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Removing Yellowing from Plastics - Part 3

Merlin

Experienced Member
Joined
Apr 23, 2008
Messages
290
Location
Manchester, UK
Iso Propyl Alcohol (found in De-Icer aerosols) does a pretty good job of removing magic marker as well, and it won't damage the plastic.
 

barythrin

Veteran Member
Joined
Oct 5, 2005
Messages
6,256
Location
Texas
Out of curiosity does the peroxide mix or these other tricks do anything if sharpie is on the plastic? I know sharpies are different and seem to melt the plastic a little or something odd.
 

Merlin

Experienced Member
Joined
Apr 23, 2008
Messages
290
Location
Manchester, UK
A Sharpie is a pointed tip Magic Marker and it contains a xylene-based ink. Xylene is enough of a solvent to slightly etch the surface of the plastic; however, if you are careful, it can be removed without damaging the plastic with methylated spirits, iso propyl alcohol or a dewatering aerosol like PlusGas or WD-40.

Just don't use something too aggressive, like acetone or nail varnish remover.
 

Rich113

New Member
Joined
Mar 29, 2009
Messages
6
If your reference to Sally H2O2 cream was the stuff I used (ie: hair bleaching/coloring products), don't do it ! It messes with blue and black plastic, to the point of it not being blue or black anymore. Its use was an experiment gone wrong. We now know better because of it, and the Xanthan gum mixture is the preferred route.

Several people have commented on the Sally H2O2 cream as being bad for dark plastic. I can't comment on that because I haven't tried it on that, but I have to say it works GANGBUSTERS on the Apple biege plastic. A little goes a long way. I bought a quart back in April, have done (perhaps) six or seven batches of parts and still have most of it left. It is still quite effective, too. Which leads me to my purpose for posting.

Yesterday I decided to clean up a batch of Apple cases (monitor, IIGS case, and about six disk drives). Heretofore I have been doing them indoors using a Sun lamp (big spotlight with high UV penetration). I've been pleased with the spotlight in general, which will restore a side in somewhere about five to six hours. I use the Sally cream with a 'glug' of Oxibright (mine came in liquid form).

Being as we are having beautiful summer days here in Michigan (USA), I decided to take advantage of the sunlight, out of doors.

WOW! :eek:

I set up the first batch with their first surfaces aimed at the sun (covered with plastic film to prevent drying) and took a break for some lunch. Glancing out the window, it seemed the parts were quite lightened, but thought it must be the angle or the whiteness of the gel or something. Went out a bit later and THAT SIDE WAS DONE! Continued on to the next side (for generally cubic shapes, it seems like I need five exposures). I quickly found that I could effectively treat each side with about one half of an hour of exposure. It was well done, too! (Well done, not well-done, if my meaning is clear.)

By mid afternoon, everything I had prepped was complete. I'm coming down the homestretch now on a second batch for today.

Two things; I am amazed at how much more powerful the sun is than that apparently-strong sun lamp, and also that my outdoors results seem so much quicker that what others have reported.

I'll invite comments and questions.

Rich
 

tezza

Veteran Member
Joined
Oct 1, 2007
Messages
4,720
Location
New Zealand
Two things; I am amazed at how much more powerful the sun is than that apparently-strong sun lamp, and also that my outdoors results seem so much quicker that what others have reported.

I'll invite comments and questions.

Yes, from what I've read around the web, the UV output in sunlight is way stronger than your standard UV lamp.

Tez
 

Lorne

Veteran Member
Joined
Jul 27, 2008
Messages
1,164
Location
Chandler, AZ, USA
Being as we are having beautiful summer days here in Michigan (USA), I decided to take advantage of the sunlight, out of doors.

Rich

That sun has its pros and cons. I don't think you'll see the cons in Michigan as bad as I do in Arizona.

Again: don't use it on dark plastic unless you want light plastic.

(I might have missed something, but I thought we went to a Part 4. If we did, and we've switched back to Part 3, Good - it's as though Part 4 was the kiss of death).
 
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