Welding Tips and Tricks

Good Afternoon,

I have been practicing vertical TIG on some 1/2" plate. I beveled them, had a successful root pass, and started filling it in. When I got close to the cap, I couldn't prevent the undercut seen below. Should I be using larger filler wire?

1/2" plate
1/8 filler wire
135 amps
#8 cup
3/32 tungsten

Hi Ant,
Two things.
Looks to me like you’re running a little cold. Go up 10 amps.
Secondly, tig undercut is mostly actually underfill. Hold the edges a little longer and give it a little more wire. I


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It’s been my experience doing vertical that undercut is often a result of the innerpass temps are too high still. You might increase your time between passes and have a go again.

Thanks for the reply. I was holding the edges, it wasn't filling in. I was using the laywire technique. There was no wait time in between passes though. I went one after the other. I am teaching myself through Joey's videos, so I don't have anyone telling me what I'm doing wrong. That's why this forum is so great! I appreciate your feedback. How long should I be waiting in between passes?

ant428
Interpass temperature is also an important parameter for which maximum values are specified in the WPS. Generally

For Carbon & Chrome-moly steels - 300 to 350 degC max
For Stainless Steel - 175 degC max
For Nickel ALloys - 150degC max
For superaustenitic steels - 98degC max

hope this is helpful
craig

Motox,
I will need a inferred temp gun I suppose. I was not waiting at all between passes.

tempil sticks work will too
craig

Temp sticks are more reliable than a laser or ir temp gun. Unless you buy one of those high end Fluke thermal imaging cameras. We have one of those at work, but temp sticks are lots cheaper.

I just ordered a $10 temp gun on amazon. I figure it just needs to be close and not too accurate. I did another pass with the metal cooled off and it was better. What amperage would you suggest? I feel like 135 was pretty good.

Ant428 wrote:I just ordered a $10 temp gun on amazon. I figure it just needs to be close and not too accurate. I did another pass with the metal cooled off and it was better. What amperage would you suggest? I feel like 135 was pretty good.

I know I have a cheap one I got for free from my uncle that I use for plate tests. Like I just did my vertical v-groove butt joint on 3/8" plate and didn't light an arc in the cover pass until it was 200-250 degrees.

Just wanted to add an update. I increased the amperage to 165 and the puddle was much more fluent. Also waited till the metal cooled to 300 between passes. I have no undercut and a much better weld . Thank you everyone for your help!

Thanks for putting up all this trouble shooting tips here. I'm going to keep some of that information in storage and make sure that I keep the limits memorised or something for the next time I’m looking for a solution for my vertical work. Would anyone be able t recommend a good video that I could look at for technique in the meantime?

CameronRobertson wrote:Thanks for putting up all this trouble shooting tips here. I'm going to keep some of that information in storage and make sure that I keep the limits memorised or something for the next time I’m looking for a solution for my vertical work. Would anyone be able t recommend a good video that I could look at for technique in the meantime?

Jody’s YouTube channel is literally filled with a hundred well made, helpful, insightful videos for all processes, all positions. YouTube channel is “weldingtipsandtricks” coincidentally

@Ant428 - up your Tungsten to 1/8” for starters. 135A for 1/2” Ally, irrespective of welding position amd joint preparation, is cold/cold.

You’ll need a baseline amperage of 280+A to fuse this joint, IMPO. Use 1/8” 4043/5356/4943 filler. A 280A rig with H25 (75Ar/25He) may have the boost to inject adequate root fusion.

Prove to yourself that the 165A yielded a solid joint, sans discontinuities/LOF, by excising the welded joint and macro etching with EasyOff oven cleaner (ie. ethanol + sodium hydroxide) and mensurating the cross-section.

Arclight Ironworks wrote:@Ant428 - up your Tungsten to 1/8” for starters. 135A for 1/2” Ally, irrespective of welding position amd joint preparation, is cold/cold.

You’ll need a baseline amperage of 280+A to fuse this joint, IMPO. Use 1/8” 4043/5356/4943 filler. A 280A rig with H25 (75Ar/25He) may have the boost to inject adequate root fusion.

Prove to yourself that the 165A yielded a solid joint, sans discontinuities/LOF, by excising the welded joint and macro etching with EasyOff oven cleaner (ie. ethanol + sodium hydroxide) and mensurating the cross-section.

135a is low, but 165a on carbon steel that has been beveled and filled with multiple passes would be more than adequate. Certainly wouldn’t be sufficient for a single pass. But this is vertical up, beveled, filler passes. A 3/32 tungsten will Weld all day long at these amps too. A 1/8 will certainly work, but it’s not truly required for these amperage ranges.

Arclight Ironworks wrote:@Ant428 - up your Tungsten to 1/8” for starters. 135A for 1/2” Ally, irrespective of welding position amd joint preparation, is cold/cold.

You’ll need a baseline amperage of 280+A to fuse this joint, IMPO. Use 1/8” 4043/5356/4943 filler. A 280A rig with H25 (75Ar/25He) may have the boost to inject adequate root fusion.

Prove to yourself that the 165A yielded a solid joint, sans discontinuities/LOF, by excising the welded joint and macro etching with EasyOff oven cleaner (ie. ethanol + sodium hydroxide) and mensurating the cross-section.

280 amps? No way. This is a multiple pass weld. The root was a feathered edge with gap. As long as your burning those edges, your good. Hot pass and filler can be hotter, it I'm never at the 200 amp range. 165 would be a good setting. I'm just filling a gap and fusing the sides.

@Ant428 - material error, on my part. Wrongly assumed you were talking about welding 1/2” thick ALUMINUM vice carbon steel. In context for steel, my amperage numbers are way hot/hot. Sorry for the confusion.