Wet sanding for orange peel removal

[Scooby24]

I will be attempting wet sanding on my car for the first time and would like your guys` advice. I have an 03 BMW with relatively hard paint that to my knowledge is all original. Same hardness, relatively consistent paint thickness numbers throughout the car, etc. On the hood I measure a very healthy 140-190 microns but on the rear doors, towards the window it thins out considerably, measuring as low as 84 microns.



My goal is remove the orange peel, acid etching, rids, etc so I`m looking at doing the entire car top to bottom. I have a Flex 3401 and PC 7424, should I be looking into DA sanding with unigrit disks? Should I go for 3" or 6" or should I stick with doing it by hand?



For the time required, I`m assuming if doing it by DA I should do similar speeds as polishing but only 1 pass? More? I`m sure I could figure out how much I need to be doing by doing a pass and measuring, but I thought I`d check with you guys first.

[Barry Theal]

Please don`t take this the wrong way, but if this is your first time sanding an entire car. In fact sanding in general, please stop and get some practices panels first. Complete orange peel removal is an advanced skill that is a major job. Its the king of kings in this industry.



To answer your questions, You should have 6 inch 3 inch in da and hand paper. I would recomend at least 1500 and higher grits. When I doing a complete orange peel job I prefer 800 grit and up. Also I would recomend a rotory to speed polishing up. Grab a few wool pads. Do yourself a favor, Im sure you have done a lot of reading and seen the pictures. Doing a job like this right isn`t easy. Please continue to read and educate yourself with the know how then get the expeiriance on a junk panel or 2. Best of luck and if you are serious on this please contact me on my cell phone and I will try to help answer any questions you may have.



Best of luck.

Barry Theal

[Scooby24]

Thanks Barry! I do have a couple of test panels to try but didn`t know if they would be very applicable experience since they are from a subaru impreza which is about the polar opposite on the hardness scale. I suppose if nothing else I`ll know on the softest of paints how much paint I`d remove in the process.



I`m definitely a little apprehensive of this job which is why it`s taken me so many years to attempt it, but with your guys` advice I`m sure I can tackle it. I just really need to leverage that expertise.

[togwt]

Wet-sanding (colour-sanding) a complete vehicle body may be beyond the capabilities of the average detailer or enthusiast; in this case we strongly encourage the reader to consult a professional detailer. Correct wet-sanding takes a lot of experience and practice to perfect. This statement is not meant to question anything related to your detailing or paint re- finishing abilities just my opinion on the risks involved. I have received many requests to write a technical article on this subject but for the reasons stated I have resisted posting on this subject matter

[Concours.John]

I agree with the above posts. Wet sanding is something that needs to be practiced and learned. Although almost all my experience is in paint finishing and wet sanding, peel removal is reserved for refinished vehicles.



This is why "I" reserve.



1 OEM paint is only given a specific amount of clear without the thought of being sanded flat.



2 Unless the paint is sanded edge to edge and up to body lines it will look unfinished (the peel around these areas will stand out) There is also proper technique to not have "ridges" from sanding near body lines once polished.

(How much are you left with once all the sanding is polished out?)



3 Many times near edges there is a build up or ridge and valley. This area tends to be an E-coat build up. This is under base and clear. There can be false base clear measurements causing break through.



4 Removing the sanding process near thin areas compromises the clear even more (areas noted in your measurements)



5 Unless the vehicle is rarely driven peel serves a purpose of reducing visible micro marring. A flat finish will show even the slightest marring.



6 Wet sanding on OEM really should be reserved for correction purposes.



Reducing peel will yield a more reflective surface but removing will require much more maintenance and care to preserve.



There are still manufacturers who hand spray vehicles which do give more room for this procedure. The biggest thing is are you prepared for a proper tear down and repaint if going through or clear coat failure happens.



Of course these are opinions based on a professional/liability point of view. The decision is up to you just weigh the pros and cons carefully. Repaints are never the same unless the money is paid to tear a vehicle down all the way where needed.

[Barry Theal]

I agree with the above posts. Wet sanding is something that needs to be practiced and learned. Although almost all my experience is in paint finishing and wet sanding, peel removal is reserved for refinished vehicles.



This is why "I" reserve.



1 OEM paint is only given a specific amount of clear without the thought of being sanded flat.



2 Unless the paint is sanded edge to edge and up to body lines it will look unfinished (the peel around these areas will stand out) There is also proper technique to not have "ridges" from sanding near body lines once polished.

(How much are you left with once all the sanding is polished out?)



3 Many times near edges there is a build up or ridge and valley. This area tends to be an E-coat build up. This is under base and clear. There can be false base clear measurements causing break through.



4 Removing the sanding process near thin areas compromises the clear even more (areas noted in your measurements)



5 Unless the vehicle is rarely driven peel serves a purpose of reducing visible micro marring. A flat finish will show even the slightest marring.



6 Wet sanding on OEM really should be reserved for correction purposes.



Reducing peel will yield a more reflective surface but removing will require much more maintenance and care to preserve.



There are still manufacturers who hand spray vehicles which do give more room for this procedure. The biggest thing is are you prepared for a proper tear down and repaint if going through or clear coat failure happens.



Of course these are opinions based on a professional/liability point of view. The decision is up to you just weigh the pros and cons carefully. Repaints are never the same unless the money is paid to tear a vehicle down all the way where needed.

Incredible reply!

[imported_RZJZA80]

I agree with the above posts. Wet sanding is something that needs to be practiced and learned. Although almost all my experience is in paint finishing and wet sanding, peel removal is reserved for refinished vehicles.



This is why "I" reserve.



1 OEM paint is only given a specific amount of clear without the thought of being sanded flat.



2 Unless the paint is sanded edge to edge and up to body lines it will look unfinished (the peel around these areas will stand out) There is also proper technique to not have "ridges" from sanding near body lines once polished.

(How much are you left with once all the sanding is polished out?)



3 Many times near edges there is a build up or ridge and valley. This area tends to be an E-coat build up. This is under base and clear. There can be false base clear measurements causing break through.



4 Removing the sanding process near thin areas compromises the clear even more (areas noted in your measurements)



5 Unless the vehicle is rarely driven peel serves a purpose of reducing visible micro marring. A flat finish will show even the slightest marring.



6 Wet sanding on OEM really should be reserved for correction purposes.



Reducing peel will yield a more reflective surface but removing will require much more maintenance and care to preserve.



There are still manufacturers who hand spray vehicles which do give more room for this procedure. The biggest thing is are you prepared for a proper tear down and repaint if going through or clear coat failure happens.



Of course these are opinions based on a professional/liability point of view. The decision is up to you just weigh the pros and cons carefully. Repaints are never the same unless the money is paid to tear a vehicle down all the way where needed.

Listen to this man right here. I have gotten to the point where I won`t wetsand anything, it`s just not worth it in the end to me.

[Shawn F.]

The above replies are great and should be taken into consideration heavily. Wet sanding an OEM finish to rid of clear coat may look nice but NOT recommended and the above replies tell you why. Now if this were on an aftermarket finish with 5-6 coats of clear for a show quality look then I`d say go for it. When I restored classics and hot rods and built show vehicles, we`d spray 3 coats of clear, wet sand to perfection smooth then throw 3 more coats and wet sand smooth again. The reason for doing 3, then wet sanding before another 3 is because if you see some vehicles with this much clear all done at once, there is a wavy look underneath to the base coat and it has an odd effect. When you get rid of every bit of orange peel you will notice EVERY wavy panel, every single scratch, etc. If you still are insisting on doing this then all I would do is go over the car with 3Ms finish paper on a DA at 3000 grit, buff with compound, polish, seal, and whatever you want to finish with. This will nib down the tops of the orange peel just slightly and even down any small imperfections.

Besides that I wouldn`t touch that car with anything else. This is just my 2 cents worth...

[imported_DJ Mayo]

Agreed. Just because you can doesn`t mean you should. Leave the material for correcting not sanding. Sanding is overrated as is.

[SVR]

I`m very very selective of what vehicles I do a rotary orange peel reduction job on. Sure I can take as little as 10%, 50% or even 95% off but I will only perform peel reduction if the OEM paint has 110 microns or more on it, the same as Australian made cars. However 10 to 20% is all I`ll removal from those cars finishes.

Plus if the paint on any cars are poor quality which is quite common these days, I won`t perform the peel reduction. it`s got to be fairly decent quality clearcoat at the least



As for sanding, I am still on the learning curve with that and have friends who paint professionally to paint test panels for me but I usually will only hand or machine sand in spots where quite deep scratches reside. their not so bad to take care of but sanding the whole car just for 50 to 100% peel removal, no way. Will never sand to remove peel on OEM or refinished paints when I can buff out whatever amount I wish just by adjusting which pads, rpm and hand speed



Working on DA peel reduction at the moment