Re: [ATM] Lemon Juice and Optics

[Woodchuck <djv@bedford.net>]

On Sun, 9 May 2004 jroweapp@postoffice.swbell.net wrote:

> Dear Richard;
> I agree!!  When companies that manufacture and or, distribute glass
> polishing compounds post the ideal pH values for the use of their
> polishing compounds, there must be a reason. I can site Salem
> Distributing for one. If you have bought goods from them and received a
> catalog, they post optimum working pH values for their polishing
> compounds. I doubt their information is meant to misleed or win trivia
> contests. They try to provide information so their clients can produce
> the optimum result. I would suggest acetic acid, (white vinegar) and pH
> papers or a decent pH meter to arrive at the advised pH.
> Regards
> Jeffrey Rowe

Better yet would be a buffer solution at the proper pH.  The challenge
would be to find one that keeps its pH as it evaporates, and does
not leave any nasty-scratchy salts as it does evaporate in use.  Vinegar
has this nice property of evaporating completely, but it's not a buffer.
I suspect that vinegar ought to be adequate, though.  It's probably
a range that is wanted.

Question now on the table, *why* an acidic pH? Possibilities:
	*) formation of sodium silicate or borates from the glass being
ground?
	*) control of flocculation of the grinding slurry, i.e. breaking
up clumps of abrasive/polishing compound and other substances?
	*) control of staining from certain compounds? (on certain glasses?)
	*) needed for certain "exotic" glasses to prevent or encourage
something? (If so, what?)
	*) something obscure, like hydration of the glass surface?

Dave

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