Welding Tips and Tricks

Bought this torch kit second hand and it advertised having reverse flow check valves. I already bought a flashback arrestor kit and was wondering if the arrestors are needed.

Welcome to the forum Juliano-R.
Yes you should have both - the check valves on the torch really only prevent intermixing of gasses due to large pressure differentials & help prevent hose damage due to high pressure shocks caused by a flash back - the flash back arrestors prevent a flame traveling back up the pipe to the regulator & causing damage or even getting to cause burn back into the cylinder - the better ones will shut off the gas even after a small " pop " until reset - only after seeing a cylinder on fire does the cost of buying flash back arrestors seem cheap !

I would call the manufacturer and see what they recommend. Some manufacturers specifically say not to use both because these devices cause flow restrictions which can increase your risk of a backfire or flashback.