Welding critique please

[Todds69]

Here are a few of my welds with couple different settings. Are these OK or is there something I need to do? I was using Lincoln .025 wire on 16 gauge mild steel, I ended up losing my 1/16" gap as I welded but thisis just practice, right? I guess I should say C, D are the same as well as A, E.

[Mathius]

You have a very bad case of cold roll. Could be your technique, could be your heat settings are too low.

You see the bottom and top of your welds? There is no visible penetration. It looks like a log of steel is sitting on the two plates. Very little strength there, not enough penetration.

Your weld should look flat on the edges of the weld where you can visibly see it burned into the plate.

Your gap isn't an issue. You're running what's referred to as a "T" joint. Because one plate is butted up against each other, like a corner. This is also a fillet weld, not a groove.

Your motion should flow from one plate to the other, spending more time on the top half, because gravity is going to try to pull the weld down.

Mathius

[parsonsj]

Right: not enough heat, or moving too fast. You should swirl the puddle, as that will slow you down and give some more penetration time. How 'bout a pic of the other side of the coupons?

jp

[gt1guy]

Rule #1. Clean the metal before you weld it! You welded right over the mil scale. That doesn't help anything.
Slow your wire speed down, and don't use so much drag angle. The welds were done flat, pulling the gun, right? It looks like you were pushing the weld on top of itself as you traveled. That's drag angle and/or wire speed. If your voltage was too low, the bead wouldn't be as smooth and straight as it is. The wire melted fine, you just put it in the wrong spot.
Take JP's advice, swirl the puddle, it will give you a better looking bead.

To keep from loosing your gap.........use more tacks.

Kevin

edit: spelling

[parsonsj]

One other thing to consider when MIG-welding sheetmetal: stitch weld it.

jp

[Mathius]

One other thing to consider when MIG-welding sheetmetal: stitch weld it.

jp

I've always hard stitch welding described as several intermediate tack welds.

I heard you talk about stitch welding on another forum, and you said to drill holes and weld into the holes where the metal overlaps. I've always heard this referred to as plug welding, or spot welding.

It doesn't really matter to me what terminology you use, just as long as you can clarify so I know what you're talking about.

It's definately easier for the novice welder to do either.

However, I caution you to make sure that there is no gaps at the edge of the metal because if water gets trapped in there, your metal will rust from the inside out. Also, it's impossible to paint where your metal overlaps unless you do it beforehand and grind off where you're plug welding, but you still run the risk of your paint or other coating to burn off.

I think if you're going to have any overlapping at all, you'd be better off using a lap joint to keep water out, unless for some reason you can't get to the inside panel.

To prevent rust, your metal has to be either coated, or secured air-tight.

Mathius

[parsonsj]

Mathius,
Stitch welding and plug welding (sometimes called spot welding) are different things.

Stitch welding is a way of putting a series of tack welds along a seam (usually a butted seam) that reduces warpage and burn through.

The technique is to put a series of tack welds so that they are an inch or so apart. Then, starting with one of the tack welds, you "stitch" your way to the next tack. The stitch technique is a rhythmic on-for-a-second, off, move-slightly-forward, repeat. The on/off/move allows more heat in the weld, plus more control of the puddle by varying the amount of time "off".

Hope that makes sense.

jp

[Mathius]

Mathius,
Stitch welding and plug welding (sometimes called spot welding) are different things.

Stitch welding is a way of putting a series of tack welds along a seam (usually a butted seam) that reduces warpage and burn through.

The technique is to put a series of tack welds so that they are an inch or so apart. Then, starting with one of the tack welds, you "stitch" your way to the next tack. The stitch technique is a rhythmic on-for-a-second, off, move-slightly-forward, repeat. The on/off/move allows more heat in the weld, plus more control of the puddle by varying the amount of time "off".

Hope that makes sense.

jp

That's how I was always taught as well. In fact my buddy's old Lincoln machine has an automatic stitch setting. The gun will actually turn on and off and make the tack motion for you, you just have to move the gun along the seam. We never messed with it though.

I must have had you confused with another poster. I just wanted to clarify what you were saying.

Mathius

[Todds69]

Thanks guys, the pieces that I welded were laying flat. I feel it is more of my technique than anything. Two of the pics are at the suggested setting the other two, I went low just to see. I will try and get another pic of the the flip side and try a couple more welds.

[Twin_Turbo]

I agree, you have to turn up the heat, move slower, maybe lower the wire speed a bit. Recommended settings are just that, a guide line, everyone is differet...also when welding. Play with the settings till you get the proper ones for your style and for what you are welding.

[jason@gmachine]

personally i prefer a more of a weave technique, and stitch works for sheetmetal but not for cage work.

Jason

[parsonsj]

stitch works for sheetmetal but not for cage work

Good point ... I TIG weld cages, so I didn't think about that. Stitch welding is a sheetmetal technique, not a tube technique.



jp

[jason@gmachine]

Good point ... I TIG weld cages, so I didn't think about that. Stitch welding is a sheetmetal technique, not a tube technique.

jp

yes, another that agrees with me. You so just got some brownie points!

Jason

[Speed Raycer]

^^^^You'd be surprised at how many cage builders don't know that.