# Introduction to Wet Sanding.



## Mirror Finish Details (Aug 21, 2008)

I have been asked by a few members about wet sanding after comments in other posts about wet sanding. Mainly how do yo do it and is it safe.

So I have been meaning to to do my car for ages and as the weather was nice I gave Victor the Volvo a good wet sanding.

Firstly in an ideal world we all have paint thickness meters and I would be very reluctant to do this without one, especiallly as I attacked a £50k Range Rover with a piece of 2500 grit last week.

I prefer to sand by hand always using a sanding block, this keeps the paper pressure on the panel flat. If you used your hand you could end up with different amounts of clear coming off due to your fingers. Some areas you will have to use by hand but just go carefully.

So, how do you do it?

Take lots of paint measurements all over the car and inside the door shuts etc. The difference in the readings will give you a fair idea of how thick the clear coat is, this is shown in Um measurements.

Many people want to wet sand to get rid of scratched quickly or the horrid orange peel in a lot of clear coats. I am finding Audi and BMW to be the worst offenders at the moment, some of the clear looks horrid.

I prefer to wet sand as it saves a lot of time working with the rotary and having to use harsh pads.

Regarding grits, I will never use anything harsher than 1500 grit. I prefer to start with 2000 grit and see how it goes. Then 2500 grit and finally 3000 grit. Constantly keeping the paper soaking wet and making sure the panel is well lubes at all times. Never use anything like 1000 or 800 grit like our friend the Master Detailer in the states, you will just ruin your car.

I only use automotive paper, usually Meguires Uni Grit and Elite sell it by the sheet.

I prepare a bucket the night before with my sheets in and some fairy liquid, but a good half hour soak will be fine.

I just wipe the panel with last touch and then bagan to sand. Couldn't be bothered washing it.:thumb:

Here is the reading that I used. You can see the door shut is 70um and the panel is 155um. This was a common reading on most of the panels so I have 85um clear coat to play with. 

















And a 50/50. Other side not sanded yet.









And finally what it will look like after 2000,2500 and 3000 grit passes. Looks horiffic to some people. 
























This is the wing after one pass of Menz IP on a white Sonus spot pad. 5 minutes is all it took. I still need to refine the finish but that whole precess took only 20 minutes.








Rear panel. Again meter reading were taken and I had average of 96um on the back of the car. Another 50/50.








Reading before the process.








Reading after the process. You can clearly see wet sanding and the polishing stage removed 13um of clear. Leaving me with 83um for further work. Well within safety limits.








Final pic. You can clearly see that the drain pipe in the reflection is almost straight. I forgot to take a before but it was all deformed.









Not the biggest write up, but I hope this has given you a basic understanding of the wet sanding process.

If you have the tools and are confident give it a go. Or try a scrap panel first.

Cheers
Steve :wave:​


----------



## ArcticVXR (Apr 10, 2007)

Great write up and very useful :thumb:


----------



## Allblackdup (Oct 17, 2006)

Excellent information - cheers for posting.


----------



## Mirror Finish Details (Aug 21, 2008)

Your welcome guys.

Wool pads will be my next one.


----------



## clcollins (Jul 30, 2007)

Thanks for this post, nice to see the finer point explained, thank you :thumb:

PS. You need to keep up with your manicures to keep your nails looking like they do in pic 6 :lol:


----------



## ChrisJD (Apr 15, 2009)

That is excellent. It does feel like a scary thing to do to a paint surface. Haven't attempted it myself, yet, but at least I know now that it can be done safely and isn't as daunting as most would think.

Chris.


----------



## Mirror Finish Details (Aug 21, 2008)

I can understand how daunting it is, but the end results are far better than tyring to machine polish clear down.


----------



## Nick_S (Dec 20, 2008)

Thanks for the write up :thumb: , I may try and attack my hood soon.


----------



## wd40 (Jun 20, 2007)

Thanks for this wee write up , i`ve always wanted to have a go and now feel confident to try it, albeit on a small panel first !!. :thumb:


----------



## Christian6984 (Dec 20, 2007)

superb expaination many thanx


----------



## Auto Finesse (Jan 10, 2007)

Sorry to pic holes here but this is not a very accurate guide at all, please guys dont go out and wet sand your car on the back of it.
as its likely to end in tears and paint.

Firstly you dont get very accurate readings from checking door shuts to panel, as door shuts etc are not hit with a flat spray on production they get blowen over (hence the finish not being as good) there is not 96Microns of Clear Coat on there, your looking at an average of 30-50 max CC on most vehicles. 

Your second problem is what where you trying to achieve ? there was no damage removed, wet sanding should be the very very last resort, after pad and compound then wool pad and compound, the only thing your not likley to remove with the two previous is "orange peel" and by the looks of the pics you dont seem to have cracked it with the sanding either (you can still see the highs, you need to go a bit further than that to be dead smooth) wet sanding can cause "groves" in the finish that are very very hard to remove and require alot of polishing time to get out also the need for heat (built up from friction of pad on panel) to level totaly, so its not the best option unless there is no other, and by no means the quickest.

Sorry to be a bit fussy about it, but its wrong


----------



## ianFRST (Sep 19, 2006)

im no expert, so i cant comment, but i wouldnt advice wetsanding full panels unless you have a PTG that can actually measure clearcoat

also, i see no sanding block? so how do you know you have been putting even pressure over the whole panel? if you were doing it just by hand, you press down harder on certain parts of your hand than others....


----------



## Paul_r26 (Jul 31, 2007)

May I just ask how many passes would you usually do when sanding each area? As sanding one stop 20 times will take alot more than 2!


Great advice, will be getting a scrap panel soon!


----------



## Mirror Finish Details (Aug 21, 2008)

james b said:


> Sorry to pic holes here but this is not a very accurate guide at all, please guys dont go out and wet sand your car on the back of it.
> as its likely to end in tears and paint.
> 
> Firstly you dont get very accurate readings from checking door shuts to panel, as door shuts etc are not hit with a flat spray on production they get blowen over (hence the finish not being as good) there is not 96Microns of Clear Coat on there, your looking at an average of 30-50 max CC on most vehicles.
> ...


Points taken James.

I only did this after numerous PM's from members about wet sanding- it was only a demo to help people.

The paint readings were taken on the backs of the inner doors, clear coat would never get here. Been doing this long enough to know where clear does not go. Like a professional sprayer for 5 years. I always use a block to sand, so no grooves for me.

Perhaps I should just not bother as that took a fair few hours to answer a lot of PM's on wet sanding. And that is my towing car so it does not have to be perfect. Just was an ideal candidate as it was there at the time.

There was a lot of orange peel on the back as it has just got back from the body shop, and that drain pipe was really crooked. So looked fine to me and over 25 PM's about how staright it looked.

So why have I had two Audi TT's from a dealer for a full wet sand to remove orange peel?? And their drain pipes are now straight in the reflection. Oh yeah only took a day to do, some other detailer quoted 3 days.

I suggested people try a scrap panel first.

But hey I just won't bother again. Every time I try to be helpfull people just pick nasty bits out of it.


----------



## Mirror Finish Details (Aug 21, 2008)

ianFRST said:


> im no expert, so i cant comment, but i wouldnt advice wetsanding full panels unless you have a PTG that can actually measure clearcoat
> 
> also, i see no sanding block? so how do you know you have been putting even pressure over the whole panel? if you were doing it just by hand, you press down harder on certain parts of your hand than others....


I used a sanding block, Jeez I cannot photograph everything.

I advised people in the post to use a sanding block.

Do I need to show the tissue if I blow my nose now.

Plus if your not an expert don't make comments about peolpes work.


----------



## Ninja59 (Feb 17, 2009)

very informative thanks....


----------



## Auto Finesse (Jan 10, 2007)

Mirror Finish said:


> Points taken James.
> 
> I only did this after numerous PM's from members about wet sanding- it was only a demo to help people.
> 
> ...


I was not pointing it out to put you down, i have a lot of respect for any one who puts in the time and effort to do a write up, but i think this is a case of you trying to run before you can walk, you dont seem to know enough about the make up of paint and how to interpret your PTG readings properly, the % you allow as CC is way way off and will have you unstuck before long.

If you can fully wet sand a car in a day your not doing it properly FACT, it would take my self (and most of the other good detailers on here) 3-5 days easy to do a full wet sand on a car that size.


----------



## ianFRST (Sep 19, 2006)

Mirror Finish said:


> Plus if your not an expert don't make comments about peolpes work.


oooooo, so i cant comment because im not a pro? so only pro's can ask you questions and comment on as to how you do things?

well im sorry then, i WILL NOT comment on any more of your threads, seeing as i only play in the minor league :wall::wall::wall:

so ill just stand behind james, a "pro" and agree with what he says!!


----------



## Kelly @ KDS (Aug 4, 2008)

Not trying to cause a fight here but , i agree with james on many points he has made :thumb:

Wet sanding a full car correctly WILL take 3-5 days and sometimes even longer , just finished wet sanding a Brand new bmw X5 which took 6 days start to finish , and i did not even detail interior just full wet sand machine polish and wax .

If this link breaks the rule then please say so 

http://www.pistonheads.co.uk/gassin...d by KDS wet sanding, how to refine top-coat?

Here is another link to wet sand on Bmw E92 M3 which do to such hard clear coat took 8 days to complete , i tried to post as much as i could on this one to explain the process .

http://www.pistonheads.co.uk/gassing/topic.asp?h=0&t=685712&r=11243924&hm=127202&mid=127202#11243924

I have another M3 booked for mid July for same process which is with me for 3 weeks , with this one i am hoping that a friend is going to help film and take loads of photos to write a detailed write up .

Wet sanding is the last resort and really should be kept to show cars and garage queens , should only be done when there is a large amount of clear coat to play with (never found an Audi with enough for this process from the factory)

I can see from your pics that you have not wet sanded for long enough or left the sanded finish flaw free .

There is nothing wrong with the original post in its idea , but i think that it could be very dangerous for members to read then think hay only takes a day to do may give it a go myself .

Had a customer ring me/reception girl yesterday asking for a price to full wet sand his E92 bmw , when he was told its a week at the very least he replied that could it not be done in a day as he needs his car and thinks it only takes a day to do .

Had another M3 owner asked for full detail and then to come back months later when he has the funds to have it wet sanded , as he has been told you machine correct paint then wet sand after as this is the last stage so why can he not split the process up into 2 stages :lol:

Kelly


----------



## Ti22 (Mar 24, 2009)

Good to see you on here kelly. Been a long time admirer of your work from PH. 

Thanks for the post. 

Wet sanding complete cars is certainly not something I'm rushing into doing just yet!


----------



## Kelly @ KDS (Aug 4, 2008)

Ti22 Vehicle Services said:


> Good to see you on here kelly. Been a long time admirer of your work from PH.
> 
> Thanks for the post.
> 
> Wet sanding complete cars is certainly not something I'm rushing into doing just yet!


Thank you glad to here that :thumb:


----------



## Mr OCD (Apr 18, 2006)

james b said:


> Sorry to pic holes here but this is not a very accurate guide at all, please guys dont go out and wet sand your car on the back of it.
> as its likely to end in tears and paint.
> 
> Firstly you dont get very accurate readings from checking door shuts to panel, as door shuts etc are not hit with a flat spray on production they get blowen over (hence the finish not being as good) there is not 96Microns of Clear Coat on there, your looking at an average of 30-50 max CC on most vehicles.
> ...


I wasnt going to say anything James... but I'm glad you did... :thumb:


----------



## Finerdetails (Apr 30, 2006)

wet sanding, the last resort, and must be an absolute last IMHO. Removing that much lacquer has got to be for the highest of reasons. You cant put it back on afterwards.

Take pic four. Under the sanding, you can see scratches still. This is what you would have expected wet sanding to take out, and when you try to machine back, the sort of defect you then spend an age trying to machine back.

My comments are not aimed at the OP, they are regarding the wet sanding, its pit falls and why I personally will not wet sand unless there is absolutely no options and the owner really cannot live, sleep, breathe and eat due to the defect.


----------



## Buck (Jan 16, 2008)

Kelly

Read your thread on the M3 a while back - I was jaw droppingly impressed - immense work and removal of OP - the last photo - the reflection and background almost blur into one.

Just one criticism - you need to post on here more!!

CM


----------



## Kelly @ KDS (Aug 4, 2008)

cheekeemonkey said:


> Kelly
> 
> Read your thread on the M3 a while back - I was jaw droppingly impressed - immense work and removal of OP - the last photo - the reflection and background almost blur into one.
> 
> ...


Thanks :wave:

I have been meaning to join DW and post on here under the studio section some time now , but due to work load have had no chance too .

I dont reply on other forums and only now and again on PH as i dont get the time now .

I have got thousands of photos and videos of top car detail work that i have carried out over the last 6 months , not even had time to process the photos into correct files just on my laptop , in a very same way as clark i find myself working gone midnight on many nights keeping up with demand ..

got 5 cars this week and next week 2 Rolls Royces , Maserati Gran turismo , M3 , Ford Gt in 2 weeks time , then if goes to plan a E92 carbon Black in for full wet sand , bespoke wheel colour change , carbon goodies , and maybe sports exhaust , sports steering wheel with shift lights , set aside loads of time for this one. The plan is to document the whole process in depth to clear up some of the silly comments about the do's and dont's of wet sanding .

Got to update my website which i have been trying for over 9 months ..

I really dont know how all you top detailers find the time to post in such depth write up's aswell as take so many photos during the day while detailing and finish the job in question :thumb:

If i get a quiet week you may see a lots of cars appear on the studio section all detailed by me 

Kelly


----------



## Buck (Jan 16, 2008)

Cheers Kelly - your reputation clearly has them queueing!!

Nice to be busy for all the right reasons :thumb:

CM


----------

