Can I use sodium silicate waterglass to cast a glass object?

In summary: M.In summary, waterglass is a solution of sodium silicate and water that is used in various applications such as creating crystal gardens and pottery. It can also be used to preserve eggs and join clay pieces. However, it is not suitable for casting glass objects due to its brittleness and alkaline properties. The best option for clear-casting would be to use acrylic resin, which may require techniques such as deaeration to remove bubbles.
  • #1
Christofer Br
51
0
Waterglass is sodium silicate dissolved in water that upon drying forms soda glass. Could it therefore be used to cast a glass object like a slab or will it not form nicely?
 
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  • #2
https://en.wikipedia.org/wiki/Sodium_silicate#Crystal_gardens said:
Crystal gardens[edit]
When crystals of a number of metallic salts are dropped into a solution of water glass, simple or branching stalagmites of coloured metal silicates are formed. This phenomenon has been used by manufacturers of toys and chemistry sets to provide instructive enjoyment to many generations of children from the early 20th century until the present. An early mention of crystals of metallic salts forming a "chemical garden" in sodium silicate is found in the 1946 Modern Mechanix magazine.[24] Metal salts used included the sulfates and/or chlorides of copper, cobalt, iron, nickel, and manganese.

Pottery[edit]
Sodium silicate is used as a deflocculant in casting slips helping reduce viscosity and the need for large amounts of water to liquidize the clay body. It is also used to create a crackle effect in pottery, usually wheel-thrown. A vase or bottle is thrown on the wheel, fairly narrow and with thick walls. Sodium silicate is brushed on a section of the piece. After 5 minutes, the wall of the piece is stretched outward with a rib or hand. The result is a wrinkled or cracked look.

It is also the main agent in "magic water", which is used when joining clay pieces, especially if the moisture level of the two differs.[25]
 
  • #3
It's been a while, but I've used sodium silicate 'water glass' both for 'crystal gardens' and egg preservation.

IMHO, 'water glass' is much too brittle for use in casting. Worse, it is sufficiently alkaline for 'manual handling' issues.

( And Sufficiently alkaline to eat through an aluminium pan... )

FWIW, I don't know if any-one has tried glass-fibre reinforced 'water glass', but I'd expect even quality fibre mat, as used in GRP boat and car etc repairs, may have a colour taint, plus sufficiently differing refractive index to not be transparent as requested...

I'm sorry, I'm told 'clear-casting' with acrylic resin is probably the better option. How you get the bubbles out remains beyond me...
 
  • #4
Nik_2213 said:
How you get the bubbles out remains beyond me...

A) Be careful in pouring into mold to not mix air in the liquid... as in pour gentle down the side of the mold
B) Deaerate if needed
  • Vibrating the filled mold may be sufficient with low viscosity liquids
  • Put in vacuum chamber... doesn't have to be fancy, for small items such as will fit into a canning jar, a hand operated vacuum pump may be adequate.

(This is not applicable in your case, included here for completeness)
  • If it's a two-part compound: Mix as you would mix car repair Body Putty. Don't stir, smear out on a flat surface with a spatula, fold the layer over itself, repeat.
  • If bubbles are not real critical in final product, just letting it sit for a few minutes after mixing may be sufficient; depends a lot on viscosity.
  • If bubbles are critical, put in a vacuum chamber after mixing; may have to repeat after pouring into casting mold.

Cheers,
Tom
 

1. What is sodium silicate waterglass and how is it used for casting glass objects?

Sodium silicate waterglass is a chemical compound made of sodium oxide and silica, commonly used as a binder or adhesive in various industries. When mixed with water, it forms a thick, syrupy solution that can be used to bind glass particles together for casting. It is often used in combination with other materials to create molds for casting glass objects.

2. Is sodium silicate waterglass safe to use for casting glass objects?

Yes, sodium silicate waterglass is generally considered safe to use for casting glass objects. However, it is important to handle it with care and follow proper safety precautions, as it can be caustic and irritate the skin and eyes. It is also important to use it in a well-ventilated area to avoid inhaling the fumes.

3. Can I use sodium silicate waterglass for all types of glass casting?

No, sodium silicate waterglass is not suitable for all types of glass casting. It is commonly used for small-scale casting projects, but it may not be strong enough for larger or more complex objects. Additionally, it is not recommended for use with certain types of glass, such as lead crystal, as it can cause cloudiness or other defects in the finished product.

4. How do I mix sodium silicate waterglass for glass casting?

The exact mixing instructions may vary depending on the specific product you are using, but generally, you will need to mix one part sodium silicate waterglass with one part water. It is important to mix it thoroughly and let it sit for a few minutes to allow any air bubbles to dissipate before using it for casting.

5. Can I reuse sodium silicate waterglass for multiple castings?

Yes, you can reuse sodium silicate waterglass for multiple castings. However, the strength and effectiveness of the solution may decrease with each use, so it is recommended to mix a fresh batch for each casting project. You can also add a small amount of new solution to the old one to help maintain its strength.

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