PTFE Coated Bolts
PTFE-Coated Bolts

Recently we received a call from a customer inquiring about a colorful set of bolts they found on a job site, trying to figure out what they were. The customer described the bolts as normal steel grade nut-and-bolt sets, but dark blue in color and noticeably slick to the touch. We were happy to shoot over information that identified the bolts as PTFE-coated A193 steel. Given how versatile PTFE materials are in fastener applications, and being reminded by our customer’s call that they’re still not widely known in the market, we put together this article to share insight into PTFE hardware.

PTFE Properties

Chances are, you’re already familiar with PTFE material without being aware of it. If you take a quick look through your kitchen cupboards, we’d bet that you’ll quickly find something that has the word ‘Teflon’ on it. Teflon is a trademarked name for PTFE material, found most often on cooking wares in the form of a non-stick coating. As common as Teflon coating is in cooking, baking, and food-prep wares, it’s non-branded equivalent PTFE is just as common in industrial and construction settings.

PTFE is a synthetic fluoropolymer, with the abbreviation standing for polytetrafluoroethylene. In English, this translates to PTFE being a man-made plastic consisting of fluorine and carbon elements, that is molded under high temperatures and then solidified upon cooling into its final form.

The main benefits of PTFE include:

  • Very low surface friction – the material slides easily, and is used in many forms as a lubricant
  • Non-stick surface – easy to clean and resists contamination
  • Chemical resistance – inert to a very wide range of solvents and chemicals
  • Hydrophobic – resists water and moisture absorption (<0.1% in 24 hours)
  • Temperature stable – usable between -350F and 500F, melting point over 600*F
  • High flexibility – very bendable even below freezing temperatures
  • Electrically Resistant – widely used as an electrical insulator

With so many useful properties, PTFE is hard to beat in terms of wide useability, stability, and resilience. That said, it does have a few properties to be aware of before selection for every project:

  • Low strength – being a deformable plastic, PTFE has a low tensile strength of 3,000 PSI (compared to A193 steel’s minimum 75,000 PSI)
  • Flowable – PTFE is not elastomeric, meaning it does not naturally retain shape and is subject to ‘creep’
  • Polymeric toxicity – as with many polymers, there are risks of fume and component chemical impacts when used outside of their acceptable thermal range. (PTFE is highly recyclable, so always recycle it instead of burning to dispose of).

To wrap up our review of PTFE’s properties, we’ll nod to a fun fact started at UC Berkeley then tested by the University at Akron: was PTFE (a la Teflon) the only known material to which a gecko lizard cannot stick? Read here to see the findings.

Do you have questions about PTFE coating versus full PTFE hardware? Do you need all parts in PTFE, or just the nut and washer? E&T Fasteners can help with these types of questions and more, helping you select the right solution for your project. To explore our material fastener offerings, see our plastic product selection here.

Selection and Applications

The range of PTFE applications is far and wide. With careful consideration, we can find many projects in which it beats more traditional materials selected out of habit.

The first step in selecting a PTFE hardware solution is to clarify what you’re requesting of your vendors. In any specification, you are requesting either ‘PTFE material’ for hardware pieces made entirely of PTFE, or ‘PTFE coating’ for hardware of other core materials that have an external coating of PTFE applied. There are multiple trademarks and brand names on PTFE materials across several industries – Teflon, Syncolon, Gore-Tex, to name a few – and this can cause confusion on what exactly is being requested. To keep things simple, stick to the term ‘PTFE’ for your specifications.

For general applications, ‘standard PTFE’ is plenty to define the specification.

In food-contact or other hygienic applications, specify ‘Virgin PTFE’ to meet FDA requirements.

If you do have a specific brand-name of a PTFE variant hardware piece, please include the manufacturer’s name along with their material trade name. Part numbers or series numbers are even more helpful to clarify the request.

PTFE material hardware is most often used in these applications:

  • Semiconductor and electrical assemblies
  • Clean-room and static-sensitive equipment
  • Food-grade, FDA-compliant food and pharmaceutical manufacturing
  • Light-weight, low-strength projects such as consumer hardware and electronics
  • High temperature applications such as automotive, food prep, powder coating, and testing environments
  • Chemical processing equipment and areas
  • General commercial construction materials such as hanger, signage, trim, and fixture hardware
  • Any other wet environments such as for marine, outdoor, and recreational projects

The key guidance on PTFE material hardware is to make sure the hardware does not need to be structurally high in strength. PTFE material is a light-weight plastic, so should not be used for anything where strength is a major factor. In cases where strength is a major factor, this is where PTFE coatings come into play.

PTFE coatings are most often applied to steel or stainless steel hardware. The PTFE coating adds low friction, corrosion resistance, and non-stick properties on top of the base material’s strength and resilience. Some examples include:

  • PTFE coated steel bolts and nuts – adds chemical and water resistance, protecting the high-strength steel underneath
  • PTFE coated nuts used with non-coated steel bolts – used primarily to benefit installation of the nut, reducing friction and galling
  • PTFE coated stainless steel bolts and nuts – adds non-stick and further chemical resistant benefits to the already robust stainless steel material underneath, used in advanced hygienic applications where the failure of the coating will only expose stainless steel, not standard steel which would rust or corrode
  • Anti-bacterial applications such as medical and emergency response equipment
  • Extreme weather resistant applications
  • Electrical projects needing non-conductive material protection

E&T Fasteners is here to help you navigate fastener options to best meet your application and project needs. Price quotes, availability, lead times, delivery confirmations, unique application suggestions – whatever your need, we’re here to take your call or email. For support and advice from our fully trained staff, speak with an E&T sales representative today.

About E&T Fasteners

With sales and support teams spanning the Continental US, E&T Fasteners is here to serve your hardware, fastening, and component needs both domestically and internationally. We are a stocking distributor of metallic, plastic, and exotic alloy fasteners, backed by our technical staff directly experienced in your unique applications. We can assist your specifying and selection efforts, providing engineered solutions, record-fast lead times, and stellar customer service from quote through delivery. Please let us know how we can help!