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Caustic Soda?


#1
    G'day; Lye is caustic soda, sodium hydroxide. Fine for semi
precious metals such as gold, silver, palladium, platinum, rhodium,
etc, and modern stainless steel.   But don't let it anywhere near
articles made of aluminium or titanium (or flesh) which it will
rapidly dissolve and ruin.   A strong hot solution of washing soda;
sodium carbonate has less potential for harm, and will adequately
clean all the aforesaid precious metals, but don't let that near
aluminium or titanium either. -- Cheers now, 

John, I thought the only way to dissolve Ti was with Hydrofluoric
acid or or very strong oxidizers. It seems that caustic soda would be
easier to deal with than HF. Please enlighten me.

Jim
James Binnion Metal Arts
Phone (510) 533-5108
Toll Free (877) 408 7287
Fax (510) 533-5439


@James_Binnion
Member of the Better Business Bureau


#2

For exposures to sodium hydroxide at concentrations under 50%
and ambient ttemperature conditions titanium is rated excellent
(Less than 2 mils penetration per year) At concentrations above 50 %
it falls to good ( less than 20 mils penetration per year) At 70%
concentration it is good to about 380 F where it becomes
unsatisfactory ( greater than 50 mils penetration per year). Titanium
is not suitable for HF or HCl. Jesse