Plumber’s putty is a soft, pliable sealing compound that is used to make watertight seals around faucets, drains, and other plumbing parts. If you've ever removed an old faucet and found a bead of clay-like material along the underside of the faucet body or where the body meets the sink, most likely it's old, dried plumber's putty. In the old days, plumber's putty was used in many places where caulk is used today, but it's still the best option for many situations.
Why Use Plumber's Putty
Plumber’s putty is one of the basics tools in a plumber's tool bag. Plumbers use it because it remains soft for a long time and maintains a watertight seal, but unlike silicone and other types of caulk, plumber's putty is not an adhesive, so a fixture or drain part sealed with putty remains easy to remove if you ever need to replace it. Also, silicone is not as easy you work with and is not as dense as plumber’s putty, so it's not as good at filling wide gaps, and plumbers don't need time to dry just like caulk does.
Where to Use Plumber's Putty
Plumber’s putty is commonly used to seal along the base of faucets and other sink fixtures before setting them onto the sink. It's also applied to the undersides of sink strainers and pop-up drain fittings for sinks and tubs. In all of these common applications, the putty is hidden under a flange, lip, or edge and is not visible when the part is installed. If caulk were used instead of putty, it would be difficult to access these areas to cut through the caulk to remove the part.
How to Use Plumber's Putty
Plumber's putty is a very inexpensive material that is sold in small plastic tubs. It is always shaped by hand before it is applied to the plumbing part. Follow these basic steps to apply plumber’s putty:
- Scoop out a ball of putty from the tub with your fingers.
- Roll the putty back and forth between open palms to create a continuous rope (much like making a snake out of Play-Doh). Make the rope any length you need and of a consistent diameter that is slightly larger than the gap you need to fill.
- Lay the putty rope into place on the part you want to seal, starting at any point and working in a continuous loop, running around the part and meeting back at the starting point. If the rope is too short, it's best to start over and roll a longer rope; splicing in sections of putty can lead to leaks. Tear off excess putty at the end of the rope.
- Gently press the rope into place without deforming it. This is just to keep it from coming to lose when you turn the part right side up. It will squish down when you install the part. If you press the putty flat at this stage it might not seal against the mating part.
- Install the part as required. When you tighten down the part, putty will likely squeeze out from the edges; this is desirable, as it means you used plenty of putty. Tighten down the part all the way (as applicable), then wipe up any excess putty with your finger. If the excess putty is clean, you can put it back into the tub for future use.
Tips for Using Plumber's Putty
While plumber's putty is better than caulk in some situations, it's not a universal caulk alternative. Do not use plumber's putty where you need adhesive strength (to bond materials or prevent them from moving) or where you need a watertight seal in exposed areas. Follow these other tips for the best results:
- Plumber’s putty should be pliable and easy to roll. If it's too hard to roll or it cracks when you try to shape it, it is too old and dried out. Get a new tub of putty.
- Keep the tub of putty sealed tightly so the putty will last as long as possible before getting hard. It eventually dries out in the tub, but this can take years.
- Read the label of the plumber’s putty before using it on porous surfaces. Plumber’s putty is petroleum-based and can stain some materials, such as granite. The directions on the container of putty will let you know what surfaces it can be used on. There are stain-free forms of plumber’s putty for use on stone and other porous materials.