Joint Sealant

Joint Sealant collection banner for Sun Brite Supply of Maryland

Joint Sealant

Joint Sealant and Thread Locker for Pressure Washer Fittings

Every leak on a pressure washer rig starts at a threaded joint, and most of them trace back to a fitting that went together dry. This is the cheap stuff that keeps the expensive stuff working: PTFE thread tape for sealing pipe threads and Loxeal anaerobic threadlockers for bolts and plugs that vibrate loose. Questions about which one your fitting needs? Call 301-519-9274 and describe the joint.

Thread Sealant Basics: Tape, Paste, or Threadlocker

These three products get mixed up constantly at the counter, so here is the split. Thread tape and pipe dope seal the spiral leak path in tapered NPT pipe threads. Threadlocker is an adhesive that keeps a fastener from backing out under vibration. They are not interchangeable. Tape on a pump bolt does nothing for vibration. Threadlocker on a hose fitting is not a reliable water seal at 4,000 PSI. Use each for its job.

Where PTFE Tape Belongs

NPT threads are tapered and seal metal to metal, but the machining leaves a tiny spiral gap that water follows under pressure. PTFE tape fills that gap and lubricates the threads so you can pull the joint up tight without galling, which matters most on stainless fittings. Wrap it right: start one thread back from the end so tape shreds cannot wash into your pump or clog a nozzle orifice, wrap in the direction of tightening, and use 3 to 4 wraps. Our 1/2" x 520' roll costs under two dollars and will outlast a season of fitting swaps.

Just as important is where tape does not belong. Quick connects, garden hose threads, o-ring sealed fittings, and flare connections all seal on a gasket or a machined surface, not on the threads. Taping them solves nothing and the loose shreds end up in your injector or unloader check valve.

Blue or Permanent Threadlocker

Loxeal threadlockers are anaerobic. They stay liquid in the bottle and cure only when trapped between metal threads away from air, reaching handling strength in about 20 minutes and full strength in 24 hours. Blue is the medium-strength grade. It holds pump mounting bolts, engine fasteners, and coupler set screws against vibration, and it still breaks free with ordinary hand tools when you service the machine. The permanent grade is for studs and plugs you never want to move again, and removing it later takes serious heat, in the neighborhood of 250 degrees C. Buy blue unless you have a specific reason not to. Threads should be clean and dry for a full-strength cure, and stainless hardware cures slower than plain steel.

Loxeal blue threadlocker 50 ml bottle, medium strength joint sealant for pressure washer fasteners

Pick Your Size

Product Grade Best For Price
Teflon Tape 1/2" x 520' PTFE tape All NPT pipe thread connections $1.91
Loxeal Blue Threadlocker 10 ml Medium, removable Toolbox bottle for service calls $20.54
Loxeal Blue Threadlocker 50 ml Medium, removable Shop bench, regular rig maintenance $38.70
Loxeal Blue Threadlocker 250 ml Medium, removable Fleet shops and rebuild benches $81.38
Loxeal Permanent Threadlocker 10 ml High strength Studs and plugs that must never move $12.99
Loxeal Permanent Threadlocker 50 ml High strength Assembly work, permanent joints $58.82
Loxeal Permanent Threadlocker 250 ml High strength Production and heavy fleet use $81.36

From the Field

The most common comeback we see is a rebuilt pump that leaks at the discharge nipple a week later. The fitting was reused with the old flattened tape still on it. Strip the old tape completely, every wrap, before you reseal. Old tape under new tape leaves channels. The second one is the burner coil plug that loosens every few weeks from vibration until someone finally puts a drop of blue threadlocker on it and the problem disappears. A ten dollar bottle rides in the truck for years. And if a taped joint still weeps after proper assembly, stop adding wraps. Six wraps of tape will crack a brass fitting when you crank it. The threads are probably damaged, and a new fitting costs less than the callback.

Keep Shopping the Plumbing Aisle

Need it today? The Gaithersburg store keeps tape and threadlocker at the counter.

Frequently Asked Questions

Should I use Teflon tape or pipe dope on pressure washer fittings?

Tape handles most fittings 1" and under, which covers nearly everything on a pressure washer. Paste sealant earns its keep on larger fittings and on stainless threads that gall easily. Some techs use both together on a stubborn joint, tape first with a light coat of paste over it.

How many wraps of Teflon tape should I use?

Three to four wraps, pulled snug in the direction the fitting tightens. Start one thread back from the end of the fitting so loose tape cannot enter the water stream. More than five wraps stresses the female fitting and can split brass.

What is the difference between blue and permanent threadlocker?

Blue is medium strength. It stops vibration loosening and still comes apart with hand tools during service. Permanent grade is a near-weld that needs around 250 degrees C of heat to release. For pressure washer work, blue is the default and permanent is for joints you have decided are forever.

Do quick connects need thread sealant?

The plug-and-socket connection itself does not. It seals on an internal o-ring. The threaded end that screws the coupler onto your pipe or fitting is NPT and does want tape or paste.

Why does my fitting still leak after I taped it?

Usually old tape left under the new wrap, damaged threads, or a joint that seals on a gasket where tape does nothing. Strip it clean, inspect the threads, and check whether the fitting has an o-ring or seat. If threads are chewed, replace the fitting.

Will threadlocker work on wet or oily threads?

It cures best clean and dry. Light oil slows the cure and heavy contamination stops it. Wipe threads with solvent, let them dry, then apply. On stainless hardware give it a full 24 hours before the joint sees vibration.