We often get asked, "What is the difference between Grade R & Grade T Twin Welding Hose?" Here we have taken the time to make a distinction between the two for everyone to see.
It is designed & recommended for acetylene gas & oxygen. Up until 15 years ago or so it was the only grade of twin welding hose available. It is not recommended for use with lp, propane, natural gas or propylene. The reason it is not recommended for propane is that the oils in propane will eventually dry rot the hose. This generally takes about 1 year to happen. The hose will appear cracked on the surface & lose pliability. This can be a very unsafe situation that requires immediate replacement of the hose. It's not like the Grade R hose will be unsafe from the start but its' life will be shorter. The longevity of the hose matters to some cutters & welders while to others it doesn't. Grade R twin welding hose is less expensive & that makes all the difference for some users. Their hose often doesn't last a year regardless of the grade.
Grade T twin welding hose is specially designed for alternate fuels such as lp, propane, natural gas & propylene. However it can also be used with acetylene. It is more expensive than Grade R because it is made to resist the effects of the oils in propane. Although Grade T can be used for "All Fuel Gases", it is recommended to change the hose when switching between acetylene and alternate fuel gases. This is because of the residual oils from the propane lodge themselves into the pores of the hose.