[tireman]

Hey guys i have been searching on how to clean/prep an aluminum engine oil pan for welding. i am using S.S. brushes but they only get in certain crevices and once you heat the part up that oil just comes right through the cracks and contaminates the weld. i have tried the acid cleaner for coils but just not working very well. Here where i live there are many car lots that rebuild salvage vehicles. Lot of these cars have broken oil pans and they prefer to pay 50 to 70 dollars to weld an oil pan than to buy one from the dealer or salvage yards. Many of the salvage yards will not sell them if the motor is in good condition. For many of these guys the best option is to weld the pan. i just started welding the pans but having issues cleaning it before welding.

Anyone out there recommend another method to remove oil from pan and prep it for welding.

[jpence38]

When you have an oil-soaked or carbon permeated part, you can try to heat with a torch to burn most of it out, but you are probably stuck with having to weld, grind, weld, grind, and weld some more till you get good metal in there that will not crap up on ya. That kind of work is a pain in the @*!

[nova_70_383]

with oily and greasy aluminum parts i have the best luck with plain soap and water!

[pro mod steve]

I did a engine case on a floor scrubber for a customer. Stainless brush run the torch around the area low amp to boil out crap. Grind brush and repeat. Then started adding filler to edge of hole and it still looked like pourus lava rocks grind and repeat till I got a clean base then welded in new filler piece. It is time consuming and a pain but it is doable.If they want to pay for the actual time and materials to do it right.

[Steve from Ohio]

I have been welding oil soaked aluminum diesel tanks for local trucking companies for several years. I've also done a few aluminum oil pans and aluminum motorcycle engines.

I've tried all the tricks to try to get a decent tig weld on oil soaked aluminum but could never get the aluminum clean enough to get a decent leak free weld. Yeah, I've tigged a tank or two but they always came back when it started leaking. So I adapted.

Sometimes tig welding is not the answer.

I learned that gas welding of oil soaked aluminum is the only way to ensure a leak free weld. I use a torch called a Henrob (AkA Cobra 2000) for gas welding. It allows for real good control of the flame and is soft enough to prevent blow through on aluminum. The flame on a Henrob is different from any other torch. The flame is hotter in a smaller area than any other torch I've owned. You have to see it in action to see what I am talking about.

The Henrob burns off the oil and any other contaminant better than a tig which allows for a stronger more solid weld on aluminum.

All the other posts on this topic are right on though. Cleaning is most important. I use a combination of Dawn dish liquid soap and Cascade powder dishwasher soap. I clean the daylights out of whatever I am welding and then finally hit it with tar and grease remover.
I spend more time prepping and cleaning than I do welding. It takes time but is worth it.

[NT Unique]

I use a solution of "Tanker Cleaner", it has 10% hydrofluric acid in it so you gotta be real careful with it. I water it down a little, probably20% into a tub then immurse it into it and let it soke for a while (I would always heavily degrease auto parts before this stage). I pull it out, wash it down with the pressure washer, then bake it for an hour or I gets the bottle of BBQ gas and flame heat the area for about 15-20min. This tends to draw out pretty much all the crap, then it's just a matter of running the tig over it to confirm if its all clean. If not back in the acid and then the heat torch.
Havn't had a problem yet.
Not sure on availability of the tanker cleaner over there. Over here you have to get a chemical licence to buy it, but worth it in my opinion.

Cheers

[Rbeckett]

Not to be a buzz kill or anything but why would you risk an oil out and engine job for a few welding bucks? Too large of a chance that it will leak or crack at some later time and you will be liable since you welded it. If an oil pan is damaged I replace it with the factory approved part with new gaskets and proper cleaning to protect myself and my shop from an expensive comeback. Welding has it's merits but the actual cost to do it correctly (which means removal and new gaskets) is very close to the replacement cost of the pan. If you are fabbing a specialty pan then that is a completely different issue, but if your just welding up cracked pans then that is a very dangerous policy that will cost you in the longrun. Unfortunately it isnt a matter of if the weld fails merely when. The pan got damaged somehow, it will probably get damaged again. Just some thoughts from a former Master Tech and shop Foreman and small shop owner. Hope this helps you decide.
Bob

[weldin mike 27]

Hi,

I think this post started as a question about old pans or sumps as we call em in Australia. Where replacement parts were not availible.
Mick

[jakeru]

First you've got to clean off the "bulk" of the oil from the area of the weld.

One way you could do that - put the whole thing in an oven, crank up the temp to 400F or so... and let it "smoke" When done smoking, the oil is converted into a powdery, dry carbon you could probably pretty easily wire brush away. Another idea besides the oven: a torch. Like a disposable propane bottle torch, but that will probably be too slow, so maybe a big "weed burner" on a barbeque bottle. Those put out insane BTUs, you know. Don't get it too hot though, or you'll ruin the heat treat / distort it or even melt it! Just until it stops smoking would be perfect. Obvisouly, this is going to stink really bad so use good ventilation. After the heating, brush away the dry residue with a stainless scratch brush.

Another way to remove the oil besides using heat - use solvent like (non-chlorinated) brake parts cleaner and paper towels and wipe, wipe, wipe away until dry (at least in the area of your weld.) Be sure to do both sides of your weld, front and back, if you'll be "fully penetrating" (which for repairing a crack, you would be.)

OK after removing the "bulk" of the oil, use low-amps on your TIG torch to "test" the cleanliness and to convert any remaining oil into charcoal (or whatever powdery black solid) go over the area with low amps until the aluminum leaves a whitish "etched" color, not a black or dark colored one, or it means you have more cleaning to do. A crack will likely have contamination down within. I would suggest using a carbide burr to vee out the crack (and along with it, most of the contamination inside it.) This will aid you in more fully penetrating. Welding both sides (if accessible) would be the best way to go for crack repair.

It's important to remove the oil before welding to prevent a porous weld deposit. Hydrogen from the oils dissolves into the molten puddle and can't stay dissolved when the puddle solidifies, so it causes gas pockets in the weld deposit = porosity.

I have a link to web post I made of a welded BMW oil pan somewhere; let me see if I can find a link.

[jakeru]

Here's the link to that BMW aluminum oil pan weld I posted on-line:
http://weldingweb.com/showthread.php?t=47202

Cheers

[Otto Nobedder]

When I have a cracked aluminum part I can't easily clean, I'll cut out the crack using a 1/4' grinding wheel like a cut-off wheel. This eliminates ALL the crap. Then I'll back up the weld with a slab of yellow brass I keep for such occasions. It has several profiles ground into it to fit a lot of shapes. I'll then fill and cap from one side then remove the brass. Then a clean up and fusion pass (no filler) on the back side, followed by a cap pass.

It's a little extra work, but there's no guessing.

Steve