Question

post-test
what gas is used to shield the plastic weld from carbon contamination?
a. argon
b. helium
c. oxygen
d. nitrogen

Explanation:

In plastic welding, nitrogen is commonly used as a shielding gas to prevent carbon contamination. Argon is more used in metal welding, helium has different shielding applications, and oxygen would promote oxidation/contamination. So the correct option is D.

Answer:

D. Nitrogen