Custom Self Seal Mailing Boxes

Custom Self Seal Mailing Boxes for Every Product

Self seal boxes suit almost any product that goes in a mailer: cosmetics, supplements, books, clothing, small electronics, candles, subscription boxes and gift sets. They come in the same styles as regular mailers, mainly the roll-end tuck front style that most online shops use, as well as slimmer letterbox-friendly versions.

For heavy or fragile items, we use stronger corrugated board and can add inserts to hold products in place. For light items such as clothing or stationery, a single-wall E-flute box keeps postage costs down.

Subscription brands find them especially useful because they pack large numbers of identical boxes on a fixed day each month. Lining up a row of open boxes, filling them and then sealing each with a single press keeps the line moving at a steady pace, and every box leaves looking exactly the same.

If your products vary a lot in size, consider pairing one self seal box with a simple card insert for smaller items. The insert holds the small product in the centre of the box, so you do not need a separate box size for every product in the range.

Sizing and Postal Size Bands

Pick a size based on your product plus any inserts or padding, and leave a small gap so items are snug but not forced. Too much empty space means you need void fill; too little and the lid will not close flat enough for the adhesive to grip.

Letterbox-sized self seal boxes are very popular, because they fit through a standard letterbox and the customer does not need to be home to receive them. Check your carrier's maximum dimensions before choosing a size; even a few millimetres over can push a parcel into a more expensive price band.

If you sell lots of different products, two or three box sizes usually cover most orders.

Before ordering a full run, pack a few real orders in a sample box and run them through your normal courier. It is the quickest way to check the size, the board strength and how the adhesive holds up on your route. p3 The guide to measuring a product covers clearance for inserts and padding.

How Strong Is the Adhesive?

The adhesive used on self seal boxes is designed to hold the flap shut through sorting machines, courier vans and doorsteps. It bonds to the board itself, so once sealed, the flap cannot be lifted without tearing the board, which also shows if the box has been tampered with.

Store boxes flat in a dry place, away from direct heat, to keep the adhesive in good condition. Use older stock first. In very cold warehouses, give boxes a little time at room temperature before packing, as adhesive grips best when it is not chilled. p1 Board grades are compared in the guide to board and card types.

Printing on Self Seal Boxes

The outside of the box is a clean canvas without tape across it. A logo on the lid, a pattern on the sides and a printed tear strip instruction make the box look professional. Inside print on the lid and base turns the unboxing into a moment worth sharing.

Kraft board with one colour print is the most affordable option and looks natural. White board with full colour print gives brighter, bolder designs. Matt lamination protects the print from scuffs in transit.

Make sure the printed design leaves the adhesive area and the tear strip clear of heavy ink coverage and lamination where possible, so the strip bonds well and tears cleanly. We set this up on the dieline so your artwork lines up correctly.

Post a Sample Through Your Own Courier First

An adhesive strip is tested on the route, not on the bench. Before a full run, pack three real orders in sample boxes, seal them as your packers will, and send them through your normal courier to a colleague; if the flaps are still down and the tear strip opens cleanly, that is the specification to print. Send the sizes you use now too, since we can often match them so inserts and postage bands stay the same.

Say if returns are common, which adds a second strip, and tell us the board from the heaviest product; B-flute for anything over a kilogram. The custom quote arrives by email within one working day with the minimum set per job, so a trial run before switching the whole range is normal.

The free proof shows where the adhesive strip, the tear strip and the artwork fall on the flat blank. Production takes 4 to 7 working days after approval and the flat boxes reach UK mainland addresses by free tracked delivery. Shops that still need a tuck closure for some lines keep our tuck-top mailer boxes without adhesive beside them.