Turbo Refinish with Powder Coating

Posted: March 23, 2016 By: JamesR

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Whether you’re adding a turbo to your car or just refinishing the one you already have, the best option is powder coating.  Eastwood has everything you need to completely restore your turbo in an extremely durable corrosion-free finish that other coatings simply can’t match.

 

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The turbine, or exhaust side of a turbocharger can get very hot during operation; sometimes exceeding 400 degrees. Standard powders are usually only rated to withstand around 250 degrees and cure at 400 degrees. To coat the turbine side I will be using Eastwood High Temp Paint which is rated to 1200 degrees.  As soon as you decide that you will be taking your turbo apart it’s a good idea to pick up a turbo rebuild kit.  Most of the kits include gaskets, bearings, and any other parts that may commonly wear out.

 

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The first step of the process is to completely disassemble the turbo. Not only will this allow you to clean off all the dirt, it will separate any pieces that are bolted together.  If you apply powder over two surfaces that are bolted together it will make it difficult to separate them in the future without destroying the powder. If your rebuild kit does not come with extra hardware make sure to keep track of all the tiny bolts and other parts.

 

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Now that I have the turbo completely taken apart I set aside everything but the the two halves of the compressor.  They are the only parts that I will be powder coating.  I first sprayed them down with Chassis Kleen to remove as much of the heavy grease and dirt that was visible on the surface.

 

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To prep the compressor housing for media blasting, I taped off all of the areas that I didn’t want the media to get in.  It’s a good idea to first stuff the compressor housing with clean shop rags to reduce further damage if the tape happens to fail. The areas taped included machined surfaces, threaded holes, and the entire inner face.

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As an extra safety precaution I stuffed a clean shop rag on the inside of the housing before taping and putting it in the cabinet to be blasted. Even though these areas were taped, I still took my time and avoided pointing the blasting nozzle directly at the tape edge. Glass bead  is known to be on the gentler side, but still could have easily peeled up a corner.

 

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I chose to use glass bead because it won’t damage the cast aluminum surface.  With the turbo out of the blaster I used an air blow gun to remove any media that was still left on the surface and removed the tape and rag.  No matter how much effort you put into taping of the parts, it’s nearly impossible to not have a even a very small amount of media make it past the tape.  Because of this it’s important to take extra time to make sure all areas are free of any remaining media. The last thing you want happening is blast media ending up inside your engine.  I wiped the turbo down with Low VOC PRE to remove any chemical contaminants still on the surface.  The normal PRE can be used but our Low VOC version is the preferred option because it will evaporate much faster which will allow you to speed up the preparation process.

 

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You may think this is a lot of effort just in cleaning before applying the powder, but you definitely don’t want to take any shortcuts.  Powder is much more durable than paint but this higher durability does require that the parts be completely free of all contaminants. The next step is to preheat your oven to 410 degrees to outgas the pieces. Outgassing is a method used to remove any contaminants that still remain on the surface of the parts.  Heating them above the cure temp will allow the contaminants to burn off before the powder even touches them.  The size and thickness of the part will determine how long to outgas, but 10 minutes is a good average. Make sure you use an infrared thermometer to see when the ENTIRE part reaches a surface temp of 410 before it is removed from oven.

 

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Allow the parts to fully cool and wash them down again with Low VOC PRE as the final preparation step before applying powder. You should wear nitrile gloves during the final cleaning because the oils on your hands could affect the outcome of the powder.  With the parts washed again I taped off all of the openings with High Temp Fiberglass Tape. I used aluminum foil to cover the inside faces and Eastwood Paint and Powder Coating stand to hold the oven trays in place while mounting the turbo pieces and applying the powder. The stand is nice because it holds the oven tray in the same orientation as when it goes into the oven, making it very easy to transfer to the oven itself. 

 

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Due to the way our shop is set up, I was able to put the paint and powder rack on top of a folding welding table in order to take full advantage of our filtered spray booth.  Because many of you may not have access to a system like this, its recommended that you apply powder in a well ventilated area with the use of a standard dusk mask.  Powder Coating does not require the use of an activated charcoal respirator like painting does, but it will work just as well if that’s all you have.

 

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The powder color I chose for the compressor side of the turbo is Eastwood Mirror Black, which will give the turbo a very glossy black finish. I coated the parts and put them in the oven to cure for 20 minutes.  the 20 minute cure time is not from the time you put them into the oven, rather the time once the powder flows out.  You will able to tell when it flows out because the surface of the part will become smooth, it is from this point the 20 minutes begin.

 

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Now that the compressor housing is powder coated it’s time to move on to the turbine housing. Like I mentioned before, I’ll be using Eastwood High Temp Matte Silver for the turbine and center section, it will give the turbo high heat durability and a good contrast from the mirror black on the other side.

 

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There was a good amount of surface rust on the exhaust side so it too must be media blasted before painting.  Before blasting, I used a small wire brush to remove any loose rust or dirt.  This will make it easier to blast and remove the risk of any loose rust clogging the air hose.

 

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Just like the compressor housing I taped off all of the openings with masking tape so no media would get in.  When blasting, make sure not to direct the nozzle directly at the tape edge because the tape may start to peel.

 

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Before removing the tape, I made sure to blow off any loose media that was still on the surface. I then removed the tape and wiped everything down with PRE

 

IMG_2660 Using some scraps of metal, I made a stand that would support the turbine housing vertical allowing me to paint every area without touching it.

 

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I put on nitrile gloves again because skin oils can contaminate the metal causing poor adhesion. Using the foam brushes included in the kit I applied the High Temp Coating.  The kit comes with different size brushes so you will easily be able to find one that will work well with the part you are coating.

 

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I let it dry to the touch which will take about 30-40 minutes, The High Temp Coating does not fully cure until it is put on the car and heated up by the exhaust.

 

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Leaving the turbine housing on the stand, I reassembled the turbo using the parts from the rebuild kit.  If you don’t remember exactly how it goes back together, try and find instructions online.  Turbos have very tight tolerances and even if one part is missing or out of place it could cause damage to the turbo or your engine.

 

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Side by side you would never know that this is the same turbo, and that all could easily be done in your garage at a fraction of the price it would take to get done professionally.  Visit Eastwood.com and order your very own powder coating equipment today, you’ll be powder coating in no time.

 

Check out the Eastwood Blog and How-To Center for

 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

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10 thoughts on Turbo Refinish with Powder Coating

  • Why aren’t there any pictures of the Mirror Black coating being applied? No mention is made at all as to how it is done. Is it brushed on or what? The only process that I have ever heard of being used for powder coating anything, is by applying a high voltage electric charge to the parts, which makes the dry powder stick to them when it is sprayed on. Then the rack is moved into an oven with the charge still applied so the powder doesn’t fall off before it is melted onto the surface.
    One last note here, please correct the spelling of “your” on the intro page, it should be “you’re”.

  • After bead blasting and cleaning, use a light and check out the part and if there are any beads they will glow.

  • How can you do raised and recessed lettering in different colors from the base color in powder.
    Ex. The “GARRETT” lettering on the compressor cover in red to contrast the black.

  • looks like you guys screwed up on the last pix. or the assembly.
    Why does the original pix of the part show 2 ports on one side and then the main port in the middle central of the snail, but then in the finished Pix it shows the 2 side ports on different sides

  • Why on earth would you use black on the compressor housing? Black will retain heat.

    Why make the intercooler work harder?

  • You left out one very important step. The rotating assembly is balanced at the time of manufacture, and has to be reassembled in exactly the same orientation relative to the shaft. It needs to be marked prior to disassembly. If its reassembled in a random orientation, it will be out of balance and can destroy itself when its spinning at well over 100,000 RPM.

  • Hi Chris,

    You can spray the letters first and mask all around them or vice versa. Similar to spraying normal solvent paint.

  • Typical turbine inlet temperatures can reach around 1600F -1800F. Your 1200F exhaust coating is only good for exhaust headers, not turbine housings. Even ceramic coatings have a hard time holding up to those high turbo exhaust temperatures. You can expect that the coating applied to this turbine housing is going to burn off after a while of running unless you don’t go into any significant boost.

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