Hanging the plate: screws, tape or magnets

By Tiehl Roberto Matías · 7 min read · Updated 27 October 2026

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The plate is printed, the code reads perfectly in your hand and all that is left is putting it on the wall. That last step, the one that looks trivial, is the one that can leave it unreadable: because almost everything that holds a plate up goes exactly where the code needs nothing to be.

The hole the plate already has

The plates this generator makes come with two 4.6 mm holes in the top strip, one on each side. They are meant for hanging it and they do their job, but it is worth knowing exactly where they sit relative to the code.

A code needs four clear modules all round it. Measured on a 90 mm plate, with 2.67 mm modules, the edge of the hole sits 3.20 modules from the first dark module. In other words, the hole already reaches eight tenths of a module into the area that should be clean.

It is not a fault that wrecks the piece, and the reason is that an empty hole in a light base is not a dark mark: it is a small gap of the same colour, which the reader fits around without trouble. The plates read. But it explains why what goes inside that hole matters so much, and the table is the same at every size:

Plate	Module	Hole to code
70 mm	2.00 mm	3.60 modules
90 mm	2.67 mm	3.20 modules
120 mm	3.56 mm	3.04 modules
150 mm	4.45 mm	3.17 modules

The keychain is different and has room to spare: its ring hole leaves 5.55 modules, because the tab is proportionally much taller. There is nothing to watch there.

Screws: which head and which not

If an empty hole already eats eight tenths of a module, a screw eats more, because the head is always wider than the hole. And a metal head is a dark mark. The numbers, on the 90 mm plate:

• Ordinary M3 head, 6 mm across: leaves 2.94 modules to the code.
• With an 8 mm washer: leaves 2.56 modules. Barely over half what the standard asks for.

Three easy rules come out of that:

1. Countersunk head, sunk flush. A conical-head screw sitting level with the surface is what gets in the way least: it is still a mark, but a flat, small one. You have to countersink the hole with a wide drill bit by hand, turning it with your fingers, no drill.
2. No washers. A washer adds nothing on a 3 mm plastic plate and it is what adds the most dark surface.
3. A screw the colour of the base. If the base is white, a white screw or a drop of paint on top solves the whole problem: what bothers the reader is the contrast, not the lump, as the colour guide explains.

Double-sided tape, which nearly always wins

For a plastic plate under 150 mm, double-sided tape is the best option and it is not close. It does not touch the code, it adds nothing dark, it cracks nothing and it comes off without leaving holes in the wall.

What you do have to look at is something else: flatness. Tape needs the plate to sit flush all over, and a large plate with a thin base warps as it cools. If it rocks when you put it on a table, the tape will only stick in the middle and within weeks it will peel off at one corner. The answer is not more tape: it is more base, and the relationship between thickness and stiffness is in the base thickness guide.

Two practical details:

• Foam tape, not the thin kind. Foam absorbs the irregularities of the wall and of the plate. The thin kind demands two perfect surfaces.
• Four pieces at the corners, not one strip down the middle. That is what stops the corners lifting, which is always where it starts.

What tape does not forgive is the wall: on textured plaster, bare brick or old paint it will not grip. There it has to be a screw, or a desk stand instead of a plate, which is what the stand guide covers.

Magnets: the sum for the recess

For a fridge, a metal door or an electrical cabinet, a magnet is convenient and reversible. The good way to fit one is to sink it into a recess on the back face, and that is where a sum appears that is worth doing before printing.

The recess has to be 0.2 mm deeper than the magnet for it to go in, and there has to be enough floor left underneath for the printer to close it properly: 0.8 mm, which is two passes of a 0.4 nozzle, exactly the same minimum that governs everything else on this site.

Magnet	2.4 mm base	3 mm base	4 mm base	6 mm base
6 × 2 mm	0.2 mm: no	0.8 mm: just	1.8 mm	3.8 mm
10 × 2 mm	0.2 mm: no	0.8 mm: just	1.8 mm	3.8 mm
8 × 3 mm	will not fit	will not fit	0.8 mm: just	2.8 mm
12 × 3 mm	will not fit	will not fit	0.8 mm: just	2.8 mm

The practical conclusion: with the 3 mm base the generator uses, only 2 mm thick magnets fit, and only just. For 3 mm ones the base has to go up to 4.

And there is an effect the table does not show. Where the recess is, the plate is no longer 3 mm thick, it is 0.8. Since stiffness goes with the cube of the thickness, at that point the plate keeps under 2 % of the stiffness it had: the recess is a hinge. That is why they belong at the corners and not in the centre, and never right behind the code.

To fix them, a few drops of superglue in the recess. And before gluing, check which face is attracted to the wall: a magnet glued the wrong way round works the same against iron, but if the wall has other magnets on it, it can repel.

Hanging it from a cord or a hook

Using the plate's two holes to thread a cord and hang it from a hook is the most reversible option of all, and the one that touches the code least: the cord stays behind it and above it.

The drawback is that the plate hangs loose, and a plate that turns or swings is a plate the customer has to hold still to scan. If you are going to do it, keep the cord short and use both holes, not one: with a single support point the plate pivots.

What to use where

Where it goes	What to use	Why
Smooth painted wall, indoors	Foam tape	Touches neither the code nor the wall.
Rough wall or outdoors	Countersunk screw	Tape will not grip; paint it the colour of the base.
Metal	2 mm magnets at the corners	3 mm base minimum, 4 better.
Shop window glass	Thin clear tape	It is seen from both sides; foam looks ugly.
Somewhere temporary	Cord through both holes	Reversible, but it moves.

Whichever it is, the final check is the same and it has to be done with the plate already up, not before: scan it in place, at the height people will be looking at it from and in the light that is actually there. It is the last step of the protocol in the testing guide, and it is where the reflections and shadows that did not exist on the workshop table show up.