Hypalon glue (polychloroprene adhesive) is a heavy-duty contact adhesive formulated specifically to bond Hypalon (CSM) and neoprene synthetic rubbers. It is most commonly used for repairing and manufacturing inflatable boats, RIBs, life rafts, and wetsuits.
Glue Selection: 2-Part vs. 1-Part
| Type | Best Used For | Key Features |
|---|---|---|
| 2-Part Adhesive (Glue + Isocyanate Hardener) | Permanent repairs, transoms, handles, high-stress seams | • Maximum bond strength & UV/heat resistance • Essential for structural repairs • ~3–4 hour pot life once mixed |
| 1-Part Adhesive (Single Tube) | Field fixes, minor pinholes, temporary trail repairs | • No mixing required • Lower heat and chemical resistance • Best suited for small emergency patches |
Popular Brands: Polymarine 2990, Clifton Hypalon Adhesive, Bostik 1400, and Stabond.
Important: Never use PVC adhesive on Hypalon (or vice versa). PVC and Hypalon require entirely different chemical solvents to adhere properly.
Step-by-Step Application Guide
1. Surface Preparation
- Sanding: Sand both surfaces (the boat surface and the patch) using medium-grit sandpaper (80–120 grit) until the shiny surface layer breaks up and feels soft like suede.
- Cleaning: Wipe away all rubber dust using MEK (Methyl Ethyl Ketone), Toluene, or a dedicated Hypalon solvent cleaner. Allow it to evaporate completely.
2. Mixing (For 2-Part Kits)
- Mix the base glue with the curative hardener according to the manufacturer’s ratio (typically 25:1 or 10:1 depending on the brand).
- Stir thoroughly. Only mix what you can use within 3 to 4 hours.
3. Glue Application (The 2-Coat Method)
- First Layer: Paint a thin, even coat onto both mating surfaces using a brush. Let it dry completely for 20–30 minutes.
- Second Layer: Paint a second thin coat onto both surfaces. Let it dry for 5–15 minutes until it feels tacky (tacky like sticky tape, but not transferring liquid to your finger).
4. Bonding & Pressing
- Align the patch carefully—contact adhesives grip instantly upon contact.
- Press from the center outward using a smooth roller or seam roller to force out all trapped air bubbles.
5. Cure Time
- Initial bond: Hand-tight in 10–15 minutes.
- Working cure: Wait 24 to 48 hours before inflating or placing under pressure.
- Full strength: Achieved after 7 days.
Working Conditions & Safety Tips
- Humidity: Avoid gluing in high humidity (above 60%) or cold temperatures below 15°C (59°F). High humidity causes the adhesive to “bloom” (turn white), which ruins bond strength.
- Ventilation: Work outdoors or in a well-ventilated space while wearing a respirator and nitre gloves; Hypalon glues contain strong flammable solvents.
Building a dedicated Hypalon repair kit ensures you have all the chemical, mechanical, and safety components required for both quick water side fixes and permanent seam-strength bonds.
Key Tips for Kit Maintenance
* Pre-cut Round Patches: Pre-cut several patch sizes with rounded corners (minimum 2-inch radius). Sharp corners on patches catch on gear and peel prematurely.
* Rotate Shelf-Life Items: Unopened 2-part Hypalon glue containers generally last 12–18 months. Mark expiration dates on cans in paint marker and replace before long expeditions.
* Solvent Storage: Standard plastic water bottles melt when exposed to MEK or Toluene. Keep solvents strictly in original metal cans or glass bottles with solvent-resistant caps.
Removing old, failed adhesive is the most critical step in re-sealing a Hypalon seam. Old glue prevents new adhesive from bonding directly to the synthetic rubber, leading to premature failure if not completely stripped back down to the bare, abraded Hypalon layer.
Phase 1: Removing Old Failed Adhesive
1. Soften and Scrape
* Solvent Soak: Wet a lint-free cotton rag with MEK (Methyl Ethyl Ketone) or Toluene. Press it directly against the old glue for 30–60 seconds to soften the chemical bond.
* Scrape Carefully: Use a stiff plastic scraper, putty knife, or dull chisel to peel up the gummy glue layers. Work slowly to avoid gouging or tearing the underlying Hypalon fabric weave.
* Heat Gun (Optional): If the adhesive is extremely stubborn, apply low heat with a heat gun (keep it moving, held 6–8 inches away) to soften the residue while scraping.
2. Mechanical Abrasion
* Once the bulk residue is scraped off, use 80 to 100-grit sandpaper to manually sand the seam area down to bare rubber.
* Sand until you reach a uniform, dull matte finish that feels soft like suede. All remaining shiny spots or hard glue patches must be completely removed.
3. Final Chemical Wipe
* Wipe the sanded region thoroughly with MEK on a clean rag to remove all rubber dust, oils, and trace adhesive particles.
* Let the solvent evaporate completely (10–15 minutes).
Phase 2: Re-Sealing the Seam Step-by-Step
Step 1: Prep & Mask
* Mask off the border around the seam using high-tack masking tape to keep glue off clean tube surfaces.
* Ensure working conditions are ideal: temperature between 15°C–25°C (60°F–77°F) and relative humidity below 60%.
Step 2: Mix 2-Part Hypalon Adhesive
* Mix only the amount of 2-part Hypalon glue and hardener needed for the seam using the exact ratio on the manufacturer’s label (typically 25:1 or 10:1).
* Stir thoroughly for 2 minutes.
Step 3: Apply the 2-Coat System
* First Coat: Brush a thin, even coat onto both mating surfaces (inside the seam flap and on the boat tube). Allow it to dry completely for 20 to 30 minutes.
* Second Coat: Brush a second thin coat onto both surfaces. Wait 5 to 10 minutes until tacky (it should feel sticky like tape without transferring liquid glue to your finger).
Step 4: Mate and Roll
* Align the seam carefully and press the surfaces together starting from one end to avoid trapping air pockets.
* Use a hard rubber or steel seam roller, rolling firmly from the center toward the edges to press out air bubbles and lock the contact bond into place.
Step 5: Cure Time
* Clamp/Tape: Apply painter’s tape or sandbag weights across the seam while it sets initially.
* Wait: Allow at least 48 hours before inflating the boat or placing stress on the seam.
Full cure strength takes 7 days.