Long glass fiber nylon: LGF PA6 and PA66 pellets from 30% to 60% glass
For molders who run structural nylon parts and the buyers who source the resin. We quote long-glass nylon through our supply partners, case by case, by base resin, glass level, color and spec, from one gaylord where the grade is available. A polymer chemist checks every match against the grade you run now and tells you plainly if we can’t source it.
Request a QuoteThe short answer
Long glass fiber nylon is PA6 or PA66 reinforced with glass fibers that run the full length of the pellet, often about 10–12 mm for injection molding. The pellets are made by pulling continuous glass through molten nylon and cutting the strand into pellets. Compared with short-glass nylon at the same glass level, stiffness is similar, while notched impact, creep resistance and fatigue life are usually better, as long as the molding process keeps the fibers long. Common levels are 30%, 40%, 50% and 60% glass. It is chosen mostly to replace metal in structural parts.
Long glass vs. short glass nylon
Both are glass-reinforced nylon. Short-glass nylon is compounded on a twin-screw extruder, which breaks the fibers down to well under 1 mm. Long-glass nylon is made by pulling continuous glass through molten nylon and cutting the strand into pellets, so the fibers start as long as the pellet. In the molded part they form a connected network, and that network is what carries load after a crack starts and what resists slow sagging under load.
| Property | Short glass nylon | Long glass nylon (LGF, LFT) |
|---|---|---|
| Pellet | Often about 3 mm long, fibers well under 1 mm | Often about 10–12 mm, fibers parallel and the full pellet length |
| Stiffness at the same glass level | Baseline | Similar |
| Notched impact | Lower | Higher, and it holds up better in the cold. The gain grows with glass level and can be modest at 30%. Ask for the value at 23°C and at −30°C |
| Creep and fatigue | Good | Better, especially when hot |
| Warp | Shrinks less along the flow than across it, so flat parts can warp | Often more even, because the fiber network holds the part together. Check the grade sheet for both directions |
| Surface | Smoother | Fibers show more easily. Plan texture or a hot mold for visible faces |
| Molding | Standard reinforced-resin setup | Needs low shear, open flow paths and low back pressure to keep the fibers long |
Typical comparison. Individual grades vary, so confirm against the data sheet for the exact grade.
PA6 or PA66 base, and how it compares with long-glass PP
| Property | Long glass PP | Long glass PA6 | Long glass PA66 |
|---|---|---|---|
| Heat | Lowest of the three. HDT at 1.80 MPa is often about 155°C / 311°F | Higher. Short-glass PA6 at 30% is often about 200–210°C / 392–410°F | Highest. Short-glass PA66 at 30% is often about 240–255°C / 464–491°F |
| Strength | Lowest | Higher | Highest, and it keeps more of it when hot |
| Weight | Lightest. 30% glass is about 1.12 g/cm³ | Heavier. 30% glass is about 1.36 g/cm³ | Heavier. 30% glass is about 1.37 g/cm³ |
| Moisture | Absorbs almost no water. Filled grades can pick up surface moisture | Absorbs the most water. Properties and size change with humidity | Absorbs less than PA6, still needs drying |
| Surface and flow | Good flow | Better surface and easier flow than PA66 | Sets up faster in the mold, with a narrower processing window |
| Cost per pound | Lowest | Higher | Usually the highest of the three |
HDT and density figures are typical short-glass family values, given for scale. Long-glass grades are in the same range or a little higher, and some copolymer-based grades run lower. Confirm on the data sheet for the grade.
If the part works in long-glass PP, PP is usually the lighter and cheaper answer. Choose nylon when the part runs hot, carries a high load for a long time, or sees fuels and oils. See long glass fiber PP, nylon 6 vs. nylon 66 and glass-filled PP vs. nylon.
Dry and conditioned values differ. Nylon takes up moisture after molding, which lowers stiffness and strength. Impact can move either way on long-glass grades. Most data sheets list both sets of values. Compare both, and design to the conditioned numbers if the part lives in normal room air.
Glass levels and where each one fits
| Glass level | Where it is used | Notes |
|---|---|---|
| 30% | Housings, brackets and covers that need more impact than short glass gives | Easiest to mold and the best surface of the range |
| 40% | Structural brackets, carriers, pedal and seat parts | A common metal-replacement level |
| 50% | Highly loaded structural parts | About 1.55–1.57 g/cm³. Stiff, with less flow |
| 60% | The stiffest parts, and thick sections that replace die-cast metal | Needs generous gates and wall sections. A fiber-free surface is harder to get |
Molding long-glass nylon without breaking the fibers
- Dry it first. Nylon must be dried in a desiccant dryer before molding, often at about 80–82°C / 176–180°F for 2 to 4 hours from a sealed bag or box. Long-glass data sheets often ask for 4 hours, and longer once the package has been open. The moisture limit is on the grade sheet, often 0.2% or lower. See the drying guide.
- Set the melt temperature from the processing guide. Long-glass producers often ask for a hotter melt than for short-glass grades of the same nylon, because a softer melt breaks fewer fibers.
- Keep shear low. Low screw speed, low back pressure and a moderate injection speed. High shear is what shortens the fibers.
- Open the flow path. A general-purpose screw with a low compression ratio, a free-flow check ring, a generous nozzle, full-round runners and large gates. Avoid sharp corners and small pin gates.
- Run a warm mold. Long-glass nylon producers usually ask for a warm tool, about 80–120°C / 176–248°F. A warmer tool hides fibers on the surface.
- Limit regrind. Regrinding shortens the fibers, so producers set a low limit for long-glass grades. Follow the grade sheet.
- Plan the weld lines. Long fibers do not cross a weld line, so a weld stays a weak spot. Place gates so welds fall in low-stress areas.
- Check the fiber length you kept. Burn the nylon off a molded part and look at, or have a lab measure, the glass that is left. That shows whether the process is protecting the fibers. An ash test alone only gives the glass content.
General practice from producer processing guides. The data sheet and processing guide for your exact grade come first.
Where long-glass nylon is used
- Automotive: seat structures, pedal brackets, structural brackets and reinforcements, gearshift and steering column parts, and front-end parts where PP runs out of heat or stiffness
- Power tools and outdoor equipment: housings and handles that take drops
- Industrial: pump and valve bodies, brackets, levers and frames that were die-cast metal
- Sporting goods and furniture: frames and load-bearing fittings
What to put on the RFQ
- Base and glass level. PA6 or PA66, and the percent glass.
- The grade you run now, or the print callout or OEM material spec. A different grade is a starting point for a trial, never a drop-in.
- Color and stabilizers. Natural or black, heat-stabilized, UV-stabilized, impact-modified.
- Pellet length, if your feeding or dosing equipment needs a certain length.
- Required tests on the COA. Usually ash (glass content) and moisture. See what a COA shows.
- Quantity and ship-to. This order, yearly use and the city. Our RFQ package page lists what helps a chemist match a structural grade.
Common questions
What is long glass fiber nylon?
Nylon 6 or nylon 66 reinforced with glass fibers that run the full length of the pellet, often about 10–12 mm. It is also called LGF nylon or LFT nylon. The long fibers form a network in the molded part, which raises impact strength and resistance to creep compared with short-glass nylon.
Is long glass nylon stronger than short glass nylon?
At the same glass level, stiffness is similar and tensile strength is similar to somewhat higher. The larger gains are in notched impact, creep and fatigue, and in how well the part holds its strength when hot. Those gains depend on a molding process that keeps the fibers long.
Does long glass nylon need to be dried?
Yes. Like all nylon it absorbs moisture and must be dried in a desiccant dryer before molding. Follow the temperature, time and moisture limit on the data sheet for the grade.
Long glass nylon or long glass polypropylene?
Long-glass PP is lighter, costs less per pound and absorbs almost no water. Long-glass nylon is stronger, takes more heat and resists fuels and oils better. If PP meets the temperature and load, it is usually the lower-cost choice.
Can I run long glass nylon on a standard molding machine?
Usually yes, with a low-shear setup: a general-purpose screw, a free-flow check ring, a generous nozzle, large gates, low back pressure and low screw speed. Small gates and high shear break the fibers and give away the benefit. Very small machines can be a problem, because long pellets can bridge in a small feed throat and some producers set a minimum screw diameter. At 50% and 60% glass, expect faster wear on the screw, barrel and check ring unless they are hardened.
Can you quote long glass fiber nylon?
Yes. We quote long glass fiber nylon through our supply partners, case by case, by base resin, glass level and color. Send the grade you run now or the spec, and a polymer chemist will tell you plainly whether we can source it.
Talk to a polymer chemist
Have a grade on a print, a bag label, or just a part you need to make? Send what you have.
- Send the grade, a callout or a photo of the bag label.
- A polymer chemist checks it, and suggests an alternative grade to trial if yours is hard to get.
- We aim to quote within one to three business days, from one gaylord where the grade is available.
Tell us the long-glass nylon grade you run now
A polymer chemist reviews every request, then quotes your grade or suggests an alternative grade to trial.
What to send for an accurate quote
- The grade name, from any supplier, or a data sheet
- Base resin (PA6 or PA66) and glass percent
- Color and stabilizers (natural or black, heat or UV stabilized)
- OEM or print spec, if there is one
- Quantity for this order and what you use in a year
- Ship-to city and state or province
A source for long-glass nylon
Send the grade or material spec, base resin, glass level and color, plus your yearly volume. A polymer chemist reviews it and tells you whether we can quote the same grade or an alternative that would need approval. We aim to quote within one to three business days.
Request a QuoteNot sure which grade fits your part?
Send the grade you run now, or describe the part.