welding question

[MURF]

can a 73 e 7R case be welded..the alternator circle has been broken off section on distributor case side no internal damage ..any ideas on welding rod type for tig repair?

[Zeke]

Welding this type of AL (or any AL) requires the utmost in cleanliness. Oils will seep out under the high heat that you never knew could be there. Most of the time preheating and slowed cooling are necessary. If your cases are assembled with internals, this is going to be tough. If not, then it's doable but I'd bolt them together first.

I ripped this from the Net: "
"> Situation;
>
> Mid 1940's Buffalo drill press cowling tipped over and broke apart.
> Approx. 1/4" cast aluminum, into about 6 pieces. Would you TIG it or maybe
> one of those aluminum brazing processes? I've ordered some of that hts 2000
> rod just for fun.
>
> Ben

It can be TIG welded.

The best generally available aluminum TIG rod for castings in 4047.
It is not always easy to find.
I have a stock of it.

All parts have to be cleaned as good as possible.

The trick is to tack weld the pieces together so the whole piece is
reassembled.
Take a die grinder with a narrow carbide burr and grind out the crack,
leaving bridges where your tacks are.

Preheat the whole piece in your kitchen oven to about 500 degF.

Lay in short stitch welds about 1 inch long, moving around the whole
piece to break up the heat.
Try to keep the piece from cooling down too much by keeping it wrapped
in a wool blanket, only exposing the area you are welding.

Once you have all the ground areas welded up, grind out the tacks and
finish the welds.
Put the piece back in the oven and return it to 500 degF.
Then turn off the oven and let it cool inside slowly.

BTW this is the same procedure for welding cast iron and cast bronze. "

Here is the credit:
http://209.85.173.132/search?q=cache:lRlDdQrFsbsJ:newsgroups.derkeiler.c om/Archive/Sci/sci.engr.joining.welding/2005-10/msg00156.html+cast+aluminum+welding+rod&cd=54&hl=en&ct=clnk&gl=us

[MURF]

are you sure this is an aluminum only case..not alloyed with magnesium?

[Zeke]

Alloys containing AL and magnesium can be welded.

[E Sully]

When magnesium starts to burn, no fire extinguiser will put it out.

[Zeke]

Class D will. Why do you say that?

Anyway, I have watched the AL/Mg alloy being welded. No histrionics.

Here's another diddy from some forum. This is for Mg, not an alloy like we've been considering.

"Weld it with AC TIG, large gas cup, (magnesium rods) and extra flow of argon. Turn the post flow up to about 12 seconds and keep the gas flowing on the welded area after you terminate the arc. As you would with aluminum cleanliness is essential for good results. If you do any filing or grinding make sure to dispose of the dust like down the drain or toilet as it's very unstable. Scrape the anodize of the weld area and even if it doesn't look like it's anodized scrape anyway as it might be clear. I know this sounds overkill, but it's what you should do. DON'T try aluminum rods no matter what and not even the 50 series which are magnesium based."

[ClickClickBoom]

Milt has it nailed, the key is the pre/post heat retention. Magnesium can be welded and can even be extinguished if burning. Rod choice and technique are all thats left.
Good luck
eric

[wowzer911]

I had my 915 mag case welded, a large crack and chunk broken off at the bell housing.
It turned out great. Need to find a competent welder, not for the novice. Even then, it took a few trys to find the right filler.

[mb911]

Yup fairly easy repair for someone that does Mag. I teach it all the time. the big issue is you need the tungsten very close to the puddle or the Arc can actually cause cracking on a newly solidified puddle.

[304065]

Send it to Ollies.

[Zeke]

Jeez, Cramer, you're in NY, he's in NY, there's no one closer?

Send it to Ben.

[304065]

Originally Posted by milt

Jeez, Cramer, you're in NY, he's in NY, there's no one closer?

Send it to Ben.

Well known Porsche restoration experts in the Northeast send their cases to Ollies. If the case is valuable enough to save (e.g. numbers matching) it's valuable enough to trust to somebody who has done it many times.

While it's out there, have the oil bypass mod, case savers, case resize, align bore, ceramic tumble and oil passage cleanout performed!

[Fishcop]

Try aircraft specialty welders - they weld exotic alloys fairly regularly.

[mb911]

Originally Posted by john_cramer

Well known Porsche restoration experts in the Northeast send their cases to Ollies. If the case is valuable enough to save (e.g. numbers matching) it's valuable enough to trust to somebody who has done it many times.

While it's out there, have the oil bypass mod, case savers, case resize, align bore, ceramic tumble and oil passage cleanout performed!

yeah I have done it just a few times as well

[Jim Williams]

Here is my first and only attempt at mag welding - on a 2.2 liter mag case. There are some pits, as I quit while I was ahead. So it's not as pretty as some one with a good deal of practice can produce. The problem (at least for me) with getting practice is finding a source for scrap magnesium to practice on. Practice is what produces nice welds.

The case had sat with water in the sump for some years and caused some significant corrosion. Magnesium is a lot less tolerant of water than aluminum. The opening in the bottom of the case where the sump cover fits looked bad, so I cleaned it up with a rotary cutter (Dremel) and the filled it back in with a magnesium rod using basically the same techniques and basic rules as for aluminum. Like aluminum welding (TIG) the weld area needs to be CLEAN. Clean up all the small magnesium chips from the Dremel as this is greatest danger of starting a fire.









The last photo shows 4 areas that were repaired.

[mb911]

Got some scrap if you like in fact I have a few sheets 1" thick should want to machine something. the biggest thing when welding them is to preheat and "boil the contaminants out then weld it

[TimT]

I know Fairchild/Rebublic and Grumman shut down most manufacturing here on LI years ago...but

Did all the little job shops they used close also?

I bet if you called some aircraft maintenance shops... they might steer you to people who can weld Mg

Maybe off New Highway, or Railroad Ave in those industrial parks..

[mb911]

I suppose it could be hard to find someone but I can think of 3 shops locally that do it all the time and I live in a town of 10,000 people so i would guess you would have better odds. now keep in mind we are a town of faa repair stations(my former life) and feed the light aviation sector so that might be the issue.