Immersion Suit Zipper Lubricant — Why It Matters and the Best Products to Use
Immersion Suit Zipper Lubricant — Why It Matters More Than You Think
The zip on an immersion suit is the most critical component on the whole garment. And it is also the most neglected. They are also a pain to use!
I have never personally applied lubricant to an immersion suit zip — that maintenance has always been handled by whoever is responsible for the equipment on the vessels I have worked on. But having donned immersion suits more times than I can count in drills, I know exactly how uncooperative a stiff, poorly maintained zip can be, its the same with Wetsuits and Dry suits. i have had to maintain my own suits regularly. The zips can go at funny angles. They catch material. They slow you down when speed matters.
Here is why this matters more than most people realise — and it is a real story, not a warning for the sake of it.
After the sinking of the F/V Wayward Wind, an investigation by the National Transportation Safety Board found that corroded zippers on immersion suits worn by three deceased crew members most likely contributed to their deaths. The suits were not fully zipped. Cold water flushed in and out. The NTSB concluded they might have survived if the suits had been properly maintained.
A zip. Three lives.
Why Immersion Suit Zips Fail
Immersion suit zips are watertight seals, not ordinary zips. They are designed to keep cold water out under pressure. This means they are deliberately stiff and tight — and that stiffness increases significantly without regular lubrication.
Salt residue, sand, organic debris, and UV exposure all degrade the zip over time. Without lubrication the sealing edges dry out and crack. The slider becomes harder to move. The teeth misalign. And a zip that does not close fully is a zip that lets water in.
How to Lubricate an Immersion Suit Zip — Step by Step
Step 1 — Clean first. Before lubricating, clean the zip thoroughly. Use soapy water and a soft brush — an old toothbrush works perfectly — to remove salt, sand, and any debris from between the teeth. Rinse thoroughly with fresh water. Never use a hard implement that could damage the teeth.
Step 2 — Open the zip fully. Always lubricate with the zip fully open, not closed.
Step 3 — Apply lubricant to the teeth. Apply a small amount of lubricant along the zipper chain approximately every four inches. Work it into the teeth gently. Do not over-apply.
Step 4 — Also apply to the sealing edges. The sealing lips either side of the zip need conditioning as much as the teeth. Apply lubricant to both sides.
Step 5 — Exercise the zip. Run the slider up and down 5 to 10 times after application to work the lubricant into the mechanism evenly.
Step 6 — Wipe away excess. Remove any excess lubricant with a clean cloth.
Step 7 — Store with zip closed. After maintenance, store the suit with the zip fully closed.
How Often Should You Lubricate?
At minimum — before and after every use, and before long term storage. For suits used regularly in salt water, lubricate every time you rinse the suit down. For suits used infrequently, lubricate at least every three months regardless of use. This seems excessive but don’t neglect it
The zip is the most expensive component of an immersion suit to replace — and the most safety-critical. The cost of a tube of lubricant is negligible compared to what a failed zip can mean.
Important — Check Your Manufacturer’s Guidance
Different immersion suit manufacturers specify different lubricants for their specific zip systems. Some zips require silicone-based lubricant. Some require wax-based products. Some specifically prohibit petroleum-based greases which can destroy the rubber sealing elements.
Always check the manufacturer’s instructions for your specific suit before applying any product. The products below are widely used and suitable for most waterproof zipper systems — but verify against your suit’s documentation first.
Our Recommended Products — Available on Amazon
1. 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.
2. 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.
FAQs
Can I use WD40 on my immersion suit zip?
No. WD40 is a water displacer and light lubricant but it is not suitable for watertight zipper systems and can damage the sealing elements. Use a product specifically designed for waterproof zippers.
What if my zip is stuck and will not move at all?
Apply a penetrating oil like Stormsure ZipOil and work it gently into the teeth. Do not force the slider — forcing a stuck zip can break teeth and require professional repair. If it will not free up, take it to an authorised immersion suit service centre.
How do I know if my zip needs replacing rather than just lubricating?
Signs of a zip needing replacement include visible corrosion on the teeth, cracking or brittleness of the sealing lips, the slider not closing the teeth fully, or water ingress despite the zip appearing closed. Major repairs and zip replacement must be done at an authorised service facility — not DIY.
The information in this article is for general guidance. Always follow the manufacturer’s specific maintenance instructions for your immersion suit and take it to an authorised service centre for annual inspection.
