Home made green sand

[100model]

If anyone is interested in making thier own green sand this recipe is for sand used for cast iron. It can also be used for aluminium or brass/bronze, just leave out the coal dust addition. [ame="http://youtu.be/3x4Fp85594c"]http://youtu.be/3x4Fp85594c [/ame]

 

[metalmad]

That Sand mixer is the Ducks guts Mate
Got me thinking!
Pete

 

[gus]

If anyone is interested in making thier own green sand this recipe is for sand used for cast iron. It can also be used for aluminium or brass/bronze, just leave out the coal dust addition. http://youtu.be/3x4Fp85594c

Please advise the reason for using coal dust. Does it replace Bentonite???
Please enlighten me.

Done a bit of gravity casting of aluminium with cast iron mold to make auto condensate traps.

 

[MuellerNick]

Please advise the reason for using coal dust. Does it replace Bentonite

But he is adding bentonite.
Coal dust makes a smoother finish.


Nick

 

[100model]

gus bentonite is the binder, it holds the sand together.

 

[chucketn]

Coal dust is added to green sand used only for casting iron.

Chuck

 

[gus]

Hi ! 100model/Chuck.

I must admit adding on coal dust is new to me in China. Or Perhaps during my foundry audits I missed out. Gus is no foundry expert. Auditor ate bad food in China and Gus had to chipped in with
Ingersoll-Rand Audit Training Material for reference to audit foundry. Went in to visual audit foundry floor,listen to the plant QA Manager Video Presentation. Counter check his claims.
However I grew up in a foundry district which now all gone. A young lad of 16 cannot pick up much know how in 1960.

 

[SmithDoor]

Coad dust/charcoal dust is use in cast iron and steel to stop sand from melting on to the casting.

If you get lucky you can use the sand in your back yard for green sand this can be use for both Al and brass.

Dave

Hi ! 100model/Chuck.

I must admit adding on coal dust is new to me in China. Or Perhaps during my foundry audits I missed out. Gus is no foundry expert. Auditor ate bad food in China and Gus had to chipped in with
Ingersoll-Rand Audit Training Material for reference to audit foundry. Went in to visual audit foundry floor,listen to the plant QA Manager Video Presentation. Counter check his claims.
However I grew up in a foundry district which now all gone. A young lad of 16 cannot pick up much know how in 1960.

 

[SolarFreak]

Please advise the reason for using coal dust. Does it replace Bentonite???
Please enlighten me.

It creates a reducing atmosphere in the mold, preventing oxidation of the hot metal, other than that, to my knowledge contributes little to nothing.

 

[UnkleFuzzy]

"Coal Dust", or Seacoal in the industry vernacular is used primarily as a plasticizer at the metal/mold interface. It becomes flexible at high mold temperatures and allows the mold to give, rather than crack from thermal shock.

The Seacoal also burns out during the pour and causes the surface of the mold to loose it's bond and release from the casting more readily during "Shake Out".

The reducing atmosphere is commonly cited, but is of indeterminate value. Many scientists disagree as to this effect which is often referred to as "Lusterous Carbon" or even "Ludicrous Carbon" by it's detractors.

Coal used in castings MUST be of a low sulphur variety, and is not dust, but actually a carefully ground and classified EPA compliance grade of coal.

Other sand additives include, but are not limited to....
Soda Ash
Cobb Flour (ground corn cobbs)
Wood Flour (trade name Cellflo)
Cereal Binder (ground corn kernal with the skins removed)
Corn Starch
Dextrin
Gilsonite (asphalitc resin, or hardened tar)

 

[ELM6061]

G'day 100Model and thanks for the video. Nice simple muller, what rpm is it running at and what transmission, hp motor do you have?

G'day Uncle Fuzzy, first post, welcome to the forum and thanks for the contribution.
Do these additives/coal, burn out in the casting process (iron & aluminum temps) and do you have to re-mull new one's in after each casting?
If you were to use any of the other additives you suggest; would they all be used at the same % rates?

Ed

 

[100model]

ELM6061

It runs at 22 rpm but can run quicker for a faster mix. I used an old washing machine gearbox and is powered by a 1/4 horse motor.

At iron casting temps coal dust and bentonite have be replaced when the sand feels weak. At aluminuim temps the sand will last a long time. Other additives can be used you will have to experiment as to how much you will need.