Tuesday, August 19, 2008

How Powder Coating Works!

It's a lot like painting, with half the mess! Powder Coating has a few very distinct advantages over conventional paint aside from it's toughness and durability factors.

The powder particles are a dry, almost dust like consistency compared to the liquid based paints which have pigments suspended in a solution that has to dry out. In a clean setup using only one color, powder coating over spray can actually be recycled and used again and again until 100% of the powder is used up. In contrast, once paint is sprayed, it's pretty much there for good, and there's no looking back.

Powder Coating also supplies the piece with a far thicker coating then conventional paint, which is a key to it's durability. In fact, powder coating a piece compared to painting it will result in it's finish being approximately 10x thicker, and with it's baking process, or flow out as some call it, it comes out smooth as glass with absolutely no orange-peel. In some instances though, a person may want a thinner application on their piece, which a hobby system will fail to give, but this is where your major corporations with fluid transfer tanks come in.

Enough about why powder coating is so much better then painting, lets get into how it really works.

Your specialized powder coating gun has a polarized rod running through the center of it, which basically charges the powder particles running past it. The piece that you're working with will have a ground strap running of it, to basically complete this 'static charge' type situation it's looking for. It's not exactly static charge, but since this site is built for beginners, I'm sparing you all the technical jargon in the beginning, we'll get into that stuff later on once you're up and running. Since the powder is now positively charged from the gun, and the piece is holding a slight negative charge from the unit, the powder actually clings to the piece you're working on. At low air pressures, you can actually see the powder make turns in mid air to find the path of least resistance to the ground (i.e. the parts of the piece you're making with the lightest coating). This significantly reduces the amount of powder over spray by utilizing up to 95% of the powder exiting the gun on some systems and settings.

Anything capable of holding a small electrical charge can have powder applied to it. Some pieces will conduct far better then others, and more advanced methods such as hot flashing are needed. You will also un-doubtably run into the dreaded faraday cage effect eventually with a hobby unit, and later articles will help you with fixing that.

The act of curing the powder is done by raising the temperature of the powder coated piece past the flow out temperate of the powder you're using. This will vary depending on the different types of powder available, but basically what it boils down to, is melting that dry powder that is clinging to the part. As the temperature comes up, the powder melts, and some powders actually re-align their chemical makeup to add further strength properties to it. After the part has been heated up for the powder to flow out, it is removed from it's heat source (often an oven, but can also be heat lamps) and cooled to room temperature slowly so that the powder and the piece come down to room temp at the same time.

That's really all there is to how it works, well the basics at least. There is still a ton of information to learn on different techniques and applications, as well as different equipment setups to get you started.

11 comments:

Christina said...

how do u acheive no orange peel and have a glasslike finish

Powder Coating Equipment said...

Powder coating is the new age and environment friendly technology.. It is nothing but dry painting and done by powder coating guns. Corona guns with the help of electric power are used for electrostatic charging.

taminsong said...

Hi,

I'm puzzled about round objects, how do they powder coat it?

Can you share an idea? Please?

Thanks.

wall coatings specialist said...

Today many people like power coating. Powder coating is based on the principle that objects with opposite electric charges (positive and negative) attract one another.

Duncan said...

Are furnace oilfired burners c/w atomizing and combustion aire suitable for oven applications in powder coating process?

Powder Coating said...

Well explained - Although powder coating is environmentally friendly it doesnt rate to high on carbon emmissions which are produced indirectly via power/gas consumption during the baking process unless you are sourcing your power from renewables.

vip escort said...

Pretty helpful data, lots of thanks for your post.

Anonymous said...

how do you move the powder coated item to the oven?

Anonymous said...

You can move the parts either by racks or like my company has a conveyor that feeds the parts to the oven. You don't want to touch the part after you spray it of course so maybe the hooks or whatever it is that are holdn the part up cary it by that to your oven.

Shiva Khandelwal said...



Powder Coating is an alternative to conventional wet painting for automotive and other metal parts. Before an item can be coated, it must be cleaned and free of any dirt, grease, or oil from the hands
The item covered in powder is then swung over to a large industrial oven. It's fitted inside, making sure to remove the winch chain and electrode, and then baked



Powder guns india

Leviticus Bennet said...

That's really neat that powder coating can be so much thicker without any negative aesthetic effects. I've heard of powder coating being used to paint rims. I thought it looked cool, but I didn't know it was more durable.