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Waterproof Drysuit Zippers

Updated June 30, 2015

METAL OR PLASTIC? WHAT IS THE BEST WATERPROOF ZIPPER?

In June 2014, DUI began offering divers the choice of YKK (metal) waterproof zippers and TiZip MasterSeal (plastic) waterproof zippers in their drysuits.

After one year of experience, we have an update. Which is better? Metal or plastic?

As of June 30, 2015, DUI recommends YKK metal waterproof zippers. DUI has been using these zippers for over 25 years and they have proven reliable. These are the zippers of choice for most high performance divers.

In our experience, TiZip MasterSeal zippers, while acceptable for less demanding recreational divers, have shown inconsistencies in their performance. Some customers have experienced small or intermittent leaks in relatively new zippers.

DUI will continue to offer TiZip MasterSeal zippers as an option for divers who still prefer this type of zipper. However, all tests show that YKK metal waterproof zippers are more reliable and, when properly maintained, will outlast the current TiZip MasterSeal zippers.

We will be the first to provide new information as it becomes available.

CURRENT DAY DUI dubbed 2013 “The Year of the Zipper” and did unprecedented testing on seven metal tooth and five plastic tooth waterproof zippers under laboratory conditions. Tests included:

ZIPPER TAPE

  • Fraying: Tumbled for 1,000 hours in a cement mixer
  • Adhesion resistance
  • Biological degradation (6 months in a warm microbe-active environment. This is the same environment as putting your wet drysuit in the warm trunk of your car)
  • Sea water and salt spray compatibility and its impact on metal components of a drysuit
  • Cold storage and operation
  • UV and ozone exposure (over one year in the sun)

ZIPPER PULL

  •  Cycle testing: DUI designed and built a device that opens and closes the zipper 100 times then pressure tests the zipper and checks for leaks using two procedures:
    • With lubrication of teeth and slider
    • Without lubrication of the teeth and slider
  • Derailing: SPECIAL NOTE: Some plastic tooth zipper manufacturers promote that should their zipper pull derail, the diver can fix the zipper. In our tests, 75% of the time the diver can get the slider back on the chain yet in 15% of these cases the zipper will leak after it is repaired and the repaired zipper will have only about 70% of its original breaking strength.
  • Cross breaking strength of zipper chain
  • Cycle test over curved surfaces (zippers do not lay flat when used in drysuits)

ZIPPER TEETH

  •  Breaking strength
  • Tearing strength of zipper tape between teeth
  • Maximum operating pressure and impact of cycle testing on operating pressure
TOP PERFORMERS Based on all of these tests, DUI is pleased to offer both of these zipper options on their drysuits:

BEST – YKK METAL TOOTH ZIPPER (LUBRICATED)
GOOD – TiZIP MASTERSEAL PLASTIC TOOTH ZIPPER

WHICH ONE IS BEST FOR ME?

Use the following list of PROS and CONS to help you determine the best type of waterproof zipper for your DUI drysuit:

BEST – YKK METAL TOOTH ZIPPER – MADE IN USA

PROS

  • Proven
  • Higher breaking strength
  • When properly lubricated (lubrication of the zipper chain and slider once per dive day), the zipper will last for more cycles
  • Docking of slider at the bottom stop is not as critical – a diver can leave up to a 3mm gap without leaking

CONS

  • Zipper tape fraying (primary failure)
  • Stiff and does not conform to the divers body as well
  • If not lubricated, the zipper has a greatly reduced life cycle – entire zipper should be lubricated after every dive day
  • Zipper chain can be broken from tight bends
  • Packing volume is larger

GOOD – TiZIP MASTERSEAL PLASTIC ZIPPER – MADE IN GERMANY

PROS

  • Flexible and conforms better to the divers body
  • Comfortable and flexes with movement
  • Easier to clean
  • Smooth and easy operating slider
  • Lubrication of zipper chain is not required – lubricate closure/docking area only

CONS

  • Does not last as long as metal tooth zippers
  • A gap bigger then >1 mm between the slider and bottom stop will result in a leak
  • Lower breaking strength / Not for use in close-fitting neoprene drysuits
  • Slider can derail
  • Lubrication of docking area critical (bottom stop is critical) – failure to do so will the result in a zipper leak
INTERESTING FACTS ABOUT WATERPROOF ZIPPERS NO WARRANTY EXPRESSED OR IMPLIED

Neither YKK nor TiZip offer any type of warranty on the performance of their zipper. Any warranty extended by DUI is done so at the full expense of DUI.