Your Reliable PVDF Rod Manufacturer in China

What a PVDF Rod Is

A PVDF rod is a solid round bar of polyvinylidene fluoride, supplied unfilled and machined into parts rather than moulded into a finished shape. The long form — polyvinylidene fluoride rod — names the same item. You will also meet it as Kynar, which is a trade name for the polymer rather than a different material.

The chemistry sets the limits. Half of the carbon backbone carries fluorine and the other half carries hydrogen. That single difference from a fully fluorinated polymer is why a PVDF rod is stiffer, weldable and stable outdoors — and it is also why the material is not the most chemically inert fluoropolymer you can buy. If you are designing a part, the useful question is not whether PVDF is better than PTFE, but which of those two properties your duty actually turns on.

Two things this page is not about, and the reason is that the buyers are different. A welding rod is a thin filler strip fed into a hot-gas or fusion weld to join sheet and pipe; the bar described here is stock that gets machined. Printing filament is feedstock for an extruder. All three share a name and nothing else. You are in the right place if what you need is a PVDF rod to machine into a part.

PVDF Rod vs PTFE Rod: Where the Two Diverge

Engineers arrive at this comparison constantly, and the honest answer is that neither material wins. PTFE is the more chemically inert of the two and the better high-temperature choice. A PVDF rod is the more rigid, the more dimensionally stable under sustained load, and the easier to weld and bond. Which one you specify depends on what your part has to survive.

Read the table by duty, not by column. If your part sits in an aggressive medium at elevated temperature and carries no structural load, PTFE is usually the right answer and HANSA will say so — see PTFE rod for that route. If your part has to hold a thread, keep a bore round, or be welded into an assembly, the rigidity of a PVDF rod is what you are buying. For those duties the PVDF rod is the specification, and HANSA’s size range on this page is the starting point.

PVDF vs PVC and PVDF vs PFA

The two comparisons buyers make least often are also the two where the answer is clearest.

Against PVC, PVDF wins on the two axes that usually decide the job: solvent resistance and service temperature. PVC is cheaper and perfectly adequate for water, dilute acids and indoor ductwork. It is the wrong choice where the part sees ketones, esters or chlorinated solvents, and it is the wrong choice above the modest ceiling PVC tolerates. If your line already runs PVC and you are replacing parts regularly, that replacement frequency is the signal to look at a PVDF rod.

Against PFA, the gap narrows. Both are fluoropolymers with good chemical breadth, and PFA keeps more of the flexibility and the temperature headroom. PVDF is the stiffer of the two and the less expensive, which is why it is the default for machined structural parts that must sit in a chemical environment. Reach for PFA when a hose, a liner or a continuously flexing part is what you actually need, and note that HANSA covers that route on a separate page. The same material in flat form is covered on the PVDF sheet page, which is the one to read if you need a lining rather than a machined bar.

Chemical Resistance of PVDF Rod, and Where It Stops

Chemical compatibility is the property buyers ask about first, and it is also the one most often reduced to a slogan. The useful statement is narrower.

Unfilled PVDF holds up well against most inorganic acids, bases and oxidisers, including the strong mineral acids and the hypochlorite solutions that attack many plastics. It is widely used in chlor-alkali and water-treatment duty for exactly that reason. Resistance to hydrocarbons is good and resistance to most alcohols is good.

Where it stops matters more. Strong bases at high concentration and elevated temperature are the classic failure mode, and polar solvents — ketones, esters, some amines — will attack it. Aromatic solvents are a poor fit. So is any duty where the part is simultaneously hot, highly basic and under stress, because chemical attack and stress cracking compound rather than add.

The rule that keeps you out of trouble is to test the finished part in the actual medium, at the actual temperature, rather than to trust a table with a single tick. HANSA will machine a sample PVDF rod to your drawing so you can run that test before you commit to a production order.

Temperature Capability and Continuous Service

PVDF behaves predictably across its range, and the range has two ends worth knowing.

The maximum continuous service temperature is 150 °C (302 °F), and it is a continuous figure rather than a short-term peak — the material does not need an excursion allowance built into the design. The minimum service temperature is -40 °C (-40 °F). The glass transition temperature sits at -35 °C (-31 °F) and the melting point at 175 °C (347 °F).

Read those two middle numbers together and the behaviour makes sense. Because the glass transition sits below the service floor, the material stays out of its brittle range across the whole working band, which is why a PVDF rod does not become fragile in a cold store. Because the melting point sits only a little above the service ceiling, the material is melt-processable, which is the property that makes it weldable and the reason it can be supplied as a smooth bar.

Those figures describe an unfilled PVDF rod. Load, medium and part geometry all move the practical limit, and packaging a hot part against a cold one moves it too. Tell HANSA the duty and the number can be confirmed for your application rather than left as a table value. If the duty runs colder than this material allows, PCTFE rod is the grade to look at instead, and if it runs hotter, the answer sits in the PEEK rod range.

Strength, Stiffness and Impact

The mechanical case for a PVDF rod is straightforward: it is the strongest of the common fluoropolymers and it holds its shape.

Typical unfilled PVDF sits at a tensile strength of 40 to 85 MPa with a compressive strength of 13 to 14 MPa, an elongation at break of 30 to 50 percent and a hardness of 75 to 85 on the Shore D scale. Density is 1.76 to 1.78 g/cm³, which is lighter than a metal replacement and heavier than most commodity plastics. Moulding shrinkage of 1.4 percent is a processing figure and not a machining one, but it explains why a moulded part and a machined part start from different allowances.

The number that matters most in service is the one that never appears in a datasheet: creep. PVDF resists cold flow far better than a fully fluorinated polymer, so a part under sustained load keeps its dimensions over years rather than weeks. That stability is what a PVDF rod buys you over a fully fluorinated bar, and it is the first thing HANSA asks about when you send a loaded part. That is the property that lets you hold a thread in it, and it is why the material turns up in load-bearing chemical hardware rather than only in linings.

Impact resistance is moderate. A PVDF rod will absorb a knock that would crack an acrylic, but it is not a substitute for a polycarbonate or an ultra-high-molecular-weight polyethylene rod in a genuinely shock-loaded duty. If your application is impact-dominated rather than chemical-dominated, say so and HANSA will point you at the right material in the range.

Standard Length, Diameter Range and Cut Length

The bar is stocked from Ø10 mm (0.39 in) to Ø250 mm (9.84 in), in two standard lengths: 1000 mm (39.37 in) and 2000 mm (78.74 in).

Thirty-one diameters are held as standard across that range, and the full list with nominal weights sits in the specification table above. Nominal weights are quoted for freight; they are not a theoretical figure derived from the density of the polymer, so do not use them as a material-take-off.

Two practical notes about ordering a PVDF rod. First, diameters that fall between the listed stock sizes are not held as bar — they are machined, so send the finished diameter and the length you actually need rather than the nearest stock size. Second, if you are machining the part yourself, specify the diameter you need to receive, not the finished diameter you have in mind. The bar arrives at nominal diameter, so a finishing allowance has to come out of your drawing.

Machining, Welding and Bonding

A PVDF rod machines like a soft engineering plastic and it behaves far better than a fully fluorinated polymer at the tool.

Turning, milling, drilling and threading all work with sharp, positive-rake tooling and generous clearance, and the material takes a clean thread, which is unusual in this family. Expect the usual thermoplastics discipline: keep the tool moving, keep the chip clear, and let the part cool before you measure it, because a warm machined part will measure undersize. If your shop has not run one before, HANSA will send the speeds and feeds that work on a PVDF rod.

Welding is where the material separates itself from PTFE. Hot-gas welding, butt fusion and socket fusion all work, which is why PVDF appears in welded assemblies such as tank linings, ductwork and wet benches. The welding rod you feed into those joints is a separate product from the bar on this page. So is printing filament, which is a different grade made for a different machine. Bonding also works with a properly prepared surface — abrade it, degrease it, and use a system the adhesive maker recommends for low-surface-energy plastics. Do not expect a solvent cement to hold; it will not.

How to Order PVDF Rod from HANSA

Send HANSA three things and you will get a usable answer rather than a range.

Whether you buy one PVDF rod or a year’s supply, the same three things decide the answer. Send the diameter and the length, whether that is a stock bar cut to length or a finished part machined from the bar. Send the duty — the medium, the temperature and whether the part carries load — because that is what decides whether the standard grade is right or whether a different material in the range is the better answer. Send the quantity and the date you need it, so the quote carries a committed delivery date instead of an estimate.

You will get one reply with the price, the tolerance the part will be held to, and the date. If a value needs confirming on the material rather than on the drawing — a chemical, a continuous temperature, a finished dimension — HANSA will say which one before the order is placed, so nothing on the quote is an assumption.