Pure Silica Sand (which is almost like powder) can be elusive. Some Landscape supply stores carry this item – some don’t. But almost EVERY Pool Supply store does (it’s pool filter sand).
To locate your local pool supply store, jump on the Google machine and type “POOL SUPPLY” and your ZIP CODE in the search bar. Or you can just click here - Google.com/maps/search/Pool+Supply
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ONLY USE THESE TYPES OF SAND -
Pool Filter Sand
Fine Sand
Fine Silica Sand (All mesh sizes) (The Finer the Grain the Better)
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DO NOT USE -
All-Purpose Sand
Concrete Sand
Course Sand
Mason Sand
Medium Sand
Mortar Sand
Multi-Purpose Sand
Natural Sand
Play Sand
Sand / Topping
Step 5 from the ‘Mattone Barile Grande with Ceramic Fiber Blanket Insulation’ reads, “Cover the Insulated hearth slab with about 1” - 2" of ALL PURPOSE SAND. It goes on to say ''DO NOT USE SILICA SAND!!"
Given the information above, hoping for some clarification. I was prompted to post this question as the bag of “All Purpose Sand” says, “Contains Silica Sand.”
All sand consists of silica, but finer-grain sand is preferred for high-temperature mortar. Fine sand grains are 3 to 6 times smaller than larger, coarser grains. Finer sand grains blend and adhere better with other bonding compounds such as fire clay, lime, and Portland cement, all of which are finely powdered. The finer the sand - the stronger the bond.
ALL PURPOSE SAND (labeled as such on the sack) is okay even if it “contains silica sand.”
As @BrickWood says, FINE SAND is a different product meant for mixing mortar. It is too fine for the hearth leveling layer that you are building now.
ALL PURPOSE SAND is a coarser blend that will give enough support to your hearth brick layer without prematurely freezing in place.
Fine Sand is like a memory foam pillow—you’ll mush it into position but will then find it doesn’t want to shift when you do fine leveling steps on your hearth.
All Purpose Sand is like an open-foam pillow—it has enough springiness to help you get each hearth brick where it needs to go.
So in my opinion, you are good to go with ALL PURPOSE SAND.
