On Monday, May 21, 2018 at 10:22:21 AM UTC-4, Leon wrote:
On 5/20/2018 11:06 PM, DerbyDad03 wrote:
I've been using this '1/8" method' to clean the brushes I use for oil based
primer. The primer is Zinsser Cover Stain, just white, no tint.

https://www.youtube.com/watch?v=DDvDbKBTbic

I collect the used mineral spirits in a jar and let the primer settle out
so I can recycle the mineral spirits and use it to clean the brushes again.

I've found that instead of the mineral spirits being clear after the primer
settles to the bottom of the jar, it is sort of an amber colored clear. I
don't think it's a matter of not waiting long enough because I've gone weeks
without touching the jar.

The recycled spirits seem to work just as well as new spirits for cleaning
brushes, but I'm curious as to why it is no longer clear. What is in the
primer that would cause the spirits to turn amber?



Do you remember chemistry class, some ingredients settle and separate
others remain mixed.


Yep, that's why I ask *what* is in the primer that turns the MS Amber. ;-) According to
dadiOH the answer is "linseed oil".


I typically keep two jars of MS. One for the initial cleaning and the
second to clean out the other colored stuff that has not settled out of
the first.

Yes, my final rinse is with new, clear MS which typically results in a virtually clear residual.