Description
Round Rubber Caps with Flange for Sealing and Masking
Barbieri Rubber round rubber caps with flange are push-in cylindrical caps with an external flange that prevents them from sliding past the hole edge. They are catalog rubber components, available in multiple diameters, in compounds suitable for sealing, protection, paint masking and isolation of threaded or plain holes.
| Code |
Male Ø (mm) A |
Tot height (mm)
B |
Male height (mm)
C |
Ø Head (mm)
D |
Height (mm) E |
|---|---|---|---|---|---|
| TAP 05X18 | 5 | 18 | 12,5 | 12 | 5,5 |
| TAP 5.9X13 | 5,9 | 13 | 10 | 12 | 3 |
| TAP 06X09 | 6 | 9 | 6,5 | 8 | 2,5 |
| TAP 06X10 | 6 | 10,5 | 7,5 | 11 | 3 |
| TAP 6.9X13 | 6,9 | 13 | 9 | 20 | 4 |
| TAP 06X20 | 6 | 20 | 10 | 10 | 10 |
| TAP 07X22 | 7 | 22 | 16,5 | 12 | 5,5 |
| TAP 08X14 | 8 | 14 | 10 | 12,5 | 2,5 |
| TAP 08X16 | 8 | 16 | 8 | 19,5 | 8 |
| TAP 08X18 | 8 | 18 | 7 | 15 | 11 |
| TAP 08.5X20 | 8,5 | 20 | 15 | 13 | 5,5 |
| TAP 09X20 | 9,5 | 20,5 | 8,5 | 15 | 12 |
| TAP 10X19 | 10 | 14 | 10 | 19 | 4 |
| TAP 11.8X20 | 11 | 20 | 12,5 | 17 | 7,5 |
| TAP 14X18 | 14 | 18 | 12,5 | 19,5 | 5,5 |
| TAP 17X22 | 17 | 22,5 | 20 | 20 | 2,5 |
| TAP 17.5X20 | 17,5 | 20 | 18 | 19,5 | 2 |
| TAP 18X34 | 18 | 33 | 30 | 22 | 3 |
| TAP 20X17 | 20 | 17 | 14 | 45 | 3 |
| TAP 21X18 | 21 | 18 | 12,5 | 25,5 | 5,5 |
| TAP 25 | 25 | 36 | 30 | 35 | 6 |
| TAP 28-39X38 | 28-39 | 38 | 30 | 55 | 8 |
| ETBG 48.2 | 42 | 26 | 20 | 48,2 | 7 |
| TAP 50X22 | 50 | 22,5 | 16 | 54 | 6 |
| TAP 52X12 | 52 | 12 | 7 | 63 | 5 |
| ETBG 57 | 50 | 26 | 18 | 57 | 7 |
| ETBG 60 | 53 | 25 | 18 | 60 | 7 |
| TAP 57X20 | 57 | 20 | 17 | 60 | 3 |
| TAP 60X27.5 | 60 | 27,5 | 20 | 90 | 7,5 |
What round caps with flange are for
Round caps with flange are used to seal through-holes or blind holes, to mask threads during painting, to protect fittings during transport or storage, to isolate pipe and fitting ends, and in general to plug round openings on bodies, frames, equipment and technical components. The flange simplifies positioning and prevents the cap from slipping into the hole.
Available compounds and typical hardness
For paint masking the most common compound is VMQ silicone. NBR is chosen in workshops where oil is present, FKM (Viton®) for chemically aggressive environments, NR/SBR for general use. The cap must be soft enough to insert and stiff enough to stay in place.
| Compound | Temperature range | Feature | Typical applications |
| EPDM | -40 / +100 °C | Water, steam, ozone resistance | Painting, outdoor |
| NBR (Nitrile) | -40 / +130 °C | Mineral oil resistance | Workshops, hydraulics |
| VMQ (Silicone) | -60 / +200 °C | High-T resistance, reusable | Oven painting, high-T |
| FKM (Viton®) | -10 / +180 °C | Aggressive oils, solvents | Chemical, automotive |
| NR / SBR | -50 / +90 °C | Good mechanical elasticity | General caps, masking |
Catalog standard version and custom designs
The standard range of round caps with flange covers an extensive series of diameters, shank lengths and flange diameters, with active tooling at Barbieri Rubber and no tooling cost for the customer. For special sizes, threaded-hole caps with flange, dedicated compounds or colors, we produce custom caps: at least a preliminary drawing from the customer is required. The dedicated mold is manufactured in cooperation with our trusted toolmaking partners.
Industrial applications
Round caps are used in metal fabrication, automotive, vehicle service equipment, hydraulics, pneumatics, agricultural machinery, appliances, technical furniture, electrical systems and photovoltaic. They are among the most requested catalog rubber components because they cover recurrent sealing and masking needs both in production and on painting lines.
Frequently asked questions
What is the difference between round caps with flange and cone caps?
Round caps with flange have a cylindrical shank and an external flange that locks against the surface. Cone caps have a tapered shape and self-center, fitting a range of diameters. Selection depends on hole geometry and required precision.
Are round caps suitable for paint masking?
Yes, with the right compound. VMQ silicone withstands oven cycles and is reusable. The flange makes removal easy after painting.
Are they available from stock?
Yes, an extensive range of diameters, lengths and flange sizes is catalog standard, with no tooling cost. For special sizes the custom-design version applies.
Can I order caps in a specific color?
Yes. On request caps can be produced in dedicated colors for visual identification (e.g. red for painting line, blue for hydraulics, etc.). Coloring is agreed at order stage.
Are they reusable after oven cycles?
Yes. In VMQ silicone, caps can be reused over multiple paint cycles. Lifespan depends on oven temperatures and history of previous cycles.
