Sand Casting & Etching

ENGR 45 - Santa Rosa Junior College,

F2014

- Earliest discovered cast parts originate from

the Middle East and India.

- Date back to 3000 B.C.E.

Early Sand Casting

Iron Casting in China

- China had mastered iron melting since 500

B.C.E.

- New excavations have shown that the

Chinese were successful in mass producing

cast tools and farm equipment.

Iron Casting in Europe

- Europeans had mastered this technique

2000 years after China.

- Gun barrels and bullets were amongst the

first cast iron products in Europe around

1400 B.C.E.

And it continued...

- Development of new technology in casting

along with an increased demand for cast

parts resulted in a significant growth of

production during the 18th century.

- Used for machine parts and artistic design.

Applications

- Mostly used to make medium to large parts where

smoothness and precision are of most importance

- Can also be used to make sculptures

- Most popular materials used include cast iron, steel,

brass, bronze, and aluminum

- Sand casting is cost effective and has low amount of

waste

Supplies of Sand CastingGathering Supplies! You will need:

1) A Furnace, used to achieve the melting temperatures of various materials.

2) Casting Sand, there are many types but we used oil tempered sand.

3) A Striker, used to compact the sand around a model to make the mold. We used a heavy object

found in the lab and a hammer to achieve tightly compacted sand.

4) Materials to sand cast with. For our sand casting we used Aluminum, Plastic in the form of glue

sticks, and Solder which is lead and tin.

5) A Model, This can be made from anything you have as long as it is hard enough to withstand

compacting and can be as smooth as possible to reduce casting sand from sticking into crevices

and creating imperfections in the mold.

6) Various hand tools such as: hammers, Hack saw, and vice grips.

7) Miscellaneous items used for crafting your model such as: hot glue guns, oil, and cardboard

crafting letters.

Crafting the Model1) Use Hacksaw to cut base to size 2) Grind burrs for safe handling

3) Add cardboard letterings for desired words

Process of Sand Casting

1. Lightly pack the casting sand to ensure a nice clean pattern from the model can be molded.

2. Place the model face down into the sand and using a striker, apply pressure on the back of the

model to create the sand mold.

3. Remove the model carefully to prevent the sand from deforming.

4. Inspect the mold for any defects and

repair any deformations in the mold.

6. Pour the molten metal into the mold

cavity and let harden

5. Melt material down.

7. Break up the sand surrounding the casting and clean up the casted part.

8. Repeat steps 1-7 with different materials.

our plastic and aluminum casting melting the solder

Chemical Etching Background

● It is the process of using etching chemicals to remove material to create

patterns

● 400 BC organic chemicals are used to etch metals

● 1400s mineral acids are used to etch armor

● 1600s etching is used to make measuring instruments

● 1782 John Senebier discovers light sensitive resin allowing

for photochemical etching

● 1927 first commercial uses of chemical etching

● modern applications include printing circuit boards and

fabricating semiconductors

The Process of Etching

1. Design and print out artwork onto a transparency sheet.

2. Prepare the copper-clad board by cutting to size, scuffing the entirety of the copper surface, and

cleaning the surface with water.

3. Dry and apply photo resistive film to the board.

4. Attach transparency to the board with

the photo resistive film.

5. Expose for 7 minutes to UV light to harden photo resistive layer onto the board.

6. Allow to sit for 10 minutes to harden exposed photo resistive layer

7. Place the board into a developer solution to remove excess non-hardened photo resistive layer.

8. Clean off developer solution.

9. Submerge the board into an etching solution and lightly scrub while submerged to remove

exposed copper.

10. Clean and dry board for final chemical bath.

11. Submerge board into resist remover similar to acetone to remove hardened photo resistive layer.

Nicholas Diaz

Vatsal Pandya

James Hochstetler

Louis DeMello

Sources

- http://www.industrialmetalcastings.com/casti

ng_sand_castings.html

- http://en.wikipedia.org/wiki/Chemical_milling

- http://www.metal-

technologies.com/docs/default-

source/education/historyofmetalcasting.pdf?

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