While every year more manufacturers convert from wet spray paint to powder coat, the powder coat process is still unfamiliar to many and often misunderstood. The following includes some common powder coat misperceptions and questions, with explanations to help clarify the confusion.
Myth: Powder coat is a functional coating like galvanizing and or anodizing and is only available in black and a few other industrial colors.
Fact: Powder coat can be either functional or decorative in emphasis. The majority of modern powder coats are classified as decorative finishes, formulated to maximize color, gloss, and texture. Powder coats formulated for maximum corrosion resistance, as might be required for outdoor applications in the marine and architectural industries, are classified as functional finishes.
Myth: Powder coat is primarily a corrosion barrier coating, and all powder coatings are excellent corrosion barrier coatings.
Fact: Some powder coats are excellent corrosion barrier coatings, and some are not. Powder coats classified as decorative finishes, while smooth and glossy to the naked eye, can be porous on a microscopic scale and therefore not the best corrosion barrier coating. In outdoor applications requiring a decorative finish, excellent corrosion resistance can be achieved by using a two coat primer-top coat finish, or even a three coat primer-top coat-clear coat finish. The ultimate in corrosion barrier coatings are powder coats classified as functional finishes, as they do not have the porosity inherent in decorative finishes.
Myth: Powder coating is a commodity service and all powder coat shops pretty much do the same thing.
Fact: It is important to use a powder coat shop that you have confidence in. The performance of powder coat is equally a function of the coating process and the metal pretreatment prior to coating. Pretreatment may include washing, degreasing, paint stripping, abrasive blasting, phosphate coating, rinsing, and high temperature out gassing. The coating process requires stringent controls on handling, masking, cleanliness, compressed air quality, and oven operation. If corners are cut it is possible to coat a part that will initially look beautiful but with a finish that will chip or rub off, fade, or have no corrosion resistance.
Myth: You can buy a hobbyist powder coat kit for under $100 and get the same results as a professional powder coat shop.
Fact: You can buy a hobbyist powder coat kit for under $100, and you may be able to get satisfactory results. It all depends on what coating you are putting on, what results you are expecting, what kind of pretreatment you can do, and what size and type of oven you have. Typical non-convection kitchen ovens heat radiantly from the bottom, which can scorch powder on one side of your part while the other side is undercured. You can’t expect the same process control and uniformity of finish as a professional shop with a $5k powder gun and $80k oven, but you can have a lot of fun.
Question: Are there high temperature powders that you can use to coat my BBQ or exhaust manifolds?
Answer: Yes, these are specialty powders that Seattle Powder Coat can help you with.
Question: Can you put a two-color coating on my part, or add artwork like flames or pinstripes?
Answer: In some cases we do coat more than one color, but we don’t do artwork like flames or pinstripes. One limitation is masking, which must be done to any area that is not to receive the powder coat. High temperature masking materials are not flexible enough to bend around complex designs, and instead must be cut like a stencil. This is time consuming and usually prohibitively expensive. Another factor is the thickness of the powder coat, which causes distinct edges at the borders between one color coat and a second color coat. Clear coats can be applied to smooth these borders, but the dry film thickness of the three coats must be maintained within the powder manufacturer’s specifications to maximize coating performance.
Question: I just need some parts sand blasted. Is that something Seattle Powder Coat can do even if I don’t want my parts powder coated?
Question: I just have a little part that I want a basic black. Do you have minimum charge?
Answer: A lot of Powder Coat shops have an official $125 or $150 minimum, but we don’t. That said, a single paper clip will probably cost the same to coat as a single coat hanger, and if you want it bright pink we might not be able to get to it the same day you drop it off…The reality is that as your parts get smaller you are not paying for the powder so much as you are paying for the handling, set up, and overhead.
Question: Can you powder coat a car body?
Answer: Yes, but it is pretty rare. Because powder coat cures in a high temperature oven and non-metals are typically not coated, car bodies need to be stripped of all non-metal components. Any existing coatings also need to be stripped, including the removal of any lead or plastic (Bondo) fillers. It is a rare craftsman who can smooth sheet metal well enough for top coating without lead or plastic fillers. Finally, because powder coat is not easily spot-repaired/touched up, door dings and fender benders in powder coated car bodies usually have to be repaired with wet paint and it may be difficult to blend the finishes to completely hide the repair.
Question: Can you buff out powder coat?
Answer: Yes, but it is also pretty rare. If you have something coated with flat or semi-gloss powder and decide you’d prefer it glossy, your best option would be to have a high gloss clear powder coat applied. “High gloss” powder coats are very glossy (with manufacturer gloss factors of 95% +/-5%) but some formulations or incorrect application can have a slight orange peel appearance. There are cases where people use 800-3000-grit sand paper followed by light buffing on powder coat with varying effects, but the use of buffing compound can make it impossible to recoat without complete (expensive) stripping. Most people are delighted with the gloss and look of powder as-coated and would never consider further buffing.
Question: Can you coat just the spokes of my alloy car wheel?
Answer: In most cases, but it is very expensive and generally cost prohibitive. To properly coat just the spokes (or centers) of car wheels, or to apply a 2-coat finish, we need to do a lot of masking. Wheel manufacturers get around this by using custom made 1-piece masks that fit their wheels exactly, or by coating the entire wheel and then machining the powder off the rims in a big lathe. Since we will only be coating 4-5 of your wheels, those techniques are not economical and we are left with manual masking. It can take hours to mask each wheel, which in most cases is cost prohibitive. Often times you are money ahead to buy new wheels. We do coat a lot of sets of wheels, several a week, typically coating the entire wheels in a single color.
Question: Can you powder coat my aftermarket chromed wheels to repair the flaking, peeling, corroded chrome?
Answer: It is very difficult to get chrome to last on aluminum wheels, and winter road salts make the problems worse. Unfortunately, it is usually impossible to abrasive blast the failed chrome off without damaging the aluminum itself. Because of that, we usually recommend people take their chrome wheels to a chrome plater to have the chrome and nickel chemicallly removed before they come to us for powder coating.
Question: Can you powder coat the lug nuts on my car?
Answer: Yes, but they may not fit in your lug nut socket any more. To get an effective corrosion protection on steel lug nuts, the powder needs to go on with a dry film thickness of between .003" and .006". That means the overall size of your lug nut may increase as much as .012", which may not seem much but which is more than the clearance between the nut and some sockets. We generally recommend people look to see if they can buy lug nuts in the color they desire, as those manufactured to be coated are made undersize to allow for the thickness of the coating.
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