I’ve been researching linseed oil, and discovered the SRO method by Tad Spurgeon.  I also was surprised to see that linseed oil can be bleached separately from thickening.

The cold refining process

Start of Bleaching

L:R: 3 moths of bleaching in UV Chamber and 12 year of bleaching in a window

L to R: 3 months in UV chamber, 15 and 18 months of bleaching in natural sunlight

The results speak for themselves.  The picture above (with the coffee stirrer) is 18 months of exposure to sunlight in the window.  It was covered during this time.  No appreciable thicking has occurred.  Up to 12 months slight lightening had occurred, but after 12 months the bleaching accelerated rapidly with very clear oil achieved at 18 months.  This oil was in a fairly sheltered window with little direct sunlight and in a northern latitude.

Next, I’ll be testing out the oil to determine the yellowing properties when dried.  Stay tuned.