Frequently Asked Questions

Below are some questions we are frequently asked.  If you do not find an answer to your question please call or email us.  You can also use our feedback form which can be found on our "Contact Us" page.

 

  • What is powder Coating?

  • How is it done?

  • What are powder coating guns?

  • How is color introduced?

  • Why powder coat?

  • How do I remove powder coating?

  • What kind of things can I powder coat?

 

Q: What is powder coating?

 

A: Powder coating is by far the youngest of the surface finishing techniques in common use today. It was first used in Australia about 1967.

 

Powder coating is the technique of applying dry paint to a part. The final cured coating is the same as a 2-pack wet paint. In normal wet painting such as house paints, the solids are in suspension in a liquid carrier, which must evaporate before the solid paint coating is produced.

 

The powder coating process uses a solvent free dry mix of plastic resins, pigments, and fillers that melt and fuse together when heated.  The solid particles of coating are electro statically charged in a spray gun and carried by low velocity air to the surface of the piece to be coated.  The electrostatic charge holds the powder particles in place while the part is cured in a 400-degree oven.  The heat of the oven causes a chemical reaction to occur and the powder to cure, creating a highly durable finish.

In powder coating, the powdered paint may be applied by either of two techniques.

 

  • The item is lowered into a fluidized bed of the powder, which may or may not be electro statically charged, or
  • The powdered paint is electro statically charged and sprayed onto the part.

 

The part is then placed in an oven and the powder particles melt and coalesce to form a continuous film.

 

There are two main types of powder available to the surface finisher:

 

Thermoplastic powders that will remelt when heated, and

 

Thermosetting powders that will not remelt upon reheating. During the curing process (in the oven) a chemical cross-linking reaction is triggered at the curing temperature and it is this chemical reaction which gives the powder coating many of its desirable properties.

 

Q: How is it done -- electrostatic spray?

 

Before the powder is sent to the gun it is fluidized:

  • to separate the individual grains of powder and so improve the electrostatic charge that can be applied to the powder and
  • so that the powder flows more easily to the gun.

Because the powder particles are electro statically charged, the powder wraps around to the back of the part as it passes by towards the air off take system. By collecting the powder, which passes by the job, and filtering it, the efficiency of the process can be increased to 95% material usage.

 

The powder will remain attached to the part as long as some of the electrostatic charge remains on the powder. To obtain the final solid, tough, abrasion resistant coating the powder coated items are placed in an oven and heated to temperatures that range from 160 to 210 degrees C (depending on the powder).

 

Under the influence of heat a thermosetting powder goes through 4 stages to full cure.

 

MELT, FLOW, GEL, CURE


The final coating is continuous and will vary from high gloss to flat matt depending on the design of the powder by the supplier.


A: There are at least three types of electrostatic guns in use:

 

  • Corona charging guns where electric power is used to generate the electrostatic charge. Corona guns are either internal or external charging.
  • Tribo charging guns where the electrostatic charge is generated by friction between the powder and the gun barrel.
  • "Bell" charging guns where the powder is charged by being "flung" from the perimeter of the "bell"

Not all powder is applied using guns. One system makes use of electrostatic tunnels.

Q: How is color introduced?

 

A: Color is added to powder coatings during the manufacturing process, i.e. before the powder reaches the powder coater. There is little that can be done to change the color consistently, once the powder leaves the manufacturing plant.

Q: Why powder coat?

 

A:

  1. The Benefits of Powder Coating: Environmentally friendly process powder coating is an environmentally friendly process unlike solvent based wet paint systems.  With EPA regulations growing ever stricter, powder coating is fast becoming the technology of choice.  Since the powder coating process does not use solvents in any way, VOC emission problems are eliminated.
  2. Extremely Durable: Powder coatings resist cracking and peeling and are extremely abrasion, corrosion, and chemical resistant.  The performance characteristics of powder coating match or exceed the characteristics achieved from conventional solvent-based coatings.
  3. Versatility: With powder coating, your imagination is your only limit.  Apply a textured coating to the handle of an existing product to give it a more reliable grip.  Provide UV coating for outdoor furniture to make your product stand the heat of a mid-summer.  The options and applications for powder coating are almost staggering.
  4. Appearance: Expand your inventory by providing your current products in color or with a texture.  Powder coating is available in almost any color available which can easily enhance the appearance of your current line, whether it be metallic vent fan covers or stamped metal toy cars.  Don't fall behind the competition, provide superior products that look superior.

Q: How do I remove powder coating

 

 

A: Methylene Chloride is generally effective at removing powder coating, however most other organic solvents (Acetone, thinners, etc.) are completely ineffective. Most recently the highly dangerous Methylene Chloride is being replaced by Benzyl alcohol with great success. Powder coating can also be removed with abrasive blasting. 98% sulfuric acid commercial grade also removes powder coating film.

Q: What kind of items can I powder coat?

 

 

A: The list below represents just a few of the items you can powder coat.  There are thousands if not hundreds of thousands.  If you have an item that you are un-sure of give us a call, email, or use our feedback form.  We like challenges.

AIRCRAFT AUTOMOTIVE MOTORCYCLE HOME INDUSTRIAL
Instrument Panel Air Breather Air Breather Lawn Furniture Machinery
Valve Cover Valve Cover Rocker Box Cover Door Knobs Plows
Dip Stick Dip Stick Clutch Levers Drawer Knobs Monster Truck Parts
Alternator Wheels Wheels Light Fixtures Wheels
Induction Pipes Alternator Clutch Cover Vent Gates Frames
  Intake Manifold Handle Bars Door Hinges Bumpers
  Frames Frames Gates/Fencing Tanks
  Bumpers     Hitches
  Exhaust Manifold      
  Headers      
  Pull Trailers  

Contact Information:

Advanced Powder Coating, Inc.
8969 S.E. 58th Ave.
Portland, OR 97206

(503)-774-4626  Phone
(503) 517-0967  Fax

Operating Hours:

Mon.-Thur. 8AM-4:30PM

Fri. 8AM-4PM

Sat./Sun. Closed

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