Fumed silica questions

[customcutter]

I mentioned in another thread I scored a free 55# bag of fumed silica Monday when purchasing materials.  However, it was on the shelf for at least 7 years, management didn't even know they had several bags left over from a job years ago.  One of the employees said they had some when I asked about it.

When I got home I did an internet search and one website said that it had a shelf life on 2 years in a sealed bag in the warehouse.  On a second website, it said it had an indefinite shelf life in a sealed bag, but only 2 years after it was opened.  I'm going with option 2, it's got an indefinite shelf life and it's been in a sealed bag.

I've looked all over this site and the internet about mixing fumed silica to make colloidal silica.  I think colloidal silica actually involves more of a chemical process than just dissolving or suspending fumed silica in water?  Anyway that's what I did dissolved all the fumed silica I could in regular tap water and buttered my inswool and then sprayed about 1/2 gal of fumed silica solution into it.  I'm going to let it air dry overnight.  Tomorrow I will light my turkey fryer burner and see if I can get it dried out and properly hardened.

What say ye?

Thanks in advance Ken

[Jasent]

55#'s is a lot of rigiddizer!  I believe it only goes bad  once mixed. Hopefully some one who knows for certain will chime in

[Mikey98118]

Fumed silica is just one more form of glass. Once it is mixed in water, becoming colloidal silica, there can be shelf life issues, but my bottle of silica rigidizer (colloidal silica and blue dye) has lasted for years, without settling out. The shelf life problems that have been reported, have occurred due to super concentrated containers of colloidal silica being stored too long; these become concentrated bases, causing chemical reactions. 

Once mixed with water, do not allow the solution to freeze, or it will settle out.