Activity 1.3 Concept Sketching

Joinery, Fasteners and Adhesives

Introduction When you look at a fine piece of furniture, such as a chair with many different parts, it is sometimes hard to determine how the pieces were put together. The same is true of a wooden candlestick holder that has been made by joining many different pieces of wood and then turning the candlestick on a wood lathe to look like a single piece of wood.

How does someone securely join the wooden components together? How does someone decide on which method of joinery is best for the application? How do people determine whether they should use hardware, such as nails, adhesive, such as glue, interlocking wood joints, or a combination of those? All of the questions will begin to be answered as you study about the various wood joinery techniques used in basic materials processing. This knowledge will be helpful when you disassemble a product to see how it works. By thoroughly understanding wood joinery techniques, you can understand how a product was designed and made; if you are lucky, you may be able to prevent damage to the product as it is disassembled. In the Optional Activity 3.3.1b Wood Fasteners and Adhesives Classification, you will learn about various wood fasteners and adhesives.

Take a few minutes to look around you. Can you find a metal object that was made without fasteners or an adhesive? How about the trashcan in your room? How is it held together? What about your teacher’s filing cabinet? In the future, you may want to design similar types of products – metal products without mechanical fasteners or adhesives. This activity will provide you the opportunity to learn about various metal joining processes used in metal assembly. This knowledge will be helpful to you as you learn more about how metals are joined and when you disassemble a product.

Wood Joining Methods Picture / description of each? Nails Screws Adhesives

_____Common _____Oval head _____White glue

_____Finishing _____Round head _____Carpenter’s glue

_____Brad _____Flat head _____Casin

_____Box _____Fine-thread _____Contact cement

_____Casing _____Course-thread _____Hot glue

_____Upholstery tack _____Phillips head

Metal Joining Processes Riveting a. High current at a low voltage passes through two pieces of metal (usually sheet metal) for a short period of time.

b. Occurs at temperatures below 800 degrees Fahrenheit, performed with a gun. Soldering c. Joining processing where the filler material flows into the joints using capillary action.

Soft soldering d. Used when fastening metals together that are not easily welded, or where welding is not practical.

e. Process of fastening two metals together with a nonferrous metal that has a lower melting point than the parts being joined. Hard soldering f. Occurs above 800 degrees Fahrenheit with heat of a torch flame. g. High current at a low voltage passes through two pieces of metal (usually sheet metal) for a short period of time. Brazing h. Occurs at temperatures below 800 degrees Fahrenheit, performed with a gun.

Spot welding i. Joining processing where the filler material flows into the joints using capillary action.

Rivets a. Most frequently used for metal joints but sometimes used to join sheet metal to small diameter rods or small flat bars.

Solder b. Upon solidification, it adheres (sticks) tightly and forms a strong bond between the two surfaces.

Soft soldering c. Metal pins that look like bolts with no threads and may be either solid or tubular.

© 2012 Project Lead The Way, Inc. Introduction to Engineering Design Joinery, Fasteners and Adhesives – Page 2 Hard soldering d. Uses a material called rosin core 60-40 which is made up of 60% tin and 40% lead.

Brazing e. Often used in jewelry and art metalwork for joining copper, silver, and gold.

Spot welding f. Used to join intial metal before quality metal is joined

Equipment Paper Pencil Various objects to sketch (see below)

Procedure

Conclusion 1. Explain the concept of proportion. How does the concept of proportion relate to creating a realistic sketch?

2. Why would the ability to create realistic sketches make a person a more competent designer?

3. Give an example of a visual or graphic representation of information that has more impact than an explanation of the information in text.

4. In your opinion, what is the most important thing to know/do in order to create a realistic sketch of an object?