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Silicone Flanged Pull Plugs for Chamfer & Lead-In Thread Masking

  • Silicone Flanged Pull Plug for masking weld nuts and first threads
  • Silicone Flanged Pull Plug for fast/effective weld nut and top thread masking
flanged pull plug diagram for weld nut masking plugs

Diagram of Dimensions for Flanged Pull Plugs

Ideal for Single-Sided Countersinks in Powder Coating & Anodizing

Standard pull plugs often leave the countersink or lead-in thread exposed, leading to costly thread chasing. Our Silicone Flanged Pull Plugs (SFPP) are specifically designed to mask the internal threads of a through-hole AND the chamfer on one side only, ensuring a clean, coating-free seat for your fasteners.

These indispensable masking aids reduce your costs speeding up your process of masking 82° and 90° countersinks. To use, insert 'tail,' pull plug into place for first thread seat protection. These specialized plugs prevent powder build-up in chamfered entries with a single-sided flange masking.

To see all pull plugs with a flange plus other plugs that work with common thread sizes, see our Masking Plugs & Threaded Holes Chart.

Custom sizes available with low cost tooling. Try a FREE sample of a flange cap today - Contact Us for more information!

NOTE: These plugs are manufactured from a softer (40-45 durometer, Shore A) silicone rubber material than many of our other caps and plugs (55-60 durometer, Shore A). This is to allow the flange to pass through a hole fully when removed from a part to be masked. Due to this softer durometer, some plugs will experience a higher rate of tearing and/or shrinking.

  • Available Products
    Part # Color A (in.) B (in.) C (in.) D & E (in.) Use for Price Qty/Bag Qty (bags)  
    SFPP-0118-GREEN GREEN 0.118 0.079 0.168 1.0 / 1.0 6-32 $85.00 1000 Add to Shopping List
    SFPP-0142-PUR PURPLE 0.142 0.094 0.204 1.0 / 1.0 M4 $90.00 1000 Add to Shopping List
    SFPP-0173-RED RED 0.173 0.098 0.250 1.0 / 1.0 10-24, 10-32 / M5 $50.33 500 Add to Shopping List
    SFPP-0210-WHITE WHITE 0.210 0.130 0.360 0.5 / 0.5 M6 $43.80 500 Add to Shopping List
    SFPP-0218-BLUE BLUE 0.218 0.125 0.340 1.0 / 1.031 1/4-20 powder/paint $47.39 500 Add to Shopping List
    SFPP-0230-GREY GREY 0.230 0.125 0.350 1.0 / 1.031 1/4-20 anodize/plate $50.86 500 Add to Shopping List
    SFPP-0285-YEL YELLOW 0.285 0.160 0.400 1.0 / 1.062 M8 $55.56 500 Add to Shopping List
    SFPP-0335-OR ORANGE 0.335 0.160 0.460 1.0 / 1.031 3/8-16 / M9 $58.51 500 Add to Shopping List
    SFPP-0350-PINK PINK 0.350 0.187 0.473 1.0 / 1.062 M10 $65.30 500 Add to Shopping List
    SFPP-0420-GREEN GREEN 0.420 0.235 0.540 1.01.062 M11 $44.61 250 Add to Shopping List
    SFPP-0445-PUR PURPLE 0.445 0.240 0.560 1.0 / 1.062 1/2-13 / M12 $49.25 250 Add to Shopping List
    SFPP-0490-WHITE WHITE 0.490 0.255 0.610 1.0 / 1.0 M14 $53.03 250 Add to Shopping List
    SFPP-0545-RUSTY RUSTY 0.545 0.275 0.663 1.0 / 1.0
    		$68.63 250 Add to Shopping List
    SFPP-0580-RED RED 0.580 0.295 0.700 1.0 / 1.0 M16 $77.24 250 Add to Shopping List

    Custom sizes available with low cost tooling.

    Try some FREE silicone flanged pull plug samples – Contact Us for more information!

  • Technical Specifications
    • Temperature Range: Up to 600°F / 315°C
    • Ideal for powder coating, e-coating, plating, and anodizing.
    • Material: Silicone
    • Color: Various
    • Great chemical resistance for most metal finishing applications.
    • Re-usable.

    Flanged Pull Plug

    flanged pull plug diagram

    Diagram of Dimensions for Flanged Pull Plugs

     

    Custom sizes available with low cost tooling.

    How to Mask a Chamfer or Lead-In Thread for Coating

    One of the most common headaches in powder coating and anodizing is "thread chasing" caused by coating buildup in the countersink or lead-in thread. If you use a standard plug, the first thread remains exposed, often requiring a secondary tapping operation.

    Step 1: Selecting the Right Flange Size
    To mask a chamfered entry effectively, don't just measure the hole's minor diameter. You must measure the outer diameter of the chamfer (the 'C' dimension in our diagram). Choose an SFPP plug where the flange is roughly 10-15% larger than the chamfer diameter to ensure it seats firmly against the angled surface.

    Step 2: Ensuring a Gasket-Like Seal
    Insert the "tail" through the hole and pull until you feel the flange seat. The 45-durometer silicone is specifically engineered to be more pliable than standard plugs, allowing the flange to act like a gasket against 82° or 90° countersinks. This creates a liquid-tight seal for anodizing and a powder-tight barrier for coating.

    Step 3: High-Temp Removal
    After curing (up to 600°F), these flanged pull plugs are removed by pulling them through the hole. The soft silicone allows the flange to compress and pass through the bore without marring the newly finished lead-in thread.

    Try some FREE silicone flanged pull plug samples – Contact Us for more information!

    NOTE: These plugs are manufactured from a softer (40-45 durometer, Shore A) silicone rubber material than many of our other caps and plugs (55-60 durometer, Shore A). This is to allow the flange to pass through a hole fully when removed from a part to be masked. Due to this softer durometer, some plugs will experience a higher rate of tearing and/or shrinking.

  • Masking 101 Helpful Hints

    When sizing for Silicone flanged pull plugs, look for the major (larger) diameter of the plug to be approximately 2 - 4% larger than the hole when used for powder coating and wet spray, and 3 - 7% larger for applications where the part is immersed in fluid (plating, anodizing, e-coating) to ensure the best seal.

    • Ideal for use in powder coating, e-coating, plating, and anodizing.
    • Use in temperatures up to 600°F / 315°C.
    • HINT: If the plug is a bit on the large side for the hole, but no smaller stock size is available/suitable for the hole, try dipping the plug in water, alcohol, or some other liquid to lubricate it before pulling the plug into place.

     

    Custom sizes available with low cost tooling. Contact Us today for a quote.

    NOTE: These plugs are manufactured from a softer (40-45 durometer, Shore A) silicone rubber material than many of our other caps and plugs (55-60 durometer, Shore A). This is to allow the flange to pass through a hole fully when removed from a part to be masked. Due to this softer durometer, some plugs will experience a higher rate of tearing and/or shrinking.

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