[mpete53]

I it harder to get a shinny weld on hot rolled carbon steel then cold rolled?

Jody seems to always use cold rolled and get beautiful welds, while no matter what I try, mine on hot rolled are almost all gray. Gray enough that when padding beads I seem to be making my own mill scale with each bead. I have spent time cleaning the mill scale off to bright metal before welding. Played with cup size, gas flow, rod size, travel speed, changed gas leans, tested for leaks and amperage. still no shine

After a wire brushing the look good, but the heat effected zone appearance has also changed after wire brushing.

see photos

1/8 hot rolled steel clamped to 1/4 aluminum
1/16 2% thoriated
#6 gas leans
15cf/h
70 amps but petdding
1/16 rod

My guess is that its still me. Any help would be greatly appreciated.

Mark

[Poland308]

Part of it has to do with how thin your metal is. When you puddle metal that thin with that many amps, the puddle becomes molten all the way through. As the back side oxidizes those oxides are pulled up to the top of the puddle. Try running on a piece of 3/8 or thicker but with the same amps. You will still be able to pad beads but you will get the shiny look your wanting.

[Louie1961]

Part of it has to do with how thin your metal is. When you puddle metal that thin with that many amps, the puddle becomes molten all the way through.

I respectfully disagree. I weld on 1/8 in steel all the time and rarely get a puddle that is molten all the way through. I personally believe the OP's issue is that he is overheating his welds considerably. 70 amps is not enough for 1/8 plate especially since he has it mounted to a chill block. Jody had a video on this very topic where he welded out 3 sets of lap joints on 1/8 inch coupons and he did it at 80 amps, 100 amps and 120 amps. The 120 amps put the least amount of heat into the material, and had the smallest HAZ. What happens is at 70 amps it takes so long to get a puddle established that your speed of progression is extremely slow and you put too much heat into the work. Jody does a better job of explaining in the video.

To the OP, change to a 3/32 tungsten, set your amps for 130, and pedal it from there. I don't believe you need the aluminum backing plate either. Remember to cool off your plate every 2-3 weld beads, otherwise that will overheat your weld as well. In my opinion, what you are seeing is a product of overheating. Notice how you are losing the distinct ripples? Too much heat.

https://www.youtube.com/watch?v=DmVCLi6cxok

https://www.youtube.com/watch?v=uzIF0H02fBw

[cj737]

I too believe you are too low on your amps, and too small on your cup and tungsten.
But, Poland is also right: repetitive welding on 1/8” will draw millscale through from the backside.

1/8” material for padding is very thin if you want to crank out some practice. The chill bar is helpful to prevent it from becoming a taco, but in reality, you want thicker material anyway. During practice, run a bead, and quench it in a bucket, wipe dry, and repeat. This is fine for practicing.

I’d encourage up to use at least a 7 or 8 cup, it makes a difference. And ditch the skinny tungstens. For most carbon, upto 1/8” the amps run nearly 1:0.001. So for 0.125 material, 125 amps. Padding beads, you can probably drop to about 115 after 2 or 3 runs even with the quenching.

[mpete53]

I setup a video camera and shot at the same settings as before. From that video see my torch angle looks a bit much and my travel speed seems to be about 6" /min which I am guessing is a bit slow.

As for using heaver material, 1/8" is about as heavy as most of my projects are so I need to master the thin stuff.

Mark

Can a video be uploaded? if so what format?

[Oscar]

Upload to your YouTube channel then just link it here (embed)

[mpete53]

I guess I am have to get a youtube channel now

[mpete53]

here is the video of my weld details listed above


http://www.youtube.com/watch?v=xzVLGXK8 ... e=youtu.be

Mark

[jwmelvin]

here is the video of my weld details listed above

I think you need to set the video to public or unlisted rather than private. Doesn’t play for me.

[mpete53]

sorry new to posting on Youtube.

I think it is public now

Mark

[cj737]

My impression is you’re dipping too frequently because your travel speed is too fast. Slow down a bit and let the weld drive in, dip, then move, dip, then move. Try to make the dip-move as two distinct actions with a pause between them.

At the end of the video, your tungsten shows to be rather blunt and not clean. The taper should be defined and the tip pointed for steel TIG.

A slower and more methodical travel will eliminate the “humpy worms” of welds and produce flatter, better penetrating welds.

Thats my opinion.

[Poland308]

Looks like your varying your arc length by bobbing the torch every time you dip.