Soda Blasting and Painting your Engine Pt 1


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SanDogDewey
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Joined: Tue May 18, 2010 9:15 am
Location: San Diego, CA, USA
Location: San Diego, CA, USA

Soda Blasting and Painting your Engine Pt 1

Post by SanDogDewey »

Soda Blasting and Painting your Engine
Materials:
14 Lb Soda Blaster
Harbor Freight $99.99

2 - 50# Medium Grade Soda Blasting Media
Harbor Freight $66.00

Rubber stoppers
http://www.widgetco.com/rubber-stoppers

Alumiprep 33
http://www.aircraftspruce.com/catalog/c ... miprep.php
$17.75

Alodine 1201
http://www.aircraftspruce.com/catalog/c ... ne1201.php
$18.95

8 CFM @ 90 PSI Compressor

Prep your engine for blasting. Based on Nils’ advice I ordered a bunch of rubber stoppers from widetco. Along with the stoppers for the intake and exhaust, I order a stopper for every hole in the engine, measuring with a micrometer and ordering the appropriate stopper. In order to seal up your motor you will also need to install the two bolts for the tachometer gear. I bolted my clutch, crank caps and alternator on with some Three Bond Liquid Gasket 1194, to seal up those areas. If you’ve finished polishing your clutch and covers, you may not want to use them to seal the engine as the soda blasting will take off some of your shine. I contemplated borrowing a set and then settled on using mine and re-polished them when I was done. I also had my engine on an engine stand which makes the process much easier (Harbor Freight again).

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The only problem I had with the Harbor Freight blaster is the small orifice that you fill it through. Even with the right sized funnel, it takes considerable time for each filling.
Blasting is easy. Just make sure you get both the upper and lower sides of the cooling fins. This is where having the engine on the stand comes in handy by rotating the engine as needed. My engine took me about 4 hours and two bags of media. Face shield and gloves are a must.

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You will have a small snow storm of used baking soda to sweep up when you're finished. I blasted this engine in an industrial area, so I just hosed everything down after I was finished.
After I blasted the motor, I scrubbed it down really well with soap and water. You need to get all the baking soda out of the cracks and crevices. I then applied Alumprep 33 which is a phosphoric acid based cleaner, brightener and prepaint conditioner for aluminum. This cleans and etches the aluminum.
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Dilute the Alumprep 33 according to instructions. I put the mixture into a spray bottle and sprayed the complete engine. Scrub the entire engine with a Scotchpad.
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This can be nasty stuff, so wear appropriate gloves and eye protection. Do not let it dry and rinse with clean water. Repeat until water does not bead on the surface.
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After etching the motor, I applied Alodine. You apply this undiluted with a brush. The produces a conversion coating on aluminum that resists corrosion and provides for good paint adhesion. Let it sit one to three minutes and rinse.
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After rinsing the alodine, I blew the excess water off the motor with compressed air and let it sit out in the Socal sun for a couple of hours. I was fortunate enough to have a nice hot day. At this point it isn't going to look pretty, but you've got a solid base for paint. (Late additional edit) "Make sure you let the alodine cure according to the instructions on the bottle. I did not and the beautiful silver motor at the end of this post is now gold. I really like the color as it matches the gold stripe in my tank, but it was purely by accident. I can only attribute it to not letting the alodine cure completely."
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ICOA #6266
1977 CB750K
1980 CBX

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NobleHops
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Location: Tucson, Arizona, USA
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Re: Soda Blasting and Painting your Engine Pt 1

Post by NobleHops »

Bumpitty
Nils Menten
Tucson, Arizona, USA '80 CBX, sort-of restored :-)

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