Wick Hole and Wick Channel Design in Silicone Candle Molds

The wick feature is often the smallest geometry in a candle mold and one of the first places to tear.

Why?

Because a wick hole or slit combines:

• repeated stretching;
• a sharp notch;
• wax leakage risk;
• operator pulling;
• local thin silicone.

Treat the wick path as a fatigue feature, not an afterthought.

There are several ways to create the wick path

1. Molded pilot hole

A small formed hole is built into the mold.

Good when:

• wick location must be repeatable;
• production volume justifies a defined feature.

Risk:

• thin surrounding silicone can tear if the hole is too small or sharp.

2. Wick pin / removable pin

A rigid pin forms a larger wick channel.

Good when:

• a straight central hole is required;
• the operator can remove/reinsert the pin reliably.

Risk:

• alignment and sealing become additional variables.

3. Piercing the silicone

A needle/awl creates or reopens the path.

Good for:

• simple artisan use;
• low precision requirement.

Risk:

• uncontrolled cuts can propagate.

4. Post-drill after demolding

The candle is drilled after release.

Good when:

• mold integrity is more valuable than molded wick access.

Risk:

• extra labor;
• wick position can vary.

There is no universal best choice.

A sharp slit behaves like a crack starter

If the operator cuts the wick path with a blade, the end of the cut concentrates stress.

Repeated opening can extend the cut into the mold body.

Useful controls:

• rounded termination;
• reinforced local section;
• controlled slit orientation;
• avoid placing the slit into another thin feature;
• inspect whitening before a visible crack forms.

A clean-looking new slit can still have poor fatigue behavior.

Hole diameter should be linked to the production method

The hole must balance:

• wick clearance;
• wax leakage;
• operator threading;
• pin removal;
• local silicone strain.

Too small:

• difficult threading;
• repeated stretching;
• tear growth.

Too large:

• wax leakage;
• oversized tunnel in the candle;
• wick centering issues.

Define the wick/pin system rather than guessing a hole size from photos.

Seal strategy matters during the pour

Depending on design, leakage can be controlled by:

• tight pilot hole;
• external putty/seal;
• plug;
• base fixture;
• wick holder;
• clamp.

The correct solution should fit the buyer's production method.

A wick hole that needs hand sealing on every unit may be acceptable for a premium low-volume line and unacceptable for scaled production.

Reinforce the wick zone without making demolding worse

Local reinforcement is preferable to globally hardening the mold.

Options:

• thicker base around the wick path;
• rounded transition;
• local boss;
• replaceable insert;
• support fixture.

The goal is to reduce strain at the notch while keeping the main cavity flexible.

Replaceable plug or pin can protect the silicone

For high-use molds, a sacrificial rigid or silicone insert can be designed so the most damaged wick feature is replaceable.

This is project-specific and adds assembly, but it can be useful when:

• candle shape is expensive;
• wick zone is the repeated failure point;
• the rest of the mold remains in good condition.

Prototype-cycle inspection should focus on the first 20-50 pulls

Do not wait until the mold tears completely.

Inspect:

• whitening;
• slit growth;
• rough cut edge;
• hole elongation;
• leakage;
• base distortion.

Track whether the same feature changes with each pull.

If the failure starts immediately, it is a geometry/process issue, not normal aging.

Wick location can interact with the parting line

Avoid combining:

• wick hole;
• main mold seam;
• thin flange;
• vent/gate

in the same small area if possible.

Too many functions in one zone create a complex stress concentration and leak path.

Current RUUIPON cleanup

The candle product page and old candle guides already mention wick holes, but only briefly.

P56 should become the dedicated wick-design article.

Generic candle pages should link here and remove fixed "pin-size" or "always do X" rules.