Professor Hammer’s Metalworking Tips

Q. I am an accomplished stick and MIG welder, and all of my autobody welding has been done with a torch or a MIG welder. I am restoring a 1938 Ford pickup and plan on butt-welding the sheetmetal repairs with a TIG welder. I have an old Miller 330 transformer machine that I repaired, and I finally have the TIG function working well. I will be butt-welding 18-gauge panels to the existing 19-gauge body. I have been practicing butt-welding 18-gauge panels and have it dialed in pretty well. I watched you butt-weld panels at two of your workshops, and I have some questions. I get the best results at approximately 50 amps using a 1/16-inch tungsten with a #5 cup, after trying #4, #5, and #6 cups, with argon set at 20 CFH, and a 5-second post flow. I have tried 0.040, 1/16-, and 3/32-inch tungsten, both thoriated and ceriated. I have heard ceriated doesn’t work on the old transformer machines, but it seems to work fine for me. I have a few of your DVDs, including the one on TIG Welding.

I have tried 1/16-inch TIG rod, 0.035 and 0.045-inch MIG wire, and get the best results using the 0.045-inch MIG wire as a filler (ER70 S6 from Harris). Here are my questions:

1. What tungsten do you recommend for this, thoriated or ceriated?

2. What size tungsten do you recommend?

3. What cup size do you use for this application?

4. How much should the tungsten stick out of the cup?

5. Is 5 seconds post flow too much? At 3 seconds post flow I get a pinhole at the end of the weld that I don’t get at 5 seconds.

6. What flow do you use for Argon?

7. I have not tried a gas lens. For this type of work, would you recommend a gas lens?

8. What type and size filler rod would you recommend?
Bruce Jakubauskas
Via Email

Great questions! I will answer them in order:
1. I prefer ceriated tungsten.

2. I normally use 3/32-inch tungsten. Low-amperage arc starts are improved with smaller tungsten, but 20-gauge steel is the thinnest I normally weld, and the 3/32 handles that very well, plus I can weld steel up to ½-inch thickness without needing to change the tungsten. The ceriated tungsten works well for aluminum, too

3. I usually keep a #7 cup on my torch unless I need to get into a tight area. The #5 cup should work well for flat panels, too.

4. I keep the tungsten “stickout” between 1/8 and 3/16 inch.

5. The “standard” for post flow is 1 second for every 10 amps. For 18-gauge steel you are probably welding around 45 amps, so 5-second post flow is probably sufficient.

6. I normally use 12-14 CFH argon flow for steel. You may need a bit more if you go to larger cup sizes.

7. Gas lenses have their place, but I don’t use them much for everyday welding.

8. I most often use 0.035-inch ER 70-S6 (or S2) rod for the type of welding you are doing; 0.045 should be OK, too, but I can make a smaller weld bead and still get sufficient penetration with the 0.035 rod. The S6 rod is more heavily deoxidized, and has more cleaning agents, so it is preferred for any material that may have contamination, such as rust, corrosion, or traces of paint or filler. You probably won’t have any problem with the S2 rod on clean metal.

Let me know if you have more questions!

You can email your questions to Professor Hammer- [email protected] – or mail a letter to Covell Creative Metalworking, 106 Airport Blvd., Suite 105, Freedom CA 95019. You will receive a personal reply. Ron Covell has made many videos on metalworking, and they can now be STREAMED or DOWNLOADED from his website! Check these out at covell.biz, along with his ongoing series of workshops held across the nation, or call for a current schedule of workshops and a free catalog of DVDs. Phone (831) 768-0705. Also, check out Ron’s YouTube channel – www.youtube.com/user/covellron.

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