Q. What is Teflon?

A. Teflon is the registered trademark and a brand owned by Chemours (formerly DuPont). Teflon is not a specific substance or product name. Teflon relates to a wide range of coatings used for industrial and consumer applications.

Q. What is Xylan?

A. Xylan is a registered trademark and brand owned by the Whitford Corporation. Xylan relates to a wide range of fluoropolymer and fluoropolymer composite, industrial coatings.

Q. What is a fluoropolymer?

A. A fluoropolymer is a polymer that is made up of monomers that contain fluorine atoms. There are many types but the principal fluoropolymers used in the coatings that we apply are PTFE (polytetrafluoroethylene), FEP (fluorinated ethylene propylene) and PFA (perfluoralkoxy).

Q. If PTFE is non-stick, how do you make it stick to another surface?

A. PTFE on its own will not stick to any surface. The first step is to roughen the surface, normally by grit-blasting. Some PTFE coatings need a primer, which is a blend of highly adhesive resin, fluoropolymer and other pigments. When the topcoat is applied, the fluoropolymer in the primer bonds with the topcoat during the curing process to form a fully bonded coating. Coatings that do not need a primer are a blend of resin and fluoropolymer and because the resin provides substrate adhesion, this type of coating can be applied in only one layer.

Q. What is the temperature range of PTFE coatings?

A. PTFE coatings can withstand maximum operating temperatures of 260⁰c and intermittent exposure (up to 30 minutes) of 285⁰c. PFA (perfluoralkoxy) has similar operating temperatures but FEP (fluorinated ethylene propylene) has a maximum operating temperature of 205⁰c.

Minimum operating temperatures of PTFE, PFA and FEP coatings are well into the cryogenic range at around -195⁰c.

Q. Can you mask off areas that don’t need to be coated?

A. Yes we can. We have numerous methods of masking areas that need to be free from coating, such as threaded holes, dowel pins and general features. However, it is important to note that masking can be quite labour intensive and consequently adds cost. This is particularly important to consider at the design stage as once masking detail has been specified on an engineering drawing, it can be difficult to make changes in the future.

Q. Do you apply coatings that are FDA approved?

A. There is no such thing as an FDA approved coating. The US Food & Drug Administration (FDA) publishes a list of substances and end uses that are permissible where surface coatings are used in food contact situations. The correct terminology is FDA compliant as the ingredients that make up the coating need to be compliant with FDA requirements. It is also important to understand that FDA compliance is not a global, overarching standard. It only applies to the USA. There are different regulations that relate to coatings that are suitable for food contact that apply to other regions in the world, including Europe and some that relate specifically to Germany.

To answer the question, we do apply coatings that are FDA compliant and suitable for food contact applications in all other regions. If required, we can request a Regulatory Compliance Statement from the coating manufacturer.

Q. What is the best chemically resistant coating?

A. As there is an almost infinite combination of substances, concentrations, operating temperatures and pressures, some fluoropolymers may be more suitable in certain circumstances than others. Although the fluoropolymers that we apply are inert to almost all substances, they all have distinct physical properties that need to be considered. We have a vast library of testing data relating to exposure of almost all substances to the fluoropolymer range. It is always wise to have a discussion regarding the application before selecting the most suitable coating system.

Q. What does the coefficient of friction mean?

A. The coefficient of friction is a measurement of the force that resists movement between two surfaces that are in contact with each other. The lower the value, the lower the friction. There are two forms of friction – static and dynamic. Static friction is the force resisting initial movement of a static object. Dynamic (or kinetic) friction is the force resisting movement of two objects that are already moving against each other. Static friction values are normally higher than dynamic friction values.

Q. Are there additives in the coatings to improve performance?

A. Yes. Some coatings contain additives such as ceramic or metallic fillers to improve abrasion and wear resistance. Solid lubricants such as MoS2 (molybdenum disulfide) and graphite can also be added to improve lubrication for bearing surfaces in very high pressure applications. Metallic powders can be added to provide a degree of electrical conductivity and superior abrasion resistance.

Q. What is the thickness of the coatings that you apply?

A. There are several factors that affect the overall coating thickness. The first factor is the type of coating that is applied. One coat, resin based systems have a DFT (dry film thickness) of around 15 – 25 microns. Two layer systems (primer & topcoat) have a DFT of around 35 – 50 microns although some systems with pure fluoropolymer topcoats can be built up to well over 100 microns on certain types of geometry, with multiple topcoats. Some three layer systems (primer/mid-coat/topcoat) can have a DFT of 50 – 100 microns.

Q. Do your coatings provide electrical insulation?

A. Yes, but only for relatively low current values. Although fluoropolymers have excellent dielectric strength, coatings are not suitable insulators where high electrical currents are involved.

Q. Do your coatings provide electrical conductivity?

A. There are a handful of coatings that are designed to provide electrical conductivity. There are also some coatings that are conductive by nature of their composition. For instance, where carbon is used to colour a black coating, it will also provide a degree of electrical conductivity.

It is important to note that conductive coatings are designed for applications such as static dissipation, not to operate or control electrical devices.

Q. What temperatures do you cure your coatings at?

A. Most single layer coatings are cured at between 180⁰c and 400⁰c. In certain applications, temperature/time can be varied to achieve specific properties from the coating. Multi coat and pure fluoropolymer topcoats need to be cured at between 360⁰c and 420⁰c, depending on the application. Coatings that are used in food contact applications need to be cured at a minimum of 315⁰c and in most cases 400⁰c.

Materials such as plastic, rubber, elastomers and resins can also be coated. There are coatings that are specifically designed for this type of substrate and are cured at temperatures around 60⁰c - 80⁰c.

Q. Do you only apply PTFE coatings?

A. No. We apply a huge range of coatings that contain the three principal fluoropolymers that are either PTFE (polytetrafluoroethylene), FEP (fluorinated ethylene propylene) and PFA (perfluoralkoxy). As well as pure fluoropolymer topcoats, we have a very wide range of coatings that are blends of fluoropolymer and thermosetting or thermoplastic resins which have exceptional mechanical characteristics and also provide excellent chemical and corrosion resistance.

Q. What colours are available?

A. There are a range of colours that are available and some are produced to a specific RAL colour standard. It is important to note that the industrial coatings that we apply are primarily designed to be functional and not as decorative coatings. If you have a specific colour requirement, please contact us and we will be happy to discuss your requirements.

Q. Can an existing coating be removed?

A. In the vast majority of cases, yes. We have several methods of removing worn or damaged coatings and we can re-apply either a direct replacement or even an improvement if required. Either way, this is a very cost effective way of extending the life of the part without having to re-manufacture.

Parts that are manufactured from very thin materials are not generally suitable for re-coating and if a plating operation has been carried out prior to coating application, this may have to be repeated prior to the re-application of the coating.

Q. Can you provide a Data Sheet?

A. Yes. There are two types of data sheet. A Product Data Sheet (PDS) is primarily designed for applicators and contains basic information about the intended use of the product and handling, mixing, application, curing and testing information. The other type of data sheet is a Material Safety Data Sheet (MSDS) which contains important information about the health and safety aspect of the coating material, specific hazards, handling, disposal and first aid precautions. In most cases, some of the hazardous substances that are listed in the coating solution will be driven off during the flash off and curing cycle and will not be present in the cured coating film.

Data sheets are produced as an aid for the applicator and will not contain information about the composition or ingredients contained in the coating. Coating manufacturers obviously keep this as a closely guarded secret.

Q. What types of material can you coat?

A. Virtually all metals can be coated, including aluminium, all types of steel, cast iron and most types of brass. Copper and alloys with a high copper content normally need special pre-treatments such as a layer of electroless nickel, as formation of an oxide layer on the substrate during the curing cycle can cause adhesion failure.

Many plastics can be coated although the curing temperature must be well below the temperature at which the material softens or any degradation of polymer occurs.

Some rubbers and elastomers can be coated, although Viton and silicone rubber are not generally suitable for coating.

Q. Will a coating hide and cover marks and imperfections on the surface?

A. In the vast majority of cases, no. Some of the thicker coatings that we apply may hide very shallow marks but generally, the coating will follow the contours of the substrate material.

Q. Can you coat internal bores?

A. Yes we can but there are limitations in relation to the diameter and length of the bore and whether it is open at both ends or blind.

Q. How are your coatings applied?

A. The majority of our coatings are applied using a conventional spraying method, driven by compressed air. Some of our PFA (perfluoralkoxy) and FEP (fluorinated ethylene propylene) coatings are applied electrostatically as powders. The coating material and the part are oppositely charged, using specifically designed application equipment.

Q. Can you carry out any coating works on our site or do we have to send the parts to you to be coated?

A. We can only carry out coating operations at our site. This is due to the specialist equipment and machinery required, health and safety regulations and also the fact that all of the coatings that we apply need to be cured in a carefully controlled environment at elevated temperatures that can be between 180⁰c and up to 425⁰c.

Q. Can you measure coating thickness?

A. We have electronic instruments that can measure coating thickness on most ferrous and non-ferrous metals down to fractions of a micron. We also have conventional micrometers and calipers where the overall dimension of the part, including the coating thickness is required.

Q. How long will the coating last?

A. There is no simple answer to this. The most accurate way to determine the life of a coating is to test in the environment that it will be operating. There is some testing data available relating to salt spray exposure and for abrasion and wear resistance but there are an almost infinite combination of factors that can affect the life of a coating, so it is very difficult to give an accurate answer.

Q. Can you process one-off’s or very small batches?

A. We have no restrictions on how many or how few parts we can process. We are more than happy to carry out one-off’s or prototyping work as well as large batches of many thousands of parts.

Q. Do you sell Teflon or Xylan coatings?

A. We do not sell any coating materials; we apply coatings to customers’ free-issue parts.

Q. Can you re-coat my frying pan?

A. Unfortunately, we do not re-coat any domestic cookware. Such items are manufactured in a mass production environment and to strip off an old coating and re-apply a new coating to one item can be very labour intensive. It is always more cost effective to replace the item with a new one.

Q. What is your normal lead time?

A. We normally work on a lead time of 7 – 10 days. Large volumes or in cases where complex processes are involved, may be subject to longer lead times but we will always be able to give a reasonably accurate prediction of when the job will be completed.

In situations where small volumes are required urgently, we can offer very fast turnaround in most instances. Please call us to discuss your requirements.

Q. Do you have ISO9001:2015 approval?

A. Yes, our quality management system is registered to the ISO9001:2015 standard. Please click on the link for a copy of our certificate. http://www.ptfecoatings.com/images/iso9001.pdf

Q. What are your payment terms?

A. Once a credit account has been established, our payment terms are 30 days from the end of the month that the invoice is dated.

Q. Can I pay by credit card?

A. We do not accept credit card payments.

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