Installing a connector fitting on a corrugated tub side often leads to leaks—standard rubber gaskets on fittings can’t seal the uneven, ridged surface effectively. Singema’s solution? Strategic use of Teflon (PTFE) tape and inside-out installation with a purpose-built barrel drum fitting. This step-by-step guide simplifies the process for a leak-proof result.
What You’ll Need
- Compatible connector fitting (match tub material: plastic/metal)
- High-quality PTFE (Teflon) tape (food-grade for water contact)
- Drill with hole saw (matching fitting diameter)
- Fine-grit sandpaper (240-400 grit)
- Clean cloth, adjustable wrench
- Silicone sealant (optional, for extra protection)
- Measuring tape, marker, safety goggles, gloves
Step 1: Prep the Installation Spot
Empty the tub and place it on a stable surface. Measure and mark the desired fitting location—avoid seams or sharp corrugation peaks. Wear safety gear, then drill slowly with a hole saw to create the hole; prevent cracking by applying gentle pressure. Use sandpaper to smooth hole edges (inside and out) to remove burrs, then wipe clean with a cloth to eliminate dust.
Step 2: Wrap Fitting with Teflon Tape
This is the leak-prevention key. Unlike typical thread-only wrapping, Singema recommends covering the flange and shaft:
- Locate the fitting’s flange (flat contact surface) and cylindrical shaft.
- According to the space between fitting and hole edge, wrap 8-10 or more overlapping layers of Teflon tape around the shaft (from flange base outward) and the flange’s outer edge. Wrap tightly but don’t tear the tape—this builds a compressible barrier for corrugated gaps.
- Add 2-3 layers to the fitting’s threads (if applicable) for extra pipe/hose connection security.
Step 3: Install Fitting Inside-Out
Inserting from the tub’s interior keeps the tape pressed against the corrugated surface—critical for sealing:
- Push the taped fitting through the hole from inside the tub until the flange sits flush against the inner wall.
- From outside, attach washers and locknut (included with the tub fitting). Tighten snugly with a wrench—avoid over-tightening, which can crack the tub or damage the seal.
- Secure any hoses/pipes to connect tub fitting and wood fired heater coil.
Step 4: Seal and Test for Leaks
Optional step: apply a thin silicone bead around the flange (inside the tub) and locknut (outside) for maximum protection,. Smooth with a tool for even coverage, then let dry 24 hours (per sealant instructions). Fill the tub with water and let sit 30-60 minutes. Inspect for drips—if leaks occur, gently tighten the locknut or add more tape and sealant.
Pro Tips to Avoid Mistakes
- Never skip sanding: Rough edges puncture tape/gaskets.
- Don’t skimp on tape: 8-10 layers or more are needed to fill corrugated gaps.
- Inside-out is non-negotiable: Outside installation pushes gaskets away from the surface.
- Match fitting to hole size: Ill-fitting parts guarantee leaks.
- Go easy on tightening: Corrugated tubs are flexible—over-tightening warps or cracks them.
That`s all. Singema’s method eliminates the frustration of corrugated tub leaks when installing tub fittings. By using much Teflon tape generously and installing from the inside out, you’ll achieve a reliable, long-lasting fitting that works for residential or camping hot tubs—no more wasted time mopping up drips!
For more details about choose heater coil to connect your tub, please find this article “How to Choose the Right Wood Fired Hot Tub Heater Coil“