Thread: Powder coating DIY?

My son reckons at tech school, they used to dip metal parts in something, he can't remember if it was a liquid or what, dust the part in paint powder, then bake it in an oven for a powder coated finish.

Anyone else heard of this DIY process? Sounds a bit easy!

Would be great for those little bits and pieces followed with a batch of scones, just kiddin.

Ken

Originally Posted by neksmerj

My son reckons at tech school, they used to dip metal parts in something, he can't remember if it was a liquid or what, dust the part in paint powder, then bake it in an oven for a powder coated finish.

Anyone else heard of this DIY process? Sounds a bit easy!

Would be great for those little bits and pieces followed with a batch of scones, just kiddin.

Ken

You can buy kits, Ken. Basically you gently spray the powder towards the object you want to powdercoat (must be conductive and small enough to fit in your oven) and it clings to the surface. Then chuck it in the oven.

Low volt electrical wires are attached to the object and the spray gun, and the current helps the powder cling to the object. I'm being vague but it's some time since I looked into it. There are Australian distributors, and the kits are cheap enough from memory.

http://www.caswellplating.com/#

Originally Posted by neksmerj

My son reckons at tech school, they used to dip metal parts in something, he can't remember if it was a liquid or what, dust the part in paint powder, then bake it in an oven for a powder coated finish.

Anyone else heard of this DIY process? Sounds a bit easy!

Would be great for those little bits and pieces followed with a batch of scones, just kiddin.

Ken

Ken, there are basically 2 powder coating processes, fluidised bed and electrostatic spray gun.

The fluidised bed process, which sounds like what your son is talking about, uses thermoplastic powder (ie it will re-melt when heated). The process goes something like this, The powder (usually polyethylene) is put in a container with a porous bottom and air is pushed through this (low pressure-high volume). This makes the powder behave like a fluid. A metal object (ie dishwashing racks) is heated to above the melting point of the polyethylene powder and dipped in to the fluidised bed, the podwer melts on the object, the object is withdrawn and allowed to cool.
This process results in relatively thick, relatively soft coatings of fairly low gloss (again, like dishwashing racks)

The other powder coating process uses thermosetting powders (epoxy or polyester) and is applied using a special electrostatic powder coating gun. The gun cgarges the poweder with an electrostatic charge, the object to coated is earthed (and conductive), the powder is sprayed on the object and adheres loosely because of the electrostatic charge. The object is then heated, the powder melts and forms a hard, decorative coating which will not re-melt when heated again (hence thermosetting).

Depending on what you want to coat and for what purpose determines which process is applicable. In general the fluidised bed, thermosplastic powder coating process is used for objects used indoors and needing low abrasion resistance.
The electrostatic, thermosetting powder coating process is used on objects that can be used outdoors (think Hills play equipment) and will have good abrasion resistance and appearance.

Of necessity I have simplified this somewat, but that's the general idea.

Ken, some of the spraying powders used in industry are toxic, might be wise to use a kit where this issue has been taken into account.
Regards, Phillip.

Originally Posted by Big Shed

The fluidised bed process, which sounds like what your son is talking about, uses thermoplastic powder (ie it will re-melt when heated). The process goes something like this, The powder (usually polyethylene) is put in a container with a porous bottom and air is pushed through this (low pressure-high volume). This makes the powder behave like a fluid. A metal object (ie dishwashing racks) is heated to above the melting point of the polyethylene powder and dipped in to the fluidised bed, the podwer melts on the object, the object is withdrawn and allowed to cool.
This process results in relatively thick, relatively soft coatings of fairly low gloss (again, like dishwashing racks)

My engineering class in high school had this setup many many years ago and it worked very well, i've still got all the models I powder coated to. The only area it didnt do so well on was very sharp tips.

Matt.

If you want the best finish on Aluminium, then go down the anodising track, but it will only work on Ali. The set up is cheap and cost is very low, if you want more info just let me know and I will point you in the right direction.

Here is a link to get on with http://www.thefintels.com/aer/homealuminumanodizing.htm

Let me know if you want more info,

Steve