When aluminium castings stick or drag on ejection, the die usually needs a fresh, thin release film on a clean surface. Micron 1160 Aluminium Die Cast Release Agent is a silicone-based release spray formulated for aluminium die-casting; Micron 1168 is the same type of release as a 5 L liquid for sprayer use. For a longer-lasting non-wetting coating on die-casting moulds, extrusion dies or forging tools, Micron 2138 CeraCoat Z is the boron nitride option.
Why it happens
Molten aluminium bonds readily to an unprotected die surface. The common causes are:
- Release film insufficient or burnt off. Each shot strips some film, and at die temperatures it can burn off quickly.
- Deposits on the die surface. Build-up gives aluminium a rough surface to bond to.
- Die temperature and alloy conditions. A die running too hot, or a change of alloy, makes soldering more likely.
You will see castings sticking or dragging on ejection, aluminium build-up or soldering on the die surface, and a poorer casting finish.
How to fix it
Pick by how you apply it:
- Spot application, small dies or maintenance: Micron 1160, the 550 ml aerosol.
- Line use with a sprayer and larger volumes: Micron 1168, the 5 L liquid version of the same silicone-based release.
- A longer-lasting high-temperature non-wetting coating rather than a per-shot release: Micron 2138 CeraCoat Z. Its page says it prevents molten metals such as aluminium, zinc and copper from wetting treated surfaces, and lists die-casting moulds.
Directions from the 1160 page:
- Make sure the die surface is clean, dry and free from excessive deposits.
- Shake the can well.
- Hold the can about 20–30 cm from the die and apply a light, uniform coat over the required areas. Avoid excessive application.
- Let the release film settle and flash off before casting.
- Reapply as required during production. Use the minimum effective quantity.
Micron says to set the spray frequency and quantity according to die design, alloy, casting conditions and production cycle. For 2138, follow the surface preparation and drying guidance on its page and TDS.
What to avoid
- Avoid excessive application of release. More is not better; it can build up on the die and affect the casting surface.
- Do not apply 2138 on oily or rusty surfaces. Its page says the substrate must be clean, dry and free from oil, grease, rust, dust, paint or lacquer.
- 2138 is water-based. Let it dry completely before any contact with molten metal, and ask Micron for drying guidance on your die.
- 1160 and 1168 are silicone-based. If castings will be painted or powder coated, check with your finishing line before relying on them.
When to ask an expert
Ask a die-casting process engineer if:
- soldering or sticking persists with a clean die and a fresh film;
- sticking started after a change of alloy or die temperature;
- the die surface is eroded, cracked or damaged.
These are die temperature, alloy or die-coating issues that a release agent alone will not fix.
FAQ
What is the difference between 1160 and 1168?
Both are silicone-based releases for aluminium die-casting with the same directions. 1160 is a 550 ml aerosol; 1168 is a 5 L liquid applied with a sprayer.
When should I use a boron nitride coating instead of a release spray?
When you want a longer-lasting coating on die-casting moulds, extrusion dies or forging tools rather than a film reapplied during production. 2138 states up to 900°C in air. Ask Micron if your process is close to that.
How much release should I spray per shot?
Micron does not give a fixed amount. Its page says to use the minimum effective quantity and set the frequency by die design, alloy, casting conditions and cycle.
Will the release affect painting the castings?
1160 and 1168 are silicone-based. Micron's pages do not discuss painting. If castings go to paint or powder coat, test a batch through your finishing line.
See the products: Micron 1160 Aluminium Die Cast Release Agent and 1168, 5 L. Related: 2138 CeraCoat Z. More moulding fixes: moulding hub.