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Posted: Tue Apr 01, 2014 3:56 pm
by XTA
See images:

http://postimg.org/gallery/aiu2z7jg/

BEFORE - 5 years of tree sap, bird sh..t, etc etc

AFTER - high pressure sand blast, bought it up LIKE NEW !!!

The bonus with sand blasting is it also completely ripped out 100% of the stuff beginning with G and ending in FIX so all gaps are beautifully cleaned out ready to re-grout.

Time is not an issue for us so whilst we can see the merits in using a top end resin like GFTK 800 its going to be cheaper if we use a traditional sand and cement mix.

We want the mortar mix as black as possible to contrast against the granite colour.

Were planning to use 4 sand to 1 cement with a black cement dye (added as per manufacturers instructions)

Do we need anything "special" or can we just go to Jewson etc and get their bog standard sand, cement and black dye ?

Is there anything else we should add to the mortar mix ?

FYI were planning to use a pointing gun to make sure all the gaps are completely filled and also minimise spilling mortar on to the granite surface.

Posted: Tue Apr 01, 2014 4:58 pm
by r896neo
Ideally I would use a slurry type jointing because if it removed the pointing chances are it may have removed some beddding so a slurry applied product would help shore up any little gaps.

If you really want the dark colour you need to use a resin. Mortar dye will not hold its colour for more than a year or two is your very lucky.

If you do go sand and cement then i prefer plastering sand as it stains less and i feel gives a harder joint than building sand.

Posted: Tue Apr 01, 2014 5:18 pm
by lutonlagerlout
if you want black you need a basalt sand as dyes tend to fade rapido
LLL

Posted: Tue Apr 01, 2014 5:24 pm
by XTA
Ok thanks for info was not aware dyes would fade ... Don't want to be doing this every two years ... So in view of this it probably going to be the black 840+ slurry we roll with

Posted: Wed Apr 02, 2014 6:16 am
by cookiewales
nexus and romex do black basalt resin joints look wide enough :D

Posted: Sun Apr 06, 2014 10:51 am
by Tony McC
840+ is the blackest of all the polymeric mortars I've seen. The 'basalt' colours in epoxy slurries are, to be honest, dark grey at best, and some are notably darker than others. However, the epoxies are better suited to regular power washing (if you really must), so you need to decide on which is the more important: the colour or the maintenance?