View Single Post
  #8   Report Post  
Posted to rec.crafts.metalworking
Eric R Snow
 
Posts: n/a
Default A caution about the excellent Castrol purple cleaner

On Fri, 18 Nov 2005 16:16:25 -0800, Grant Erwin
wrote:

It does contain lye, Eric, in which aluminum is highly soluble ..

GWE

Eric R Snow wrote:
I bought this stuff because Grant and others said it worked well to
remove oils. And it sure does. I suspected that it might be pretty
strongly alkaline because of the soapy feel. And I got proof when
washing some anodized parts that came in for mods. The Castrol purple
stuff started to remove the dye (black) and on the machined surfaces
started to dull them slightly. I will still use the stuff on aluminum
if I need to but will not let it sit for long. I wonder if it would
make a good weld prep for aluminum?
ERS

Well, there ya go.
ERS