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/EWClick Here To Read Full Post...