gas pressure settings

Date 07-17-2007 22:41

hi everybody. im a little confused on my argon pressure setting. i currently run 20 cfh for 16 thru 20 gauge mild steel. i have all the different size tungstens to work with. i dont seem to have any problems with this setup but, i have heard of people running as little as 7 cfh. is there a table that will tell you how much for what and where? also is there a difference between mild steel and cold rolled steel? i hear these two terms alot and dont see the difference. thanks for any help.

By DaveBoyer (*****)

Date 07-18-2007 03:38

Mild steel/cold rolled steel: Mild steel is a term refering to steel with a low carbon and insignificant alloy percentages, while cold rolled steel refers to the finish rolling of the material being done cold rather than at red heat. Cold rolled steels could have up to about 40 point carbon, altho most are much lower, generally 5 point to 20 point.

By Tommyjoking (****)

Date 07-18-2007 08:42

Hello rtnnhazel!

Basically you can turn you gas lower or higher dependant on the size cup your using and the amperage.....for the gauges you are describing you could run a #4 cup with a .040 or a 1/16 tungsten as low as say 10 in a nice (still air) envoirment. I am presuming you are using a 98-100% argon with your setup. If you were using a #6 cup I would bump it up to 15 or so. Basically a good rule of thumb is if you are not getting a lot of carbon buildup on top of your weld and you are not seeing it start to burn (turn bright red, throw sparks, boiling) then you have enough gas shield. Too much gas flow can actually be harmfull ....it can cause enough turbulence to actually pull oxygen over your weld puddle. 10-15 cfh will give you quite a bit of welding time on a full size bottle.....

By rtnnhazel (*)

Date 07-18-2007 21:27

sorry i left that info out. i am running an htp dc/hf 130 amp. i use the gauge with the ball in it, i believe it is a flow meter? i have never used the alumina cups that come with my machine, i have always used my pyrex setup, which works great.i also run 100% argon

By Sourdough (****)

Date 07-19-2007 01:21

Take into consideration that if there is a breeze from the shop door being open or from a swamp cooler, you need to crank up the gas to compensate.