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ALUMINIUM FOAMING

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ALUMINIUM FOAMING

Postby ESENTI » Fri Sep 08, 2017 12:43 pm

As the time goes by seems more and more obvious that aluminium must be perfectly clean when its is to be welded to a degree to almost sterilized !!!. some times due to rush to finish and to avoid the long time to clean it it creates spots of
dirt or foam like in the weld puddle. What do you do then any ideas how you can tell the difference that it is dirt or the aluminum alloy like any help will be appreciated.
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Re: ALUMINIUM FOAMING

Postby Warrenh » Wed Sep 13, 2017 12:52 pm

I weld a lot of aluminum and I rarely clean it at all. I have read many post that talk about cleaning and acetone. I do have to clean contaminated aluminum if its been in salt water or has oil or grease on it but not new material. Im guessing that some of your issues are gas or torch angle related. If you angle your torch forward like with steel you could see some of the foaming you describe. Try keeping your torch at 90 degrees to your workpiece. I have never seen what you describe on new aluminum. Post more details on what you are doing.

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Re: ALUMINIUM FOAMING

Postby cj737 » Wed Sep 13, 2017 2:25 pm

You might also check the AC Balance on your rig. Sounds as though you might not have enough cleaning action occurring in the arc?
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Re: ALUMINIUM FOAMING

Postby ESENTI » Wed Sep 13, 2017 3:26 pm

Thank you of what I have seen if a dirt bit it is entrapped in puddle it will not be easily removed and the amount of effort to remove it will be multiple of the original effort to have it clean in the first place .We speak here for dirty old
contaminated oily parts . As you may know I am Greek and Iam proud of my heritage, Hippocrates father of medicine have said better prevent a disease than cure it .
Any way the game starts in the early beginning i you do not see a clear aluminium puddle then there is
something wrong.Once an Audi crank sub when the arc is first created and melt is makes many small black craters boiling
black smoke, maybe hell it will be nicer something of course impossible to weld or with a lot of struggle.
About cleaning it is another story I have a fronius magic wave 2200 which is a good machine in this the cleaning is -5 to +5
easy, usually I am happy to use +5 in every dirty part and does not ball badly tungsten .usually I use 15 cfh or 12 but lately
I used 1/16 2% lanthanated and a 6 cup and I was Impressed how good it was no oxidation and a small shaft in DC welding
was perfect.
So I think there must be a ideal setting for each selection of gas flow + tungsten size +diameter of tungsten and kind
or else you get aprox close to the ideal, then there is the angle and quality of gas .Definitely my english are a lot better since I joined forum and I make less mistakes.I try a post a picture a.s.a.p. ( as soon as possible ).
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Re: ALUMINIUM FOAMING

Postby cj737 » Wed Sep 13, 2017 3:54 pm

2% lanthanated doesn't ball as much as 100% pure tungsten. I'm not sure I understood correctly, or if you misspoke, but there's no cleaning action on DC only AC (in case there's a misunderstanding)

If your machine only offers AC Balance range between -5 and +5, I'd refer to the manufacturers documentation to understand the actual numeric range and whether it's EN or EP as the percentage.

A 1/16 tungsten for aluminum is not a common choice. 3/32 is far more widely used and often 1/8 due to the amps required on ally welding. And a larger cup helps with protecting the weld and puddle during welding. Might try to use a larger cup and tungsten to see if your results improve. Then tinker with the balance...
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Re: ALUMINIUM FOAMING

Postby ESENTI » Thu Sep 14, 2017 5:40 am

No it is not a mistake just i want to make it clear , I speak for aluminium but i was impressed to see that if a you get it right with ceramic cup gas flow and tungsten it works also well in DC welding too as I have tried , same settings DC mode nice weld no contamination . Usually I weld well but it turned to be very oxidised in dc when i finish this time it was ok ( tiny parts or small parts ).
I am aware that there are some limitations in current and duration of the shape of tungsten . Zank has used 250 amperes
in 1/16 which is impressive I use maximum 130A in AC . Please make this trick , 1/16 2% lanthanated 6 cup and in same amperage say 130 , try 6, 10 , 12 , 15 cfh , use argon flow as the only variable and see it is not the same result and you get impressed to see it works best in lower flow find the best flow possible in the same other parameters
















dec mode
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Re: ALUMINIUM FOAMING

Postby ESENTI » Thu Sep 14, 2017 9:50 am

so this is a picture that gave me hard time to weld and i did all tips and tricks to do , this is about if you are one of few or one of many welders
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Re: ALUMINIUM FOAMING

Postby cj737 » Thu Sep 14, 2017 9:58 am

From that picture...
You are going to have a contaminated weld no matter what CFM of gas, cup size, tungsten size, AC Balance setting, and amp setting. That appears to be some type of cast aluminum machine/engine case. It is very likely saturated (soaked) with oil and grease deep below the surface. When you apply a TIG torch to it, those impurities will bubble to the top, contaminating your weld.

You can reduce this by, preheating the area, degreasing, re-heating, degreasing, and cleaning aggressively with a stainless brush. But you may still have intermittent areas of impurities show up. When you do, stop. Grind that off, and heat again. Continue to reheat until the impurities stop. You may of course not do this if the weld is not critical, but aluminum is not tolerant of impurities within the weld.

This type of repair is the bane of any TIG welder because you almost never get it clean and done without a LOT of extra work. Even then its trial and error.
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Re: ALUMINIUM FOAMING

Postby AndersK » Thu Sep 14, 2017 12:29 pm

Even if it's not soaked in oil you will get bubbles in your weld. Cast aluminium has always a degree of porosity. Some of it will go thru your weld and some will be trapped inside your bead, that's the nature of it.
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Re: ALUMINIUM FOAMING

Postby ESENTI » Thu Sep 14, 2017 4:26 pm

Say it is simply impossible additionally when it got hot a lot of of oil fumes came out .
I had to do it since this was in rush to use the engine ( it is the crank case of honda engine XLR 250)The chain broke and in consequence
the crankcase broke.He wanted to do it with engine in the frame no manipulation of torch was possible no room to move i did
what i did and then i use some glue to the portion was not possible to tig. I should not have done it but he was continually
kept persuading.Same thing would had been a piece of cake if it was dismantled an properly prepared and cleaned.
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