https://stream.echo6.co/videos/watch/5d511cf0-ea5e-4174-bd9b-4273433c9fca Visit my store at https://weldmongerstore.com for TIG cup Kits, TIG Fingers, Gloves, Tungsten, Filler metal, and other quality welding tools. New products being added weekly. The challenge with a 1/4” aluminum single pass lap joint is getting penetration into the root of the joint...while at the same time, not chopping up the edge. It can be difficult to hit the root while not chewing up the corner. So I tested a single pass weld along side a 2 pass weld to check for depth of penetration. I set the Primeweld TIG325 to 250 amps so that I would have extra power at first when the aluminum was cold. AC frequency was set to 150HZ to focus the arc. I used 3/32" 2% lanthanated tungsten and a #5 clear cup for the first welds. I noticed some oxides floating around in the puddle with the #5 cup so I switched to a #6 gas lens cup for the 2 pass weld. I use clear cups a lot for filming but I think a pink ceramic #6 gas lens cup is a good cup for a whole lot of aluminum jobs. Penetration to the root was not that great on the single pass welds. So I decided to try welding 2 passes....one focussing on penetration...and a second pass to get the adequate weld size. A cut and etch test revealed much better penetration in the root of the 2 pass weld. But because I didn't clean the aluminum at all before welding, there was a large pore. That in itself is a lesson. I should have taken a few minutes to wipe the aluminum with acetone and wire brush with a clean stainless brush. Follow me on social media to see what I’m up to: Instagram: https://www.instagram.com/weldmonger/ Facebook: https://www.facebook.com/weldingtipsandtricks Join the discussion with thousands of welders at the Welding Tips & Tricks forum http://forum.weldingtipsandtricks.com Wed, 15 Apr 2026 09:51:16 GMT https://validator.w3.org/feed/docs/rss2.html PeerTube - https://stream.echo6.co https://stream.echo6.co/client/assets/images/icons/icon-512x512.png https://stream.echo6.co/videos/watch/5d511cf0-ea5e-4174-bd9b-4273433c9fca All rights reserved, unless otherwise specified in the terms specified at https://stream.echo6.co/about and potential licenses granted by each content's rightholder.