Smooth-On XTC-3D 20 Mold Making & 3D Print Coating - Clear Finish

In this review the Smooth-On XTC-3D 20 is evaluated as a dedicated clear top coat for smoothing and finishing 3D printed parts. The bottom line: it is best for hobbyists and small shops who need a fast-curing, self-leveling epoxy that hides layer lines and leaves a hard, glossy surface. The reviewer found the 2A:1B by volume mix and roughly 10 minute working time straightforward for small parts, and the cured 80D Shore hardness gives a noticeably impact-resistant finish that reduces post-processing for many rigid prints.

Key Features

• High-performance 3D print coating: Delivers a clear, glossy surface that smooths layer lines on SLA, SLS and fused filament parts for a cleaner final look.
• Wide material compatibility: Works on PLA, ABS, Laywoo and powder printed parts so a range of rigid media can be finished with one product.
• Practical mix ratio and cure: The 2A:1B by volume mixture and 10 minute working time suit small to medium projects and cures to a hard coating in approximately 3.5 hours.
• Self-leveling epoxy: Wets out uniformly and minimizes brush stroke marks, which simplifies finishing for users without spray equipment.
• Durable finish: Cures to about 80D Shore hardness, producing an impact-resistant top coat for parts that see handling or light use.

Who It's For

The XTC-3D 20 is aimed at makers, prop builders and product prototypers who need a reliable clear top coat to conceal print artifacts and provide a glossy, tough surface. It suits those finishing SLA and SLS parts as well as common filament materials like PLA and ABS.

It is less suited to large-volume industrial production where long pot life or automated dispensing is required, and anyone working with flexible or highly heat-sensitive substrates should perform a small-scale test first to ensure compatibility.

Pros & Cons

Pros

• Provides a smooth, glossy finish that noticeably reduces visible layer lines on rigid prints.
• Self-leveling formulation covers evenly and often removes the need for heavy sanding between coats.
• Reasonable working and cure times for quick turnaround on small projects.

Cons

• Short working time can be challenging on larger pieces or for less experienced users.
• Some users report stickiness or compatibility issues on certain surfaces, so test pieces are recommended.

Specifications

Our Verdict

The Smooth-On XTC-3D 20 is a practical, value-oriented clear coating for anyone finishing rigid 3D prints who needs a glossy, impact-resistant surface quickly. It is especially useful for hobbyists and small shops that want to cut sanding time and produce a professional-looking finish, provided users respect the short working time and test for stickiness on unfamiliar substrates.

Frequently Asked Questions

Can this be used on PLA and ABS?
Yes, the formula is intended for PLA and ABS as well as SLA and SLS parts, but perform a small-scale test to confirm adhesion and cure behavior.

How long does it take to cure?
The product has about a 10 minute working time and typically cures to a hard coating in roughly 3.5 hours.

Will it leave brush marks?
The epoxy is self-leveling and designed to wet out uniformly to minimize brush strokes, though careful application helps on visible surfaces.