Vanguard News Network
VNN Media
VNN Digital Library
VNN Reader Mail
VNN Broadcasts

Old September 19th, 2005 #21
Kind Lampshade Maker
The paranormal silent type
 
Kind Lampshade Maker's Avatar
 
Join Date: Jan 2004
Location: Where you least expect
Posts: 8,265
Default

Quote:
Originally Posted by SiliconHillbilly
...Don't know too much about aluminum, except its a bitch to de-gas...
What do you mean by that Billy Boy? Are you patting the mold on the back to get it to fart? Please enlighten us with specifics
General Motors research
Chrysler research
Ford research
__________________
 
Old September 19th, 2005 #22
SiliconHillbilly
Junior Member
 
Join Date: Nov 2004
Posts: 18
Default

Quote:
Originally Posted by Kind Lampshade Maker
What do you mean by that Billy Boy? Are you patting the mold on the back to get it to fart? Please enlighten us with specifics
General Motors research
Chrysler research
Ford research
De-gassing is getting the hydrogen out of the melt. Aluminum has an affinity to entrap H2 when it is molten, which then shows up as gas bubbles in the casting. One has to flux the melt and then flush with nitrogen, or use the old chlorine-based tablets
 
Old September 20th, 2005 #23
Kind Lampshade Maker
The paranormal silent type
 
Kind Lampshade Maker's Avatar
 
Join Date: Jan 2004
Location: Where you least expect
Posts: 8,265
Default

Quote:
Originally Posted by SiliconHillbilly
...One has to flux the melt and then flush with nitrogen, or use the old chlorine-based tablets
In a previous post, an expert recomended throwing a handful of ordinary table salt, to prevent "Lunker". I tried looking up this German word, but couldn't find a translation. Perhaps, they meant these unwanted gas bubbles
__________________
 
Old September 24th, 2005 #24
JohnAFlynn
Banned
 
Join Date: Dec 2003
Posts: 1,789
Default

Quote:
Originally Posted by Kind Lampshade Maker
What do you mean by that Billy Boy? Are you patting the mold on the back to get it to fart? Please enlighten us with specifics
General Motors research
Chrysler research
Ford research

What's up with the white text? Laying some spider bait for the car companies?
 
Old September 24th, 2005 #25
Kind Lampshade Maker
The paranormal silent type
 
Kind Lampshade Maker's Avatar
 
Join Date: Jan 2004
Location: Where you least expect
Posts: 8,265
Default

More likely to bait their employees, investors and those who would otherwise read an economic page- in a newspaper or weekly publication. They might want to browse the website on other issues.
Now that you mention it, one can see the white print . What color does one use to make the spiders invisible?
__________________

Last edited by Kind Lampshade Maker; September 24th, 2005 at 01:29 PM.
 
Old September 24th, 2005 #26
"Maguire"
Junior Member
 
Join Date: Feb 2004
Posts: 6
Default

Quote:
Originally Posted by Pale Horse
Anyone here ever try it?I'm looking hard at it,make old pistons,etc into a $2000 metal lathe,milling machine,drill press.Could make a lot of other useful "tools" with those.
Yes. Aluminum works well without usually needing degassing if you follow proper procedures. "Clean foundry practice". Mainly following proper preheat procedures for tools and scrap charges to make sure all moisture is evaporated first.

Al is a lot easier to do starting out in the backyard than trying iron straight away. Al only needs temperatures up to 1350 F to melt, and much simpler home made foundry equipment.

Iron needs to reach 3000F, usually in a cupola.

Go here if your really serious on following this up.

http://stephenchastain.com/store.htm

This mechanical engineer has written several practical books on home foundry work. Order both "Sand Casting Manuals", I & II, and also the "Iron Melting Cupola Furnace". "Oil Fired Tilting Furnace" is optional.

I have all four books and highly recommend them as worthwhile investments.

Also go here: http://lindsaybks.com/ and request a paper catalog first. Most of their inventory isn't listed online, FYI. You'll be amazed at the range of books they offer in small scaled technology.

"Maguire"
 
Old September 25th, 2005 #27
"Maguire"
Junior Member
 
Join Date: Feb 2004
Posts: 6
Thumbs down

Quote:
Originally Posted by Kind Lampshade Maker
Aluminum is difficult to work with and requires much more energy than does iron.
Where on earth did you come up with all that?

Iron's heat of fusion is 13.81 kilojoules per mole.
Aluminum's heat of fusion is 10.71 Kj/Mol.

Iron melts at 2800 F
Aluminum melts at 1221 F

Iron has nearly 3x aluminum's density. Meaning you need
three times the volume of metal for equally sized parts. This is what made aluminum so popular in aircraft.

Then factor in energy losses due to foundry efficiencies which run from 1% to maybe 35% for a Siemans' reverberatory furnace. Wrap it all up and you need about 10x the BTUs to cast the same size part in iron than in aluminum.

You can melt aluminum in a home made steel pipe crucible, using grocery store charcoal in a crude foundry. The small scale foundrymen are unanimous on this point. Start with aluminum first and gain some competence before stepping up to iron.

The equipment needed to melt and pour iron is more elaborate, but still doable on a very small scale. The skill requirement is far higher. You'll need clay graphite or silicon carbide crucibles, propane or oil fuel for a fuel source, good burners, a strong blower and also a good foundry refractory design. And preferably a small cupola furnace fired with coal coke or very high quality hardwood charcoal. i.e. forget the grocery store stuff.

Aluminum is softer than iron and easier to work with hand tools or machine tools. Are you referring to these softer working characterisitics as being 'difficult' just because it clogs up regular files or because saw-cut parts have to be dressed?
 
Old January 27th, 2009 #28
Kind Lampshade Maker
The paranormal silent type
 
Kind Lampshade Maker's Avatar
 
Join Date: Jan 2004
Location: Where you least expect
Posts: 8,265
Default

http://www.p2pays.org/ref/01/text/00778/chapter4.htm

Quote:
...Aluminum production from bauxite ore is a three step process. First the alumina is extracted from bauxite ore usually using the Bayer Process. In the Bayer Process, finely crushed bauxite is mixed with sodium hydroxide and placed in a `digester.' High temperatures and pressures in the digester cause reactions in the ore / sodium hydroxide mixture. The result is dissolved aluminum oxide and ore residue. The residues, which include silicon, lead, titanium, and calcium oxides, form a sludge in the bottom of the digester. The aluminum oxide is evaporated off and condensed. Starches and other ingredients are added to remove any remaining impurities from the oxide...
__________________
 
Reply

Share


Thread
Display Modes


All times are GMT -5. The time now is 02:21 AM.
Page generated in 0.05973 seconds.