Gas Flow

[redmule1154]

With tig welding what happens when welding thin Ga. sheet metal (16 ga S/S) and the gas flow is to high? Also just the opposite of that if the flow is to low. What kind of an appearance on my bead will tell me that the flow is incorrect? I see that for the above material some say 15Cfh and some say 20 cfh. I would think more is better than less. Thanks.
Redmule1154

[Azphiks]

gas flow

Thin material will require a backing gas or tape. This will prevent a sugaring or porosity, ruining any strength in the weld. However, up to 40 lbs gas out of the tig torch will only protect your weld better from oxidation.
On a side note, keep moving. Experience will tell you if your travel rate is appropriate. Look to see a pink or blue to the metal that wipes off easily. Any black is an indicator. Good luck

[Azphiks]

whoops

sorry, the 40 lbs should says Cfh as you noted

[shovelon]

More is not always better. Too small a nozzle, with too much gas will cause a venturi effect at the orifice of the nozzle. Aside from just wasting gas, you risk pulling air into the gas stream.

Any more than 20 cfh is too much imo for 16 ga.

Any less than 5 chf is too little imo.

Gas lenses always save money.

[duaneb55]

Rule of thumb - 1cfh per 10A outout although I rarely go below 10cfh regardless.