Welding Tips and Tricks

Hello all,

Since I don't have a more experienced welder in my shop to say "hey what's going on here" I'll have to ask all you fine people who are more knowledgeable than I and have probably seen this particular issue before.

So the weld in question is a cast ally charge air cooler tank approx 3/16" thick welded to a 1/8" header plate of the CAC core.

The issue I'm having is A) the Smut in my welds (Think that is due to carbon and oil boiling out of the casting or it's the left over flux residue from the CAC core)

and B) That black stuff in my cleaning band.

I"ll try to attach a couple pics to show what I'm talking about. Also trying to get a decent pic of my tungsten which keeps doing funny things as well (Won't stay balled) Gets all broccoli like (but seems to weld fine still)

Anyways here's the pictures of what I'm talking about.

Black edges of your ally weld points to a long arc, insufficient gas coverage, or contamination on the tungsten. What cup size? Gas lens or collet body?

A broccoli end of your tungsten is too sharp a point in AC and too low a cleaning action. A 60* taper is what I use, but I do run near 65% cleaning action, especially with smut-filled work. You can put some heat in the area, then wipe it down with Acetone to help clean it up some. Stop periodically and wipe some more. And remember to wipe down your filler rods I bet they’re filthy...

cj737 wrote:Black edges of your ally weld points to a long arc, insufficient gas coverage, or contamination on the tungsten. What cup size? Gas lens or collet body?

A broccoli end of your tungsten is too sharp a point in AC and too low a cleaning action. A 60* taper is what I use, but I do run near 65% cleaning action, especially with smut-filled work. You can put some heat in the area, then wipe it down with Acetone to help clean it up some. Stop periodically and wipe some more. And remember to wipe down your filler rods I bet they’re filthy...

So for the setup to start. 1/8" 2% lanthanated tungsten, #8 cup gas lense with 20-25cfh(where I'm usually at can check tomorrow when back in shop) settled in at 250amp max no pulse with 72% balance and think I dropped my frequency to 90hz.

And for the rod I ended up using the 1/8" 4043 that's been in our dirty shop 5+ years stored poorly in a open topped pvc pipe. I swear I can wipe it down 2 or 3 times and it's still dirty.

I guess my next job with a casted tank I'll try some new rod and see if it clears up the pepper in my weld cause there's not much else I can think of to add to my tank prep I already do.

Thanks for some things to check into and cross off the list of culprits



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Don’t forget that if your welding on car parts (especially aluminum) that were in service there probably embedded with contamination. Like sand blasted with road salt and engine grime at 60mph.

an intercooler will have engine oil soaked into it.

the black looks typical of contamination of the metal. either cook it out and/or do a quick pass on it to get the cleaning action clean it up a bit before you weld.

tweake wrote:an intercooler will have engine oil soaked into it.

the black looks typical of contamination of the metal. either cook it out and/or do a quick pass on it to get the cleaning action clean it up a bit before you weld.

Yeah it most certainly was oil soaked. Not nearly as bad as most I see. (About a tablespoons worth in one tank and not too. Baked on.)

I've seen these CAC's before that come in literally 3/4 full of oil or where the oil is baked on to the cast so bad nothing removes it but sand blasting which in reality probably just punches the contaminates further into the metal but makes the surface look 'clean'.


Ah but perhaps I'm just trying to perfect it too much. Because after all it is rebuilding with used parts that are in a rough dirty service environment. Maybe I'll always just live with a bit of pepper in the welds

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Get a Green ScotchBite pad and wipe yuor filler down with it, then follow with Acetone. I think that will help clean up your weld pool some and reduce the soot around the edge. But I still suspect your arc length is a bit long and that is causing a lot of the edge soot.

No doubt oil-soaked aluminum is a MFer to gt a pretty weld on, but diligent cleaning and preheat followed by cleaning helps a lot.

cj737 wrote:Get a Green ScotchBite pad and wipe yuor filler down with it, then follow with Acetone. I think that will help clean up your weld pool some and reduce the soot around the edge. But I still suspect your arc length is a bit long and that is causing a lot of the edge soot.

No doubt oil-soaked aluminum is a MFer to gt a pretty weld on, but diligent cleaning and preheat followed by cleaning helps a lot.

Well I'll give that a whirl and see if it helps. I think I'll always have some pepper here a d there when dealing cast CAC tanks.

And yes my arc length was probably much too long. I was having a great time trying to prop and get close enough without cooking my hands.

Really need to get me a together finger xl so I can fit more fingers in it. (Local LWS only stocks small even though I told em the xl is much better)

Anyways thanks for some pointer on things to work on and check off the list etc

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Well I feel like I am making some progress. This unit is a hydraulic oil cooler that the core was damaged in during a accident on the highway.

Definately less smut floating around in the puddle with this unit (Extruded tank not Cast) Not sure if the tank material had more to play with that or the type of service the unit has seen.

As far as I can tell it appears the smut is coming from the acetone wipe down rag leaving lint on the parts (Someone cheaped out and bought fleece rags)

It's weird because I go to start my weld and the ally gets black crud on it immediately but then when I put my first dab of filler in it seems to clear up (Or go under the filler).

Anyways, pictures show some close ups of the welds, Please critique and give some pointers if you guys have any.

Here's the pictures, hopefully they loadup alright.

If it appears promptly after arcing, it’s purging from the base material. Cooked in grime is all.

That makes sense to me. Just weird how it only happens at the start before filler is added. Once I get filler in there it seems to disappear and not poke it's ugly head back up.

Now it's got me wondering if I'm penetrating properly of I'm just laying a bead over top of the material.


Hmm perhaps one day i'll have to spend the money to make a cooler and then cross section it to see what's going on in inside it cause it probably be money well spent.

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The second go at it does look much better though.