PCTG outperforms PETG on impact resistance, flexibility, and heat tolerance. Igor Gaspar of My Tech Fun tested both transparent filaments from the same manufacturer side by side, making this one of the cleaner direct comparisons available.
The chemistry is the deciding factor. PETG replaces less than half its glycol monomers with CHDM. PCTG replaces more than half. That shift past the 50% threshold produces a meaningfully different material: higher ductility, better thermal resistance, and impact properties that PETG cannot match. The tradeoff is print temperature, which climbs into ASA territory.
The original piece is worth reading for the molecular-level breakdown of PET polyester modification and the specific test results on springs and compliant mechanisms. If you print functional parts that live in hot or high-stress environments, this comparison reframes what your filament choices actually are.
[READ ORIGINAL →]