[WSeaWelder]

I'm a relatively new welder working on a little table frame using 1.5" tubing (0.12" thickness). I'm running into an issue where sometimes I'm getting holes in my welds and I have no idea why:

IMG_20180704_083513785.jpg (39.71 KiB) Viewed 2906 times

IMG_20180704_083545907.jpg (38.08 KiB) Viewed 2906 times

Other relevant details:
+ I'm using 3/32 7018 electrodes that I do not store in an oven but...
+ When using the same electrodes on 1/8 plate I have no such issues
+ Using a 200st Everlast machine set at 70amps
+ Welding in Seattle where it's around 60% humidity
+ I run a harbor freight portable ventilator when welding to extract the fumes (have tried turning it off to no avail)
+ For the joint in the images above I apply a little vertical zig zag motion (I'm not running a straight bead)

Any ideas/tips/suggestions for why this is happening and how to prevent it would be greatly appreciated!

[Demented]

If I had to guess I'd say you're not holding a tight enough arc. Long arcing 7018 will lead to porosity quite quickly. How's your rod angle?

[Otto Nobedder]

A second guess is what may lie on the back side of the tubing. Clean it inside and out.

Steve

[Poland308]

Yeah that looks like oil contamination from the back side.

[Coldman]

Judging from all the BB's you have there I'd suggest more attention to:
- keep a short arc
- rod angle, 45 degrees up and almost straight in, very little drag angle, 10 degrees max.
- try a straight bead (no weaving)

If none of the above helps, the rods are not coping with whatever contamination is on the backside. 7018 usually cope with some gunk, maybe it's bad gunk.

[Ant428]

My guess would be that your long arcing in the beginning and then holding tight after a few seconds. Looks like the porosity is only in the beginning of your weld. When you strike your arc, try not to long arc too much. Once you start the weld, hold tight. If your having trouble, then try holing tighter than you think is ok (works for me).

Id guess its not porosity from the back side. Chances of you burning all the way through on that tee joint is slim IMO.

Let me know if this worked.

[E T]

7018 is prone to porosity at the start. Start a bit further in the joint and longarc a little bit back to the beginning to heat up the electrode and base material. Then keep a short arc en weld over the start to burn out the start porosity.

Eric

[Louie1961]

Actually, failing to long arc at the beginning of the weld will cause porosity. Lincoln recommends you long arc a second or two to get the rod up to temp. I usually do this by striking my arc head, and in the path of the arc bead, pause a second then back up to the beginning of the weld a only then close up the arc gap. I am not saying it is your problem here, but it could be contributing to it. Have a read of this item explaining the issue from Lincoln.

https://www.lincolnelectric.com/en-us/s ... etail.aspx

[tweake]

thats a good point.
i usually long arc it to start with because by the time i scratch it i'm a distance away from where i want to start welding. so i have to long arc it to keep it lit while i move it into position.

also this is where using a file on the tip is a bit better than tapping the rod. if you chip a chunk of flux off its really hard to start or even weld at all. with the file you can get a nice flat face on the rod and it starts really easy. just don't earth the file