Howdy, fairly newby-ish TIG welder trying to do a simple butt weld to merge two pieces of 1/4" thick HRPO (hot rolled picked and oiled) steel together. Figured I could tack it and run a nice little bead down the middle, but having issues with porosity which seems to kick up as I'm about an inch into it. One of the benefits of HRPO steel is that it doesn't have mill scale, and usually just needs to be hit with some acetone before welding, but I'm wondering if the porosity in this case might be caused by the very, very small amount of "slag" resulting from the laser cut edge? Here's a picture of the edge quality:

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Experimenting, I took a couple test pieces (with laser cut edges) and wire wheeled and strip-disced them, and attempted a butt weld on those pieces. While it seems like I could run a bit of a longer bead, it still ended up giving me quite a bit of porosity (it didn't bubble up but I could feel it).

Any suggestions? I'm trying to avoid hitting it with my big grinder or flapdisc since, well, there's no point in paying for the precision of laser cutting if I'm just going to grind the edges down.

Here's a picture of the piece in question, with some porosity visible (sorry, don't have a macro lens). The hair was from my rag I was using to clean it. And yep, I know I need to step up the amps to get better penetration here.

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