Alex Bennett-Ford

 

Electro plating





 

Electroplating, the process of coating a metal object with a thin layer of another metal by means of electrolysis. Electroplating is used to give metal objects a better appearance or to protect them from corrosion, wear, or rust. Tableware, trays, decorative pieces and jewelry are plated with gold or silver to make them more attractive.It's done by filling a container with a solution of salt that will be the coating, this is called an electrolytic bath. The object to be plated is immersed in the bath. A metal bar, composed either of the metal that is to form the coating or of a metal that is not affected by the electrolytic bath, is also immersed in the bath. The entire apparatus is called an electrolytic cell.

 

 

 

 

http://science.howstuffworks.com/electroplating-info.htm

 

 

Anodising

 

Anodising is an electrolyic passivation process that is used to increase the thickness of the natural oxide layer on the surface of the metal parts. Anodising is done through positive and negative charge, the cathode's material is transfered to the anode creating a thickeroxide layer on the surface metal. This is so that it has increased corrosion resistance and wear resistance and also provides a better surface adhesive for paint primers and glues. Anodization changes the microscopic texture of the surface and changes the crystal structure of the metal near the surface. Thick coatings are normally porous, so a sealing process is often needed to achieve corrosion resistance. The positive electrode called anode is the material that is to be treated as if it attracts all of the wanted material and the cathode, the negative electrode attracts all of the unwanted materials. The thickness of the oxide layer is determined by the amount of time you leave the anode in their for.

 

 

 

 

The tanalising of timber process

Alex Bennett-Ford

Tanalising timber

 

 The Tanalising process. 

 

 

 

 

 

Stage one

The Tanalising process involves placing the timber within the treatment cylinder and creating an initial vacuum within the timber cells.

 

Stage two

The cylinder is then flooded under vacuum with the preservative treatment.

 

Stage three

Hydraulic pressure is then applied forcing the preservative deep into the timber cells.

 

Stage four

After a pre-determined period of pressure depending on the species of timber being treated and its eventual use, the treatment solution is pumped back into storage and a final vacuum extracts any excess treatment solution from the timber.

 

Stage five

Low pressure inside the timber draws in surface solution when vented to the atmosphere and the treated timber is left for a specified period for fixation of preservative to occur.

 

 

Basic summary

Tanalised timber is a type of timber that is usually impregnated under pressure with highly toxic substances such as arsenic in order to protect it against rot and termites.  This treatment process ensures deep penetration into the timber cells, for a longer-lasting protective results against fungal decay and insect attack. The Tanalising process is environmentally friendly, also the residue isn't harmful. At times the process can leave green residue on the surface which will usually wear off with use. The treatment described above gives softwood the qualities of a long service life and long term protection from fungal and insect attack.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 



Joints

Alex Bennett-Ford

 

Wood joints  

 

 

Corner mortise+tenon joint

 

 

Haunched mortise + tenon joint

 

Dowel joint

 

Corner briddle joint

 

Stopped mortise + tenon joint

 

 

Through dovetail

 

Finger joint

 

Lap joint

 

 

 

 





Steam bending

Alex Bennett-Ford

Steam bending

 

 

Steam bending is a woodworking technique where strips of wood are steam heated using a steam box which I have put an image of below. The heat and moisture being applied  makes the wood pliable enough to easily bend around a mould to create a specific shape, an example is producing for boats, violins and chairs. Steam bending is a traditional process step in history. It was once a vital method to the production of weapons, tools and water vessels such as boats during many wars. Due to the advance of technology the method has become less common in manufacturing. Steam bending is also a low energy method of manipulating wood. It doesn't need  drying time of glues to join together several wood pieces to make the desired shape. Steam bending also leaves lower levels of waste so can be beneficial towards the environment and not wasting material waste. Below is a jig for steam bending, they come in all different shapes and sizes due to how you want the wood to shape. After the wood has been through the steam bending process the wood is usually clamped firmly to jigs to take its shape, the length of time it takes depends on the thickness of the wood.

 

 

    Click on the link below to view the process of steam bending.

http://www.finewoodworking.com/how-to/video/free-form-steam-bending-technique.aspx

 

 



Timbers, Kiln drying/Air drying

Alex Bennett-Ford

                                                                          Timbers/Theory 3

 

 

Air drying-

 

Air drying is a simple method where the various types of timber are stacked on top of eachother but are separated by something called stickers, this allows the air to circulate around it speeding up the process. The process requires a place where it is clean, cool, and dry. The process can take months and even years depending on the climate, so therefore it is a very slow process.

 

 

Kiln drying-

 

Kiln drying is where the timber is basically introduced to heat, this can be directly using natural gas and/or electricity or indirectly through steam heated heat exchangers. Bear in mind solar energy is possible. The timber is stacked in chambers, called wood drying kilns, the process takes place here which is an enclosed area where the temperature is deliberatly regulated.

 

 

 

Extrusion, compression and rotation moulding/Homework

Alex Bennett-Ford

Extrusion, compression and rotation moulding 

Extrusion moulding uses a standard extrusion machine. Plastic particles are dropped into a hopper and a screw thread sends them past heaters making them melt. The screw thread then forces them through a nozzle which produces a shape called a parson. The parson is put into a mould and trimmed at the top and squashed at the bottom. Air is then blown down the parson so that it takes the shape of the mould.

The compression moulding process is a method of moulding in which preheated polymers are placed into an open heated mould cavity. The mould is closed with a top plug and pressure is applied to force the material to contact all areas of the mould. Throughout the process heat and pressure are maintained until the polymer has cured.

Injection moulding is a production process for producing large quantities of identical items. Granulated or powdered thermoplastic material is heated, melted and then forced under pressure into a mould. Once in the mould the material cools, forming a component that takes on thenshape of the mould cavity. 

Theory one/notes

Alex Bennett-Ford

Polymers

.Polymers come from crude oil, crude oil is a non renewable source 

.Plastics are manufactured using a process called polymerisation. Polymerisation occurs when monomers join together to form long chains of molecules called polymers. 

General summary of plastics

.Good electrical and thermal insulators 

.Good strength to weight rati

.Generally good resistance to atmospheric and chemical erosion

.Low melting point

. Lightweight 

Available in a wide range of colours and transparency

.Two main categories: thermoplastics and thermosetting plastics  

Fillers: These are added to the polymer powder to give the material some more bulk

Flame retardants: These are used to reduce the risk of combustion

Anti static agents: Reduce the effects of static charges that can build up in a product 

Plasticisers: These make the material less brittle 

Stabilisers: Reduce the effects of ultra violet light found in sunlight