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Airborn Coatings - Jet Coat Header Coating- the best Jet Hot Coating available
Powder Coatings
Painting with Powder
An article by Jim Rizzo, from "Street Rodder Magazine", October '96
The popularity of powder coating in street rod construction is growing rapidly these days. It seems more and more street rodders are opting to powder coat their chassis, suspension, and underhood parts than ever before. The use of powder coating technology in the industrial field has been around for a long time, and the benefits of this refinish method are now being realized in the automotive aftermarket as well. Street rodders have found that powder coatings are extremely durable and perform well when it comes to resisting cracking, chipping, and peeling. Plus it's abrasion, corrosion, and chemical resistant to boot. Heck, if it's good enough for rocket and missile casings, it may just be good enough for Deuce frames and IFS components, wouldn't you think?
Well, on a recent trip to the right coast we made a stop (virtually unannounced) at the home of AirBorn Coatings in East Hartford, Connecticut, to see for ourselves just what's involved in the coating process. We timed it perfectly, for as we walked through the door, Gene Schaeffer and his crew were about to prep and finish a complete chassis.
The first step in the process is to strip, clean and degrease the item to be coated (just as with paint refinishing, a completely clean surface is needed for optimum adhesion of the base coat). Once it's cleaned up, and all visual signs of contamination are removed, the piece is placed in what's called a bake-off oven for thermal degreasing. Thermal degreasing basically burns off any impurities missed in the initial cleaning stage.
The next step is to abrasive blast the frame. This removes any scale or rust that a cleaning will not take care of. Abrasive blasting also aids in adhesion by giving the coating a rough surface to "bite" into. Once the prep work is completed the chassis is then set up on a "spit." This fixture allows the frame to be rotated 360-degrees, and ensures that every surface of the frame can be properly coated.
After being installed on the fixture, any areas that are not to be coated (if any) are masked off. Because the coating mil thickness varies with different types of powder coating materials, you must plug any threaded holes so the coating does not interfere with the threads.
Now the actual coating begins. Because this is dry powder there are no fumes emitted in the spraying process. A respirator is worn when powder coating because the fine dust-like powder is a respiratory irritant (as is all dust), rather than for protection from toxic fumes.
The powder exits the gun in a cloud rather than a fan like spray. The electrical charge pulls the powder (much like a magnet) to the surface of the frame. Care is used in the spraying process as you want to apply an even coating of powder to achieve a uniform mil thickness. In most cases over-spray can also be reclaimed for subsequent use, which is much more cost effective than the material loss suffered with conventional sprayed finishes.
Even though the powder coat is drawn to the chassis, close visual inspection is still necessary to ensure complete coverage. In some tight corners, or in areas that have many intersecting angles, the powder is sometimes repelled, like the same poles of a magnet repel each other. Careful application of the powder coat from different angles will most times overcome this problem and allow for complete coating.
The last step in the process is baking the coated chassis in the oven. Different types and colors of powder have various cure temperatures and bake times. For this particular situation, 15 minutes at 400 degrees will effect a good cure for the chassis, and ensure a smooth glossy finish. Bake times are very important, especially on an item such as a chassis that has many different size and diameters of tubing. A thinner or smaller diameter piece will reach temperature much quicker than a larger diameter one, causing the part with less mass to stay at full temperature for a longer period of time than the portion with a larger mass. This (in extremes) will cause what is known as an over-bake situation on the smaller diameter part. This is more of a problem on light color coatings, as an over-bake situation tends to cause color changes. In severe cases of over-bake, adhesion and durability may be compromised.
And here is the finished product.
As you can see, the flat, velvet-like appearance of the pre-cured chassis is a far cry from the glossy, smooth finish you see now. After cooling, the chassis will be ready for immediate shipping, or as the case may be, assembly.
AirBorn Coatings
North Carolina 108 Rush Street
Mount Holly, NC 28120
PHONE: (704) 483-5000
FAX: (704) 483-5100
The popularity of powder coating in street rod construction is growing rapidly these days. It seems more and more street rodders are opting to powder coat their chassis, suspension, and underhood parts than ever before. The use of powder coating technology in the industrial field has been around for a long time, and the benefits of this refinish method are now being realized in the automotive aftermarket as well. Street rodders have found that powder coatings are extremely durable and perform well when it comes to resisting cracking, chipping, and peeling. Plus it's abrasion, corrosion, and chemical resistant to boot. Heck, if it's good enough for rocket and missile casings, it may just be good enough for Deuce frames and IFS components, wouldn't you think?
The next step is to abrasive blast the frame. This removes any scale or rust that a cleaning will not take care of. Abrasive blasting also aids in adhesion by giving the coating a rough surface to "bite" into. Once the prep work is completed the chassis is then set up on a "spit." This fixture allows the frame to be rotated 360-degrees, and ensures that every surface of the frame can be properly coated.
The powder exits the gun in a cloud rather than a fan like spray. The electrical charge pulls the powder (much like a magnet) to the surface of the frame. Care is used in the spraying process as you want to apply an even coating of powder to achieve a uniform mil thickness. In most cases over-spray can also be reclaimed for subsequent use, which is much more cost effective than the material loss suffered with conventional sprayed finishes.
Even though the powder coat is drawn to the chassis, close visual inspection is still necessary to ensure complete coverage. In some tight corners, or in areas that have many intersecting angles, the powder is sometimes repelled, like the same poles of a magnet repel each other. Careful application of the powder coat from different angles will most times overcome this problem and allow for complete coating.
The last step in the process is baking the coated chassis in the oven. Different types and colors of powder have various cure temperatures and bake times. For this particular situation, 15 minutes at 400 degrees will effect a good cure for the chassis, and ensure a smooth glossy finish. Bake times are very important, especially on an item such as a chassis that has many different size and diameters of tubing. A thinner or smaller diameter piece will reach temperature much quicker than a larger diameter one, causing the part with less mass to stay at full temperature for a longer period of time than the portion with a larger mass. This (in extremes) will cause what is known as an over-bake situation on the smaller diameter part. This is more of a problem on light color coatings, as an over-bake situation tends to cause color changes. In severe cases of over-bake, adhesion and durability may be compromised.
