped.
Back on topic, I just thought I should mention the success I've had with the SBR OPC 50/50 slurry bond.
I trialed 5 indianstone 100mm cobbles with varying different bonding techniques, 24 hours later I tried them all with reasonable force and only one lifted, which was the most liberally treated, it was still wet and I replaced it,I tried them again today and I swear I could have swung from them, they were not for moving,believe me when I say I tried.
I have refit the lot now, mixing in a billy can with 1 cup of SBR and 1 cup of Cement and stirring until I got a constant colour/consistancy, I then dipped the lower part of the cobble in the can and let the excess drip off for a moment and then down,I applied a little pressure until you can see the mixture being squeezed from underneath, you get a certain amount of adhesion straight away, I was suitably Impressed!!
I agree with Tony though, if they are not moving then there is little problem, however I can't see me being able to convince a customer so...lol
Posted: Tue Jan 26, 2010 9:01 pm
by simeonronacrete
Generally a mortar or concrete made with sharp sand is stronger than using soft sand. Also more likely to achieve water resistance as there are fewer gaps in the matrix.
Unibond is PVA, not SBR. PVA's break down in contact with water, liquid or vapour, SBR doesn't.
Ronafix is based on SBR and IS waterproof, IS watertight, and WILL bond securely to building surfaces.
Posted: Wed Jan 27, 2010 11:55 am
by Tony McC
What Sim is trying to say in his polite way is that Ronafix/SBR sticks like the proverbial to a blanket!
Posted: Wed Jan 27, 2010 4:42 pm
by lutonlagerlout
i went in 3 BMs today and none of them had SBR
when i asked why,they said they can get it but its so expensive no one stocks it
LLL
Posted: Wed Jan 27, 2010 7:18 pm
by GB_Groundworks
last time i bought it last year was about £15/5 litres sealocrete branded one from local independent bm
Posted: Wed Jan 27, 2010 11:13 pm
by Bob_A
At Toolstation 5L of SBR is £16.37 and 5L of pva is £7.48.
After reading about SBR on here it seems worth the extra money and in most cases in the future I'll be using it in preference to pva.
Posted: Thu Jan 28, 2010 8:34 am
by Tony McC
BMs - the curse of the building trade (along with architects).
How many time have we been told that they don't stock such-and-such because there's no demand. Eh?? I'm here, now, demanding it!
Never forget that BMs are run for *their* benefit, not the benefit of contractors or manufacturers/suppliers, and they will only ever stock items that they can shift in volume and at a hefty profit, after screwing the manufacturer on pricing and then screwing the contractor on cost.
Posted: Thu Jan 28, 2010 1:24 pm
by lutonlagerlout
i have told butterfields and dandys that geo-fix is rubbish,yet they both still stock it sky high for the unsuspecting mugs
they have targets to meet
LLL
Posted: Fri Jan 29, 2010 7:32 pm
by ambient
been in travis perkins today they stock two brands of sbr ???
Posted: Fri Jan 29, 2010 9:13 pm
by cookiewales
Unibond is PVA, not SBR. PVA's break down in contact with water, liquid or vapour, SBR doesn't. i have been useing ronofix since 1987 never failed me yet best to buy in 25 litre drums it dosent go off am sure when my eyes could read the back of a tin it said sbr as well on the unibond i was looking at was a long time ago ??? :;):
Posted: Sat Jan 30, 2010 12:20 am
by lutonlagerlout
well after 26 years at work, used SBR on some rendering today
met the labourer tonight in "the compasses" and both of us have it stuck all over our hands
will report update tomorrow
LLL