What Methods Are Used To Finish Metal Flashcards
What are some methods used to finish metal ? TASK
Metal finishes:
- Anodising -
- Powder coating
- Zinc plating
- Chrome plating - for something that is exposed to moisture - or something that you want to have an aesthetic finish as it’s shiny.
- Nickel plating
- Polishing
- Galvanising
- Gold plating
- Painted
Surface preparation examples:
- Bead blasting
What is bead blasting ?
It’s a surface preparation technique:
However it can also be a surface finish on a material that has corrosion resistant properties and it would give it a matte finish. However you cant use it as a surface finish for materials that aren’t corrosion resistant because it would make it rust - such as mild steel
It makes a clean surface and leaves microscopic holes so that it prepares it for paint finishes etc so that the paint goes into the holes and sticks to the product more
It can generate heat due to friction so it shouldn’t be used with materials that are temp sensitive such as some plastics etc.
Bead blasting is literally firing little particles onto the material and this removes dirt and debris and cleans up the material and leaves a kind of matte but rough ( because of the particles making little holes ) surface.
Spray paint application process:
So as the paint gets out of the gun there is an ionisation process that happens which charges the paint and the thing that is getting painted is earthed so its negatively charged so the paint and the thing getting painted gets attracted so there is a better connection and less waste
Powder coating process:
Pre-treatment:
They might place the product in an acid bath which would clean the product and remove any dirt etc
Powder application:
A gun is used to to spray the powder which charges the powder as it is released out of the gun
How is the galvanising process done? ( Hot zinc dipping )
- It protects steel from corroding
- It is extremely durable
- It is one of the most sustainable methods from non corroding steel because of the durability and recyclability
Basically you dip steel into molten zinc
- the problem with this is that the hot zinc could warp the steel
- it very good for huge products - and it makes that product last for like 100 years - very durable
If a bit of the zinc gets damaged and that bit that got the zinc rubbed off, that bit would rust however the good thing about galvanising is that the rust wouldn’t spread to the other bits of zinc and corrode them like something like paint. The zinc would stop it from spreading further
How does galvanising look like ?
It is not all one straight colour, you didn’t get a very attractive clean finish ( its very inconsistent ) — it is used for more building structures, fire escape etc where you don’t really care that much about aesthetics
Electroplating explained ?
It’s like nickel plating using electrolysis
It’s a multi step process - cleaning etc.
Anodising method explained :
It is used on aluminium to change its colour and makes it thicker and more durable
It is placed into a sulphuric acid
Sulfuric acid
What is enamelling ?
It is adding a ceramic or glass layer onto metal and this would give it a glossy finish
