Cleaning Cast Aluminum "Kegger" Before Welding

[Mr onetwo]

I am going to do a couple of mods to the intake manifold of my '92 Dodge Dakota while it is off the engine fix the pan gasket.One involves installing volume reduction plates or "VRP's" to improve low end torque and throttle response.I am looking for suggestions on what procedure to use in getting it as clean as possible before I have it TIG welded.This is not a structural weld, just to hold in place and seal up the plates.Photos courtesy of Marty Fletcher at http://utawesomeperformance.com/index.htmlThanks!:bowdown:

 

[pepi]

Acetone is always the last prep before the TIG torch comes out. So I say start there.

Pep

 

[vpd66]

Start with getting some Simple Green Pro. It is only available at Home Depot and is purple in color.It works great for cleaning aluminum without etching it or turning it grey/black. If you can heat the Simple Green to around 150-180 degrees and soak the intake for about a 1/2 hour it works even better. Fully rinse it with water and dry then clean the areas your going to weld with acetone and you should be good to go.

 

[MoonRise]

Wash with appropriate solvent(s) to remove grease, oil, dirt, rodents, paint and so forth.

Solvents can include detergent cleaners (like Simple Green or others) as well as acetone.

Note that most detergent type cleaners (like Simple Green) WILL etch aluminum, because they are alkaline (pH greater than 7).

After you think you have the aluminum clean, then you use something like a carbide burr in an die grinder to remove the surface layer of aluminum oxide that has formed on the aluminum.

Then you clean it all again with the acetone.

You want (and NEED) to get to clean, bright, shiny aluminum before you go to the TIG welding step.

Then, when welding the cast aluminum, you may have to deal with 'crud' (technical term ) that floats up into the weld puddle from the cast aluminum. When that happens, relax (or say a few choice words) and stop welding. Then break out the carbide burr and the die grinder again and remove the crud. Clean again with acetone, let dry well. Start welding again.

Sometimes it may take multiple times of floating up crud from the casting into the weld puddle and then grinding it out with the burr before you can get to 'decent' material from the casting to get decent welds.

 

[Bigblue&Goldie]

I's say get all of the oil and other visible contaminants clean and then leave it up to the guy doing the welding to final prep it. If you are doing the welding, then follow the advice already given.

 

[MBfreak]

Sorry for posible OT.
When you reduce the plenum volume the tuning will have to be altered from stock.
And this might not be so easy , especially to tune to low torque low rev condition.

I have bult a couple of V8s with low plenum volume and they were really hard to tune to a condition usable for performance as well as driveability.
The pic shows a 427 in a Pantera. Dyno tuned, 525 hp.


Ola

 

[dffay]

Scothbrite Roloc discs on an angle die grinder work very well. Cautious use though since some of the discs are really aggressive cutters into aluminum.

 

[Ohmthis]

Scothbrite Roloc discs on an angle die grinder work very well. Cautious use though since some of the discs are really aggressive cutters into aluminum.

I’m not a fan of any abrasives (scotch bright is an abrasive) on aluminum. Parts of the abrasive are embedded into the base metal and can really reek havoc on the weld. A carbide cutter is what’s to use on aluminum. If it’s really oily/ greasy, I hit it with purple power and a pressure washer to break up the heavy stuff. Sometimes a brush Is needed first. I’ve also used an old propane grill to bake some of the **** off of it.

 

[Mr onetwo]

Sorry for posible OT.
When you reduce the plenum volume the tuning will have to be altered from stock.
And this might not be so easy , especially to tune to low torque low rev condition.

I have bult a couple of V8s with low plenum volume and they were really hard to tune to a condition usable for performance as well as driveability.
The pic shows a 427 in a Pantera. Dyno tuned, 525 hp.


Ola

That is certainly true in some cases but, the "Kegger" style manifold has such a huge amount of extra volume that this is not necessary.Marty has done a bunch of dyno work involving this and other mods for the Mopar magnum series engine.Take a look at his site.