Smooth-On XTC-3D 3D Print Smoothing Epoxy — 6.4 oz Clear, Self-Leveling High-Gloss Coating

Smooth-On XTC-3D™ is a two-part, clear epoxy coating formulated to smooth, seal, and create a hard, impact-resistant finish on 3D printed parts and other rigid substrates.

Designed for makers, prototypers, and small-scale manufacturers, XTC-3D™ provides a low-viscosity, self-leveling surface coat that fills layer lines, wets out detail, and cures to a durable, high-gloss finish. It works across a wide range of printing processes and materials — including SLA, SLS, PLA, ABS, Laywoo, and powder-printed parts — and delivers an 80D Shore hardness once fully cured. With a 2A:1B mix ratio by volume and about 10 minutes of working time, it’s built to be efficient for small batches and touch-ups while providing excellent coverage and resistance to impact.

How does XTC-3D™ improve the look of 3D prints?

XTC-3D™ smooths visible layer lines and creates a continuous, glossy surface that highlights detail while minimizing sanding. Its self-leveling formulation reduces brush marks and flows into recessed areas to produce a uniform appearance.

• Fills and conceals layer ridges for a cleaner finish
• Self-leveling to reduce brushing artifacts
• Clear gloss enhances colors and painted finishes
• Compatible with many common print materials for wide use

What are the application and cure times I should expect?

Mix at a 2:1 ratio by volume and work quickly: the mixed epoxy gives about 10 minutes of usable pot life depending on temperature. It reaches a hard, impact-resistant state in roughly 3.5 hours, though full mechanical properties develop over longer ambient cure times.

• Mix ratio: 2 parts A to 1 part B by volume
• Working time: ~10 minutes at room temperature
• Initial cure to handleable hardness: around 3.5 hours
• Post-cure properties increase with extended room-temperature cure

Which printing materials and part types are best suited for this epoxy?

XTC-3D™ adheres well to rigid substrates commonly used in additive manufacturing, including SLA and SLS resins, thermoplastics like PLA and ABS, Laywoo, and powder-printed objects. Because surface chemistry varies, a small test on the intended material is recommended before coating a final part.

• Compatible with SLA, SLS, PLA, ABS, Laywoo, and many rigid media
• Not intended for extremely flexible or highly porous substrates without testing
• Perform a small-scale compatibility test before full application
• Technical bulletin available on the Smooth-On website for specifics

How should I apply XTC-3D™ for best results?

Apply with a brush, squeegee, or pour method to allow the epoxy to self-level and wet out surfaces uniformly. Work in thin, even coats and monitor pot life — thicker pours increase heat and shorten working time.

• Stir components separately, then combine and mix thoroughly
• Apply thin, even coats to avoid excessive exotherm and runs
• Use gloves and eye protection; work in a ventilated area
• Sanding between coats can help with adhesion for multi-coat builds

Who is this for: XTC-3D™ is ideal for hobbyists, professional model-makers, product designers, and small production shops that need a reliable, clear topcoat to smooth and strengthen 3D printed parts. It’s particularly useful when you want a fast-curing, high-gloss finish that preserves fine detail and improves impact resistance. Before committing to a final piece, test your specific substrate and follow the Smooth-On technical bulletin for optimal mixing, application, and safety guidance.