Consider the wipes you are using; cotton, synthetic,or paper? All of them are hydrocarbon based. The lint adhering to the filler metal or the base metal is a source of hydrogen.
I didn't mention it in my last post, but one could break open an area containing the porosity. If the interior surfaces of the pore holes are silvery, hydrogen is most likely the problem. If the porosity is discolored, shielding gas or surface contamination could be the issue. Hoses, connections, etc. need to be checked for leaks. If the hoses are old, they can have small leaks that could aspirate air into the system.
Check the filler metal to ensure the surface is clean and free of drawing lubricants. Reputable suppliers put their filler metals through a cleaning process to remove the lubricants. Some suppliers "scrape" the surface of the filler metal before packaging to ensure it is clean.
Make sure the filler metals are stored properly. They must be kept clean. Store the filler metals in a closed cabinet and place the unused and partially used spooled filler metal in the plastic bag and then back into the cardboard container to keep it clean. Rods should be stored in a plastic sleeve to keep it clean. Storing the filler metals in the welding booth, on the wire feeder,or in open cabinets is an invitation to contamination. I cannot tell you how many times I see spools left on the wire feeder in the open, uncovered for days at a time. Considering the grinding and if working adjacent to a machining center, the oily mists in the air, it isn't that difficult to see how the filler metals get contaminated.
Keeping a spool of filler metal covered while it is mounted on a wire feeder isn't that difficult. I use the same cardboard container it was shipped in. I cut a slot in the side of the box so it can be slipped over the spool. Presto! Instant spool cover and it free!
I do not allow more than one type of filler metal to be in the welding booth. Stored filler metals in opened containers exposes it to the shop environment; contaminated air containing oily mists and dust. Also, multiple filler metal types (classifications) stored in the welding booth increases the potential for the inadvertent use of the wrong filler metal.
I was in one shop teaching the welders to weld pipe using GMAW when I spied the helper actually greasing the "lubricator" on the wire feeder. That explained the black grimy goo built up on the guides and liners. The filler metals were stacked on the work bench where they serviced hydraulic pump, cylinders, and hoses. Can you say "oil contamination"? When I pointed out the issue, the supervisor moved the filler metals. Several days later one of the welders said, "You're not going to like this. Don't ever tell the boss I was the one to show you this."
The filler metals were moved to an outside open storage shed. In short order the containers and open boxes where covered with bird droppings. You can't cure stupid.
Best regards - Al
