Stains on freshly polished valve cover.

K

KaeROeS

New member
So I decided to polish my valve cover. I started sanding with 80grit and than did 120,220,400,800,1000,1500 and 2000. After than few coats of blue magic and mothers metal polish. I used wd40 while wet sanding. For some reason there are few spots on the cover that have some smear spots. I have no idea what did I do wrong, I did everything like I always do. The only thing I can think of is that i did not wash the cover between the grits but I always wiped it out with a clean towel. I even went and sanded down everything again going down to 60 grit but the stains are still there. Any idea whats did I do wrong and if it's possible to clean it? Thanks



4114790149_87e4539f0a_b.jpg


4114790211_29e09d8193_b.jpg


4114790273_d8fc25bd84_b.jpg


4115560826_a79797d36d_b.jpg
 
You wet sanded using WD-40?



The spots can be a lot of things. They could be caused from heat, discolorazion in the steel, chemicals, and so on. If they are not coming out with sanding and polishing they are probably just through the steel.
 
Yea, Heard wd40 helps with sanding. I only sprayed just a little bit on the cover before I started sanding. So you think there is no way I can get rid of those stains?
 
Looks to me to be a chemical stain. Try a good wash with a degreaser. If that helps but does not eleminate the stains you could bake them out in the oven. Without protecting them, stains will return because the metal is porous. There are easier and more effective ways to level and polish cast aluminum but it is often hit and miss because of the process used in manufacturer the parts.
 
rdorman said:
Looks to me to be a chemical stain. Try a good wash with a degreaser. If that helps but does not eleminate the stains you could bake them out in the oven. Without protecting them, stains will return because the metal is porous. There are easier and more effective ways to level and polish cast aluminum but it is often hit and miss because of the process used in manufacturer the parts.
Click to expand...



It seems like the stain is on the inside of the cover, not outside. Could it be a discolored aluminum?
 
It could be in the alloy or the casting. A good washing and perhaps baking would tell you if it does not go away. If it does go away, I would think it will come back. I can not think of a practical way to seal the inside of a valve cover and retain the polished look. Although, anodizing might be an option. Still, cast aluminum is porous (to the point where I have seen liquid leak through) and prone to staining. The mixture in the alloy such as silicone can also react to various compounds such as an alcholine (sp) cleaner.
 
rdorman said:
It could be in the alloy or the casting. A good washing and perhaps baking would tell you if it does not go away. If it does go away, I would think it will come back. I can not think of a practical way to seal the inside of a valve cover and retain the polished look. Although, anodizing might be an option. Still, cast aluminum is porous (to the point where I have seen liquid leak through) and prone to staining. The mixture in the alloy such as silicone can also react to various compounds such as an alcholine (sp) cleaner.
Click to expand...



I sanded the cover again and right now I'm at 400 grit. i can already see the stains more and more visible while I go higher with the grit. So You suggest using a good cleaner or bake it? If so should I do right now while the cover is still not polished or finish sanding and polishing and than clean and bake it?
 
Finish your polishing. Clean it well... a good soaker. If that helps, baking may help but most likely the stain will return. If that doesn't help, there is nothing I am aware of that you can do about it.
 
Try out some Pledge furniture cleaner! No, I'm not joking lol. If that doesn't work, maybe Nevr-dull. Gotta love polishing aluminum engine parts! I think it's more of a disease....

user56_pic20_1226766159.jpg
 
You must log in or register to reply here.
Back
Top