Welding Tips and Tricks

I have a critical weld to make on an aluminum casting. It is about 90 years old. It has been saturated with oil and fuel
for most of that time. It has several cracks through it that need to be repaired.

I am thinking that the cleaner the casting can be made to be-- the easier the welding and the more sound the weld can be made to be. (or alternately --- completely sound but easier to get there--- )

I thought of how to clean the casting in some way that would best eliminate the gas, oil,soot and shellack residue from
the pores deep inside the thickness of the semi-porious aluminum casting. here was my idea- to prepare it for a tig weld...

Construct a vacuum chamber (maybe from a pressure cooker or a thick cook pot of some kind) big enough to hold
the casting. Soak the casting in acetone for several days. let the solvent penetrate deep into the pores and mix with
any contaminates in there. Remove from solvent and place in vacuum chamber. Place a hot plate in the bottom of the
chamber so you can sit the casting on top of it so as to warm the part. Establish the vacuum and start the hot plate
and bring it up to about 180 F. Hold vacuum for several hours. The elevated temperature should help boil the
acetone back out of the pores and to the surface--- bringing the contaminates with it- where the vacuum can get rid of it.
I was thinking to repeat this process about 3 or 4 times-- which would be like doing a serial dilution of the contaminates
in the pores. If I ONLY soaked the part in solvent I would not be able to flush it out effectively.

Has any one tried a cleaning method like this ??????????????????????????

Thanks---
Tim

Somebody has to go first, You volunteered and We have elected You also. Let Us know how it comes out.

IF SMALL ENOUGH CASTING ,PUT IN BARBECUE FOR A COUPLA HOURS AT 400*. MOST OILS FLASH/BOIL OFF AT 380*. ONE WILL SEE BROWN RESIDUE APPEAR. SS WIRE BRUSH AND REPEAT TILL BROWN DOES NOT APPEAR FOR DEEP CLEANING. I USE THIS METHOD ON OLD HARLEY MOTORCYCLE CASES.V groove and pre heat 200-250* BUTTER FIRST WELD/pass WITH 4047 AND FINNISH WITH 4043 FOR STRENGTH.

My buddy has a parts cleaner from when he owned a transmission shop and it works pretty damn good. It's basically a giant dishwasher that uses a heavy duty detergent and heated water. After I run my castings through it I'll turn them and run them again. At that point i just heat the cracks with a torch to see what boils out, wire brush them off and repeat as necessary before actually welding. Up until a couple of months ago I had never welded an aluminum casting. They are not nearly as bad as the internet would have you believe, even if they have been oil soaked for the last 20 years as was the case with my oil pan. The worst casting that I tried was on the transmission housing of a Polaris RZR. It couldn't be put into the parts washer. I just cleaned it with acetone and a stainless wire brush. I had to heat it and brush it off three times before welding because it swelled up and looked like blackened swiss cheese. Still, it was not at all difficult to weld.

You might want to consider an ultrasonic cleaner for this application. If you find a shop that has one should not be a terrible charge to get it tossed in there for say an hour.

rick9345 wrote:IF SMALL ENOUGH CASTING ,PUT IN BARBECUE FOR A COUPLA HOURS AT 400*. MOST OILS FLASH/BOIL OFF AT 380*. ONE WILL SEE BROWN RESIDUE APPEAR. SS WIRE BRUSH AND REPEAT TILL BROWN DOES NOT APPEAR FOR DEEP CLEANING. I USE THIS METHOD ON OLD HARLEY MOTORCYCLE CASES.V groove and pre heat 200-250* BUTTER FIRST WELD/pass WITH 4047 AND FINNISH WITH 4043 FOR STRENGTH.

Follow this advice!

If the part will go in a large saucepan / dutch oven, boil in on the stove for a couple of hours after a degreaser soak in a mix of Tide and a strong dish wash detergent. If you go with the torch/BBQ , this is still a good final clean method to float the crap out. Then rinse and boil again in clean water.

After give it some time in an oven to dry out thoroughly.

I understand the idea of heating it in the BBQ---- however once the oil gets hot it starts oxidizing and turning to carbon
and it might lodge in the pores and then become impossible to remove. I like the idea of boiling water and a soap solution......

If I turn the oil into carbon it will be like the carbon on top of a piston. (inert and not going anywhere...)
Might also try ultrasonic--- but I want to go below the surface too. It still might help some though.

Tim

You would be surprised how poorly a vacuum clears hydrocarbon residue. It takes me sometimes weeks to clear clean light mineral oil (the carrier of the dye-penetrant I use) from an evacuated space, even with baking.

I'm in favor of the ultrasonic cleaning for your purpose, as a first step at least.

Steve S

These guys turned me on to Blue Gold cleaner, I find it highly effective especially if slightly heated.

Just fill an old crackpot with antifreeze and set it to bake for 4hours! No seriously, I thought my buddy was full of shit until I wiped the carbon of his piston tops with a napkin and they were perfectly clean. Just make sure to rinse and dry well if you do it.

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jethro wrote:I understand the idea of heating it in the BBQ---- however once the oil gets hot it starts oxidizing and turning to carbon
and it might lodge in the pores and then become impossible to remove. I like the idea of boiling water and a soap solution......

If I turn the oil into carbon it will be like the carbon on top of a piston. (inert and not going anywhere...)
Might also try ultrasonic--- but I want to go below the surface too. It still might help some though.

Tim

Ultrasonic is a very invasive cleaning process and if air can get to it then so can the cleaner. At the microscopic level.

GreinTime wrote:Just fill an old crackpot with antifreeze and set it to bake for 4hours! No seriously, I thought my buddy was full of shit until I wiped the carbon of his piston tops with a napkin and they were perfectly clean. Just make sure to rinse and dry well if you do it.

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'Fill an old crackpot with anti freeze?' Reminds me of when my brother goes shopping for cheap wine...



Kym

MosquitoMoto wrote:

GreinTime wrote:Just fill an old crackpot with antifreeze and set it to bake for 4hours! No seriously, I thought my buddy was full of shit until I wiped the carbon of his piston tops with a napkin and they were perfectly clean. Just make sure to rinse and dry well if you do it.

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'Fill an old crackpot with anti freeze?' Reminds me of when my brother goes shopping for cheap wine...



Kym

I've had a couple "crackpot" girlfriends I filled with...nevermind

exnailpounder wrote: I've had a couple "crackpot" girlfriends I filled with...nevermind

Seems as though we may have been dating some of the same women.....

RamboBaby wrote:

exnailpounder wrote: I've had a couple "crackpot" girlfriends I filled with...nevermind

Seems as though we may have been dating some of the same women.....

Damn..I married 2 of 'em and the third one is becoming suspect

I meant crockpot lol. Autocorrect fucked me again! Last time it was supposed to be "Don't tell me how to live my life" . It got sent as "Don't tell me how to love my pig" which is hilarious, and I still haven't lived it down!

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I was being 100% serious though, the antifreeze in a crock pot cleaned a set of rods and pistons better than I could have ever believed.

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GreinTime wrote: "Don't tell me how to love my pig"

Sounds like a Freudian slip to me. Kinky.....

RamboBaby wrote:

GreinTime wrote: "Don't tell me how to love my pig"

Sounds like a Freudian slip to me. Kinky.....

I thought a Freudian slip was what a modest drag queen wore under his dress...

Otto Nobedder wrote:
I thought a Freudian slip was what a modest drag queen wore under his dress...

I don't think the pig cares what the drag queen wears under his dress. This is what happens when you have a crazy pickle moustache and smoke too much marijuanica. Now you're just being silly.