G'day Patrick,
Thanks for the warning about CT-18. But was wondering if you've mixed it up with alloy wheel cleaner/degreaser which is strongly alkaline or CLR which is acidic? My bottle of CT-18 explicitly states "pH neutral". There are also no warning symbols and it pretty well states it's benign. Not even a "use gloves" on the bottle.
Nope, I do indeed mean CT-18. BTW, the MSDS for it quotes a pH range OF 7.5-8.5; 7.0 is neutral. So it's not
very alkaline, but it's definitely not neutral, despite their claim.
This long-term corrosive characteristic of the stuff is one that's caught out the unwary [particularly trailbike owners] for some years. It's only a serious problem where 'cranny traps' exist, such as the examples I gave. But the corrosion it causes to aluminium is of the nasty 'exfoliation' type. Just what you don't want in the spoke nipple dimples of alloy wheel rims, as it propagates outwards from the spoke hole, and thus weakens the most highly stressed points of the rim first.
Maybe CT-18 ain't what it used to be anymore?!
The oldest MSDS I could find online was dated 2005 [
http://www.oztrampolines.com.au/pdfs/ct-18msds.pdf ], and the pH spec is the same as the current MSDS on the Chemtech website. So it doesn't look like the formulation has changed in that time.
BTW, the MSDS does advise to 'avoid contact with skin and eyes'...
