Wet sanding 2015 black BMW
- Thread starter jackog
- Start date
WHY are you wet standing this BMW paint in the first place?, IE what paint "problem(s)" or defects are you trying to remove?
Also, did you measure the paint thickness with a Paint Thickness Gauge (PTG) to verify how much clear coat/base coat/primer (total paint substrate) you have to work with?
Is this wet sanding being done by hand or by machine?
I will assume your question about this paint 's hardness is in reference to the OEM BMW factory paint and not a respray from body shop for whatever reason.
I will also assume that you have done wet sanding before.
Also, did you measure the paint thickness with a Paint Thickness Gauge (PTG) to verify how much clear coat/base coat/primer (total paint substrate) you have to work with?
Is this wet sanding being done by hand or by machine?
I will assume your question about this paint 's hardness is in reference to the OEM BMW factory paint and not a respray from body shop for whatever reason.
I will also assume that you have done wet sanding before.
I picked up this car recently and paint was in bad shape. lots of defects on boot lid. I did not measure thickness, but I have messed with paint on a number of this era BMW's and found it to be reasonably forgiving. Also, I'm willing to paint it if I cant get it reasonable with Sanding/polishing.
I have done a bit of wet and dry sanding both with hand and machine and various different sanding blocks and papers
I just found this particular paint, sapphire black, on this car just doesn't behave like other paints I have worked with
Paint is factory original.
With this one I have tried with hard block then softer block then different short and longer duration sanding times and different pressures
Just doesn't seem to look right
Setec Astronomy
Well-known member
Wow, 1200 is pretty extreme.
After going through the 1200, 2000, 3000 sequence, and it not looking right, did you go back and start over with the 1200?
What you want to do is start with the 1200 and use that until your defects are gone, then use 2000 to remove the 1200 sanding scratches, and the 3000 to remove the 2000 sanding scratches. If it were me, on black, I would go to 4000 or 5000 paper, but I also wouldn't have started with 1200.
Not that I know what I'm talking about.
I'm not sure how much clear you have left, but if you go back on a small area with just the 3000, see if it improves.
After going through the 1200, 2000, 3000 sequence, and it not looking right, did you go back and start over with the 1200?
What you want to do is start with the 1200 and use that until your defects are gone, then use 2000 to remove the 1200 sanding scratches, and the 3000 to remove the 2000 sanding scratches. If it were me, on black, I would go to 4000 or 5000 paper, but I also wouldn't have started with 1200.
Not that I know what I'm talking about.
I'm not sure how much clear you have left, but if you go back on a small area with just the 3000, see if it improves.
Dan
Well-known member
I'm not sure there is a particular look I go for after wet sanding, it's about defect removal and not creating sanding marks. The polish for me is what brings back the look.
Thanks all for replies.
I now see 1200 is too rough. You would only use for specific defect removal, not whole panel
Looks like most people would start at 1500.
what I ended up doing was going back to 1500. I used that and was much more careful and took my time. then went 2000, then 3000. It looked better than the first time round.
No burn throughs at this point
Then I got a rotary polisher and used my heavy cut compound.
This worked well and very quickly.
In the past i used microfiber pads and heavy cut on my DA. Did almost nothing
Seems to be really hard paint.
I now see 1200 is too rough. You would only use for specific defect removal, not whole panel
Looks like most people would start at 1500.
what I ended up doing was going back to 1500. I used that and was much more careful and took my time. then went 2000, then 3000. It looked better than the first time round.
No burn throughs at this point
Then I got a rotary polisher and used my heavy cut compound.
This worked well and very quickly.
In the past i used microfiber pads and heavy cut on my DA. Did almost nothing
Seems to be really hard paint.
Setec Astronomy
Well-known member
Glad that worked out.
Jackog:
Sorry if my initial response seemed to be somewhat critical and I came across as detailing jerk! All I know is you have a lot of "fortitude" attempting to wet sand your BMW paint as you did. The fact that you mentioned using a rotary tells me of your detailing acumen and ability and as Setec said, glad it turned out in a manner that is acceptable to you. At the end of the day, that is really all that matters.
Request for ONE after-picture so we can see how well it turned out?
I am with you on this one as to WHY this particular BMW has a hard paint, since you mentioned working on other BMWs of this era with similar Black Metallic paint. I assume this is the BMW color you are referring to from this era that you have experience with and not the Jet Black..
Sorry if my initial response seemed to be somewhat critical and I came across as detailing jerk! All I know is you have a lot of "fortitude" attempting to wet sand your BMW paint as you did. The fact that you mentioned using a rotary tells me of your detailing acumen and ability and as Setec said, glad it turned out in a manner that is acceptable to you. At the end of the day, that is really all that matters.
Request for ONE after-picture so we can see how well it turned out?
I am with you on this one as to WHY this particular BMW has a hard paint, since you mentioned working on other BMWs of this era with similar Black Metallic paint. I assume this is the BMW color you are referring to from this era that you have experience with and not the Jet Black..
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