Moulding, Casting & Artificial Stone · Solve a Problem

Casting and cast stone defect troubleshooting

Start from what you can see on the part, not from what you think the cause is. Each symptom below opens the checks in the order a shop can actually run them — cheapest and most reversible first, formulation last. Change one variable at a time, and prove it on a test patch before it reaches a production run.

Start from the defect you can see

One symptom at a time. The checks are ordered so the cheapest, most reversible test comes first.

What is the part or mould doing?

Pick a symptom above. This page does not guess a cause without an observed defect, and it will never tell you that a change is safe for your production run.

Use this when

A mould rubber has stayed tacky or liquid against the master and you need to know whether it is contamination or ratio.
Cast faces are coming out with pinholes, bubbles or a porous skin.
Parts are crazing, cracking or hazing in the hours or days after demould.
Parts are sticking, tearing the mould face, or the release is building up on the tooling.
Colour is mottled, streaked or drifting between batches.

How this works

1. Pick the symptom you can see. There is no diagnosis without an observed defect.
2. Work the checks in order. The first checks are the ones you can reverse in a single test pour.
3. Change one variable per test. Two changes at once destroy the evidence.
4. Record what you changed and what happened, so the next defect starts from data instead of memory.
5. Read every branch as a list of candidates to investigate — never as an instruction for your process.

What this page does not determine

It does not diagnose your specific failure remotely. It orders the checks; you supply the observation.
It does not set ratios, doses, cure schedules or process parameters — those come from the product data sheets you hold.
Nothing on this page is a structural, strength, durability or code-compliance statement. Cast stone, precast and GFRC elements that carry load, span, or form part of a building envelope are engineering work and belong with a qualified engineer.
It does not guarantee that any branch fixes the defect, and it makes no cure, finish or tooling-life guarantee.
Verify on a test patch or a sacrificial part before you change anything on a production run.

Relevant Allzone products

These are catalogue identities relevant to investigate. A listing here is not a recommendation to use the material in any process, and it is not a suitability, performance or compliance claim.

Ask for a quotation or a specification

Where this comes from, and what it cannot tell you

Supplier technical data sheets for RTV silicones, casting resins and release agents
Supports: Which cure systems are inhibition sensitive, and which variables a manufacturer states as controllable.
Limitation: Data sheets describe a specific product under the manufacturer's test conditions, not your shop, your master or your ambient conditions.
Manufacturer-specific · Always read the current revision of the sheet you hold
Allzone catalogue specification data for the 105 live moulding and casting identities
Supports: Which material families exist to investigate against each symptom.
Limitation: A catalogue identity is not a diagnosis and not a recommendation for your process.
Canada · Maintained with the live catalogue
Recurring failure language observed in category search behaviour (W0 Search DNA, 24 axes)
Supports: Which five defects dominate how casting shops actually describe their problems.
Limitation: Search language shows what people ask about; it is not evidence of the cause in any individual case.
Global search behaviour · W0 audit, 2026-08-22