Labels on a container that gets hot

A candle label has to survive heat, and it has a required statement that makers often do not know about.

Two constraints at once

A burning candle warms the glass, and a warm surface is where adhesive fails. A label that sat flat for six months on a shelf can lift after three burns.

And it is a container that gets handled while warm, so fingers are working at the edges.

So this needs a stock and an adhesive rated for the application, not a general-purpose paper label.

Placement

The front label goes below the fill line, so it is never directly against the melt pool. A label across the hottest band of the glass is the one that lifts and, worse, is combustible material inside the zone the standard cares about.

A base label carries the safety statements, which is the category convention and keeps the front clean for the brand.

Check the label does not obscure the wax level entirely, since that is the customer's own cue about when to stop.

Adhesive and surface

Glass takes adhesive well when clean and dry. Wax film, dust and fingerprints all defeat it.

Tin is harder: a curved, smooth, cool-to-the-touch metal surface with a seam. Ask the printer for a stock rated for metal.

Test by burning a labeled candle all the way down. That is the only test that matters and it is already part of your burn test.

What the base label carries

The ASTM F2058 fire safety labeling: a safety alert symbol, WARNING in bold uppercase, and three fire safety statements. "Burn within sight" must be text; the other two may be pictograms.

And if the candle uses a metal-cored wick, the outer container or wrapper must carry "Conforms to 16 CFR 1500.17(a)(13)". That one is not voluntary.

References