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View Full Version : New aluminum casting method - stick welder, graphite and kinetic sand



superUnknown
08-11-2014, 02:35 PM
It's so simple, it really shouldn't work. But the proof is in the pudding!

http://youtu.be/L3t-jBATM0w
Since this is my first successful aluminum casting, I'd really appreciate your thoughts!

adatesman
08-11-2014, 02:52 PM
Pretty awesome.

Correct link: https://m.youtube.com/watch?v=L3t-jBATM0w

PTSideshow
08-11-2014, 03:47 PM
Slick, other than the waxed cup!

chipmaker4130
08-11-2014, 04:01 PM
Interesting, but the definition of the cast part was poor. You'd need to oversize everything and hope it was close enough to machine to size. Perhaps with some experimenting one could overcome that.

topct
08-11-2014, 04:09 PM
What would happen if you connected the welder lead directly to the graphite crucible? Or if you used just a plain graphite rod instead of a plated one? The rods they use for refining aluminum are not plated. A way to confine that mold material that did not burst into flames would also be a plus.

Ironwoodsmith
08-11-2014, 04:12 PM
Why didn't the sand slump down when you removed the pattern?

boslab
08-11-2014, 06:02 PM
Quite impressed, mini electric arc furnace, the copper wouldent hurt, after all if any gets in the Ali it would just join whats already there, at least in Duralamin.
Poss an argon shroud might help with things too, just a guess
The play sand idea worked, though the other types of sand available might be better other than that i think he did well, somthing to try at least.
Puddle welding isnt a new thing, gantry rails on overhead gantrys are usually puddled on the joints, graphite forms and the biggest sticks i have ever seen or used, 1/2 rods about 3 or 4 feet long
Weld done that man!
Mark

loose nut
08-11-2014, 07:05 PM
No de-gasser, didn't skim off the dross and it's hard to say if the "sand" contaminated the metal but I would bet that there is porosity in the casting. With proper molds and a better arc rig (and technique) it would probably work OK.

_Paul_
08-12-2014, 06:36 AM
Does the welder have to be a DC unit?

Paul

superUnknown
08-12-2014, 04:17 PM
Interesting, but the definition of the cast part was poor. You'd need to oversize everything and hope it was close enough to machine to size. Perhaps with some experimenting one could overcome that.
Yes, this was a proof of concept run... baby steps. I got a suggestion in the Youtube comments to heat up the kinetic sand in a microwave and then tamp the part in place and allow to cool. So I'll try that next.

superUnknown
08-12-2014, 04:20 PM
No de-gasser, didn't skim off the dross and it's hard to say if the "sand" contaminated the metal but I would bet that there is porosity in the casting. With proper molds and a better arc rig (and technique) it would probably work OK.

any suggestions on "a better arc rig" or just sayin? I haven't been able to find any references on arc furnace "technique" care to enlighten us?

superUnknown
08-12-2014, 04:22 PM
Does the welder have to be a DC unit?

Paul

No, I think AC will work fine, but I haven't tested it.
Although, I think industrial arc furnaces are all DC. Slower electrode loss?

superUnknown
08-12-2014, 04:25 PM
What would happen if you connected the welder lead directly to the graphite crucible? Or if you used just a plain graphite rod instead of a plated one? The rods they use for refining aluminum are not plated. A way to confine that mold material that did not burst into flames would also be a plus.

The graphite is very low resistance, so the cables and clamps would heat up at the same rate as the crucible.
I think the arc localizes the heat better, anybody know for sure?

Old Hat
08-12-2014, 04:38 PM
What about two electrodes ?? nearly paralell, (increasing angle up toward the mounted ends)
to keep the arc at the bizness end.
Likely might have to be AC to keep from distroying the DECP electrode.

Or have the DCEP trode just a tad longer, and the short duration burn
it might end up a tad shorter.

A thin perishable copper or aluminum wire to trigger the arc, then lower into your crucible.

A helium back-gass would be a pluss too.
I did HeliArc (DC & helium) welding for three years.
I bet I could get a few cubic inches of aluminum molten in no time....
in a crucibal with a copper positive button in the bottom.

=================
Long ago I hit a ball of Silly-Puddy on a scrapped anvill with everything I could put
into a Two pound hammer.

There were small blue broken glass looking shards all over the basement,
that instantly melted back into little blue puddels of Silly-Puddy .

The hammer never saw the face of the anvill !!
>>Don't try this at HOME !<<

macona
08-12-2014, 05:25 PM
They make automated air arc torch carriages. The rod feeder feeds in until it sees current flow and then pulls the rod back to start the arc. Then the controller watches the arc voltage and moves the rod in/out to maintain the arc voltage at the set point.

Old Hat
08-12-2014, 05:35 PM
They make automated air arc torch carriages. The rod feeder feeds in until it sees current flow and then pulls the rod back to start the arc. Then the controller watches the arc voltage and moves the rod in/out to maintain the arc voltage at the set point.

Can we assume AC then.
Don't search lights Arc-lights work like that too.?

PS;
Clouds killed the Moon here :( I wanted to catch it rising out of Lake Michigan!
Did You get it?!?!

superUnknown
08-12-2014, 05:36 PM
Long ago I hit a ball of Silly-Puddy on a scrapped anvill with everything I could put
into a Two pound hammer.

There were small blue broken glass looking shards all over the basement,
that instantly melted back into little blue puddels of Silly-Puddy .

The hammer never saw the face of the anvill !!
>>Don't try this at HOME !<<

LOL...As I RUN to the store to buy silly puddy.

J. R. Williams
08-12-2014, 05:39 PM
The large steel mill electric furnaces use three large diameter carbon rods that project down into the ladle.

Old Hat
08-12-2014, 05:40 PM
LOL...As I RUN to the store to buy silly puddy.

It doesn't come with the
SAFETY GOOGLES REQUIRED labble ya know!:o

Old Hat
08-12-2014, 05:41 PM
The large steel mill electric furnaces use three large diameter carbon rods that project down into the ladle.

Great! need to find a vid of that! or at least a graphic cartOOn !

madmetric8x1
08-12-2014, 05:44 PM
The fabulous Auto-Union 12 and 16 cylinder racing cars of the 1930's and 40's used a lot a beautifully cast and polished aluminum (and magnesium at one point) throughout; engine, drum brake cooling fins, etc, and likely just to look good. Recent analysis found those amazing beasts made do with todays equivalent of "lawn chair quality" aluminum at some vital parts. Always something to be said for a bit of over-engineering and fine craftsmanship. I'm just throwing this in as food for thought, it has nothing really to do with the original post. So no offense intended to anyone about anything.

loose nut
08-12-2014, 06:41 PM
any suggestions on "a better arc rig" or just sayin? I haven't been able to find any references on arc furnace "technique" care to enlighten us?

Just rig up some rod holders so that the arc will be stable and not on and off all the time. A screw mechanism to lower the rod/s would help to. Nothing fancy.

AC should work fine, most buzz boxes "back in the day" came with a arc torch that held two rods, one could be pivoted to start and control the arc length (heat). Used for heating, melting and brazing.

I would be interested in looking at the middle of one of the castings to see the quality of it IE: contamination, porosity etc.

Old Hat
08-12-2014, 06:46 PM
I would be interested in looking at the middle of one of the castings to see the quality of it IE: contamination, porosity etc.

Pretty much.

https://www.youtube.com/watch?v=G6Uxh-xtU-g

LOAD!

schor
08-12-2014, 08:26 PM
Oh no, I can just see superUnknowns next video, you should not have shown him that video.


Pretty much.

https://www.youtube.com/watch?v=G6Uxh-xtU-g

LOAD!

_Paul_
08-12-2014, 08:45 PM
AC should work fine, most buzz boxes "back in the day" came with a arc torch that held two rods, one could be pivoted to start and control the arc length (heat). Used for heating, melting and brazing.


+1

I have a couple of this type:
http://www.hisltd.co.uk/images/FuturisCarbonArcBrazingTorch-large.jpg
Does it matter what kind of Carbon Arc rods you use ? I still have a couple of the original "carbon pencils" that came with them.

boslab
08-12-2014, 08:53 PM
Carbon rods, gouging etc all have copper cladding, mainly to stop the rods from snapping I'm told.
Mind it may be the way they get made, tube filled and cooked?, perhaps
Mark

superUnknown
08-12-2014, 10:09 PM
Carbon rods, gouging etc all have copper cladding, mainly to stop the rods from snapping I'm told.
Mind it may be the way they get made, tube filled and cooked?, perhaps
Mark
Put the electrode in the air arc holder the wrong way and find out!
That copper cladding is critical.

dian
08-13-2014, 04:22 AM
how can you put it in the wrong way?

macona
08-13-2014, 04:38 AM
Can we assume AC then.
Don't search lights Arc-lights work like that too.?

PS;
Clouds killed the Moon here :( I wanted to catch it rising out of Lake Michigan!
Did You get it?!?!

No, DC. Virtually all air-arc I know of is done with DC.

Modern arc lamps used in search lights are usually xenon short arc lamps. They use Xenon gas under extremely high pressure to create that bright, white light. They operate at only 20-30v but at a whole lot of current.

Arc furnaces at foundries use 3 electrodes because they put 3 phase power right into the electrodes. I am guessing it is just not worth it to rectify.

Do you mean the supermoon? Nah, totally cloudy here, had lightning storms earlier today and it is raining right now. I really dont get what the recent fascination is with the "Supermoon" I think 5% bigger and 7 percent brighter than normal? Most people never knew or cared until the media started to make a big deal about it a couple years ago. I have a telescope! The moon is big enough as it is!

https://farm4.staticflickr.com/3482/5823183061_c3ea197208_b.jpg (https://flic.kr/p/9SzkrX)IMG_0504_DxO (https://flic.kr/p/9SzkrX) by macona (https://www.flickr.com/people/67292116@N00/), on Flickr

macona
08-13-2014, 04:40 AM
Carbon rods, gouging etc all have copper cladding, mainly to stop the rods from snapping I'm told.
Mind it may be the way they get made, tube filled and cooked?, perhaps
Mark


I think they are electroplated.

macona
08-13-2014, 04:41 AM
how can you put it in the wrong way?

Put the exposed carbon tip in the clamp.

Old Hat
08-13-2014, 06:18 AM
Thanks, how many people have a telescope?
as a percentage maybe .02 % but fractionaly you put that 5% & 7% on the horizon. It matters.
At least a few more folks are looking at the moon instead of a Kardashian update.
I read a news clip about Kurds rescueing Yezidi reugies, had 303 comments.
http://news.yahoo.com/syrian-kurdish-fighters-rescue-stranded-yazidis-172250706.html
Robin Williams.... has 10s of thousands of comments.

I really dont get what the recent fascination is with the "Supermoon" I think 5% bigger and 7 percent brighter than normal? Most people never knew or cared until the media started to make a big deal about it a couple years ago. I have a telescope! The moon is big enough as it is!

https://farm4.staticflickr.com/3482/5823183061_c3ea197208_b.jpg (https://flic.kr/p/9SzkrX)IMG_0504_DxO (https://flic.kr/p/9SzkrX) by macona (https://www.flickr.com/people/67292116@N00/), on Flickr

loose nut
08-13-2014, 09:41 AM
No, DC. Virtually all air-arc I know of is done with DC.



Arc-air gouging is done with DC but an arc torch can be used with ac or dc.

Old Hat
08-13-2014, 10:37 AM
I had to do intence very large machining bridgemill work in the same end of the same bay
that air-arc air-gouging could happen without warning anytime.:mad:

macona
08-13-2014, 09:42 PM
Thanks, how many people have a telescope?
as a percentage maybe .02 % but fractionaly you put that 5% & 7% on the horizon. It matters.
At least a few more folks are looking at the moon instead of a Kardashian update.
I read a news clip about Kurds rescueing Yezidi reugies, had 303 comments.
http://news.yahoo.com/syrian-kurdish-fighters-rescue-stranded-yazidis-172250706.html
Robin Williams.... has 10s of thousands of comments.

Millions in the US along. And then there are binoculars which are great for lunar viewing. You have got to have a pair of binos, right?

Don Young
08-13-2014, 09:58 PM
As I recall, the old carbon arc searchlights and movie projectors used a negative carbon that was much larger than the positive one. Most of the heat and light appears at the negative carbon.

macona
08-13-2014, 11:08 PM
Electrons flow from negative to positive to the heat is concentrated in the positive electrode. That's why when you tig weld dc-reverse you have to use a large electrode for the same current.

But really, melting aluminum is really easy. You can use almost anything t ndo I it, air over charcoal or even just a small electric furnace.

dp
08-14-2014, 12:47 AM
Since the supermoon came up, two nights ago my wife said to me "there's a fire burning on the ridge line across the valley!". Well it turned out to be the moon rising into the smoke of our wildfires here in Washington State. It caught us without any camera ready, so last night I was prepared with two cameras and intervalometers on each. Unfortunately we had a rainstorm typical of the tropics - a mega downpour that hit our metal roof like hammer falls and the wind kicked up like tornadoes were set loose. The howl and drumming also blocked out any chance of seeing the blood red moon that rose the previous night, and damnation, there was no lightning or thunder save one clap. Tonight the smoke's gone - for the first time in several days there is little haze and happy happy joy joy, we're in the peak of the Pleiades meteor shower. Got to run.

Old Hat
08-14-2014, 07:38 AM
Millions in the US along. And then there are binoculars which are great for lunar viewing.
You have got to have a pair of binos, right?

I have a top tier rifle scope I kept form the 70's.
I'm a both eyes open shooter, so I'm better off viewing that way than using binoculars.
Left eye is not 'master eye', and has considerable estigmatism and a different focus and color than my right eye.

I found I could see Jupiter's moons with it one cold night in the 70's.
But theres no way I know of using that on/with a Camera.

dian
08-14-2014, 10:02 AM
Put the exposed carbon tip in the clamp.

so whats going to happen?

RichR
08-14-2014, 10:23 AM
I would imagine it would fracture or crumble since it's probably brittle.

superUnknown
08-14-2014, 01:54 PM
I would imagine it would fracture or crumble since it's probably brittle.

Actually, it can be quite spectacular. The non clad section gets white hot and begins to vaporize away, until there's nothing left and you get a huge hot arc right above your hand.

superUnknown
08-25-2014, 06:39 PM
http://youtu.be/Y9_IjUd-S6I

I sectioned the casting for show and tell. Lots of room for improvement!

Weston Bye
08-25-2014, 06:56 PM
Good discourse in the video, SuperUnk.

An observation about the lesser porosity in the lower section: my reasoning that being deeper, the "head" pressure may have reduced the voids. A tall sprue on your next pour may reduce the porosity. Also, a degassing tablet before pouring should help.*

*full disclosure: these observations from someone who has never actually done it.