Powder coating requires substantially more investment in equipment and preparation than simply painting a part, but the results are worth it. When you have set up your powder coating area and prepped your first pieces for coating, it’s finally time to apply powder, place the piece into the curing oven, and realize some of those good results.
This Tech Tip is From the Full Book, POWDER COATING: A HOW-TO GUIDE FOR AUTOMOTIVE AND MOTORCYCLE PARTS. For a comprehensive guide on this entire subject you can visit this link:
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This chapter starts with reviews of the commonly available tools and supplies specific to powder coating; there really aren’t that many on the market designed for the amateur. I have performed some detailed evaluations of commonly used available products so you can choose which application system, powder, and other supplies to purchase.
Purchasing a Powder Coating Kit
Many professional-grade powder coating kits on the market come from a variety of suppliers, but for home use you should consider The Eastwood Company kits and a less-expensive Chicago Electric option from Harbor Freight Tools. Caswell Plating also offers powder coating kits at a somewhat higher price.
Eastwood offers both low- and high-voltage guns for smaller and larger projects (respectively), or you can buy a kit with both guns. East-wood kits also include other useful items such as plugs and tape for bolt holes and caps for threaded studs to keep powder out of places where you don’t want it to go. They also carry supplies of powder in various colors as well as instruction/mixing books.
The Chicago Electric option is less expensive and not as complete. It includes only the gun and electronic current box, plus a couple of powder receptacles. The powder must be purchased separately. Harbor Freight powder options are limited to black, red, and yellow, but any powder may be used in any gun.
If you look at the professional systems available online, the sky’s the limit for price and functionality. The same places also sell large ovens, racks for shooting and curing parts, and powder recovery systems to collect the powder that doesn’t stick to the part.
In general, professional equipment is quite expensive compared to the budget of the home powder coater. If you’re willing to spend the better part of $10,000 on an oven and the infrastructure to support it, then with practice, a professional-quality gun yields fully professional results. That’s a key point because you can get perfectly acceptable results with the hobbyist-grade powder coating systems on the market for a small fraction of the professional price.
You can also find professional-grade guns and kits on craigslist and eBay from time to time; just use your common sense and try to avoid units that are worn out or broken. A good deal on a pro setup can become expensive very quickly if you have to replace several components. The usual warnings about used tools apply: Why is the seller getting rid of a perfectly good powder gun?
For this book, I performed the projects using both varieties of the Eastwood gun and the Harbor Freight gun. Wherever possible, I used all guns with the same powder and curing process on the same material to compare results.
Many industrial paint stores also carry powder and powder guns, so if you want to examine the products personally before purchase, that’s your best bet. Just remember to be fair. If you spend time with a sales-man considering a product, don’t turn around and buy it online just to save a couple of bucks.
Evaluating Home Powder Coating Systems
The three most common home powder coating kits on the market today come from The Eastwood Company and Harbor Freight Tools. Eastwood is a leading provider of all sorts of tools and products for the automotive restoration and customization hobbyist or professional. Eastwood offers two slightly different versions of the popular HotCoat powder coating system. Harbor Freight is a leading discount tool supply company, and offers one Chicago Electric kit for powder coating.
One potential weakness appears in all three common home powdercoating kits: The clip for the grounding wire is a small, lightweight unit. This offers an advantage for the many cases when you want to coat the entire part and desire a small clip point that might not get enough powder for full coverage. You need only enough connection for electricity to flow, and often you can get good results by simply set-ting the part on the clip. But the clips have a tendency to slip off, and without electrical current powder adhesion is limited. To avoid the situation, it’s a simple matter to remove the stock clip and crimp on a more substantial clip.
Eastwood Original HotCoat Powder Coating System
Eastwood’s first HotCoat system powder coating gun is still the gold standard for home powder coating. The Original kit retails for about $100 at Eastwood.com, and includes the gun and one empty cup, the trans-former with an activation switch that you carry in your hand, plus a handy color chip chart of Eastwood powder colors.
The gun delivers 11,000 volts at 15 microamperes, and works best at about 10 psi of air pressure. Some online reviewers have complained of leaks around the cup threads sending powder everywhere, but this is almost certainly due to excessive air pressure or cross threading the powder cup. The system is just too simple to have this problem on a widespread basis. Many hobbyists try to adjust tool air pressures at the compressor, and that doesn’t work. The pressure gauge on your compressor is not sensitive enough, and the delivered pres-sure varies based on the compressor’s duty cycle.
The Original HotCoat gun works very well; you can adjust the spray pattern by moving the diffuser cone forward or backward on the electrode. You must be careful that you are not actuating the thumb button as you do so because there’s no separate on/off switch on the transformer box. The gun delivers a good layer of powder on the part and is light and maneuverable.
To use the Original HotCoat gun, simply connect the air supply, plug in the transformer, squeeze the thumb-button activator, and spray.
You need to purchase the air fit-tings and moisture separator separately, as these are not included in the kit.
Eastwood’s Original HotCoat gets points for convenience. The cups in which Eastwood delivers its powders are the same as the empty cup in the kit and the spare cups that you can purchase. This makes using East-wood powders a snap; just screw in the storage cup of the powder you want. Eastwood sells 8 ounces of the powders in 16-ounce cups, which is perfect because the cup is not over-filled when you start to use it.
To change colors, disconnect the gun from the air source and connect a blower to the air. Unscrew the old color cup, knocking as much powder as possible off the pickup tube, and then blow off the tool.
Bottom Line? The Original Hot-Coat system is the best value for professional-grade results. You can buy just the tool and it will handle all reasonable powder coating needs. The best deal is to get a full starter kit with several empty cups, a supply of common powders, a moisture trap, some plugs, tape, and safety wire.
Eastwood Dual-Voltage Powder Coating System
Eastwood also offers the Dual-Voltage Powder Coating System. This gun is similar to the Original gun, but includes a switch on the transformer that allows you to select an operating voltage of 15,000 or 25,000. The 15,000-volt setting is ideal for regular surface coating, and the 25,000-volt setting is optimized for harder-to-reach places. The increased voltage increases the attraction to the powder particles on the part. The Dual-Voltage Powder Coating System retails for about $170.
The kit includes the gun, trans-former, and all cabling, plus one empty powder cup. As with the Original HotCoat, the smart buyer purchases the gun with a kit that also offers a supply of powders, plus high-temperature masking tape, silicone plugs, and safety wire.
Using the dual-voltage gun is substantially the same as using the Original HotCoat gun. You get excel-lent coverage and dispersion, and the diffuser is adjustable for different patterns. The Eastwood design is convenient and allows you to stand the gun on the cup when you’re not actively using it.
Having both Eastwood guns available makes it a simple matter to have two colors on hand; just switch the air supply hose to switch colors. Or you can have one color and clear-coat for multi-coat work.
I found no downside to using this gun in high-voltage mode, so I tend to leave it in that mode at all times. Again, online reviews suggest that some users have trouble with the system leaking, but these guns are designed to operate with just 5 to 10 psi, so bringing too much air pressure to the gun likely caused the leaking troubles. With both this kit and the Original HotCoat, used at the prescribed air pressures, I had no leak failures.
Bottom Line? The Eastwood Dual-Voltage Powder Coating Sys-tem costs quite a bit more than the Original HotCoat system. If you plan to do complicated work on irregular surfaces, or if you plan to do a great deal of coating, this kit is worth the investment. Once again, purchasing a full starter kit is well worth the money, as you will need the selection of powders and the tape, plugs, and other supplies immediately.
Chicago Electric Powder Coating System
Chicago Electric’s kit, available at Harbor Freight Tools, costs about $65, but is often on sale for less. The kit includes the gun assembly with transformer, foot switch for power activation, the gun itself, a disposable moisture separator, three empty plastic cups for powder, and a small spares kit with extra diffuser tips, O-rings, and a spare fuse.
This kit appears rudimentary compared to kits from Eastwood, but generally does a good job. Online user reviews suggest that quality may vary from box to box (or aptitude may vary from buyer to buyer). Critical reviews state that the seals often fail and blow powder out of the cup, but that seems likely to be caused by setting the pressure too high for the gun. Setting pressure at about 15 psi yields good results. Still, keep your receipt and try the product immediately to confirm that you have a good unit. If the unit leaks or is otherwise less than expected, Harbor Freight is good about making exchanges.
Be sure to pick up air fittings in your shop’s standard configuration, as these are not included.
Upsides to the Chicago Electric kit include the variety of diffuser tips that come with the kit. These allow you to get a nicely narrow and precise powder stream, or a broad dusting effect. One demerit for the Chicago Electric gun is that the cup attaches from the top, upside down at an angle, which makes changing the cup somewhat clumsier than with other kits. The gun and cup are also larger and heavier than competing models.
The foot switch that activates the gun’s electrical charge is a mixed bag. On one hand, the foot switch is more convenient than a hand-activated switch, but only if you can reach all areas of the part without walking around it. If you need to circle the part, you have to kick the foot switch around with you, or put something on it to keep it actuated, and risk a nasty shock!
As powder runs low in the cup, you have to give this gun a good shake to restore the flow, but coverage is good and the electrostatic effect works well. The on/off switch on the transformer is a nice touch. Flipping the switch allows you to be certain that the unit is off before you set down the gun. Chicago Electric does not publish the operating volt-age for this kit.
Bottom Line? This is a good starter powder coating system, and you can get good results for not much money. The Chicago Electric kit accepts any brand of powder, and that’s important because all powders are not created equal. Harbor Freight powders did not deliver the desired color, and required more powder to achieve coverage.
Your least expensive option for good results is to buy the Chicago Electric gun and then buy Eastwood supplies or quality powders from another source.
Purchasing Powder and Supplies
When you buy a powder coating gun and transformer kit, you should also be thinking about additional supplies. These include powders, a respirator, and a stash of plugs and high-temperature tape to mask off your projects.
Virtually all powder guns dispense any brand of powder, and there are hundreds of options on the market today. Many powders are expensive but offer fantastic effects, such as metallic, veined, crinkle, anodized, and candy-apple finishes. At the other end of the spectrum are low-cost powders that may or may not work well.
In addition to powders, the list of other consumables you need is mercifully short, especially after the long list of infrastructure items and cleaning supplies you already bought! The list of consumables is generally limited to silicone plugs, plastic covers, safety wire, and high-temperature tape. You can get all of them from Eastwood. I have not found them anywhere else.
Silicone plugs and covers are pretty self-explanatory. You don’t want a thick layer of hardened powder coating in threaded holes or on studs, so you plug or cover them before you apply the powder. They keep the powder out and survive the oven. You can remove and reuse them after the parts have cooled.
Use the safety wire to hang your parts. It’s nice because you can pull out any length and bend it with your fingers much easier for on-the-fly work than using heavier coat hanger wire.
High-temperature tape may seem like an extravagance, but it’s not. You need it because the glue in common masking tape bakes onto the part and is really difficult to remove. The high-temperature tape is not super-sticky for this reason, but it holds well enough to get the powder onto the part and then get the part into the oven. Once the powder has cured and the part is cool again, you can easily peel this tape off with no residue.
Evaluating Powder Sources
In the course of research for this book, I tested powders from several different manufacturers under reasonably controlled circumstances and made the following evaluations:
Eastwood powder is uniformly high quality and is offered in a broad range of colors and textures. Eastwood sells its powders in 8-ounce (1/2-pound) cups, or 2-, 5-, 10-, 25-, and 50-pound containers. Buying colors in the 8-ounce cups helps hold down the incremental cost for adding colors to your palette. When you find a color you like, you can buy the larger size. Prices vary based on the composition of the powder, but basic colors are about $20 to $35 per pound in the 8-ounce size, and about $10 per pound in the 5-pound size, and even lower in larger sizes.
Another smart way to try many Eastwood colors is to buy a powder kit. Standard, metallic, and high-tech packages of 6 or 16 colors are avail-able for less than $10 per color.
Many of Eastwood’s exotic powder colors, such as chrome, work best with a second coat of clear gloss to protect the color from the elements. The clear gloss powder costs about the same as other powders, so be sure to take that expense into account for your budget.
Bottom Line? Eastwood powders are the best choice for the home powder coater. Quality is high, and you don’t have to buy in professional quantities to get a good selection of colors.
Harbor Freight powder has the advantage of being inexpensive. You can get a pound of powder in a plastic cup suitable for direct use on the Chicago Electric powder coating gun for about $5.50. That’s a fraction of the cost of other powders, but the tradeoff is that the tone and cover-age of these powders is somewhat uneven. You often get a more trans-lucent effect than the rich, solid color of other powders. Harbor Freight powder is available in red, yellow, white, and black.
This may sound like a bad evaluation for this product, but remember this: You can get one pound each of all of the four colors offered by Harbor Freight for less than the price of a single pound of many other powders. So it makes a lot of sense to get some of this product and try it out on some test projects. When you know what results you’re going to get, you can decide when to use this powder instead of more expensive powders.
The upside of Harbor Freight powder is that it appears to be just as tough and durable as more expensive powders. This makes it an excellent choice for parts that are not seen, or that are subject to a great deal of mess, abrasion, and general abuse.
Bottom Line? Get some Harbor Freight powder. It’s inexpensive and you can use it in any gun by transferring the powder to a cup that fits onto the gun you have. Use it when appearance is not a factor.
You can find many powder providers online, and you may be able to purchase their products from a local powder coating business as well. In particular, eBay has a good selection of powders in multi-color lots. Be sure the ad specifies new powder, rather than reclaimed powder, however.
Powders purchased in bulk do not come in a convenient cup, so buy several extra cups (as many as 20 if you intend to use a lot of different colors) for the gun you own. Bulk powders generally come in quart or gallon zip-lock bags, or double bagged in open-top plastic bags that are tied shut. Use a clean plastic funnel to transfer powders from plastic bags into your own powder gun cups.
The quality of powders from eBay suppliers is a little uneven; some work better than others. I tested many through various guns without incident and they cured to a good finish, especially basic colors in flat or gloss. One batch of red crinkle finish did not crinkle as much or as nicely as the Eastwood crinkle black, but more experimentation with varying cure time and temperature may yield a better result with this powder.
A transparent gold-tone powder from allpowderpaints.com called 24 Karat yielded a nice golden effect on a stainless steel bowl. The powder cures to a medium gold finish that is mirror-bright and even.
Bottom Line? Powders you buy online are generally good, but prices vary widely and quality is not guar-anteed. Your best bet is to test any powder you buy before you put it on a part you really care about. Just make sure you get new powder, and verify its cure temperature.
Written by Jeffery Zurschmeide and Posted with Permission of CarTechBooks