How do I check a carbon fiber or fiberglass sample before I order?
You need a ruler, a caliper, a scale that reads to 0.01 g and a little of your own resin. Write down what the quote promised (weight, weave, width, hole size, diameters) and check the sample against those numbers, not against your impression of it.
10 × 10 cmTest square
× 100Grams to g/m²
0.01 gScale resolution
1 afternoonNo lab needed
How do I check carbon fiber fabric?
- Areal weight. Cut a 10 × 10 cm square (100 cm²), weigh it and multiply by 100 to get g/m². A 200 g/m² fabric should weigh about 2.0 g.
- Weave. Hold it to the light. Look for missing or broken tows, folds and gaps. Twill lines should run straight across the width.
- Handling. Drape it over a curved surface. Twill should follow the curve without the tows separating. Plain weave is stiffer, which is normal.
- Wet-out. Wet a small piece with your resin. It should go clear evenly, with no dry white spots.
How do I check fiberglass mesh?
- Weight. Weigh a 10 × 10 cm piece the same way, and ask whether the quote gives coated or raw-fabric weight.
- Hole size. Measure several openings with a caliper.
- Coating. It should be even, with no bare yarn and no sticky patches. Fold a corner sharply: a good coating does not crack or flake.
- Alkali resistance. Ask for the strength kept after soaking in cement filtrate. You cannot test that in an afternoon, so it must come from a test report.
How do I check chopped strand mat?
- Weight. A 300 g/m² mat should weigh about 3.0 g per 10 × 10 cm. Our mat is made to ±20 g/m².[1]
- Evenness. Hold it to the light. Thin spots and clumps mean uneven laminates.
- Wet-out. Wet a piece with your resin, roll it out and time how long it takes to go clear. Damp mat wets out badly, so keep samples sealed.
How do I check a carbon fiber tube?
- Diameters. Measure the outside and inside diameter at both ends and in the middle.
- Straightness. Roll it on a flat table and look for wobble.
- Wall. Look at the cut ends. The wall should be even all the way round, with no voids or layers coming apart.
- Surface. Check for pinholes, wrinkles and resin-rich patches.
| Material | Check | Pass if |
|---|---|---|
| Carbon fabric | weight, weave, drape, wet-out | within tolerance, straight weave, clears evenly |
| Fiberglass mesh | weight, holes, coating | matches quote, coating does not crack |
| Chopped strand mat | weight, evenness, wet-out | within ±20 g/m², no thin spots |
| Carbon tube | diameters, straightness, wall | in tolerance, no wobble, even wall |
Then compare prices
Compare prices only between samples that passed the same checks. A cheap fabric that weighs 10% light is not cheap.
How do I get samples?
Free A4 swatches are available for carbon fiber fabric, fiberglass mesh and chopped strand mat. Tube, sheet and part samples are charged. Samples ship in 5–7 days.[2] Ask for one through the quote form.