Hold the Line: Why Your Card Base Shouldn’t Flop — and How to Check Before You Glue

Open a drawer of handmade cards and you can often tell which ones were built on printer paper before you even read the greeting. The corners have gone soft. The fold has a memory of its own. The whole thing has the structural confidence of a lettuce leaf.

That is not a failure of your colour choices or your fussy-cutting. It is usually a paper-weight problem. And the good news is that it is one of the easiest things to fix at the kitchen table.

Why gsm is not just a number

Paper weight is given in gsm, or grams per square metre. A sheet of ordinary office paper is usually around 80gsm. A light craft card might be 160gsm. A sturdy card blank is more like 220gsm or 300gsm. Those numbers are not a macho ranking — a heavier sheet is not automatically better — but they do tell you what a paper is likely to do when you fold it, glue it and post it.

Thickness and stiffness are related, but they are not the same thing. A coated card can feel smooth and substantial while still folding like a crisp packet. A nicely sized sheet with a strong grain can behave better than its gsm suggests. That is why the packet description is only the starting point. Your hands are the real test.

The pinch-and-fold test

Before you commit a whole pack to a batch of cards, try this. Take a scrap at least 10cm square. Pinch one corner between thumb and forefinger and let it hang. If it bends immediately to half-mast, it is a layer, not a base. Next, fold a 5cm x 10cm strip in half and press the crease firmly with your thumbnail or a bone folder. Hold it by one end and look along the fold. A base-grade card should stay fairly straight. A light sheet will droop, and the crease will look soft rather than crisp.

One last check: write your name on the scrap with a normal pen. If the paper buckles and the ink feathers out, it is going to resent glue, tape and anything heavier than a stamped sentiment. Better to find out now than after you have added the tiny die-cut robin.

When 160gsm earns its place

Do not write off 160gsm completely. It is lovely for inserts, matting panels, envelope liners, decorative strips and die-cut layers. It folds neatly for small tags and quick gift notes. It is also handy for making templates and practice pieces when you are testing a new die.

The trap is treating it as a card blank just because it is sold near the card blanks. A 160gsm A6 card can work for a quick note handed straight to someone, especially if the decoration is light. But it will feel limp in an envelope, and it will not enjoy being propped on a mantelpiece. As a rule, let 160gsm be the supporting actor, not the star.

220gsm: the everyday hero

For most everyday cards, 220gsm is the sweet spot. It is sturdy enough to stand up, light enough to fold without a fight, and well behaved with both glue and double-sided tape. An A6 blank in 220gsm, paired with a 160gsm insert, feels surprisingly professional without becoming a piece of cardboard engineering.

Score the fold before you crease it, especially on darker colours where cracking shows. A bone folder is worth keeping by your cutting mat. If you are making a batch of birthday cards, cut a template from scrap card and score several blanks in one go. Your future self will thank you when the card has to go in the post.

300gsm: when you want heft

A 300gsm blank is the right choice for gatefolds, easel cards, shaker cards and designs with a lot of layered weight. It holds a crisp fold and gives a card real presence. It also needs a little more respect. Score both sides of the fold if the card is coated, fold slowly, and burnish with a bone folder rather than forcing it flat with your hand.

Heft has a postal consequence too. A standard UK letter has to fit within Royal Mail's size, weight and thickness limits — broadly, no more than 100g and no thicker than 5mm for a letter, with larger limits for a large letter. A 300gsm A6 card is usually well within that on its own, but add a foam-padded flower, a charm and a lined envelope and you may drift into large-letter territory. Keep a small ruler and a set of kitchen scales near your post pile. It is far less annoying to check before you seal the envelope than to pay a surcharge later.

Rescuing a stash of too-thin card

If you already have a pile of floppy card, do not bin it. Demote it. Light card makes excellent matting layers, inserts, belly bands, envelope liners and backgrounds for smaller toppers. It is also perfect for die-cut practice and for making the little templates you use over and over.

For a base that needs a bit more backbone, try mounting a 160gsm card front onto a 220gsm or 300gsm blank. You get the colour you love with a sturdier spine. If you want to stiffen a folded card, glue an insert only along the centre fold rather than all the way around the edges; this adds support without making the card bow. You can also laminate two sheets of light card back-to-back with a thin, even layer of glue stick, burnish them flat and leave them under a heavy book overnight. Test a scrap first, as some glues will ripple.

Smaller formats are another friendly rescue route. A 160gsm sheet that feels weak as an A6 blank may be perfectly happy as a gift tag, a 7cm square thank-you card or a little note to tuck into a parcel. Keep a box labelled Layers and Liners so you stop reaching for the thin card when you really need a base.

A quick buying checklist

When you are shopping, look for the words card blank rather than paper. Check the gsm in the listing, and if it is not there, ask before you buy a ream. A mixed pack of 160gsm, 220gsm and 300gsm in the same colour is a brilliant way to learn what you like without committing to a huge box. Make three test cards, write in them, fold them and leave them on the side for a day. The one that still looks proud of itself is your new everyday base.

Paper weight is not the most glamorous part of card making, but it is the bit that lets all the glamorous parts survive the journey. A quick pinch, a quick fold and a quick check can save a whole afternoon of gluing. And a card that holds its own just feels more like a keeper.