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Wet sand bonnet (hood)

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  • xrmte
    replied
    Re: Wet sand bonnet (hood)

    Originally posted by Michael Stoops View Post
    Wait.... now you want to sand the OEM paint on the trunk as well? With just 3.8 to 4.0 mils of total film build you really aren't working with a lot of paint there. Removing OEM orange peel will likely require the removal of more than 0.07 mil of material and, quite frankly, removing orange peel from OEM paint isn't really a great idea. Yes, it can be done and done safely - to a point. It usually takes a pretty good skill set and a fair bit of experience to do it consistently and safely. The biggest issue, however, isn't so much the initial sanding and buffing but what you're left with after the process. Yes, the paint looks amazing - smooth, super glossy, almost devoid of texture.... a real show car finish. Yay!!! Except this is not a pampered show car, it's a daily driver. And daily drivers get exposed to all sorts of damaging effects on the paint. And since that paint is now super glossy and almost texture free, those defects REALLY stand out. And now you're stuck, because removing a deep-ish defect means removing paint and, well, you're likely at the limit now so you get to live with this nasty looking, in-your-face defect. Hmmmm.....
    You made some good solid points there mike
    Great advice and your right its only a daily driver

    Leave a comment:


  • Michael Stoops
    replied
    Re: Wet sand bonnet (hood)

    Originally posted by xrmte View Post
    Ok mike done a ptg reading on the boot (trunk) which is 3.8mils and 4.0mils and thats fairly consistent on that whole area

    If i use the 3000 finishing disc and the interface pad say 5mm or 10mm pad?
    It should only remove about 0.05 -0.07 mils correct so I'll still be in the safe zone?
    Wait.... now you want to sand the OEM paint on the trunk as well? With just 3.8 to 4.0 mils of total film build you really aren't working with a lot of paint there. Removing OEM orange peel will likely require the removal of more than 0.07 mil of material and, quite frankly, removing orange peel from OEM paint isn't really a great idea. Yes, it can be done and done safely - to a point. It usually takes a pretty good skill set and a fair bit of experience to do it consistently and safely. The biggest issue, however, isn't so much the initial sanding and buffing but what you're left with after the process. Yes, the paint looks amazing - smooth, super glossy, almost devoid of texture.... a real show car finish. Yay!!! Except this is not a pampered show car, it's a daily driver. And daily drivers get exposed to all sorts of damaging effects on the paint. And since that paint is now super glossy and almost texture free, those defects REALLY stand out. And now you're stuck, because removing a deep-ish defect means removing paint and, well, you're likely at the limit now so you get to live with this nasty looking, in-your-face defect. Hmmmm.....

    Leave a comment:


  • xrmte
    replied
    Re: Wet sand bonnet (hood)

    Originally posted by Michael Stoops View Post
    Definitely start with a 3000 grit finishing disc, with the interface pad, and proceed cautiously from there depending on result.
    Ok mike done a ptg reading on the boot (trunk) which is 3.8mils and 4.0mils and thats fairly consistent on that whole area

    If i use the 3000 finishing disc and the interface pad say 5mm or 10mm pad?
    It should only remove about 0.05 -0.07 mils correct so I'll still be in the safe zone?

    Leave a comment:


  • xrmte
    replied
    Re: Wet sand bonnet (hood)

    Originally posted by Michael Stoops View Post
    Definitely start with a 3000 grit finishing disc, with the interface pad, and proceed cautiously from there depending on result.
    Ok thanks mike will have to order some soon I'll let you know how i get on.

    Leave a comment:


  • Michael Stoops
    replied
    Re: Wet sand bonnet (hood)

    Definitely start with a 3000 grit finishing disc, with the interface pad, and proceed cautiously from there depending on result.

    Leave a comment:


  • xrmte
    replied
    Re: Wet sand bonnet (hood)

    Originally posted by Michael Stoops View Post
    Well, if this was factory OEM paint I'd tell you the general rule of thumb is to not remove more than 0.5 mil (13 microns) of the topcoat. But since this isn't OEM paint, all bets are off. You have no real info on just how thick the topcoat is, so proceed with caution. That said, you can see the tremendous improvement we made with even less material removed than that, so with minimal impact to film thickness you can do wonders with texture removal.

    I'm guessing it's a safe bet that the rest of the car's OEM paint has some orange peel to it as well - they all do in varying degrees. Going easy with the sanding at first will help you match that texture so that the hood doesn't look out of place by being too flat, instead of too textured. That's easier, and safer, to achieve than trying to make it dead flat.
    Thanks mike so in my situation just to recap what sanding disc should i aim for?
    And use with or without interface pad?

    Leave a comment:


  • Michael Stoops
    replied
    Re: Wet sand bonnet (hood)

    Originally posted by xrmte View Post
    Thanks mike great information
    I would like to reduce the op texture so as you said use the 3000 finishing disc without the interface pad

    Do you know many mils could be removed when just using the finishing disc straight on the backing plate?

    What would be a safe PTG range reading to use these discs to reduce op where is the limit?

    Well, if this was factory OEM paint I'd tell you the general rule of thumb is to not remove more than 0.5 mil (13 microns) of the topcoat. But since this isn't OEM paint, all bets are off. You have no real info on just how thick the topcoat is, so proceed with caution. That said, you can see the tremendous improvement we made with even less material removed than that, so with minimal impact to film thickness you can do wonders with texture removal.

    I'm guessing it's a safe bet that the rest of the car's OEM paint has some orange peel to it as well - they all do in varying degrees. Going easy with the sanding at first will help you match that texture so that the hood doesn't look out of place by being too flat, instead of too textured. That's easier, and safer, to achieve than trying to make it dead flat.

    Leave a comment:


  • xrmte
    replied
    Re: Wet sand bonnet (hood)

    Originally posted by Michael Stoops View Post
    We used a 3000 grit finishing disc (built in thin foam) and an interface pad. We normally recommend use of the interface when doing paint correction rather than texture leveling, but if your plan is to level texture then you'd want to skip the interface pad. Just be very, very aware of any contours, great or small, when doing so. Especially if you have no prior experience!! Wet sanding, when done right, can be very non-invasive to the paint due to the lack of heat from heavy compounding. But it can also bite you pretty quickly if you're not paying attention.

    As for speed settings on the DA, stick with roughly 3 to 4 on the speed dial, depending on the tool. You want pad rotation, but it doesn't have to be spinning really fast. In fact, too much pad spin and too much water can cause you to hydroplane and lose cut. If you do lose spin you'll still cut because it's sandpaper, so pad rotation isn't quite as critical as when polishing paint. Just use the weight of the tool and let the abrasive do it's job. Oh, and 3M Trizact etc are really more of a damp sanding process - no need to soak the discs in water first, and no need to flood the surface with water. A couple trigger pulls of a spray bottle, both onto the paint and onto the abrasive disc is all that's needed. As you see residue start to build on the disc, clean it thoroughly by spraying water on it. This is critical to avoid pigtails.
    Thanks mike great information
    I would like to reduce the op texture so as you said use the 3000 finishing disc without the interface pad

    Do you know many mils could be removed when just using the finishing disc straight on the backing plate?

    What would be a safe PTG range reading to use these discs to reduce op where is the limit?

    Leave a comment:


  • Michael Stoops
    replied
    Re: Wet sand bonnet (hood)

    Originally posted by xrmte View Post
    Mike that post you were referring to were u using a megulars 3000 finished disc?

    So should i use a non padded disc and no interface pad or will using an interface pad be ok?
    We used a 3000 grit finishing disc (built in thin foam) and an interface pad. We normally recommend use of the interface when doing paint correction rather than texture leveling, but if your plan is to level texture then you'd want to skip the interface pad. Just be very, very aware of any contours, great or small, when doing so. Especially if you have no prior experience!! Wet sanding, when done right, can be very non-invasive to the paint due to the lack of heat from heavy compounding. But it can also bite you pretty quickly if you're not paying attention.

    As for speed settings on the DA, stick with roughly 3 to 4 on the speed dial, depending on the tool. You want pad rotation, but it doesn't have to be spinning really fast. In fact, too much pad spin and too much water can cause you to hydroplane and lose cut. If you do lose spin you'll still cut because it's sandpaper, so pad rotation isn't quite as critical as when polishing paint. Just use the weight of the tool and let the abrasive do it's job. Oh, and 3M Trizact etc are really more of a damp sanding process - no need to soak the discs in water first, and no need to flood the surface with water. A couple trigger pulls of a spray bottle, both onto the paint and onto the abrasive disc is all that's needed. As you see residue start to build on the disc, clean it thoroughly by spraying water on it. This is critical to avoid pigtails.

    Leave a comment:


  • xrmte
    replied
    Re: Wet sand bonnet (hood)

    Originally posted by Michael Stoops View Post
    If the panel has been resprayed and you're getting the PTG readings you are, it sounds like you've got a decent amount of paint on the panel. If it is in fact a respray then it sounds like it was a bare metal spray as those numbers aren't too far off what we'd expect to see from an OEM finish. What's perhaps a bit worrying here is that there could have been some isolated damage that required a full fix in a small spot where the color was blended, and then the entire panel was scuffed and fresh clear shot over it (you can't really blend clear, so this is a fairly standard practice).

    That said, 2000 grit on a DA sander, with an interface pad, isn't going to be terribly aggressive and, depending on the paint hardness, those 2000 grit marks should buff out pretty easily. I'm always a fan of refining the sanding marks as much as possible to make the buff out less invasive (ie, less chance of overheating the paint due to aggressive machine compounding). Orange peel reduction may be pushing it with that paint thickness, but if the texture is more of a dry spray or similar fine texture issue, then the process you describe might just be the ticket.

    The following was taken from an article dating back to our NXT Institute training session in 2014 Note that we started with even less paint than you have (roughly 90 microns) and we only used 3000 grit on a DA before polishing. This was also a respray, and a bad one at that. It's amazing the changes you can make to the appearance with very minimal paint removal.
    Mike that post you were referring to were u using a megulars 3000 finished disc?

    So should i use a non padded disc and no interface pad or will using an interface pad be ok?

    Leave a comment:


  • xrmte
    replied
    Re: Wet sand bonnet (hood)

    Originally posted by Old Bear View Post
    To help others answer your question, are you referring to the 3M Trizact foam sanding disc 3000 grit.
    The foam will help follow the paint texture contour, rather than remove it, like one of the non padded disc might do.
    https://www.detailing.com/store/3m-0...-in-p3000.html
    So use a trizact 3000 non padded disc then?

    Leave a comment:


  • Old Bear
    replied
    Re: Wet sand bonnet (hood)

    To help others answer your question, are you referring to the 3M Trizact foam sanding disc 3000 grit.
    The foam will help follow the paint texture contour, rather than remove it, like one of the non padded disc might do.
    https://www.detailing.com/store/3m-0...-in-p3000.html

    Leave a comment:


  • xrmte
    replied
    Re: Wet sand bonnet (hood)

    Originally posted by Michael Stoops View Post
    If the panel has been resprayed and you're getting the PTG readings you are, it sounds like you've got a decent amount of paint on the panel. If it is in fact a respray then it sounds like it was a bare metal spray as those numbers aren't too far off what we'd expect to see from an OEM finish. What's perhaps a bit worrying here is that there could have been some isolated damage that required a full fix in a small spot where the color was blended, and then the entire panel was scuffed and fresh clear shot over it (you can't really blend clear, so this is a fairly standard practice).

    That said, 2000 grit on a DA sander, with an interface pad, isn't going to be terribly aggressive and, depending on the paint hardness, those 2000 grit marks should buff out pretty easily. I'm always a fan of refining the sanding marks as much as possible to make the buff out less invasive (ie, less chance of overheating the paint due to aggressive machine compounding). Orange peel reduction may be pushing it with that paint thickness, but if the texture is more of a dry spray or similar fine texture issue, then the process you describe might just be the ticket.

    The following was taken from an article dating back to our NXT Institute training session in 2014 Note that we started with even less paint than you have (roughly 90 microns) and we only used 3000 grit on a DA before polishing. This was also a respray, and a bad one at that. It's amazing the changes you can make to the appearance with very minimal paint removal.
    Yes im always amazed what 3000 grit can achieve.

    So if i use the 3m 3000grit sanding disc i should be safe with the ptg readings im getting?

    What speed setting do you recommend on the da?

    Leave a comment:


  • Michael Stoops
    replied
    Re: Wet sand bonnet (hood)

    If the panel has been resprayed and you're getting the PTG readings you are, it sounds like you've got a decent amount of paint on the panel. If it is in fact a respray then it sounds like it was a bare metal spray as those numbers aren't too far off what we'd expect to see from an OEM finish. What's perhaps a bit worrying here is that there could have been some isolated damage that required a full fix in a small spot where the color was blended, and then the entire panel was scuffed and fresh clear shot over it (you can't really blend clear, so this is a fairly standard practice).

    That said, 2000 grit on a DA sander, with an interface pad, isn't going to be terribly aggressive and, depending on the paint hardness, those 2000 grit marks should buff out pretty easily. I'm always a fan of refining the sanding marks as much as possible to make the buff out less invasive (ie, less chance of overheating the paint due to aggressive machine compounding). Orange peel reduction may be pushing it with that paint thickness, but if the texture is more of a dry spray or similar fine texture issue, then the process you describe might just be the ticket.

    The following was taken from an article dating back to our NXT Institute training session in 2014 Note that we started with even less paint than you have (roughly 90 microns) and we only used 3000 grit on a DA before polishing. This was also a respray, and a bad one at that. It's amazing the changes you can make to the appearance with very minimal paint removal.



    How's this for a little non invasive paint correction: this is on a rental BMW with a truly horrid respray on the rear of the vehicle. The paint had an incredible amount of texture and therefore almost zero clarity in the reflections (if you want to call it a reflection!). Two things to observe in the images below: A) the paint thickness readings showing the minimal amount of paint removed, in this case 0.05 mil which is virtually nothing, and B) the clarity of the reflection of the paint thickness gauge in the "after" shot on the right versus the "before" shot on the left. This level of correction was achieved with a 3000 grit finishing disc on a DA followed by M205 on a microfiber cutting pad. Yes, you read that right - M205 on a microfiber cutting pad.


    A "before" reflection on the same hood.


    An "after" reflection on the same hood, after using the steps described above.


    This may not be Facebook, but this is indeed a selfie, shot in the "before" of that horribly resprayed hood. How's that for texture and lack of clarity?


    Same hood, same process as above. How crazy is that?

    Leave a comment:


  • xrmte
    replied
    Re: Wet sand bonnet (hood)

    No worries thanks old bear

    Leave a comment:

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