Welding Aluminum any Pro's on here?

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Armilite

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Is all this really less trouble than just casting a new piece? We used to do that in shop class in high school, though I don't know if the quality was good enough.
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I do plan to explore that route also. I have a Foundry about 45 miles from me that Cast a lot of Aluminium parts. Years ago, I inquired about making a 503UL Head Casting. They wanted $1,500 up front to make the Mould, then Each Bare Casting Cost so much, Cheap. Not Bad when you figure (1) New Pair of 503UL Heads Cost $900 from Rotax. Just a few sets of Heads and you would recoupe your Investment. The more you have Cast at a time, the lower the unit Cost is.

Today, you have Small 4kg / 8.8lb, LP Gas / Electric, Metal Casting kit's on ebay you can buy for around starting at $450 on up, or Build your own from the many Plans out there. With these cheaper 3D Printers you can also do a Type of Lost Wax Type Casting also. My Cast 670 Head is 2lbs, my Billet 670 Head is 4lbs. So these Singles, 377/447, and 503 Type Heads are around 2-3lbs Tops.

Small 4kg / 8.8lb, LP Gas / Electric, Metal Casting kit's $450.

Med 10kg / 22.0lb, LP Gas / Electric, Metal Casting kit's $1,076.90.

With Casting you have to deal with Shrinking. I have only Cast Lead Bullets. You could probably fill in the Voids with Modeling Clay and maybe Dip the Part in some of that Liquid Rubber Coating to make it a little over size and then Sand Cast it. But I like the idea of getting it into 3D CAD and maybe just 3D Print it, then do the Lost Wax Type Casting. If you could Melt enough Material to just Cast (4) PTO Covers, or (4) Heads at a Time, would be nice.

But a Billet part would be best! With a Billet part you could upgrade it to Pro8 even.
 

Armilite

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interesting data sheet....says 28 K strength which is not too shabby but the the temperature is such that it probably will destroy the temper of the alloy.

https://www.hobartbrothers.com/uploads/pdf/datasheets/Hobart_Maxal_4043.pdf

for a dead soft cast housing that might not be a problem
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What does 28 ksi mean?

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6061-T6 Aluminum
Physical and Mechanical Properties
Ultimate Tensile Strength, 45,000 psi
Yield Strength, 40,000 psi
Brinell Hardness 95
Rockwell Hardness B60
Chemistry Aluminum (Al) 95.8 - 98.6%
Chromium (Cr) 0.04 - 0.35%
Copper (Cu) 0.15 - 0.40%
Iron (Fe) 0.70%
Magnesium (Mg) 0.8 - 1.2%
Manganese (Mn) 0.15% max
Silicon (Si) 0.4 - 0.8%
Zinc (Zn) 0.25%
 

Armilite

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Nobody has mentioned the sheer joy of trying to weld oil impregnated aluminium. Or of repeatedly trying to get the oil out before you try again.
I've actually just bought some 4043 stick rods. I'll try them out when I get some new aluminium to play with.

If that were my part, I'd look at alternative ways to mount the whatever to what is already there. Some angle tabs could likely be affixed to the outside with multiple fasteners.
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Myself, I usually wash parts in Gas to get the majority of Oil Off, then I would Glass Bead the part, then Blow it Off, then Wash in some Alcohol to get any Oils Left Off and let dry before I would try Welding on it.
 

lr27

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I have seen foundry work done with less money than one of those kits, assuming firebrick and a crucible are cheap. Vacuum cleaner for a blower, into a sheet metal funnel shape where the gas is added, then into the firebird. Lost foam is another trick that can be done.
 

Armilite

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I have seen foundry work done with less money than one of those kits, assuming firebrick and a crucible are cheap. Vacuum cleaner for a blower, into a sheet metal funnel shape where the gas is added, then into the firebird. Lost foam is another trick that can be done.
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Yea, I'm sure you could take your Time and Shop around to make up your own Kit and Save some Money from using some of the Plans out there. As I said, it would be really nice to have one Big Enough to melt enough Material to do at least (4) (277, or 377/447, or 503) Heads, or (4) Single PTO Case's at a Time. You can Buy Melted Scrap Aluminium poured into Ignots from Salvage Yards fairly cheap, last I knew about .80 Cents a pound. A used 277, 11.8cr Head are going for $125+ on eBay. A used Dual Plug 447UL/503UL Heads are going for $225 each. A used Single Plug 377/380, 440/447, 503, Heads are going for $45+ each. Any High Performance Head, which means a High CR of 11.0+ is going to be worth $$$. Since many of these Rotax Parts aren't available New, they keep going up. So offering a New, maybe a High Performance Head can be worth some $$$. Today, an Avg Billet Sled/Jet Ski Head is $400 Retail. A New Cast 582UL Head is $820, a New Cast 447UL/503UL Head is $450 ea. A New Cast 670 Single Plug Head from The Crank Shop was $389. So a Small Home Based Foundry with your own Machining could make some money if you made the right parts and marketed them right. Which all takes Time, Space, and Money, to get started. I got the Time & Money, just don't have the Space at the this Time.

Going the CNC Machine Billet Route may Cost more to get set up, but may Pay for itself fairly quickly and give you Options to make more complex parts. Also may take up less Space & Time overall.
 

Armilite

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kips per square inch

1 kip = 1,000 lb (kilo-pound)
Ok, I didn't see "ksi" in my Conversion Calc. I see the meaning of Kip at, https://en.wikipedia.org/wiki/Kip_(unit) but it doesn't say anything about "kis" either, unless that's a Type O.

Under Force on my Conversion Calc, it doesn't show "kip" either.

A kip is a US customary unit of force. It equals 1000 pounds-force, used primarily by American architects and engineers to measure engineering loads. Although uncommon, it is occasionally also considered a unit of weight, equal to 1000 pounds, i.e., one half of a short ton. One use is as a unit of deadweight to compute shipping charges.

1 kip = 4448.2216 N = 4.4482216 kN
The name comes from combining the words "kilo" and "pound"; it is occasionally called a kilopound. Its symbol is kip, or less frequently, klb. When it is necessary to clearly distinguish it as a unit of force rather than mass, it is sometimes called the kip-force (symbol kipf or klbf). Note that the symbol kp usually stands for a different unit of force, the kilopond or kilogram-force used primarily in Europe prior to the introduction of SI units.

The kip is also the name of another unit of measure formerly used in Malaysia equal to approximately 9.19 kilograms, which is now obsolete.

So if 6061 is:
6061-T6 Aluminum
Physical and Mechanical Properties
Ultimate Tensile Strength, 45,000 psi
Yield Strength, 40,000 psi
Brinell Hardness 95
Rockwell Hardness B60

How does 28 ksi Rod compare to 6061 Yield Strength, 40,000 psi?

A Pusher Prop would be pushing towards the Engine, a Tractor Prop would be Pulling away from the Single Cylinder Engine at Max 250lbs of Thrust with (4) Bolts holding it on.
 
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Dan Thomas

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I did a lot of aluminum welding of broken castings back in the 1980s. USed a MIG (wire feed) welder with a mix of helium and argon. Did it on cold castings. I also taught the other guys to weld it, and the guys that had never welded steel learned it a lot faster. It doesn't weld at all like steel, and if you're used to steel you have a bunch of unlearning to do. Aluminum's plastic temperature range is really narrow; one second it's a solid, the next it's a liquid. By the time it's glowing it's been a liquid for a long time already.

The cheap aluminum torch brazing rod is mostly zinc, and it's not strong at all. It's chief claim to fame is that it will stick to aluminum.

Watch that what you're welding isn't magnesium. Plenty of aircraft castings have been cast of magnesium, like some wheels. Chainsaw housings are often cast from it. If you get that hot it catches fire very violently and very brightly. Even machining it you have to be careful.

Cast iron is fun, too. Did that in the '80s as well. I'm now restoring an antique woodburning kitchen range and had to weld a number of broken iron castings. I found that I'd lost my touch after too many years away from it. Use it or lose it.
 

mcrae0104

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it doesn't say anything about "kis" either, unless that's a Type O.
Yes, "kis", as you say, would be a typographical error (as opposed to type O, which is a blood type).
 
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