Fact or Fiction?

Don Crowther

Don Crowther

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Sep 4, 2007
794
Hunter 33.5 Elbow, Saskatchwen, Can.
When I dropped my main sail cover off the other day at the awning shop I was told they didn't have the same zippers. The ones on my cover were #10's and white. All they have were the # 8's in black.

The shop owner then proceeded with her sales pitch. She says that the black won't be effected as badly by the UV's and should last alot longer.

The size difference was small so I don't think that matters as much.

What do you think was I sold a bill of goods just to help her get rid of old stock or is it true that the black will last longer?

I needed all 5 zippers replaced as they had all deteriorated to a point of uselessness.
All the other canvas on my boat and the boats around me use white zippers. Maybe I'll start a new trend!
 
I

IH82BL8

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Feb 6, 2013
437
Hunter 31 Deale, MD
My AMATEUR opinion is that the shop was being lazy and simply didn't have what you needed in stock.

As far as UV goes, I don't see where color has anything to do with absorption. In any case, black absorbs more heat from sunlight than white does. This may make zippers uncomfortable to handle on hot sunny days and may also cause them to break down faster.
 
kito

kito

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Sep 13, 2012
2,011
1979 Hunter Cherubini 30 Clemmons
I would tend to think that your awning shop would know. Probably why they only carry the black. I am sure they will order the white ones for you if you wish. I know to only use black wire ties when used outside. The clear and white ones don't hold up as long.
 
justsomeguy

justsomeguy

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Feb 20, 2011
8,062
Island Packet 35 Tucson, AZ/San Carlos, MX
Fact.

Coloration in plastics and nylon does have an effect on their UV absorption rate. The lighter the color, the better.

It's something to think about when ordering a new parachute. For that purpose, I go monochromatic. ;)

Whether you'll notice the difference over time is another question. How long did your white zippers last?
 
D

Donnybrook

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Apr 2, 2011
185
Catalina 27 Niceville, FL
Black zippers and zip ties last longer than white. Don't know why, they just do.
 
kito

kito

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Sep 13, 2012
2,011
1979 Hunter Cherubini 30 Clemmons
My brother was a field service engineer for a radio/tv broadcast equipment company. He told me to always use black zip ties when using outdoors. The white ones are just not as UV stable I reck'n. Probably the same polymer used in most nylon products. Bottom line, the awning lady was not pulling your leg.
 
centerline

centerline

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Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
Black VS. White, outdoors... one would think the white would reflect the sunlight a bit more and would last longer, and its true that it does reflect better and wont get as hot, but its NOT the sunlight itself that is the problem, its the UV rays within the sunlight....

UV rays cant penetrate into a dark colored object as far as it can into a light colored object...
and some white objects are more UV stable than others, and some black objects arent UV stable at all.... but as a general rule, always go with the darker object when longevity is a requirement...

the thread used in outdoor canvas products is one of the biggest "overlooked" design flaws there is. actually, outdoor threads have had some big improvements in the past few years to make them so much better, but black still outlasts white.
and, I use the term "design flaw" lightly because sometimes black thread would not look good and it has to be white.... black thread will last about 30% longer before it becomes rotten to the point where restitching is necessary....
 
justsomeguy

justsomeguy

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Feb 20, 2011
8,062
Island Packet 35 Tucson, AZ/San Carlos, MX
I keep wondering when that mil-spec zip-tie at the top of my mast is gonna give out. It's providing strain relief for the anchor light wiring.

5 months in the Mexican sun, and counting...
 
B

Benny17441

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May 24, 2004
7,213
CC 30 South Florida
It is one of those things I have never timed; but if all my other zippers are white I would get a white replacement. Would not want the job to look like patch work. Now regarding ties I prefer the black ones as the white or clear turn yellow after a while.
 
dlandersson

dlandersson

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Feb 16, 2011
227
Macgregor 26X Michigan City, IN
In fact, dark colors are more UV resistant than lighter colors.

Don Crowther said:
When I dropped my main sail cover off the other day at the awning shop I was told they didn't have the same zippers. The ones on my cover were #10's and white. All they have were the # 8's in black.

The shop owner then proceeded with her sales pitch. She says that the black won't be effected as badly by the UV's and should last alot longer.

The size difference was small so I don't think that matters as much.

What do you think was I sold a bill of goods just to help her get rid of old stock or is it true that the black will last longer?

I needed all 5 zippers replaced as they had all deteriorated to a point of uselessness.
All the other canvas on my boat and the boats around me use white zippers. Maybe I'll start a new trend!
Click to expand
 
G

gettinthere

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Nov 26, 2008
1,970
Endeavour 42 Cruisin
Maybe apples and oranges

But I asked 2 of the major rope manufacturers whether black line held up better than white. Both said they had no information to say one way or another.
 
J

John23883

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Jun 8, 2004
278
Hunter 26 Illinois
Black is the best

All plastic made for use in outdoor environments have UV inhibiters added to the plastic formulation. Black plastic has carbon black added, which is the best and coincidentally the cheapest additive. All colors other than black use titanium dioxide which is more expensive and less effective.

From a design standpoint, we always made our products black. It does seem counter-intuitive in that black plastic will get hotter than white, but heat is not the issue, penetrating UV is the problem. Carbon black is the most effective means of preventing the UV from getting into the plastic.

When choosing plastic products for outdoor use, I always try and get black.

Your shop owner was correct!
 
Ron20324

Ron20324

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Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
Any shop should use what YOU want, not just what they have in the drawer- even if you have to supply it yourself. #10 YKKs are pretty much the norm for boat canvas, so it is what I have used since I bought my Sailrite machine. Also, if UV is a concern, there should be a way to make a flap that will cover the zipper.
 
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