Why Not Elastic Paint as UV Barier On Sail's Leach/Foot?

[rardiH36]

At the risk of opening myself up to some (OK probably much) incredulity, has anybody tried (or done something similar) as described in the next paragraphs? If not, care to venture a projection of likely outcome? OK to cut the line on my bosun's chair with the responses.

• The target of the scheme is an older roller-furling 43' luff head sail without a Sunbrella or sacrificial dacron UV cover. The sail is OK for day sailing and isn't about ready to rip apart in the next heavy wind; but not valued enough to support $ hundreds for a sail loft's material and work.
• The alternate fix (yes, probably in the Rube Goldberg category) for a few years is a ~$25 gallon can of pure white "lasts a decade" elastometric water-based roof coating. Like the product in this link: http://www.gardner-gibson.com/linedetails.aspx?id=88
  
• Roll or brush on a thin as possible coat - maybe even dilute a bit with water - on the leach and foot sections in the same'ish area that a Sunbrella cover would be sewn on. Also put a little around the leach and foot edges to protect this exposure spot. Find a way to prevent the coating to cement the leach lines in place.
• Let dry in the sun for a couple of days to avoid residual tackiness from preventing the sail to ever unfurl again. Wow what a removal from the forestay job that would be!

When dry, the sail will be a few lbs heavier. But probably less so than with many yards of Sunbrella.

Any other coating product that might work to slow down UV damage? ... Like a water thinned coat of flat white latex house paint. I have painted fabric before with thinned latex. While it stiffens the fabric up, enough flex remains that I think would be OK for the last couple of turns around a furler. The paint would soak through the no longer new dacron (as does plain H20), so the bond I think would be good.

 

[Stu Jackson]

Man, if it worked, if I were you, I'd patent it!

Have you considered doing it right at the clew for a few feet in each direction and giving it a try?

 

[Bob McL]

On a fabric covered airplane some have used "aluminum" paint to stop UV. then a color coat. The paint did show some flex marks (circles).

 

[rardiH36]

...Have you considered doing it right at the clew for a few feet in each direction and giving it a try?

Stu:

No, but after I did my original post, I recalled that I have in the basement a "real-beat-up-doesn't-fit-my-boat-end-of-the-marine-flea-market-season-please-take-it-off-my-hands-even-if-only-for-a-drop-cloth" sail that I can experiment with. Slop on some coating. A small section as you suggest. Expose it to the elements for a week or two. Evaluate.

 

[Stu Jackson]

Lemme know how it works, since I had the idea for the patent, ya know!

 

[rardiH36]

On a fabric covered airplane some have used "aluminum" paint to stop UV. then a color coat. The paint did show some flex marks (circles).

Bob:

Thanks for info about paint for covering fabric on airplane surfaces which prompted me to find this informative link. Seems that white Latex is fine for UV blocking. (I had been thinking this because the prime ingredient in white is TiO2, a very opaque and reflective mineral that is ground into a fine powder before becoming a paint additive. So it blocks UV, and UV would have a tough time degrading titanium dioxide I would think. The polymers that "glue" the paint together though would be a different matter.)

http://www.ultralightnews.com/features/latexpaint_uvbarrier.htm

From an internet search, one big difference is that once the airplane fabric is laid on, it is shrunk tight before painting. So presumably the subsequent flex of the fabric and hence any paint coatings is minimal compared to a boat's sail.

 

[Don12364]

My jib came new like that about 5 years ago. It is still okay after hardly ever being off the boat.
It is a Genesis Brand (Plastic fantastic) built by David Robinson of what was once 'Team Sails', then Sobstadt and now Elvestrom UK.
So the secret is out.

Sadly David died in an avalanche whilst off piste skiing last winter.

 

[rardiH36]

My jib came new like that about 5 years ago. It is still okay after hardly ever being off the boat. ...

Donalex:

Wonder what coating was used on your sail? Got to be higher tech than latex elastometric roof paint.

Anyway I think I've got enough info now to go ahead with giving my sail the DIY treatment. Downside I think will be minimal as waterborne paint won't damage the fabric.

The sail I've got was used as a heavy wind jib for racing. Not intended to be wrapped around the furler 24/7 which explains why it doesn't have UV protection already on. The sail must not have been used much as it is in good condition. Sure makes my boat point better than the older but still sound genoa I have been using. In central San Francisco Bay, heavy wind is the norm rather than the exception.

 

[mark_swart]

I'd be concerned about it getting thrashed when you tack, but I guess if it's a smaller sail it shouldn't be banging against the mast/shrouds too much. Interesting project...

 

[rardiH36]

I'd be concerned about it getting thrashed when you tack, but I guess if it's a smaller sail it shouldn't be banging against the mast/shrouds too much. Interesting project...

I hadn't thought of that. Great observation. Yes, the sail is short of my forward shroud by a few inches and the foot is above the life line level. So no chafing problem in this instance.