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Up Topic Welding Industry / General Welding Discussion / Trials/errors
- - By CHEVYTOWN13 (**) Date 07-30-2003 00:45
What's happenin' hometowns.

These past few days have been a crazy learning curve but one I expected and have enjoyed trying to figure out as the problems arose(and there were a few). Alls I can say are the welds look MUCH better than the first day! LOL I can't break the weld joints either, alls I get is bent pipe. So that is a good sign I guess??

I'm using the flux cored wire right now. After using the MIG set-up at the weld shop last week, I can see how much smoother MIG is. But, I'm having fun with the FCAW and will attempt my first job on my exhaust system on my truck. It's got some ugly pinches from the muffler on back. Going to buy some manderal bent tubing and a hard days work. Can't wait.

I also put together some old pipe I had it laying around the yard (Chi) and have been practicing on that. I cut it up into pieces and put it back together. Put together some curves too to practice for the chairs in the near future.

The thing I'm having trouble with is tack/spot(?) welding. When I attempt it, the weld is fine, but there is a gap directly on the other side. I'm going to do some homework on that situation. I'm guessing I'm tacking too much thus warping or movement occurs.

RM



Parent - - By ssbn727 (*****) Date 07-30-2003 02:22
Horale Caballero!

So you're really getting into it!!!
The "thing "you're having a problem with could be two "things".

Before I explain the two things, I have to ask you a question:
Are you spacing the members of the joint with pieces of the same diameter wire you're using to weld? Or are you "butting" the two members together? The reason why I ask is because, if you're butting them together, you have to spend more time on the tack weld in order to get enough penetration.
If you're spacing the joint the way I just mentioned, then you'll get a decent amount of penetration, and actually be able to close the amount of separation at the opposite side of your first tack by depositing your next tack weld 90 degrees from your first tack, then 180 degrees from your second tack, and finally 180 degrees from your first tack!!! ( if this is a critical joint then I recommend a gas purge for the inside (root)of the weld so that it does'nt get contaminated.
so getting back to those two "Things":

One is that you are welding too slow of a tack which would cause excess separation at the opposite side of the tack weld.

Two is that you're welding the correct size tack, and you're still getting separation at the opposite side of the tack weld, where the joint is'nt tacked yet.

Regardless of the two choices, it's normal to have separation at the opposite side of the tack weld because, both members surfaces that make up the joint are being pulled closer together at the location of the tack weld as it cools, and at the opposite side of the joint where it's not tacked, the two members separate from each other. The slower you weld the tack, the more heat input to the joint. This will separate the opposite side of your first tack even more. Pipe clamps help minimize and sometimes even eliminate this!!!

The key to any tube/pipe joint is fit-up!!! If you're off in your fit-up in any way, then it wo'nt matter about how much or how less the heat input you're putting into the joint because, your end result will be distortion, and a noticeable "Kink or Pinch" at the joint!!!

One way to tell if you're spending too much time on your first tack is by looking at the amount of discoloration (Heat Affected Zone) around the tack weld.
Generally speaking, if you see that the combined (from both members) heat affected zone is at least 5 times the area of the tack weld then it could be that you're spending too much time welding the tack. (this is just generally speaking!!!)

If you have access to a pipe clamp then, it will certainly help minimize your problem so much so that you could place your tacks into the joint with the least amount of separation
If your first tack is welded at the six o'clock position in order to close the opposite side (twelve o'clock), then you should deposit a tack at either the nine or three o'clock position of the joint, then finally at the twelve o'clock position of the joint, take off the clamp, and then weld the pipe up in the same sequence as you did the tacks. You should first grind or "Feather" both ends of each tack beforehand in order to achieve good fusion where the rest of the welds meet at the tacks!!!

There are some other details missing that could help in giving you some more suggestions so, I'll ask you some questions:

What is the diameter wire you use?

What size tubing/pipe? Wall thickness? Outside diameter?

How long are the members of the joint?

Is the joint beveled? On each bevel, are they chamfered?

Describe your machine to me (brand name/model)...

What is the voltage set to on your machine?

What's the wire feed speed set to?

In other words, Hometown!!! You need to feed me some more dope on this dillemma you're having holmes.... Ahhhyighttt????

Respectfully,

SSBN727 Run Silent... Run Deep!!!
Parent - - By CHEVYTOWN13 (**) Date 07-30-2003 04:02
Que onda vato loco SS!

Hey bro, it was my fault. I was just told by my brother that the piping they sell at Pepboys is tin. I totally forgot about the piping laying around in the yard. And to top it all off, the gauge was about 18-20. According to the Lincoln manual (Pro Mig 135) and for that thin a gauge, gas has to be used. I was still able to get it welded up though (real world application-LOL) by weaving back and forth with the voltage set at A and the speed set at the lowest number. Otherwise, it would burn through leaving holes. I was on a mission to get it welded and didn't care if it was tin! It looked horrible. I said, fudge it, might as well practice on it.

On the thicker gauge exhaust piping I had laying around, (it has a coating so the pipe won't rust. It looks like aluminum) the welds were much easier to do using the voltage setting set at B and the speed at 2. The wire is .35 Even with a very small gap, I was able to weld it without hearing the "hollow" sound and finding wire inside the pipe like the pepboys pipe. I understand it should be like bacon frying in a pan on a Saturday morning in the woods by the tent...LOL

I had a much easier time with tacking using the thicker gauged exhuast piping. It didn't move as much. I was able to bend the other side if needed be. Otherwise, if the cuts were smooth, tacking was not a problem. I also tested myself on uneven connections. A bit more tricky but not bad. I just weaved from side to side.

I have to get better with starting the arc. Once started, I begin to roll. Sometimes, it doesn't arc and I end up wasting wire.

I believe I am "butting" the welds but not sure. I'm basically cutting the pipe with my sawzall and welding it back together. Sometimes the way it was other times I move the pipe to get an uneven gap for "the test."

Gracias for the help.

RM
Parent - - By ssbn727 (*****) Date 07-30-2003 04:40
Cojelo suave RM...

I'ts all good... just keep practicing by adjusting your voltage and wire feed speed so that you get good penetration!!! (you know like-cuando tu practica con los mujeres, me entiendes?) You'll get it down!!!

Yeah man!!! GMAW needs the gas otherwise it looks like cancer & swiss cheese with all the holes!!!

Now remember to set your gas flow rate to the correct setting which should be listed in your manual... Also, if your welding outdoors or where there's a breeze, make sure you block the wind from blowing your gas shield away from the welding zone, comprende?

It seems like you're really enjoying this adventure, and I'm glad you are!!!

Not to bum you out but, Most important of all: THINK SAFETY!!!
I say this because, if you do'nt you'll soon lose your enthusiasm and love for this noble craft!!!

Dios te bendigas hermano!!!

Respectfully,

SSBN727 Run Silent... Run Deep!!!
Parent - By CHEVYTOWN13 (**) Date 07-31-2003 23:26
Horale compa!

I did notice when the voltage was low it was not penetrating much but melting the wire as to give it the appearance that it penetrated. I reached for the pipe and broke in two easily.

I'm getting better at it.

I even forgot to add the second tack (on the other side) on one occassion so the pipe won't distort and the other side was about 1/8 off after I welded about a 1" seam. I suddenly thought about a bridge and began to build up on both ends and then moved inward in a very fast fashion. Damn, I swear, they look awesome. I was expecting Mt. Everest or something to that nature. But in fact it was low and stout. Looked inside the pipe and no crazy breakthrough. I must have lucked out. I'll try on the rest.

I hear ya on the Safety homeboy. The shop dude gave me a Welding 101 on the do's and don'ts. I'm safety minded as hell right now. Luckily for a newbie, I have the flux cored wire. The gas is a different ball game and would rather go to school for that. But I'm jammin' on the FCAW and can't wait to do my exhaust.

Then the chairs cometh! BTW carnal....GO STEELERS!

RM

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