Smooth-On Smooth-Cast 325 liquid plastic resin, Clear Amber 862 g — fast-cure, 1:1 mix

This one-to-one, easy-to-pour casting kit cures quickly and is built for projects that require predictable colour results, fine detail, and a moderately hard finish. Smooth-Cast 325 was formulated to accept small amounts of colorants and metallic powders with minimal influence from the base resin colour; that makes it especially useful for marbling, faux metal finishes, and colour-true castings. With a short pot life and fast demold, it speeds production for small-to-medium sized parts while delivering a Shore D hardness around 72.

How fast does Smooth-Cast 325 work for quick-turn projects?

The system is optimised for speed: you get roughly a 3-minute pot life and parts can often be demolded in about 10 minutes, depending on ambient temperature and part size. That rapid schedule reduces wait time and increases throughput for repeated pours.

• Mix ratio: 1:1 by volume for simple measuring and less waste
• Pot life: ~3 minutes for quick mixing and pouring
• Demold time: ~10 minutes under typical conditions
• Cure sensitivity: faster in warm environments, slower in cool

What finishing and aesthetic options can I achieve with this clear amber resin?

Because Smooth-Cast 325 is formulated to be colour-neutral, it accepts pigments and metal powders without significant colour shift from the base resin. This makes it ideal for creating marble or wood-grain effects, translucent amber tones, or metallic-looking castings when combined with bronze/brass powders.

• Use Smooth-On SO-Strong pigments for bright, accurate colours
• Add metal powders to simulate bronze, brass, and other finishes
• Create layered pours or marbling with small pigment amounts
• Clear amber base preserves translucency and enhances depth

What are the key mechanical and handling properties I should expect?

Once cured, the material has a mixed viscosity around 100 cps and a Shore D hardness approximately 72, giving a firm, dimensionally stable part suitable for many display, prototype, and small production uses. The low-viscosity mix pours easily into detailed moulds but requires timely mixing and pouring due to the short pot life.

• Mixed viscosity: ~100 cps for good mould flow
• Hardness: ~72D for a firm, durable surface
• Pouring: low viscosity helps capture fine detail
• Mixing: precise 1:1 ratio by volume reduces measurement errors

Who this product suits: Smooth-Cast 325 is aimed at hobbyists, prop makers, prototype fabricators, and small-batch manufacturers who need a fast-curing, pigment-friendly casting resin. It’s especially helpful when accurate colour matching or translucent effects matter—such as decorative items, small sculptures, model parts, or faux-metal finishes. Always work in a well-ventilated area, follow recommended safety procedures, and review the product MSDS on Smooth-On’s website before use.