ASA Filament — The Ultimate Outdoor Material

ASA (Acrylonitrile Styrene Acrylate) is the outdoor champion of 3D printing filaments. If you’ve ever left an ABS print in the sun and watched it yellow and crack, ASA is the solution.

ASA vs ABS: What’s the Difference?

Both are styrene-based thermoplastics with similar mechanical properties — high strength, good impact resistance, and heat tolerance up to ~95°C. The crucial difference: ASA replaces ABS’s butadiene rubber with acrylate rubber, making it:

• UV-resistant: Doesn’t yellow or degrade in sunlight
• More weather-resistant: Handles rain, temperature swings, and outdoor exposure
• Slightly more dimensionally stable: Less warping than ABS (but still needs an enclosure)

When to Use ASA

ASA is the right choice when your part needs to live outdoors:

• Car accessories (brackets, mounts, grille inserts)
• Garden tools and planters
• Outdoor sensor housings
• Drone and RC parts
• Bike accessories
• Anything left in a hot car (PLA will melt, PETG will deform)

Printing ASA: The Hard Parts

ASA is not beginner-friendly. You must have:

1. An Enclosure

ASA warps aggressively if cooled too quickly. An enclosure keeps ambient temperature stable at 35-45°C during printing. Without one, expect prints to peel off the bed mid-print.

2. Ventilation

ASA emits styrene fumes during printing — the same reason ABS smells bad. Print in a well-ventilated space or use an enclosure with a filter. Don’t print ASA in your bedroom.

3. Bed Adhesion

ASA sticks well to PEI sheets at 90-110°C. For extra insurance on large flat parts, use a PVP-based glue stick or a dedicated ASA slurry.

4. Slow Cooling

Turn off your part-cooling fan entirely for the first 3-5 layers, then run it at 10-20% maximum. ASA likes to cool slowly and evenly.

Recommended Brands

Brand	Price	Notes
Prusament ASA	$30-35/kg	Premium, consistent, worth the price for critical parts
Polymaker ASA	$20-25/kg	Great value, wide color range
eSUN ASA	$15-20/kg	Budget option, works well but color consistency varies

Post-Processing

ASA can be vapor-smoothed with acetone, just like ABS. A 15-30 minute acetone vapor bath produces a glossy, injection-molded-looking finish. ASA also sands well and accepts paint readily.