More Fillet TIG Welding

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SteveHGraham
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More Fillet TIG Welding

Post by SteveHGraham » Mon Apr 17, 2017 6:48 pm

Got back to welding today. The results were a bit weird.

I took a couple of pieces of 1/8" steel and cleaned them until they were bright, using a belt grinder. I wiped them down with acetone and went to work on a fillet weld.

The first inch of weld (right to left) was horrible. I had all sorts of porosity, and I could not get the metal to move the way I wanted it to. I can't figure that out. I had to touch the metal with my gloves a number of times to get it set up, so I'm wondering if I contaminated it. I put conditioner on the gloves when I got them, so I'm afraid traces of it got on the steel.

I acetoned the metal again and got back to work. I also wiped down the filler, figuring it could not hurt. Things improved a great deal, but then a little while later, I got porosity again. Then it went away.

I feel like my technique improved a lot today. Apart from the bubbles, a good deal of this work actually looks like a weld. I found I needed to hold the tungsten closer to the joint than I had been, and that made everything go better.

I don't know what the little squiggly bits are.

The heat was frustrating. I was able to weld a little over an inch at a time, and then my right index finger got too hot to continue. I was holding the torch as far back as I could, to get away from the heat.

Feeding the rod is still a problem. It bounces when I feed it, so it's hard to keep the tip from going places where it should not.

This is slow work. After every inch, I stopped, and I gave the torch two minutes to cool. Three or more minutes per inch...over twenty minutes.
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04 17 17 TIG welding fillet w porosity small.jpg
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SteveHGraham
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Re: More Fillet TIG Welding

Post by SteveHGraham » Mon Apr 17, 2017 7:02 pm

It seems like welding practice is harder on the equipment than welding, because the welds are long and/or numerous. When you're actually welding something, you usually do short welds and spend a lot of time doing other things between beads.
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choprboy
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Re: More Fillet TIG Welding

Post by choprboy » Tue Apr 18, 2017 2:47 am

Looks like a gas shielding issue. Are you sure your running pure argon and not C25 or something else? 15-20CFH? Or possibly your holding at a weird angle and sucking in ambient air.

For more practice, try welding without filler. Lay one plate over another and weld a lap joint. Running without filler can give you a better feel for getting the underlying base metal to melt together. Don't be afraid to camp out when starting the weld to get a good molten pool, then start moving in ~1/8" step down the joint.

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warmstrong1955
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Re: More Fillet TIG Welding

Post by warmstrong1955 » Tue Apr 18, 2017 11:45 am

And....it doesn't take much of a breeze to foul things up.
Like if I leave my ceiling fan on high.

You are getting better!

:)
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SteveHGraham
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Re: More Fillet TIG Welding

Post by SteveHGraham » Tue Apr 18, 2017 4:07 pm

Thanks for the support.

I think the angle was way off when I started, but I don't know if that could account for a mess like this.

The gas is definitely argon. I also have C25 for MIG. I would like to get a tank of helium, but I know I'd just waste it on telephone pranks.
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warmstrong1955
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Re: More Fillet TIG Welding

Post by warmstrong1955 » Tue Apr 18, 2017 4:11 pm

If you et too far off of perpendicular, it can draw air under the nozzle like a venturi. Higher argon flow rates can actually make it worse.
Argon be good.
Air be bad....Don Ho syndrome....tiny bubbles.....

;)
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GlennW
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Re: More Fillet TIG Welding

Post by GlennW » Tue Apr 18, 2017 5:03 pm

I'm not sure what size cup you are using, but you may benefit (weld quality wise) from a larger one. You may get better gas coverage with less venturi effect, and the weld might not look as scaly and bubbly.

The down side may possibly be slightly impaired visibility of the puddle.
Glenn

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SteveHGraham
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Re: More Fillet TIG Welding

Post by SteveHGraham » Tue Apr 18, 2017 6:23 pm

Today's new lesson: when you do a fillet weld, it creates new scale on the back side, so when you turn it to weld the rear, you have to clean it all over again.
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warmstrong1955
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Re: More Fillet TIG Welding

Post by warmstrong1955 » Tue Apr 18, 2017 6:48 pm

SteveHGraham wrote:Today's new lesson: when you do a fillet weld, it creates new scale on the back side, so when you turn it to weld the rear, you have to clean it all over again.
Wait till you do stainless! :)

I have various little doo-dads & fixtures, to keep the insides & backsides of things I build flooded with back-up gas.
Stainless will suffer from 'sugaring', not so much scaling. It's an ugly bubbly oxidized extremely hard hard hard frothy mess. happens with any sort of welding, if the opposite side gets hot enough.
It sort of foams up when you are welding without gas on the backside, So much so, that it can almost close off a 1/4" OD tube in the inside if some dummy forgets to hook up a purge line before he welds them to the 2" pipe. (That would be me) Good thing I check my work....
FYI....it's hard to drill....

:)
Bill
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SteveHGraham
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Re: More Fillet TIG Welding

Post by SteveHGraham » Tue Apr 18, 2017 7:18 pm

I guess I won't post photos of today's bad weld, since the cause is obvious.
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dbstoo
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Re: More Fillet TIG Welding

Post by dbstoo » Tue Apr 18, 2017 7:45 pm

If you want feedback of the your welds you post, it often helps if you include information about the settings you used. For instance I'd expect that weld to have been done with 3/16 er72 filler, DC, around 120 amps with a 1/8 inch lanthanated electrode and around 15 CFH argon.

If you are only doing 1 inch a minute, that's pretty slow. It might be part of your problem.

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