Immersion suit zipper lubricant
Immersion Suit Zipper Lubricant — What to Use and What to Avoid
The zipper on an immersion suit is the most critical component of the whole suit. It is what creates the watertight seal that keeps you dry and alive in the water. A zipper that sticks, jams, or fails during donning in an emergency could cost you your life.
Keeping the zipper lubricated is one of the simplest and most important maintenance tasks you can do — and yet it is one of the most neglected. Here is exactly what to use, what not to use, and how to do it properly.
Why Immersion Suit Zippers Need Regular Lubrication
Immersion suit zippers are deliberately stiff. They have to be — the resistance of the zipper teeth creates the watertight seal that prevents water ingress in the water. A loose, easy-running zipper would not seal properly.
The problem is that stiff zippers get stiffer over time without maintenance. Salt deposits from sea air, dirt and grit in the teeth, and drying out of the rubber or plastic components all make the zipper progressively harder to operate. In a training environment this is annoying. In a real emergency where you have two minutes to don the suit — a seized zipper is a crisis.
Regular lubrication prevents this. It keeps the zipper operating smoothly while maintaining the seal integrity. Check out the SOLAS requirements here.
What Type of Zipper Does Your Immersion Suit Have?
Before choosing a lubricant you need to know what type of zipper your suit uses — because the right lubricant depends on the zipper material.
Waterproof plastic zippers — the most common type on modern immersion suits. Often made by YKK or TiZip. These require a silicone-based lubricant or a proprietary zipper lubricant. Do not use wax on plastic waterproof zippers — it can clog the teeth rather than lubricating them.
Metal waterproof zippers — found on older suits and some drysuit designs. These work well with beeswax or paraffin wax applied to the teeth. Silicone lubricant also works on metal zippers.
Check your suit’s documentation or the manufacturer’s website to confirm which type of zipper your specific suit uses before applying any lubricant.
The Best Lubricants for Immersion Suit Zippers
Silicone-based zipper lubricant — recommended for plastic waterproof zippers
Silicone lubricant is safe for neoprene, rubber, and plastic components. It does not degrade the zipper material or the suit seals over time. It repels water and provides long-lasting lubrication that stays effective in the marine environment.
Products specifically designed for drysuit and immersion suit zippers — such as McNett Zip Tech or Gear Aid Zipper Lubricant — are silicone-based and are the honest first recommendation for any modern immersion suit with a plastic waterproof zipper.
Gear Aid Zip Tech Drysuit Lubricant
High performance lubricant for watertight and airtight zippers. Recommended by YKK — the world’s leading zip manufacturer — for nylon drysuit zips. Protects against rust, corrosion, chlorine, and salt in all temperatures. Contains no paraffin or silicone — important for suits where these are contraindicated. Non-toxic and biodegradable.
Stormsure ZipOil for Drysuit and Wetsuit Zips
A specialist oil formulation specifically designed to free sticky or corroded zips. Particularly useful for suits that have not been maintained regularly and have developed stiffness. Easy to apply, penetrates quickly. Good for bringing a neglected zip back to working condition before switching to a maintenance wax or lubricant for ongoing care.
Napier EZIP
An aerosol spray to sort out sticky zips on shooting luggage, slips, holdalls, diving kit, clothing and, of course, wellingtons. Aerosol lubricant spray for sticking zips on jackets, gun slips, luggage and wellies. Penetrates the teeth to drive out grit and abrasive particles
Paraffin wax — budget alternative for metal zippers
A plain paraffin wax candle rubbed along a metal zipper works on the same principle as beeswax. YKK specifically recommends paraffin wax application on both the inside and outside of metal zippers when closed. Cheap and widely available.
What to Never Use on an Immersion Suit Zipper
WD-40 and petroleum-based products — never
WD-40 is a petroleum-based product. Petroleum degrades neoprene, rubber seals, and the gasket components of waterproof zippers over time. It may provide short-term lubrication while causing long-term damage to the suit. Never use WD-40 on an immersion suit zipper regardless of how tempting it seems when you have nothing else available.
Cooking oil, motor oil, or any oil-based product — never
Same principle as WD-40. Oil-based lubricants attack neoprene and rubber. They also attract dirt and grit which accelerates wear on the zipper teeth.
Vaseline (petroleum jelly) — use with caution
Some manufacturers permit Vaseline on specific components — usually the docking lug and horseshoe of plastic zippers rather than the teeth. Never apply Vaseline to the main zipper teeth on a waterproof plastic zipper without checking your specific manufacturer’s guidance first.
How to Lubricate Your Immersion Suit Zipper — Step by Step
- Rinse the zipper with fresh water first to remove salt deposits and any dirt. Use a soft toothbrush on the teeth if needed.
- Allow the zipper to dry before applying lubricant.
- Close the zipper fully.
- For a semi-solid or stick lubricant — apply along both sides of the closed zipper, working the lubricant into the teeth. For a spray lubricant — apply along the zipper length with the zipper closed.
- For the docking end (the horseshoe closure at the end of the zipper) — apply a small amount of silicone lubricant to both sides of the docking point and the small holes in the horseshoe.
- Work the zipper back and forth six to ten times to distribute the lubricant evenly through the teeth.
- Wipe off any excess lubricant from the surrounding suit material.
How Often Should You Lubricate the Zipper?
Before every offshore passage or trip — a quick application and a few runs of the zipper takes 60 seconds and ensures the zipper is in full working order.
After any use in salt water — rinse with fresh water and relubricate.
As part of the annual suit service — a thorough clean and lubrication should be part of every annual inspection.
If the zipper starts to feel stiff during normal use — do not force it. Stop, lubricate, and work it gently. Forcing a dry zipper risks damaging the teeth or the seal, and a damaged zipper on an immersion suit is an expensive repair. Check the MCA immersion suit guidance here.
Storing Your Immersion Suit After Lubricating
Store the suit with the zipper open — never folded closed under compression. Leaving the zipper compressed in the closed position for long periods can distort the seal and make the next opening harder.
Roll the suit loosely from the feet up, lay the arms alongside, and store in the provided bag in a cool, dry location away from direct sunlight and UV exposure. UV degrades neoprene over time.
FAQs
Can I use silicone spray instead of silicone zipper lubricant?
A standard silicone spray can work on metal zippers. For plastic waterproof zippers, a dedicated semi-solid silicone zipper lubricant like McNett Zip Tech is preferable — it stays in the teeth rather than running off, providing more effective and longer-lasting lubrication.
My zipper is completely seized — what do I do?
Do not force it. Apply silicone lubricant generously and allow it to penetrate for several minutes before attempting to move the zipper. Work it very gently with small movements. If it will not move at all, take the suit to an approved service centre — forcing a seized zipper can destroy the teeth and require a full zipper replacement.
How do I know if my zipper needs replacing?
Signs of a zipper needing replacement include visible corrosion or damage to the teeth, persistent leaking through the zipper even when correctly closed and lubricated, the zipper pull becoming difficult to attach or detach from the teeth, or any physical damage to the zipper tape or seal.
What is the lifespan of an immersion suit zipper?
With proper maintenance — cleaning and lubricating regularly — a quality waterproof zipper should last the service life of the suit (typically 10 years). Without maintenance, zippers can seize and fail significantly earlier. Regular lubrication is the single most cost-effective maintenance task you can perform on an immersion suit.
The information in this article is for general guidance only. Always follow your specific suit manufacturer’s maintenance instructions and use only lubricants recommended for your specific zipper type. For any doubt about zipper condition or suitability for use — have the suit inspected at an approved service centre before relying on it offshore. marinesafetyguide.com participates in affiliate programmes including Amazon Associates and the Awin network and may earn a small commission on purchases made through links on this site, at no extra cost to you.
