Quote:
Originally Posted by Zedn
Another question. What prep would you recommend for the rough casting? It's a brand new crate motor. I was thinking maybe a scourer disc on a drill or die grinder.
Should it be prepped within a certain amount of time of painting before it re oxidizes? I looked up the ppg product and it says to wipe down with 50/50 metho and water bofore coating. Is this to remove oxide or just clean oils.
Appreciate your help. My paint supplier has all the stuff but not the expertise. They sold me the wrong hardner with my clear and it gave me all sorts of solvent pop issues. They told me air was getting trapped and causing the pin holes.
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Happy to help Zedn.
You need to prepare the casting by removing any burrs and dags. If you need to fill any imperfections, use JB Weld and allow it the full 24 hours to cure. Use the standard version, not the 'Kwik'. Standard JB Weld can withstand 500F temperatures and it does it really well.
You'll want to finish with a P180-240 dry paper. Yes, you then need to wipe the surface down using a 50/50 mix of metho and water. This cleans any oils out of the aluminium. Wear powder free latex gloves the whole time and don't touch/rub your face (and then the block) after you've cleaned the surface down.
You then apply your etch primer immediately and go on with your topcoating from there. It's worth mentioning too that given the pretty cold weather we're currently experiencing, you would should pre-heat your block to between 23-26 degrees celcius before applying any primers or topcoats. You'll also want to maintain this temperature throughout the entire dry process.
Even then, depending on what materials you used and how much material you applied, if cured at room temperature, the paint will still be relatively soft for approximately 1 week after painting (or about 48 hours if baked @ 60C for 30 min in a low bake spray oven).
Given this, you want to resist the urge to start bolting things back onto the motor for at least a week after painting!
Cheers,
Sime