Understand the starting colour first
The phrase yellow GP resin can describe two different situations: a grade that is intentionally supplied transparent yellow, and a GP Clear Resin batch that appears different from the expected clear appearance. These should not be treated as the same issue. Start by confirming the product name, ordered grade and the appearance stated for that grade.
When GP Yellow Resin is the intended grade
Samrat Poly Resins publishes GP Yellow Resin as a transparent-yellow, general-purpose orthophthalic polyester grade. When that is the ordered product, its colour is part of the published grade description rather than evidence of a defect. The selection question is whether the colour is suitable or will be hidden in the finished FRP build-up, alongside the product’s published processing data and intended application.
Common reasons a clear grade may look different
Resin condition can be affected by storage and age. Existing storage guidance highlights heat, direct sunlight and a poorly sealed container as factors that can affect stability and appearance over time. A visible change may also arise from handling or contamination in the process, so colour alone is not enough to identify the cause.
Do not judge a batch only by visual appearance. Compare the batch details with the expected product, review the storage record and check the applicable TDS before committing it to a production run.
Prevention and purchasing checks
Keep drums sealed when not in use, protect them from direct sunlight and heat, and rotate stock by batch date. When appearance matters in the finished part, include that requirement in the original product discussion rather than assuming every GP grade has the same colour characteristics.