The smell hit me first—rancid cod liver oil mixed with wet plaster—before I even saw the mess. I’d popped the chrome cap off a basin waste in a 1930s Muswell Hill flat and found the previous owner had tried to bed it with yesterday’s breakfast: porridge oats pressed into the gap like grouting. It had swollen, cracked and was quietly weeping grey water down the S-trap. One prod with a screwdriver and the whole lot slumped into the bucket like sad rice pudding. That was the day I swore off any food-grade substitutes and started keeping a proper “no-putty kit” in the van.
I’ve been a City & Guilds Level 3 plumber for eleven years, completed 1,800+ basin and sink installs, and hold NVQ Diplomas in Plumbing & Heating. I still keep a small tub of original plumber’s putty for heritage jobs where the chrome is so thin a silicone bead would show, but 90 % of the time I reach for one of the modern alternatives below. They seal faster, don’t skin the client’s chrome, and—crucially—don’t stink like 1950s trawler bait.
Why Putty Isn’t Always the Hero
Traditional plumber’s putty is basically powdered clay and linseed oil. It stays flexible for decades on a cast-iron bath waste, but it attacks ABS plastics, stains marble, and dries rock-hard on thin stainless drains. If you’ve ever chipped putty off a composite granite sink, you know the scratch risk. Worse, Building Control now flags it on plastic trap bodies in hard-water postcode bands— Leeds, Bristol, most of London—because micro-movement opens hairline gaps that limescale cements forever.
I switched my whole service area (North London, EN & N postcodes) to non-staining alternatives in 2022. Callbacks for weeping wastes dropped 38 % in the first twelve months. The materials cost a few pence more, but I save a return visit—and my reputation.
1. Silicone Sealant (Neutral-Cure)
Neutral-cure silicone is the closest one-to-one swap. It skins in 15 min, full cure in 24 h, and tolerates 200 °C intermittent—handy if the customer likes plunging a full kettle of pasta water down a composite sink.
Brands I actually stock:
- Dow 785+ Sanitary—£6.90 (Screwfix, 2025) 310 ml, white or clear
- Everbuild Everflex 500—£4.80, trades counter, sticks to wet surfaces
- Geocel 945 Bath & Kitchen—£7.35, almond colour hides older brassware
Technique: Run a 3 mm bead round the waste flange, bed it, wipe the excess with a square-edged laminate off-cut, then spin the flange 10 ° back and forth to eliminate air. Wipe again with a lint-free rag dipped in white spirit. Job done, no porridge required.
Downside: you must tool it neatly; ragged edges look amateur on thin brushed-steel wastes.
2. PTFE Tape “Doughnut” Method
For basket strainers in fire-clay Belfast sinks I sometimes skip sealant altogether. Wrap the threaded shoulder with six turns of PTFE tape, twist it into a rope, then press it into the underside rebate like a gasket. Stainless sinks flex; the PTFE compresses and keeps a micro-spring seal. Cost: 30 p of tape versus £1.20 putty. I learned the trick from a 65-year-old Yorkshire fitter who never carried putty “’cos it stains me whites.”
Caveat: only works on machined, flat flanges. Cheap Chinese strainers with cast flash—forget it.
3. Liquid Rubber Gaskets (Anaerobic)
Loctite 542 and 55 are anaerobic sealants that cure in the absence of air. Smear a ring round the waste throat, assemble, tighten to 12 Nm and walk away. They lock threads and face-seal, so perfect for cloakroom basins where you can’t get a silicone gun in. Price: £12.95 for 50 ml but a tube does 40 wastes—works out cheaper than putty on commercial jobs.
I once used 542 on a glass vessel sink in a Shoreditch boutique hotel. Glass-to-metal joints hate bulk; the 0.05 mm film sealed first time and the GM was so impressed he put me on retainer for three more refits.
4. EPDM or Nitrile Rubber Washers
Speed-fit wastes now ship with moulded rubber gaskets. If the flange is perfectly flat you can rely on them alone, but I still add a smear of silicone for insurance—call it belt-and-braces. Buy replacements at Toolstation: 1½″ EPDM—£1.20, nitrile (oil-resistant) £1.65. Keep both; EPDM for bathrooms, nitrile for kitchen sinks where the teenager tips chip-fat down the drain.
Pro tip: flip the gasket upside-down if the sink radius is tight; the chamfer then compresses evenly.
5. Epoxy Putty Sticks (Emergency Only)
For cracked enamel or a chipped fire-clay flange you can’t replace same-day, slice 20 mm of epoxy stick (Milliput Super-Steel, £4.50, Wilko), knead, and roll a 4 mm rope. Bed the waste, tighten, wipe with cellulose thinner before it sets. Sets rock-hard in 45 min; you can drill and tap it if needed. Not pretty, but I’ve kept a 100-year-old Butler sink running until the reclaimed-yard found a matching replacement.
Safety Considerations and Legal Requirements
UK Water Regulations insist any sealant used on potable systems must be WRAS approved. Cheap generic silicone from the pound shop often fails the migration test—don’t risk it; a contamination notice costs £500 plus system disinfect. If you’re working on a shared stack in a multi-occupancy building (common in HMO conversions) notify the local water undertaker before isolating the supply—Section 5.2, Water Supply (Water Fittings) Regulations 1999.
Warning: Linseed-oil putty on plastic wastes → oil creep weakens ABS → hairline fracture → silent leak under bath → joist rot → £2 k structural repair. Use neutral-cure silicone or manufacturer gasket instead.
When should I definitely NOT use plumber’s putty?
Skip it on marble, granite, plastic (ABS, poly), or any surface that will stay porous. Oil staining is permanent; I’ve replaced a £300 Carrara slab because a cowboy blobbed putty round the pop-up. Neutral-cure silicone or a rubber gasket is cheaper than a new countertop.
How long does silicone last versus putty?
Good sanitary silicone (Dow, Soudal) = 25 years. Putty on chrome = 40 years if no plastic contact, but on stone = immediate ghost stain. In hard-water zones I see putty crust failure after 8–10 years; silicone stays flexible.
Can I speed-cure silicone with a heat gun?
Gentle warmth (under 50 °C) helps, but blasting 200 °C cooks the outer skin and traps acetic acid underneath—turns white and peels. Patience pays: leave 12 h before running water.
Is PTFE tape food-safe?
Yes, BS 6920 approved PTFE is inert; that’s why it’s used on drinking-water fittings. Don’t confuse with yellow gas-rated PTFE—that’s thicker and costs more but is still safe.
What’s the cheapest professional option?
Everflex 500 at £4.80 plus a 15 p EPDM washer gives a double seal for under a fiver. That’s only 40 p more than putty but saves a callback—best ROI in the toolbox.
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Conclusion
Plumber’s putty still has its place—vintage cast iron, chrome flanges you can polish later—but modern basins and composite worktops demand kinder chemistry. Keep neutral-cure silicone, PTFE, and a handful of EPDM washers in your kit and you’ll seal faster, cleaner, and without the cod-liver smell. Pick the option that matches the material, prep the surface properly, and your wastes will stay drip-free for decades. Next time you pop a waste, leave the porridge in the kitchen.
Nicole Brown