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Discussion Starter #1 (Edited)
After saving for a looooong time, I finally invested in a fairly good TIG welder (PrimeWeld TIG225 AC/DC welder) and have been practicing with it for the last couple of weeks. After watching tons of videos I started fusion welding mild steel as was recommended in order to get the feel of TIG welding. I've gotten fairly decent at laying down some clean beads with good penetration, and my heat signature is getting smaller, so the other day, I started using a filler rod and feel like I'm back to square one. However at the moment, I reached the end of my prepared welding metal and need to clean up some more.

WOW, talk about difficult! It's like trying to pat your head, rub your stomach and shuffle one foot....all to different beats.

Anyway, since my Ariens GT-16 has too many problems to economically fix at the present time, I've started swapping some of the parts over to my S-16. This evening when swapping the rear PTO shaft over I discovered that one of the couplers had broken. As you can see by the pic, the break in in a non-critical area, but is subject to centrifugal forces, so it really needs welded back together.

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I thought about MIG welding it, but the part isn't that big and even using .023 wire, the bead size will be substantial.

I've gotten confident enough to try and TIG weld it back together, but I've never tried TIG welding a cast material. The part is magnetic so it's not aluminum or magnesium and it's fairly light so it's not cast iron, but I have no idea of what type of steel it could be.

I'm thinking about starting with about 125 amps and fusion welding a crack and the areas that have close bolt clearances then using filler rod for the rest. I'll be using the DC neg setting, a 1/16" 2% Lanthanated Tungsten electrode in a #8 cup and a 1/16" ER70S-2 filler rod. Gas is pure Argon set at about 15 CFH and I'll definitively be taking my time.

Any suggestions? I could really use them.
 

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You need to figure out what kind of metal it is. If it's steel, you can v the edges and weld it together (don't know what settings you would use), then grind/file as necessary to make it work.

If it's cast iron, then it needs a totally different welding setup (different welding rod, preparation, preheating and post heating).
 

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It looks from here to be an alloy (AL?) of some type.

The bother and cost of trying to patch it up may be more than a new replacement...?

Any idea what caused it to break?
 

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Discussion Starter #4
It looks from here to be an alloy (AL?) of some type.
Agreed! I'm going to touch it to my belt sander to see what type of sparks that it throws. The intensity and character of the sparks will help me at least to determine the carbon content. That information will help with the settings

The bother and cost of trying to patch it up may be more than a new replacement...?
Probably true, but Aiens no longer stocks the part. Plus the Ariens parts guy I spoke to said that like the front PTO, they've consolidated several parts into one "kit"; and even if he could get it, the last price for the kit was $395. And that price was from 2012! :eek:

Any idea what caused it to break?
No idea. I thought it was just cracked when I removed the gas tank, but when I got it off the shaft, it fell apart. There was a lot of dirt and grease in the break area, so obviously it has been that way for quite a while. I've still got another cleaning using an Acetone bath before I try to weld it.
 

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Discussion Starter #5
The deed is done!
The metal spark and drill tested between cast steel and cast iron, so went with my initial settings. One other fly in the ointment; when I was drilling a hole at the end of a crack it decided to break into a 3rd piece. :rolleyes: So anyway, I feel that the project was a success for my first TIG project. Yes there is some porosity and some areas that could have used some more heat; BUT I dropped it a couple of times and it held together and when I tapped it with a hammer the welded areas have a slight ring to them indicating good fusion and that it is now one piece of metal. Best of all, the close tolerance shaft bore didn't change size and the shaft slides in like it should. The lock pin hole will need to be drilled out due to a late ending bead, but nothing major. So with that out of the way on to the pics. Here are the raw welds:

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Discussion Starter #6
And the welds once dressed. They look much better and you can see the penetration was better than it appeared at first. Not to shabby for TIG welding cast mystery metal.
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It actually looks as good as some of the youtube cast welding projects done by welders who have a LOT more.
experience than me.
 

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Great job. I am a newbie to welding. MIG is great, stick is OK and fun, TIG errrrrrrrrrrrrrrrrrrrrrrrrrrrr.............................
 

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Why did you use TIG?...I am not challenging your choice.....just wondering what made you think it would work and why instead of stick?
 

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Why did you use TIG?...I am not challenging your choice.....just wondering what made you think it would work and why instead of stick?

A small part like that would be nuked with stick welding. TIG allows the "proficient" operator to add precise amounts of heat and filler very accurately. So far for me it is like trying to juggle bowling balls. Here take a look at this video and see if you could do that with stick or spool gun MIG. (welding beer cans together.)

 

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Discussion Starter #10 (Edited)
So far for me it is like trying to juggle bowling balls.
My analogy is that for me it's like trying to pat your head, rub your stomach and tap one foot at the same time...all to different beats!

TIG welding is kinda magical, when everything is right, that little silver puddle of molten material appears on the surface of the metal under the arc, and it just sort of pulls in the filler rod when it needs more material as you move both along at the same speed. However, at my current skill level, I always seem to ruin it after a bit by either dipping the tungsten or touching the filler rod to the tungsten and have to re-sharpen the tungsten then start all over again.

One lesson that I took away from this project is its really difficult to re-melt your initial bead in order to add material to it. I tried that and as you can see from the raw pics if just looked like bugger welds. If you look really closely under those welds, you can see the initial beads which looked really good, except that I didn't add enough filler rod; hence he attempt to add some more.

Also, I'm not 100% sure where all the porosity came from in the raw pics, as I was running about 16 CFH and a #8 cup with 1/16 tungsten.

BTW, the guy in that video has some serious skills! He has to be running less than 12 AMPS (and in all probablitly less than 10 AMPS) to weld something that thin. Also look how tiny his arc is...again crazy skills.
 

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@Demented

One tip for TIG, sharpen several electrodes at once so you can just change them out and not have to run to whatever you use to sharpen. I use a belt sander and chuck it up in a drill to spin. Keeps all the striations running parallel. I wear a good respirator to when doing so.
 

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Discussion Starter #13
On the advice of my local weld shop I purchased a gas lens kit for my torch. They explained that the kit focuses the gas from a turbulent flow that kinda just drifted out of the cup to a smooth flow that extended MUCH further than the end of the cup. This does two things, 1) it allows you to let the tungsten protrude out almost twice as far as what is recommended for a specific cup size so you can see better; and 2) provides much better gas coverage at the same volume setting. The last piece is supposed to be in tomorrow, so I'm going to try to lay down a better weld on the side where I ground all the old weld off and I can see some small cracks.

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I'm definitely going to preheat the area with a torch first and probably crank the amps up to about 150-175 and see if I can control the heat better this time with the foot pedal as the material get hot.
 

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We done! 319 stainless filler works well with cast parts using a little pre and post heating. Cleaning up your mating surfaces is #1 before welding.
 
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