Wetsanded fenders w/ grease

[Finaltheorem47]

I`m helping a friend out. Heres basically what the problems are: The fenders have been wet sanded with 2500 grit, the car went into the shop to get some repairs to pass inspection, when it came out, the mechanics had touched the fenders with their dirty hands, and the grease/dirt is now in the fender. I tried a dawn wash and nothing came out. I`m going to assume that the paint isnt that porus, and the dirt/grease is only as deep as the scratches from the sanding, so if I sand it with 2k grit, it should hopefully only be a surface problem, and not require a full repaint. How does my theory sound?



BTW, its a 94 Toyota Camry, not like a Porsche or anything.

[Setec Astronomy]

IMO you`re nuts if you`re going to sand off grease. Use straight APC, straight Dawn, or some Prep-Sol or equivalent.

[the other pc]

^^^^^ What he said! ^^^^^



If you sand it you’ll just spread the grease around and grind it in deeper.



Did you sand to prep for paint? Or will you be buffing next?



If you’ll be painting, either skip the detergents and water based cleaners entirely, going straight to a solvent, or use detergent/APC first and follow with a solvent. You must finish up with a solvent before painting.





pc.

[Flashtime]

Lacquer thinner > straight iso

[Finaltheorem47]

I painted his car last fall for him and then I went sanded the car and was ready to buff it but never got around to it because it got too cold(yeh big mistake.. I know). This spring I`m going to finish it up for him. I can shoot some more BC/CC over it if its needed. I was thinking if I sand it, I`d use a very heavy dilution of dawn in my water to try to deteriorate the oils as they are sanded off instead of pushing them further into the paint. What solvents are you guys considering? I have surface prep, mineral spirits, gun cleaner and the stuff you would use in a parts cleaner.

[salty]

Mineral spirits.

[paco]

Are you sure it was just oily grease?



Is it just smearing or not coming off?



I wonder if it was something else that `etched` the paint. Otherwise, it should be relatively easy to remove with just a dish shop.

[the other pc]

... What solvents are you guys considering? ....



answered before you even asked the question (how`s that for a fast reply? :D):


... or some Prep-Sol or equivalent.



Prep-Sol is made by Dupont specifically as a paint cleaning/degreasing solvent. All paint suppliers have something similar, like DX 330 from PPG or PRE from Eastwood.



Most modern paints should be fine with hardware store mineral spirits or lacquer thinner (my favorite general purpose solvent) since you`re not planning on painting over it. If you`re painting it`s best to go with solvents that are made for painting, Prep-Sol, enamel reducer or lacquer thinner. They`re generally more pure/refined than the general purpose hardware store stuff.





pc.

[Finaltheorem47]

I`ll test it with mineral spirits today as I have some at my house.

[Altered-Image]

Why not pressure wash? works on big rigs, been there done that.

[ezemsm444]

Are you sure it was just oily grease?



Is it just smearing or not coming off?



I wonder if it was something else that `etched` the paint. Otherwise, it should be relatively easy to remove with just a dish shop.



Exactly it might be brake fluid (hydroscopic) that literally eats the paint. allot of the induction cleaner chemicals are very coarsive. I ruined a headlight when I spilled a can of bg induction cleaner, the headlight was on (daytime running lamps) and just took seconds to ruin it becuase i quickly reached for a rag to wipe it off and it was too late.