Mysterious magical minerals, or Dansand vs regular kiln dried sand

ok, so its raining, I'm part way through a jetwash-the-patio project and I like science.

Kiln dried paving sand is approximately £5/bag; Dansand is approximately £9/bag.

Dansand are a bit coy about how it works saying 'Dansand® joint filling sand consists primarily of common quartz sand from Denmark and sustainable natural minerals that give a high pH value. If you have first used Dansand® joint filling sand...between your stones, you do not have to work as hard to combat and burn off weeds. You can say goodbye to a lot of unnecessary chemicals.'

The data safety sheet says 'quartz' and 'sodium silicate'. A little research reveals sodium silicate aka waterglass is a white powder that dissolves in water to yield an alkaline solution (high pH value checks out). As the water evaporates, the solution solidifies into a glassy solid (I guess this glues the sand particles together keeping them in the joint, keeping dirt out, and preventing root establishment).

However, the data sheet states that Dansand is insoluble; can an insoluble mineral change the pH? And other sources say high pressure and steam is needed to dissolve sodium silicate to make waterglass. So will it work?

I'll report back in a year.

Cool fact: Placing freshly laid eggs in a water glass solution seals the pores of the eggs against bacteria and gases, so it can be used to preserve eggs when refrigeration isn’t an option. This is not an approved application of Dansand.

Replies

Graham Taylor November 27, 2018 at 2:13pm

The reviews for it.... Wickes and Amazon.... are generally poor so doesn't look too promising.
Dan Frazer Gardening November 27, 2018 at 9:39pm

You're going to have to pray for an amazing spell of weather to be sanding a driveway properly!
Tim Wallach February 28, 2019 at 2:48pm

Update at 3 months. Difficult to compare with regular sand as it wasn't a double blind controlled trial. Some signs of weed germination and growth alread is disappointing. The only positive is that a 1cm wide joint has stayed fairly full and the sand there seems surprisingly resilient to prodding. Regular sand would have deteoriated I think.
- Tim Wallach > Tim Wallach September 11, 2019 at 9:33pm
  
  10 months in...
  - PRO
    
    Ben Mallow > Tim Wallach September 12, 2019 at 11:07pm
    
    Blimey, I might try Dansand as a seed compost! Germination like that would rival many named seed compost brands... :D
    - Tim Wallach > Ben Mallow September 17, 2019 at 8:50pm
      
      I'll trademark it as John Innis No. 4 if you want to go into partnership!
PRO

Geoffrey King September 14, 2019 at 12:08pm

We used to do this in the 70s & 80s. We had a medium sized dustbin, in an out building with a 100-200 eggs in it. Used for baking mainly.
- Tim Wallach > Geoffrey King September 17, 2019 at 8:52pm
  
  That's an amazing memory. Did you notice what the weeds were like where the 'water sand' dust got trodden out of the door though?