Quote:
Originally Posted by Robert Grant
What is that chalky substance that gets on (and, it seems to me, into) Motorola knobs, and how do you clear it out?
P.S.: stunningly beautiful work!
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I am not sure what exactly that white stuff is. I think the material the knobs are made with is CAB, cellulose acetate buterate. We used to buy tubing where I worked, made of this compound and it has the same odor as the knobs have when new.
As for cleaning the stuff off of the knobs: I use a stiff plastic bristle brush and also use my finger nails to scrape the thick layers of white stuff off. Then I polish the plastic with white automotive polishing compound and a terry cloth rag. After cleaned and polished and nice and clean, I then spray with the ACE clear gloss lacquer and force blow dry with a hair dryer. Test the spraying of the lacquer on some old knobs to perfect your technique before you spray the knobs you are restoring. You wouldnt want to botch the spraying of the lacquer by applying to much or not enough etc.
FYI CAB plastic will melt in lacquer thinner, so this whole spraying procedure needs to be done to perfection and you can easily botch the job if you don't get it right the first time. So practice, practice, practice on old knobs before you risk doing this to the knobs you intend to restore. If you decide not to protect the knobs with clear lacquer, your knobs will continue to get that chalky residue again.. It is some sort of oxidation from the atmosphere and only clear coating with lacquer will inhibit the reformation of that stuff.
Bob