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Thinking about getting a welder

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The holes on the left weld is porosity, your tip is too far away from the exhaust or it wasnt clean enough. Welding metal this thing there really should be no stacking going on, just straight lines. Only reason to alter the straight line would be to alter your puddle, but thats my opinion. This could help ya out:

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Go to a random manufacturer that does welding (or a machine/fab shop) and ask for scrap metal, they may have metal there for ya and you may get it free or pay scrap cost.
 
Actually that one there I didnt have the gas turned on. Do you think I should redo it? Seems like it will hold and its sealed allthe way around so it wont leak.
 
AMCRambler said:
Actually that one there I didnt have the gas turned on. Do you think I should redo it? Seems like it will hold and its sealed allthe way around so it wont leak.
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Without shielding gas the weld is brittle and porous and will fail VERY quickly. You should definitely grind out all of the contaminated material and redo it.
 
Go to an exhaust shop and ask them for scraps. Some around here will give them away for free and you can use those to practice on.
 
So you're saying the newest welds are crap too and I need more practice. Ok.

Got a question though. You guys told me to crank up the voltage, but thats whats making the weld pool wider and flatter like that. Now im getting conflicting info here it seems because other people here are saying i should have a nice raised bead. Which is right?
 
AMCRambler said:
So you're saying the newest welds are crap too and I need more practice. Ok.

Got a question though. You guys told me to crank up the voltage, but thats whats making the weld pool wider and flatter like that. Now im getting conflicting info here it seems because other people here are saying i should have a nice raised bead. Which is right?
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You don't want a weld bead that is flush with the base material, nor do you want a weld bead that is super-tall. You want a weld bead that sits above the base material (say 1/8in to rectal pluck a number) that transitions smoothly into the base material. When I do initial MIG weld evaluations at work I take a ball-point pen, and if it smoothly runs across the weld bead, it's generally a good weld.

This looks like a pretty good constant voltage MIG weld (no dime stacks, only small ripples) on an exhaust pipe:

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This looks like a pretty good pulsed MIG weld (this is how you get dime stacks, this shouldn't be happening with CV MIG welding) on an exhaust pipe:

exhaust_weld_MIG_Figure_4.JPG
 
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Rambler, from what I see I don't think any of your welds will fail either mechanically or leak. Exhaust pipe is not stressed structurally like a frame tube. Typically it wears out from corrosion, or breaks when it is not properly supported.
There is more to the art of hanging IMO. Do that right and you get no bad noises, vibes, cracks for the life of the car.
The tips you are getting are all good, and will matter when you weld up something that has some loading on it.
 
JCH13 said:
This looks like a pretty good pulsed MIG weld (this is how you get dime stacks, this shouldn't be happening with CV MIG welding) on an exhaust pipe:

exhaust_weld_MIG_Figure_4.JPG
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That is not stacking dimes, that is someone overlapping his tacks. You can tell by the wire holes in the tacks, if it was a continuous weld there would be only 1 hole at the end. Ill repeat I prefer this type of weld over stacking dimes but what you like is up to you.

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or in op's case. Chances are it was done with a rotisserie but you get the idea.
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Your weld with porosity looks like this on the inside, think about redoing it or possibly grinding it smooth and trying again.
porosity-300x222.jpg
 
Soccerman06 said:
That is not stacking dimes, that is someone overlapping his tacks. You can tell by the wire holes in the tacks, if it was a continuous weld there would be only 1 hole at the end. Ill repeat I prefer this type of weld over stacking dimes but what you like is up to you.
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You might be right. To me it screams 'pulsed mig' because of the nearly perfect spacing and width, probably with the travel rate a little too fast, thus cratering.
 
You should also get (or make!) a cart with a clamp for your gas cylinder. If the valve gets damaged they turn into rockets and are extremely dangerous. I don't want to sound like Safety Sally, but I wouldn't want you to get hurt while having fun.

You may want to check out a website called http://www.weldingtipsandtricks.com (it's a bit tough to navigate IMO) or his youtube page, http://www.youtube.com/weldingtipsandtricks. He covers all kinds of techniques and has a good camera setup so you can see the puddle/arc very well. I picked up some very useful nuggets for my TIG techniques.
 
franksta said:
You should also get (or make!) a cart with a clamp for your gas cylinder. If the valve gets damaged they turn into rockets and are extremely dangerous. I don't want to sound like Safety Sally, but I wouldn't want you to get hurt while having fun.

You may want to check out a website called http://www.weldingtipsandtricks.com (it's a bit tough to navigate IMO) or his youtube page, http://www.youtube.com/weldingtipsandtricks. He covers all kinds of techniques and has a good camera setup so you can see the puddle/arc very well. I picked up some very useful nuggets for my TIG techniques.
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:thumbsup:

All of this.
 
Finished the exhaust on Wednesday this week. Didn't get a chance to upload pics till today.

Ended up going with the single exhaust run. After a lot of test fitting and head scratching there was just no way I was going to be able to get a second pipe over the rear axle on the passengers side. The way the pan hard bard runs across there and the spring and spring seat sits on the axle there's just no room. The only way duals would work is if I could dump them out the sides before the rear wheels which would look stupid on anything but a drag car. I had to be content with fabbing a Y pipe and going with a single exhaust. The 2.5" will be more than enough for the small stock V8 in the car.

Here's pics of the finished product laid out on the garage floor before I bolted it all up:
exhaustcomplete.jpg

exhaustcomplete2.jpg


Y pipe was a bitch to make. Spent about an hour grinding that into the shape I needed to fit to the drivers side pipe at a nice angle.
ypipe.jpg

ypipeweld2.jpg

ypipeweld3.jpg


And here's a pic of what I think are probably the 3 best welds I made on the whole project:
bestwelds.jpg


What I found was not having a belt sander or band saw to cut the pipes and get a perfectly flat cut was making the welding difficult. If the two pieces did not fit together perfectly with the same size seam all the way around, I would end up burning through the metal if there was a slight gap. To get around this I would lay down some bead on either side of the gap first to make it thicker and then go back over the middle of it. Made for uglier welds but it worked. Nobody is going to see it anyway as its going to be under the car.

Thanks for all the input, I appreciate it. I'll post some pics up of the floor pans when I get to those in the project thread.
 
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