How do you correctly mix expanded polyurethane resin?

Step-by-step mixing process

Start by measuring each part exactly to your resin’s specified ratio. For example, Polyform Polyurethane Casting Resin uses a 90:100 ratio by weight for component A to B. Always use a digital scale for accuracy. Combine the two parts in a clean mixing container, then blend them quickly but thoroughly. Polyurethane resins react rapidly, so you have only a short working window—mix briskly to a consistent blend before pouring.

Practical tips for success

• Prepare your workspace: Lay out all tools and materials before starting, as timing is crucial.
• Stir efficiently: Avoid slow stirring, which can cause partial curing or bubbles. Scrape the sides and base of the container for an even mix.
• Mind the temperature: Only use polyurethane resin above 8–10°C. Lower temperatures risk incomplete curing.
• Safety first: Wear gloves and eye protection during mixing and pouring. Once cured, the resin is safe to handle.

When precise mixing matters

Correctly proportioned and blended resin is key for applications requiring sharp details, such as rapid prototyping, moulded parts, or decorative coatings. Inaccurate ratios or incomplete mixing can result in soft spots, defects, or failed cures.