Foundry sand.

[100model]

I came across this video about sand for concrete. Watch from 6:33 to 10:52, the sand I use has sharp edges and makes strong molds but the workabilty as he calls it is not as good as grains of sand that have rounded edges. Before you buy sand for sand molds use a magnifying glass to see what shape the sand grains are.

 

[GreenTwin]

I went down to the local river and got some very fine river sand.
This was before I knew anything about foundry sand.
Then I discoverd OK85, which is a round grain commercial foundry sand that is very fine, and the fine river sand then looked coarse.

The OK85 has consistent a grain size, with round edges, and the river sand has a lot more variety in grain size, and sharp edges.
The OK85 will drain out of a pinhole in a sack, and the entire lot will end up on the floor.
OK85 is apparently kiln-baked too, which is a requirement of sand used for resin binders.
.

 

[SmithDoor]

Natural bonded foundry is simply you have it in backyard.

It is good just soil.
Most aluminum and bass foundries used upto 1960's. After slowly the foundry supplier talk foundry in purchasing the equipment and sand and clay.

The best part of Natural bonded foundry just add water and mix read Togo. I saw some foundries use rotary teller others used sand cutters. I built a sand cutter used for 30 years.

Dave

 

[Fidlstyks]

I cannot locate a supplier for fine flour grade sand near DEs Moines. I think I used 240 mesh, but got what I have from a large foundry
I mix 100 lbs sand, 10# powdered Bentonite and 4 # seacoal.

 

[SmithDoor]

I cannot locate a supplier for fine flour grade sand near DEs Moines. I think I used 240 mesh, but got what I have from a large foundry
I mix 100 lbs sand, 10# powdered Bentonite and 4 # seacoal.

Most foundries use 100 to 140 grit aluminum and brass.

Cast iron 60 grit

Bentonite can be foun at the garden store.

Seacoal look on internet and only used in cast iron and steel casings

Dave

 

[GreenTwin]

OK85 comes in 3,500 lb bags, which are a bit difficult to handle, but it can be done if you are determined.
A photo of OK85 is above in post #2 on the left, and it is the very fine round-grain white sand; very dry, probably kiln dried.
You basically have to find a foundry supplier who is willing to sell it, and that can be challenging.

Finding good sand has been perhaps the most challenging part of backyard casting.
Pre-mixed Petrobond (tm) can be purchased in various places, but I have found that it does not work very well with iron, as far as how it erodes the sand as it flows into the mold.
.

 

[SmithDoor]

I cannot locate a supplier for fine flour grade sand near DEs Moines. I think I used 240 mesh, but got what I have from a large foundry
I mix 100 lbs sand, 10# powdered Bentonite and 4 # seacoal.

Try see what your locale sandblasting supplier has.

I used sand blasting sand fie 60 grit they had up 120 grit but very costly too. I found for cores 60 was the best. Since did do cast iron I had no reason so never look for sea coal . Mostly it will be for decoration work.
Shipping was killer so try everthing in town.

I had a 50 lb home built sand muller and 250 sand muller also a a 8 inch wide sand cuter also home built and the belt was home built very easy to make.

Dave

 

[Fidlstyks]

Most foundries use 100 to 140 grit aluminum and brass.

Cast iron 60 grit

Bentonite can be foun at the garden store.

Seacoal look on internet and only used in cast iron and steel casings

Dave

Thankyou, I use seacoal on brass

 

[SmithDoor]

Thankyou, I use seacoal on brass

If you uses Bentonite to get a good foundry sand it needs to use muller some put in driveway and drive over sand and Bentonite. I tried a cemet mixer in work but need to dig out of mixer.

Dave

 

[Fidlstyks]

If you uses Bentonite to get a good foundry sand it needs to use muller some put in driveway and drive over sand and Bentonite. I tried a cemet mixer in work but need to dig out of mixer.

Dave

Agreee, I ram it down, break it up and ram it down some. But I think steaming helps too?

 

[SmithDoor]

Agreee, I ram it down, break it up and ram it down some. But I think steaming helps too?

If see what large foundries do for checking and mixing there sand for the perfect sand.

I found the easy to use sand was better that is a good natural bonded sand. The only problem was the welder putting to mush water in the sand. Far less testing too. I only ran the foundry from late June to September. Best propane price. Would use 20,000 pounds of aluminum Almost 500 gallons of propane each week.
Only used Welders and drill press operators. Never used a ture foundry workers. I switched wheels from aluminum to cast iron about 1980’s
Still a lot of other aluminum castings form 1976 to 2003.

Dave

 

[SmithDoor]

Agreee, I ram it down, break it up and ram it down some. But I think steaming helps too?

Most do not know I start foundry for engines and had planned to sell casting with bar stock to make engines and later expand to other thing related to whatnused with engines

My other line work got in way