Stainless Steel Pipe Fittings

Bleach eats brass. If your rig runs sodium hypochlorite, salt air, or hot water, stainless steel pipe fittings are the difference between plumbing that lasts seasons and plumbing you replace every spring. Sun Brite Supply carries 304 and 316 stainless couplers, tees, elbows, bushings, and hose barbs. Call 301-519-9274 and we will help you spec the run fitting by fitting.

304 vs 316 Stainless: What the Numbers Mean

Both grades beat brass and plated steel for corrosion resistance, but they are not equals. 304 stainless runs roughly 18 percent chromium and 8 percent nickel. It handles fresh water, most detergents, and general chemical duty without complaint. 316 adds 2 to 3 percent molybdenum, and that one ingredient is what fights chlorides. Chlorides are the active attack in sodium hypochlorite and salt spray, the two things soft wash rigs and coastal crews deal with daily. The buying rule is simple. 304 for house wash mixes, degreasers, and everyday plumbing. 316 for full-strength SH transfer lines, batch tanks, and any truck that works near the bay. 316 costs more up front and usually costs less per year.

Where Stainless Belongs on Your Rig

Most threaded stainless fittings in this class carry a 150 pound rating, which covers low pressure chemical plumbing, supply lines, tank manifolds, and downstream injection circuits. That is exactly where corrosion does its damage, so that is where stainless earns its keep. Your high pressure line from pump to gun needs fittings rated for the machine's full PSI, so keep using rated high pressure hose fittings there and put the stainless where the chemicals live.

Stopping Leaks and Galling on Stainless Threads

Stainless has one bad habit. Threaded dry against itself, the metal can cold weld and seize, which the trade calls galling. A galled fitting is a cut-it-off fitting. The fix costs pennies. Wrap the male NPT threads with two or three layers of PTFE tape, add a thin coat of thread compound over the tape on chemical lines, and make the joint up snug plus a turn or two, not gorilla tight. The tape lubricates the threads, seals the joint, and lets you take it apart next year without a hacksaw.

Stainless Fittings We Carry

The 3/8 coupler, tee, and elbow are regular shelf items. Availability on barbs and bushings moves, so call before you make the drive.

From the Field

Cut open a failed brass fitting from a soft wash rig and you will find the threads dissolved to nothing while the outside still looks fine. That is why the leak always shows up mid-job. When a crew converts a chemical circuit to stainless, our counter advice is to do the whole run at once. One leftover brass tee in a stainless line becomes the sacrificial part, since dissimilar metals in a bleach solution corrode the more active one first. And keep a wrap of PTFE tape in the truck. Half the stainless fittings we replace were not corroded at all, just galled by someone assembling them dry in a hurry.

Related Collections

• Brass pipe fittings
• Steel pipe fittings
• Polypropylene fittings
• Hose barbs
• Hex bushings
• Tees
• 90 degree elbows
• Quick connects
• Soft wash equipment
• Joint sealant

Maryland crews can grab fittings same day at our Gaithersburg store.

Frequently Asked Questions

Should I buy 304 or 316 stainless fittings for soft washing?

For diluted house wash mix, 304 holds up well and costs less. For lines that see strong sodium hypochlorite, batch tanks, or salt air, spend up for 316. Its molybdenum content resists chloride attack that slowly pits 304.

Can stainless pipe fittings handle pressure washer PSI?

Threaded fittings in the 150 pound class are made for the low pressure side, meaning chemical lines, supply plumbing, and downstream injection. Keep fittings rated for your machine's full working pressure on the pump-to-gun circuit.

Why do stainless fittings seize together?

That is galling. Clean stainless threads can cold weld under assembly friction. Prevent it by taping the male threads with two or three wraps of PTFE and tightening snug instead of maxed out. Once galled, a fitting usually has to be cut off.

Is it OK to mix stainless and brass fittings in one line?

They thread together fine, and on plain water it rarely causes trouble. In a chemical line the brass becomes the weak point and corrodes first, so an all-stainless run gives the longest life for soft wash plumbing.

What does the 150 pound marking on a fitting mean?

It is the fitting's pressure class, a rating standard for threaded fittings in normal temperature water service. It tells you the fitting suits supply and chemical plumbing, not the 3,000 PSI side of your machine.

Do stainless fittings need thread sealant?

Yes. NPT threads seal on the tape or compound filling the spiral gap, and on stainless the tape also prevents galling. Two or three wraps of PTFE, applied clockwise, covers most joints on a rig.