Only one maker we read names 3D print plastics: Smooth-On, whose XTC-3D coating lists PLA, ABS and PETG and can then be primed and painted. The spray paint and primer makers we read (Rust-Oleum, Krylon, Zinsser, Sherwin-Williams, Benjamin Moore) don’t name PLA, PETG or ABS, so a plastic primer on a print is a test-first job. For plastic primers, see paint for plastic.
Smooth-On XTC-3D
Smooth-On calls XTC-3D “a protective coating for smoothing and finishing 3D printed parts. Two liquids are mixed together and brushed onto any 3D print.” Its technical bulletin says “It works with PLA, ABS, PetG, Powder Printed Parts and other rigid media” and “It does not melt plastic.” The product page lists Laywoo where the bulletin lists PETG, and adds SLA and SLS prints.
- Working time: 10 minutes.
- Cure: one layer cures tack free in about 2 hours at 73°F, the page says, and mild heat (150°F) cures it in 15 minutes, but “some 3D print media will melt at temperatures above 200°F.” The bulletin gives 3.5 hours for a thin layer; the page says about 4 hours.
- Then paint: “XTC-3D™ can be painted and/or primed and then painted with acrylic enamel paints. For best results, lightly sand surface prior to painting.”
Plastic primers on prints: none of these makers names PLA
| Product | What the maker names | Test line |
|---|---|---|
| Rust-Oleum Specialty Plastic Primer | “polypropylene, polystyrene, resin, PVC, fiberglass, and vinyl plastics” | Polyethylene: “Test paint in a hidden area first.” |
| Krylon Bonding Primer with Fusion Technology | “Plastic” | None printed |
| Krylon Automotive Self Etching Primer | “hard plastics” | No test line |
| Sherwin-Williams Extreme Bond | “Plastics” | “a coating or coating system must be tested for acceptable adhesion” |
| Benjamin Moore INSL-X Stix | “plastic” | “Always test questionable substrates such as plastics” |
From each product’s data sheet or page. None of them names PLA, PETG or ABS, so we’d prime a scrap print or a hidden spot first.
The filler primers we read don’t list plastic
If you planned a filler or sandable primer, note what the makers list. Rust-Oleum’s Filler Primer and 2 in 1 Filler & Sandable Primer are for “metal, wood and fiberglass surfaces.” Krylon’s Automotive 2-In-1 Hi-Build names “metal, fiberglass, & wood,” and its Sandable Primer “metal, wood, and fiberglass.” None of those lists plastic.
Smooth-On says mixed XTC-3D “is exothermic, meaning it generates heat. A large, concentrated mass of mixed material in a container can generate enough heat to melt a plastic cup, burn your skin or ignite combustible materials.” Wear a NIOSH approved respirator when sanding the cured coating, it says. Its SDS lists, for Part A, “H315 Causes skin irritation”, “H317 May cause an allergic skin reaction” and “H319 Causes serious eye irritation”; Part B carries its own, stronger hazard lines, so read the SDS for both parts before you mix.