Most bag fabric specifications treat base construction as a single number. It is a distribution, and the width of that distribution is what your customer experiences after a year.
What base construction actually controls in bag fabric
Ballistic weave resists abrasion far better at the same weight.
The consequence is that this figure sets the floor for everything downstream: the process, the price and the failure mode all follow from it.
For Bag fabric, the working range is 600D / 840D / 1680D ballistic. Inside that band the choice is commercial; outside it, the product changes category and so does the price.
How to choose a base construction option
| Option | What it changes in bag fabric | When it is the right choice |
|---|---|---|
| 600D | The lowest-cost option in the family. Crocking on dark shades is where it usually ends up. | Cost-led programmes with a short service life |
| 840D | The volume middle: enough margin for process variation without paying for headroom the end product cannot use. | Most repeat programmes, and the safest default |
| 1680D ballistic | The top of the family, where the process is controlled tightly enough to guarantee it. | A warranty, a tender, or a specification that cannot be renegotiated |
These are alternatives, not points on a scale. Base construction is chosen by the application rather than by price, and a supplier who quotes one option as if it were interchangeable with another is quoting a different product.
Specifying the ceiling is only justified when the end product carries a warranty that would be expensive to honour. Otherwise it is cost without a customer-visible benefit.
The figure that decides the outcome is not base construction itself but the tolerance around it. A supplier who quotes 600D / 840D / 1680D ballistic without a tolerance has not quoted a specification, and the first lot will define the tolerance for you.
How to measure base construction
The reference method here is Abrasion, run to ISO 12947-2 Martindale, with an acceptance of >= 25 000 cycles. The method is the easy part; sampling and conditioning are where reports diverge.
Condition the sample before measuring. Results in this family move by 10-20 % between a dry laboratory and a humid one, and two labs can disagree on the same material without either being wrong.
Record the measured value rather than pass or fail. A marginal pass on base construction tells you the process is running at the edge, which is the information you need before the next lot rather than after it.
Base construction does not stand alone
Base construction moves with coating (PU 1-3 coats, 20-80 gsm total) and with abrasion (>= 25 000 Martindale). Tightening one usually costs money in another, and a supplier who accepts every tolerance without comment has either not understood the interaction or is planning to substitute.
When you change base construction, re-check the two neighbours before you approve the sample. Most of the samples we re-make are caused by a change in one figure that was not followed through.
The clause to write for base construction
The line below is the version we can quote against without inventing anything. Base construction appears with a tolerance and a test, not as a standalone number.
1680D ballistic polyester, 2-pass PU with primer, 45 gsm coating, 1500 mm hydrostatic head, 25 000 Martindale, C0 DWR, wet rub >= grade 3, Pantone 19-4005 TCX
The clause that protects you is not the value, it is the sentence that says what happens when the value is missed. Put it in the purchase order, not only in the enquiry.
When base construction goes wrong
Crocking on dark shades. Black bag straps mark a white shirt.
The cause is usually surface pigment without a fixing topcoat.
The test that catches it: ISO 105-X12 dry and wet, plus a 24 h contact test under 5 kg load.
What to specify instead: Fixative topcoat and a wet-rub specification of grade 3 minimum.
Note that the fix is a specification change, not a negotiation. By the time the claim is made, the only remaining lever is who pays for it.
Four questions about base construction, before you order
- What tolerance do you hold on base construction, and what did your last three lots measure against it?
- Which method do you use for abrasion, and which laboratory signs the report?
- When base construction falls outside 600D / 840D / 1680D ballistic, do you rework, downgrade, or ship and hope?
- Which of coating or abrasion would you move first to hit a lower price?
The answers are more useful than a certificate, because they show whether the process is controlled or merely inspected. Full ranges for bag fabric are on the product page, and the measurement regime is described on the quality control page.
Questions buyers ask before ordering
Is 1680D always better than 600D?
For abrasion, yes, if the weave is genuinely ballistic and the coating is adequate. For a promotional tote, 600D is the right answer and 1680D is wasted money.
Do you offer C0 DWR?
Yes. We moved most programmes to C0 because EU buyers ask for it, and we will say plainly that performance after 10 washes is slightly below C6.
Questions worth asking before the price is agreed
The questions below are the ones that cannot be answered from a catalogue, which is exactly why they are worth asking.
| Question | Answer that should worry you | Answer that holds up |
|---|---|---|
| Who signs the test report, and against which standard? | “Our QC department signs it.” | A named standard, a named method and a signature that belongs to somebody who can be asked again next year. |
| How do you hold backing at PU / PVC / none? | “That is standard for us, no problem.” | The last three lots’ readings, the instrument used and who signs the report. Seam slippage starts here. |
| What happens if coating misses the PU 1-3 coats, 20-80 gsm total requirement? | “It will not happen.” | A re-test clause, the tolerance on the re-test, and the point at which the lot is remade rather than discounted. |
Failure modes worth a clause in the purchase order
Claims rarely come from a batch that was obviously wrong. They come from a base construction figure that sat inside the quoted band and outside what the product needed.
| Failure | What triggers it | Test to demand on the production lot |
|---|---|---|
| Coating crack at folds | Too heavy a single coating pass, or a coating with low elongation. | Abrasion — ISO 12947-2 Martindale; acceptance >= 25 000 cycles |
| UV fading | No UV stabiliser in the base yarn or the coating. | Tear strength — ASTM D2261; acceptance >= 40 N for 1680D |
The other two, with acceptance numbers attached, are in the full failure analysis for bag fabric. A supplier who cannot name the mode he sees most often is describing a catalogue, not a process.
Need base construction specified and tested against your end use?
Send the end use, the quantity and the destination market, and we will come back with a specification that meets it, a price at your volume and the test reports that back it up. Samples are free for qualified programmes; we charge the courier only.
Related reading
Sample cut with your values on it · Neutral packing and private label · Consolidation, documents and lead times
