tig welding

ive been playing around with my tig torch lately. its a strike to arc its what came with my mig. my question is, im getting pinholes along my weld is this due to the grinding wheel residue left on the steel or am i doing something wrong

Pin holes are also known as "porosity".... Porosity is caused by not having enough cover gas flowing through the torch... try turning up the gas pressure....you should be running somewhere in the area of 15-20 lbs. of argon through the torch head..

and if your still getting porosity after you have sufficient gas coverage then your metal is probably contaminited with something such as cutting fluid maybe or its just been sitting in grease for a long time... make sure you grind off the mill scale before welding...

the metal has been sittin for a while but its not rusty or anything im actually runnin like 40 psi should i turn it down

as long as the meatl is clean and down to bare metal.. it should be fine unless like i said its had some kind of fluid on it the has gotten into it....40 psi is a little excessive your just wsting gas like that.. but i would try turning it down.. other than that i have no idea why you would be getting porosity.. grinding disk shouldnt be depositing anything into the metal.. you could try a new disk..

yea man resharpen your tip with a wheel or disk that hasnt been used on any other metal.... it keeps the tip cleaner because the disk will deposit other metal types if it was used on anything else.

are you running 40 psi or cfm? i usually run about 30-35 since we normally have a fan pushing air through the shop and all the doors open, but we have been known to crank it up to 50 cfm pipe welding to try and fight air or water coming out..... if you are in a closed room, you could run 20 cfm with no probs... take a pic of the weld and i should be able to tell you if its the welder/setup, or the material...

Edited: 9/1/2007 4:45:08 PM by BioMax

I'm seeing some red flags here...

First off, too much gas flow can cause problems. You should keep the gas flow as low as possible without having a breeze trash your weld. Too much gas will actually create a vortex and pull oxygen into the mix.

Second, the tungsten should only stick past the end of the cup by half of the width of the cup. IF the cup is 1/2" across, the tip should be no more than 1/4" past the tip.

Third, How many of you use cold rolled steel when you build? I would be willing to bet that 72layinrocker is using hot rolled steel and not grinding the grey slag off of the top of the metal. That slag is just dirt, as far as the TIG is concerned.

And lastly, make sure that your rod is clean. You can usually tell if it is dirty just by looking at it, but sometimes you will need to wipe it down real good before use.

If after all of this you still have problems, then I don't know what to tell you.

i am using cold rolled this is the type with the oil on it and not the coating that you would actually have to take down right? at least i think im using cold rolled if im not please tell me its just 1 inch 095 wall mild steel

Yeah, that should be cold rolled. TIG wants the metal to be super clean, use lacquer thinner or alcohol to clean the metal and the filler rod and see if that helps any.

one thing we've found that works great is brake cleaner from oreillys since its chlorine free, it wont leave that residue that will make you sick when it burns like std brake cleaners....