Melting sealing wax: temperature, quantity and the mistakes everyone makes once

The shortest possible kit is four things:

• Sealing wax as beads or sticks. Beads can be counted exactly, sticks are handier when you are setting many identical seals in a row.
• A heat source. A melting spoon over a tealight, or a glue gun — both work, see below.
• A wax stamp. Our brass stamps have a 25 mm face, the size that sits on a normal envelope without shouting.
• A surface nothing sticks to: baking parchment or a silicone mat. On wood or paper the wax bonds and stays.

What you do not need is wax with a wick. The romantic-looking sticks drip unevenly and soot. For seals of consistent size, wax poured from a spoon is far more reliable.

Manufacturers give different figures for their wax, and with a spoon and a tealight you can't measure the temperature anyway. So go by what you can see: the wax is ready when it is completely liquid and behaves like thin honey when you swirl the spoon — not like syrup that pulls threads.

Too hot looks like this: the wax smokes faintly, throws small bubbles or darkens. It is then too runny, runs past the edge of the seal and dries matt and brittle instead of glossy. Take the spoon off the flame and wait ten seconds.

Too cool looks like this: lumps stay behind as you pour, and the stamp leaves an incomplete impression. Back over the flame, but briefly.

If you work with a glue gun, check what the tool states. Low-temperature guns at around 120 °C are made for sealing wax. High-temperature models run well above that and overheat it — recognisable by the same smoking and darkening.

The rule of thumb is three beads for a stamp with a 25 mm face. At two the seal turns thin and cracks more easily; at four it escapes from under the stamp and the edge goes ragged.

For a wedding with 80 invitations, then, count on about 240 beads — four to five packs. Add roughly ten per cent for the first attempts: practically everyone throws the first three away.

With the flexible sticks for a glue gun the dosing is a matter of feel: press steadily, count to three in your head, release. After five seals you have it.

Mixing colours

Two colours in one spoon give you a marbled seal. Do not stir them — pour as soon as both have melted, or they blend into a single flat tone. Gold or copper as the second colour over a dark base works particularly well.

The melting spoon has one advantage the gun cannot offer: you can see the wax. You can tell when it has the right consistency, you can marble colours, and you can stir in dried flowers or glitter along the way. A spoon holding 5 ml takes enough wax for two or three seals at once, and the heat-resistant wooden handle stays holdable.

The glue gun wins on volume. It holds the temperature steady, there is no reheating, and a seal takes seconds rather than a minute. The price: you cannot see what is happening, and changing colour means pushing the whole stick through.

One thing matters here. Only wax made expressly for it belongs in a gun, in the right diameter — ours is 11 mm across and 135 mm long. Classic sealing wax sticks are brittle, snap in the feed and clog the tool.

The commonest mistake in sealing is impatience. Set the stamp straight down onto the liquid wax, press lightly, and then do nothing. No wiggling, no turning, no lifting to check.

The seal is done when the outer edge has turned from glossy to matt. In a warm room that takes up to two minutes; by a window in winter, sometimes only one. Then lift the stamp straight up, not tilting.

Working in series, you want two or three stamps in rotation — or pour all the pools of wax first and then stamp them in order. The first has cooled enough by the time you reach the fifth.

It rarely happens on the first seals and regularly from the third or fourth: the stamp has warmed through and now holds the wax instead of letting it go.

Three remedies, in this order:

1. Let it cool. Rest the stamp on a cold tile or an ice pack between seals. Ten seconds will do.
2. Oil it, barely. A drop of cooking oil on a kitchen towel, wiped across the face. Too much oil dulls the impression — it should gleam, not glisten.
3. Two stamps in rotation. The tidiest solution for larger runs, because you need no pause at all.

What not to do: dip the stamp in water. It cools instantly, but droplets in hot wax leave small craters, and brass develops a patina over time.

This is the question that arrives after the first successful wedding invitation — and the answer is: plan for it rather than hope.

Flexible wax instead of classic. Brittle sealing wax breaks when it passes between rollers. Flexible formulations give and generally arrive intact.

Move the seal inside. You can also set the seal on a band or belly band that sits inside the envelope. The outside then stays flat.

Or send it as a large letter. A thicker envelope with a stiff insert protects the seal. Hand it in at the counter rather than dropping it in a box — they will check the format against the postage while you are there.

For anything that really must not go wrong, the tradesman's trick applies: post a test copy to yourself. It costs one stamp and a week, and it settles the question for good.