On some lighter-colored blanks, a less-yellowing option than spar varnish might be preferable to me.

Not comfortable with other finish options like permagloss, epoxy, etc.

Like crosscreek, I don't know for sure either. Even way back when, some brands of conventional spar yellowed very very little, Some were extremely clear; others, and this is indicated on the label, imparted a slight amber tinge but didn't yellow appreciaably afterwords. The urethanes I've used were sparkling clear, but I don't know that they have the track record for lack of yellowing over as long a period of use, so only time would tell. The worst yellowing/clouding I've seen, not that it's particularly bad, was in the epoxy/plastic type finishes. You may just have to try both forms of spar and fish the rods hard 30 or 40 years to see what happens. My guess is that the contemporary spars have the best uv protection ever and probably resist yellowing as well as or better than ever regardless of type. You know, Corlay, maybe you'd get a good clear answer right from the technical inquiries/ consumer info section in response to an e-mail to a major manufacturer or two--one that produces both urethane and traditional--as to their relative weathering traits. Just "of your spar varnishes. . . " and then about the same query you have above. I'd be interested to see what they said. I forget which companies still produce and sell both types as urethane seems to prevail these days but there have got to be some top marine suppliers who make both.

This is a good question. I don't think any Urethane can yellow as much as some oil-based spars. Although, I have never tried to compare oil spars and urethane, I do know that Ace oil based spar yellows a great deal. Now, it is good stuff and I use it when I refinish bamboo (both rod and silk wraps), but I rarely use it to coat glass or graphite nylon wraps.

Last summer, I used Ace spar to coat some wraps and a white background decal on a glass build. I then put the rod (in a cloth bag) away in my rod closet. In January, I inspected the rod to discover that the varnish had yellowed considerably in the dark! The whites of the decal were now yellow.

One of these days, maybe I will try a urethane, but I have so much permagloss and epoxy sitting around I will probably use them first.

John

Yes, Ace spar is the brand ive been using, and yes it yellows even with the rod in storage.

Can anyone comment on other spar brands (other than discontinued, vintage brands like 'cosmo').
Man-o-war, for example?

I really like the ultra-translucence spars gives a silk thread wrap, but like I said yellowing on some blanks isn't the best result.