Plumber's putty vs silicone

The reason these two get compared is that both get squeezed out of a joint and both stop water passing. The reason they are not interchangeable is what happens next. Putty never cures. It stays a soft, pliable, oily clay forever, which is exactly what you want in a joint held together by a nut, because you can take it apart with a wrench and clean it up with a thumbnail.

Silicone cures into rubber and bonds to both surfaces. That is a seal and an adhesive at once, which is exactly what you want where nothing is clamping the joint. Removing it later means a utility knife and patience. Choosing between them is choosing whether this joint is a fastening or a bond.

• Sink strainers and drain flanges. The classic use. The flange sits in the sink opening on a rope of putty, the nut underneath pulls it down, and the putty squeezes into every gap. Kohler's Duostrainer is a basket strainer with the tailpiece integrated, and this is exactly the joint putty was made for.
• Pop-up and basket assemblies. Same principle, same reason.
• Faucet bases with no gasket, on a non-porous deck. Increasingly rare, but if the box has no gasket and the sink is stainless, putty under the base is the traditional answer.
• Anything you expect to service. A joint bedded in putty comes apart cleanly years later. That is its real advantage over silicone, and it is not a small one.

Putty works because of what it is not: it is not under pressure. A drain flange joint is sealed by compression, and the putty simply fills the irregularities. It is not holding anything back by its own strength, which is why it does not matter that it never hardens.

• The rim of a drop-in sink to the countertop. Nothing clamps that joint except the sink's own clips, and water sits on it. Silicone is the correct material, and it is what Elkay's U-channel mounting system expects on the Lustertone Classic.
• Porous stone countertops, where putty's oils would leave a permanent dark halo around the fitting.
• Plastic and composite components that putty can degrade over time.
• Any gap that has to bridge rather than fill — an uneven surface, a small void, a joint that moves slightly.

Use a 100% silicone product rated for kitchen and bath use. Read the tube: some silicones are formulated for specific substrates and some acetoxy-cure products are not recommended on certain stones and metals. Manufacturers publish their own compatibility tables, and that is the authority rather than a general rule from us.

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1. The job putty is for

Kohler Duostrainer K-8801

Kohler · Best for replacing a failed sink drain

The permanent answer rather than the drop-in one: a full basket-strainer assembly with the tailpiece included, so it replaces the drain hardware instead of sitting in it. The basket both catches debris and holds water for soaking, which is the pair of jobs a silicone mesh screen cannot do.

Published specifications

Type

Basket strainer and drain with integrated tailpiece source

Fitment

Sink outlets of 3-1/2" or 4" source

Material

Brass, in a choice of Kohler finishes source

Function

Removable basket with an open/close stopper source

What works

• +Brass body rather than plated steel, which is what makes a drain assembly last
• +Tailpiece included, so the install is one part rather than three
• +The stopper seals well enough to soak a pan, which a mesh screen cannot
• +Fits both 3-1/2" and 4" outlets, covering nearly every stainless sink

What does not

• −It is a drain replacement, not an accessory — budget thirty minutes and plumber's putty
• −Finish matching to a faucet is approximate across brands
• −Overkill if your existing drain is sound and you only want to catch peelings

Skip it if

Skip it if your drain works and you only want to keep food out of the disposal. Buy the silicone screen and keep the difference.

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Raw specifications: Kohler’s own page for the Kohler Duostrainer K-8801.

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2. The faucet that needs neither

Delta Leland 9178-AR-DST

Delta · Best for most kitchens, one or three holes

The pull-down we would fit in most kitchens, because the two parts that usually fail first on a pull-down are the two Delta engineered around: the docking mechanism and the valve. MagnaTite pulls the wand back into the spout with a magnet instead of relying on a friction collar, and Diamond Seal keeps water off the valve. It ships with a deck plate, so it covers a three-hole sink or mounts through one.

Published specifications

Flow rate

1.8 gpm source

Spout height

7-7/8" deck to outlet source

Spout reach

9-3/16" source

Overall height

14-7/8" source

Mounting

Single hole; deck plate included for three-hole sinks source

Supply lines

Integrated InnoFlex PEX, pre-attached at the valve source

Connection

3/8" compression source

Warranty

Delta limited lifetime source

Lead compliance

Meets NSF/ANSI 61 source

What works

• +MagnaTite docking is a magnet, not a friction fit — a wand that stops seating is the most common pull-down complaint, and a magnet does not wear the way a plastic collar does
• +Spout reach of 9-3/16" clears the far side of a standard 22-inch front-to-back sink
• +Diamond Seal keeps water off the valve, which is what the lifetime warranty is really protecting
• +Deck plate in the box, so a three-hole sink needs no extra part

What does not

• −1.8 gpm is higher than the 1.5 gpm most competitors now ship, which matters if your area caps flow rate
• −Zinc body rather than brass — normal at this price, but this is not a forever faucet
• −No independent lab publishes durability figures for this model, so we cannot tell you how the finish looks at year five

Skip it if

Skip it if your sink is a shallow bar sink: at 14-7/8" overall the arc will splash in a basin under about seven inches deep.

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Raw specifications: Delta’s own page for the Delta Leland 9178-AR-DST.

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3. The job silicone is for

Elkay Lustertone Classic LRS33222

Elkay · Best for a like-for-like swap in an existing cutout

The plain, serviceable American drop-in, and the one most likely to be a direct swap for what is already in your counter: 33 by 22 inches, 7-5/8 inches deep, two faucet holes, 18-gauge Type 304 steel. Elkay's U-channel mounting is the detail that matters on install day — the clips go into the channel before the sink goes in, so you spend less time on your back.

Published specifications

Overall size

33" x 22" x 7-5/8" source

Bowl size

28" x 16" x 7-1/2" deep source

Gauge

18 gauge, Type 304 stainless steel source

Faucet holes

2 (1-, 3-, 4- and MR2-hole versions are separate model numbers) source

Drain opening

3-1/2" source

Minimum cabinet

36" source

Sound damping

Bottom pads only source

Mounting

U-channel — clips are set in the channel before installation source

Shipping weight

27 lb source

Origin

Made in the USA source

What works

• +7-5/8 inches deep, which is the depth most older cabinets and shallow trap arms were built around
• +U-channel mounting is the easiest clip system to work with single-handed
• +Elkay sells the same bowl in five hole drillings, so you can match an existing three-hole counter exactly
• +Type 304 steel with a repairable satin grain — light scratches blend rather than stand out

What does not

• −Sound deadening is bottom pads only rather than full-side pads, so you will hear this sink more than a pad-wrapped 16-gauge one
• −18-gauge flexes more than 16-gauge under a dropped pan, and this is a flat-bottomed bowl, so the drumming is audible
• −Elkay publishes a list price far above typical street price, so the number on the spec page is not a useful guide to what you will pay

Skip it if

Skip it if you want a deep modern basin. At 7-1/2 inches the bowl will not take a sheet pan laid flat.

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Raw specifications: Elkay’s own page for the Elkay Lustertone Classic LRS33222.

This is the part that saves most people a purchase. Modern kitchen faucets ship with a molded rubber or foam gasket that sits between the faucet base and the sink deck, and a deck plate with its own gasket if one is included. Delta supplies a deck plate in the box with the Leland 9178 and Moen does the same across the Arbor, Method, Renzo and Sombra ranges. When a gasket is supplied, use it and add nothing.

Adding silicone under a supplied gasket is a specific mistake worth naming, and it is common. It prevents the gasket seating evenly, it makes the faucet impossible to remove without damage, and on a stainless deck it leaves a residue that is remarkably hard to clean off. The manufacturer designed the joint; let it work.

The same applies to a deck plate. Faucet hole configurations covers how a deck plate spans an unused three-hole drilling, and the guidance there is the same: fit the plate with the gasket the manufacturer supplies, and do not silicone it down. You may want to take it off one day.

1. 1Clean and dry the surface first. Old putty, old silicone, mineral deposit and grease all have to come off. A plastic scraper, a utility knife held flat, then warm soapy water, then dry. This step decides whether either material works.
2. 2Putty: roll a rope, not a blob. Warm it in your hands until it is pliable, roll an even rope about the thickness of a pencil, and lay it in a continuous ring with the ends overlapped. A gap in the ring is a leak.
3. 3Silicone: one continuous bead. Cut the nozzle to a small opening, run the bead without lifting, and do not go back over it. A tooled joint is a sealed one; a re-worked joint traps air.
4. 4Seat the part and tighten evenly. Alternate sides as you tighten so the part pulls down square. Uneven tightening is the other common cause of a leaking drain.
5. 5Trim the squeeze-out. Putty wipes away with a thumb and a cloth immediately. Silicone is cleaned up before it skins, with a damp finger or a plastic tool, and after that it needs a blade.
6. 6Let silicone cure before using the sink. Cure times are on the tube and vary widely by product. Putty needs no cure time at all, which is one of its practical advantages.

If you are doing the drain and the faucet in the same session, note that they want different materials for different reasons, and that is normal. A strainer in putty and a drop-in rim in silicone on the same sink is the correct answer, not an inconsistency.

A drain that weeps after a putty installation is almost always a broken ring or uneven tightening, and the fix is to take it apart, clean everything, and do it again with a continuous rope. Adding more putty on top of a failed joint does not work. A silicone joint that leaks has usually been disturbed before it cured, or applied to a surface that was not clean and dry.

Before assuming the sealant, though, work out what is actually leaking. Water in a cabinet can come from the drain, the trap, a supply connection or the faucet body, and they look identical from below. Kitchen faucet leaking diagnosis separates them, and garbage disposal leaking diagnosis covers the case where a disposal is involved.