Binks 2100 Spray Gun with 66SS Fluid Nozzle and 66SK Air Cap (Siphon Feed)

Start siphon feed at about 50 PSI for lacquer and 60 PSI for enamel, then back the pressure down to the lowest setting that still atomizes cleanly. For pressure feed, set tank pressure for the fluid flow you want first, then open atomizing air and adjust. The gun's maximum is 100 PSI air and 100 PSI fluid.

Measure at the gun, not the regulator. With 25 ft of 5/16″ hose and 60 PSI at the regulator you have about 48 PSI at the inlet; with 1/4″ hose only 34 PSI.

Pressure drop. Binks' own figures for a 25 ft hose with 60 PSI at the regulator:

• 5/16″ I.D. loses 12 PSI, so the gun sees 48 PSI.
• 1/4″ I.D. loses 26 PSI, so the gun sees only 34 PSI.

That missing 14 PSI is the difference between a clean fan and a coarse, spitting pattern, and it gets worse with longer runs. Trophy guns likewise call for a conductive hose of at least 5/16″, larger for long runs. Clemtex stocks 5/16″ assemblies in 25 ft and 50 ft, and bulk 5/16″ hose by the foot.

Orifice size, which sets how heavy a material the gun can move:

Table 1 — 2100 fluid nozzles by orifice. All three are stainless steel.

The 66SS is the general-purpose choice and ships on both stocked 2100 outfits. Step up to 67SS above about 28 seconds on a #4 Ford cup, and to 68SS with the 68PB air nozzle for the heaviest coatings.

No. Immerse only the front end, until the solvent just covers the fluid connection. Submerging the whole gun dissolves the lubricant in the packings (the gun starts spitting and the packings dry out), washes the lube off the wear surfaces, and lets residue from dirty solvent clog the narrow air passages.

The right routine: brush accumulated paint off with a bristle brush and solvent, flush the fluid passages, wipe the body with a solvent-dampened rag, then lubricate the needle packing, air valve packing, side-port packing and trigger pivot. Never clean nozzle holes with anything harder than brass; soak them in solvent and blow them out.

Spray a test pattern, rotate the air cap one-half turn, and spray again.

• Defect flips to the other side: the obstruction is on the air cap. Soak it in solvent and clear the horn holes with a toothpick or broom straw. Never use wire; it enlarges the hole and the cap is scrap.
• Defect stays put: the problem is on the fluid tip. Look for dried paint just inside the opening (wash with solvent) or a fine burr on the edge (remove with #600 wet-or-dry paper).

A loose air cap gives the same lopsided pattern, so tighten the retaining ring first. If cleaning does not fix it, replace the cap: stocked caps include the Binks 66SD and 66SK for the 2100 and the 64HD, 62HD and 704 for JGA and MBC guns.

Two causes, both about balance rather than dirt:

1. Atomizing air pressure too high. Reduce it at the regulator.
2. Trying to get too wide a fan with thin material (fluid starved). Open the material control fully by turning it to the left, and at the same time turn the spray-width (side-port) control to the right. The fan gets narrower but the split disappears.

On pressure feed, raising fluid pressure has the same effect. The opposite fault, a heavy center, means too much fluid for the air: reduce fluid flow or thin the material.

Spitting means air is getting into the fluid stream. Three causes cover almost every case:

1. Dry fluid needle packing. Back off the knurled packing nut, put two drops of machine oil on the packing, replace the nut finger-tight. If it keeps spitting, replace the packing.
2. Dirt between the fluid nozzle and its seat, or a loose nozzle. Remove the nozzle, wipe the back of it and the seat with a thinner-wet rag, refit and draw it up tight.
3. A loose or defective swivel nut on the siphon cup or fluid hose. Tighten or replace.

Daily, and after every pass through a gun washer:

• Fluid needle packing (where the needle enters the packing nut)
• Air valve packing or air valve stem
• Trigger bearing screw or stud
• Side-port / fan adjusting valve packing and adjusting-screw threads
• Air cap and baffle threads: clean, then two drops of lube before fitting the retaining ring

Use a light machine oil or Binks SSL-10 spray gun lube, which contains no silicone or petroleum distillates that could contaminate paint. Coat the fluid needle spring and air valve spring with a light film of petroleum jelly, keeping it out of the air passages.

Both are siphon-feed (S) external-mix air nozzles that run with the 66SS fluid nozzle and 565 needle. The difference is air appetite and pattern size:

• 66SD (46-6020): about 7.9 CFM at 30 PSI and 12.1 CFM at 50 PSI, 10.5″ pattern. The economical choice for smaller compressors. Comes on the 2101-4307-9 outfit.
• 66SK (46-6082): about 11 CFM at 30 PSI, 15.2 at 50 and 19.5 at 70, 13″ pattern. More air means finer atomization or faster application. Comes on the 2101-4308-8 outfit.

Remove the fluid control screw, spring and needle, then the packing nut, and pick out the old packings with a small stiff wire. Oil the new PTFE packings (2-28-5, sold as a 5-pack and included in the 6-229 kit) lightly and reassemble in reverse order.

To set the packing: insert the needle and tighten the nut until the needle just starts to be too stiff for the spring to move it, then loosen the nut 1/2 to 3/4 turn. Too tight binds the needle and shortens packing life; too loose lets air into the fluid passage and the gun spits.

The 2101- prefix is the 2100 gun. The middle digits encode the fluid nozzle and the last digit the air nozzle, so the number tells you exactly what is on the gun:

• 2101-4308-8: 66SS fluid nozzle with the 66SK siphon air nozzle (bigger pattern, more CFM).
• 2101-4307-9: 66SS fluid nozzle with the 66SD siphon air nozzle (less air, 10.5″ pattern).
• 2101-4300-0: 66SS gun with no air nozzle; 2101-5111-5: 68SS with 68PB pressure cap; 2101-0000-0: bare gun, no set-up.

Use the number stamped on your gun to order the right replacement nozzle, needle and cap, or compare it to the complete-gun-assemblies table in the 2100 service manual. Not sure what you have? Contact Clemtex and we will identify it.

They tell you how the nozzle feeds and mixes:

• E: external mix. Air and fluid meet outside the nozzle; the pattern adjusts from round to a full fan. Most Binks nozzles are external mix.
• S: siphon type. Will draw material up from a cup; for refinishing and touch-up where you do not need big volume. The 66SD and 66SK are S caps.
• P: pressure type. Needs a pressure cup, tank or pump pushing material to the nozzle; for production work and heavy fluids. The 68PB, 62HD, 64HD and 704 are P caps.
• I: internal mix. Air and fluid mix inside the nozzle, so the pattern shape is fixed. Uses less air and makes less fog; for heavy maintenance coatings where a fine finish is not needed. Pressure feed only.