Tag Archives: Powder Coating
Just like paint, you can create custom powder coating finishes by adding metal flakes directly into the powder . Unlike paint powders will not accept pearl additives because pearls cannot withstand the high temperatures that powder requires to cure. With that said, creating custom powders is a game of trial and error because different powders have slightly different properties and accept flakes differently. Also each metallic flake will act differently at 400ºF so the following is not a strict formula for mixing flake to powder, more of a guideline of the entire process.
After painting the valve covers on my truck with High Temp Chevy Orange Paint, I noticed that after time they began to fade and in some spots start to peel up. I'll admit that they could have been prepped better the first time but now I get to re-finish them with a custom color unlike any other.
As you'll see above, the bottom valve cover is fully prepped and cleaned, while the top one has only been thorough the blaster.
Powder can be a very stubborn material to work with because the part being coated must be super clean in order to create the best finish. Don't let this steer you away, compared to paint, cured powder will resist temperatures up to 250ºF and all types of chemicals including DOT 3 brake fluid. Powder is great for almost any metal part on a vehicle that will be exposed to the elements or will see heavy traffic. In the interest of saving time I am not going to go into detail about how to properly prep the parts, for this info refer to one of our earlier articles How to Prep Metal For Powder Coating.
Different from paint, two different colored powders cannot be mixed to create a new uniform color. What you'll end up with is a "salt and pepper" effect where you will see both colors individually. If thats the finish you are looking for it is a perfectly functional option but don't expect a new color like you would with paint. On the other hand powder will accept some metallic additives but there is not a clear ratio of how much to add because every powder and metallic are different and will not react the same way. If you decide that you want to venture down the road of adding metallic to powder there are a few guidelines to follow. Darker powders will almost always show metallics the best compared to lighter colors. Additionally translucent powders will show metallics the best because the orientations of the flake does not matter because you will be able to see it through the powder.
For these valve covers I decided I wanted to go with a twist on the classic Chevy Orange Powder by incorporating Eastwood Alsip Orange Super Flake into the powder. Not knowing how the two would mix, I decided to test my mixture on a few test pieces to ensure it had the look I wanted.
The first test piece had way too much flake in it and it ended up looking and feeling like sand paper, the exact opposite of the smooth glossy finish I wanted. Throughout this project I used the Eastwood Dual Voltage Powder Gun on the II setting.
For the next test piece I decided to dial back on the flake in hopes of getting a smooth finish while still being able to see the flake. As you can see the metallic effect is muted and very subtle but the surface is smooth just like I wanted. Below you will see the distribution of the flake in the powder, it does not look like there is much but as you will see it really shows through.
Coating the Valve Covers
Before coating the valve covers I needed to outgas them first, which in simple terms means cooking off any contaminants that may still be on the surface. To outgas, I heated the part up to 410ºF, slightly above the curing temp just in case there were any contaminants that would not bake off at 400ºF.
I applied this mixture to the valve covers and cured them at 400ºF for 20 minutes. When adding flakes to powder you have to watch the time carefully because the flakes may change slightly if cured for too long.
The coverage was great and they turned out looking really nice because you could see the metallic, but only if you really looked for it. I had a hard time getting it to even show up in a picture. Don't get me wrong, they looked great but to get that WOW! look when I open the hood, they still needed a little more sparkle.
Mixing Into Clear
Deciding between just applying clear or to mix flake into the clear was a tough choice, since each powder reacts differently I decided to use my second test piece to see how the flake/clear will end up looking and go from there. I used Eastwood Super Gloss Clear Powder at 1/3 of an 8oz container to 1 tsp. of the same Alsip Orange Flake, Above you can see the flake distributed in the clear.
The results were amazing and exactly what I wanted, this meant the valve covers were going back in the oven to be hot flocked. The clear recommends a cure temp of 375ºF, but with the added flake I decided to preheat and cure at 385ºF to make up for the added flake. I'm not sure if this was needed but it didn't affect the end result.
They looked great after the first coat but I decided that I would hot flock them again and apply one more, on the first pass I did not attach the grounding cable causing me to miss some spots. One great attribute of the clear powder is that you can layer it as many times as you would like, until you get the look you want. If you want to do multiple coats of clear make sure you use PRE to remove any contaminants that may be present.
The final result was spectacular it almost looks like it should be its own color. In good light the metallic stands out beautifully, and its great knowing that this is a one off color that no one else has. Eastwood offers such a variety of powders an additives that the possibilities are only limited by your imagination. Just remember to measure out the ratios or each component in case you need to make more later on.
Check out the Eastwood Blog and How-To Center for more How-To's, Tips and Tricks to help you with all your automotive projects. If you have a recommendation for future articles or have a project you want explained don't hesitate to leave a comment.
- James R/EW
For some unknown reason a lot of car guys are very hesitant to take the plunge into the world of powder coating. This means a lot of people are missing out on all the benefits powder coating has compared to other types of coatings. It seems like there is some fear of powder coating that is preventing car enthusiasts from buying the equipment and starting to coat on their own. You might be surprised to learn that in some cases it's actually cheaper to powder coat something than painting. The truth is that there are fewer tools and materials needed to powder coat compared to painting. For instance there are many more consumable materials needed when painting and thats not including the paint itself. If you were to compare the differences between painting or powder coating a part for your car, the first step would be to take it down to bare metal.
From here the processes are different, and also vary in the time required to complete each.
If you're coating the part with a traditional 1K or 2K paint the piece must be sealed to prevent corrosion and rusting. Using epoxy primer, which can be applied directly to bare metal is the best option. Automotive paints generally shouldn't be applied directly to bare metal because there could be adhesion issues. If you're spraying the part with a 2K primer you will need the correct activator which means another cost associated with the job.
Ok so now that you went out to buy more activator and sprayed the piece with primer, you then have to apply a top coat. Not only will you need the paint, you will also need the reducer and activator if you are using a 2K top coat. Just when you think you're finally done you realize there is still one more step, applying clear coat. The clear coat requires its own activator as well, that's more money out of pocket if you don't already have it. At this point you think you may have spent too much time and way too much money, but the end result does look great.
With Powder Coating you first make the investment in a powder gun and oven. From there all that is needed is to buy the powder itself. Pretty much any electric oven will work (just don't use one you cook food with!). No special activators, reducers, or other chemicals are needed (other than PRE, to clean the bare metal). Prepping a metal object to paint or powder coat is a similar process, the only difference is that any non-metal pieces must be removed since they will not be able to withstand the heat needed to cure the powder.
When comparing paint and powder, durability is always #1 on the list. Before we compare the two we first have to mention the different types of paint. Generally speaking, 1K paints in an aerosol can are worlds apart from the paint on your car. Most 1K aerosols paints are usually enamel paint. The down side to enamel paints are that they never fully dry, they just harden when exposed to air. Additionally they will break down and essentially melt if they come in contact with a solvent. The paint on your car is known as a 2K catalyzed paint. This means that before the paint is applied an activator is mixed into the paint. The catalyzed paint will actually change its chemical make up and cure, making it resistant to solvents. While a catalyzed paint is much stronger than aerosol paints it still does not compare to powder.
Once powder fully cures it's much harder than traditional paint, making it much more scratch and chip resistant. There's a reason almost all high-end custom cars have powder-coated frames! A powder coated part that is exposed to extreme conditions is less likely to chip off and peel like paint would.
Powder isn’t just harder than paint, it's also extremely flexible. We've tested the flexibility of powder by applying it to tin foil, crumbling it up, and flattening it back out. The results were incredible, none of the powder had flaked off! Try doing that same test with spray paint, more will end up on the floor than the foil!
One of the visibly noticeable differences between powder and paint is the actual material thickness. A functional coat of powder can be up to 10X thicker than paint. This means that there is a greater protection between the outside world and the bare metal.
When prepped and applied correctly, powder does an incredible job of preventing corrosion because of how strong it is. When a painted surface is scratched it is much more likely to go down to bare metal. At that point corrosion will begin and start to spread. Since powder is so much harder than paint the chance that a scratch will reach bare metal is very unlikely, making it the perfect coating for chassis and suspension parts.
Ease of Cleaning Up
If you've spray painted before, you'll know how awful overspray can be. No matter how much you prepare, it seems to get everywhere. Cleaning up overspray can be very difficult because it requires the use of harsh chemicals. In its raw form, cleaning up powder is no different than cleaning up sugar and flour spilled in the kitchen. Simply sweeping it up or using a vacuum is all that will be needed.
2K paint must be used once it is mixed, powder does not require any additives. This means you can use it at you own leisure. Powder under normal circumstances does not dry out or cure even when it's left out.
If you really want to be frugal, powder that doesn't stick to your part can be reclaimed and reused by sweeping it up and sifting. Just make sure you use a very fine screen to sift so that there are no other contaminants in the powder. This may be very tricky to do at home, but with some care it can be done.
Eco Friendly Application
Traditional paint guns atomize the liquid paint into the air while a powder coating gun uses air to propel the powder towards the part. As the powder is leaving the gun a slight charge is added to the powder. The powder sticks to the grounded part because the powder has a slight charge when it leaves the gun and it's then attracted to the grounded part.
Unlike liquid paints that are sprayed, there aren't any may health threats to being in the same room without a mask on. Powder coating does not even require the use of a typical carbon filter mask, just a simple dust mask to keep from directly inhaling the powder when spraying. Because powder is heavier than atomized paint, overspray will fall on the ground right around the part and won't float in the air for extended periods of time.
Check out the Eastwood Blog and Tech Archive for more How-To's, Tips and Tricks to help you with all your automotive projects. If you have a recommendation for future articles or have a project you want explained don't hesitate to leave a comment.
- James R/EW