[bap_]

Hey Folks,

I've been practicing a weldment and I just can't seem to perfect it. It's 16 gauge sheet metal TIG welded.
The image I attached is the drawing of the weldment I threw together on Fusion 360 (sorry no weld symbols since fusion is lacking.)

My settings:
- 3/32 2% lanthenated
- 1/16 er70s-2
- 60A DCEN
- foot pedal remote

The issue I am hitting is either a heat issue and maybe to large of filler diameter?
The corner joint and the butt joint are not really a problem and penetration is required per the welding symbols provided in the real drawing.

The lap weld and the tee are giving me a bit of trouble. Due to the weld order the part at this point it quite hot. I normally am doing 3 of them at once to try to rotate them and let them cool.

The lap goes in pretty well, however I am penetrating to the backside and I am curious if its possible to do this weld without penetration with the WPS I have? Is penetration on the backside expected for a lap at this size? I am aiming my arc right for the root of the joint to melt the edges of the top piece; should I be focusing more on the bottom piece and wicking the puddle up?

The tee joint is probably the trickiest and similar situation to the lap joint. The first pass I penetrate through the bottom and I also pull oxidation from the other side of the joint at times. The second pass on the other side is a complete disaster. It's so burnt that the puddle is really not smooth and is sputtery. I am also getting undercut at times.

At the root of my question is heat input which I think is the main goal to learn on the weldment. What is the best way to manage heat in such thin metal? Is it better to go hot and fast or low and slow? The lower amps I have the harder it is to maintain the puddle, however too hot and I nuke the part. Do I need to let the pieces cool more than even rotating between a few of them? Any tips would be great. I'll try to grab some pictures of the failed attempts.

[cj737]

All the descriptions of your issues say to me, “Patience, Grasshopper. Patience.”

With material that thin and the number of welds, cool down time is a must. How much depends upon how hot and long you welded.

[motox]

aluminum chill blocks can help more the heat away.
craig

[Poland308]

You can also control the heat a little by how fast you feed wire. Can you use 3/32 wire?

[bap_]

If I can find some 3/32 I'll try it, but the shop has mostly 1/16 er70, and I am trying to follow the WPS.

As far as relative temp, should I be waiting until I can touch the part with no gloves comfortably before moving to the next pass?

As far as my travel speed and heat, I am moving along with the puddle and setting my amps to just enough to where the puddle stays smooth and I can move fairly quickly. If I go hotter I feel that I don't have the skills to keep up.

[weldin mike 27]

On something that thin I would go down to a 1/16 electrode. Sharpen it to an absolute sharp point, as finely ground as possible. That will help greatly with arc control.

[LtBadd]

Does the WPS call out the filler dia.? I would think so, for me personally I would find 3/32" too large, I would even consider .045", but that's just me. Remember the larger the filler, means more heat is required, and your travel speed would have to be quite fast to not burn through, maybe some TIG welders could do this, but everyone has their "own" way of welding within reasonable limits.

You have to make 2 passes on the fillet for 16ga material?

What is this part for, looks like a weld test to me.

The parts that are cooling, set them in front of a fan so when you rotate back to them they have cooled off.

[bap_]

I have to double chcek the WPS, I don't have it in front of me at the moment, but I think it does call out 1/16 diameter. For learning sake, I'll run down to my LWS tomorrow and grab some 0.045 and 3/32 if they have any in stock and try them both.

I haven't had to make 2 passes on the fillets, they both go in fine in one pass other than me cooking the part hah.

Yes, this is a weld test I am practicing on.

I am in a booth, I suppose I could go outside and let them cool off between welds, but we don't have a fan in the shop to my knowledge. I think the heater is on this time of year as well.

[trainingGrounds]

I found that starting at 85 amps full pedal is a good heat for 16g. Then let up on the pedal as you go. You want it to be just hot enough to where you get an almost immediate puddle and that's from one of Jody's videos. Second I like 50% dig for aluminum at that amperage and gauge. To me the puddle seems to respond better and melt in quicker without blowing it out.

I agree with what others have said about chill bars and waiting until the metal is warm at least. I personally don't think you have to wait until it's cold.

And as for torch angle and distance, I would keep it pointing mainly into the bottom plate for a lap joint, 80-85 degrees or so. Then be as close as possible to it without touching or dipping the electrode. Then I'd be maybe 1/8" away from the top plate or a little less. Changing whatever is needed to fuse in the plates. Point the filler right in the corner of the puddle and the two plates and fill right before the top plate melts back. As long as you are melting the bottom plate first then you give yourself a chance to fuse it to the top plate.

Lastly, you can certainly do this weld with complete fusion without burning through at all. It will just take a critical amount of amperage and speed otherwise you will heat the base plates too hot going too slow and the puddle will flattens out. Generally the best way to control heat input is to go faster more so than reducing amperage. You will heat the plate less with high enough amperage at a faster speed.

[Kscar33]

Well I know I'm pretty late to the party, but I'm currently trying to figure out the best way to practice in my garage as well and I came across this post. Do you by chance have the fusion file for this? In my 9-5 I draw in fusion/AutoCAD all day most days and would love to be able to take this and dimension/rotate etc. Thanks!!

[weldin mike 27]

KSCAR, Don't over think it mate. Practice is a run what you brung type situation. As long as you have the 3 basic weld joints in it, the size matters little. Bigger pieces means more welding before stopping and smaller means you will overheat the part quicker.

All the best, mick.

[Kscar33]

That's a good point... No reason to complicate matters thanks for the tips! Really trying hard to become a good Tig hand and ditch the old office 8-5.. Lol

[weldin mike 27]

Keep checking out info and videos to see if your practice is working, but how you do it is your call.

[bap_]

Ya here is the fusion drawing: https://a360.co/2UNo3XC
The fusion file itself: https://a360.co/2FYWHUX

Let me know if you have trouble accessing it.

Like Mike said, it's just 5 coupons positioned to get those 5 weldments. It is great practice! The file is nice to have to share with someone or ask questions etc.

Using those approx dimensions will help you learn heat control and save material.

Cheers!