Wet-Sanding How-To, as promised.

[MusPuppis]

Wetsanding How-To, By John Rodwell (aka MusPuppis)

 

If this is worthy of sticky status I can make any changes required.

 

By way of intro let me say that I am a student. I am not a profesional. This is one way to get the job done, not THE way. It works well for me and has been compiled and altered based on information found here, in books, my own experiences, my teachers info and just general tid-bits that I pick up as I go. So again, this isnt the definitive, one and only way to do it, but it should serve as a reasonable guide.

 

Heres how I do it..

 

First and foremost, get all your tools and materials ready before hand. This includes the space you'll be doing the work. I like to start by cleaning the hell out of the area I'll be using. You want an area thats very well lit and as free from crud and debri as humanly possible. Really, doing the work outside in an open area is one of the better ways to get it done if you dont have an extremely well lit and clean garage or a paint booth handy. Good lighting is important, you need to be able see what your doing. It needs to be clean because if you get crap on the paper or finish while your sanding or buffing you can very quickly and very easily put some NASTY scratchs in your paint. Cleaning up and keeping it clean is one of those little steps that can save you a massive amount of grief down the road.

 

Now comes time to get your tools, chemicals and materials in order. I'll list a basic run down of what I use and why.

 

Water Hose - A constant supply of water is great. Keeps the surface cleaner as you work which improves your visibility and just makes it simpler as you go.

 

Bucket - Obvious.. ya fill it with water and haul it around.

 

Sponge - Put it in your bucket damnit. Ha. Simply a medium to get the water from the bucket to the car. Helpful for wiping panels off as you go.

 

Spray Bottle - Put water in it. Use it to clean the paper as you sand, spray the surface off, just handy all around.

Wet-Sanding Blocks - Dont wetsand by hand. Some areas it cant be helped, but they tend to be very few and far between. Wetsanding by hand is a good way to put little finger shaped depressions in the clear as you go. It can result in a wavy finish.

 

Sandpaper - Good paper lasts longer and does a better job. Mirka is decent, 3m is dope. The exact grit will be discussed below. Make sure its wet/dry paper.

 

Squeegy - Used to dry the car as you sand so you can see what your doing. Wetsanding blocks without paper can also be used. That happens to be my prefered method. I just keep one pad with no paper to sheet the water off as I go.

 

Cutting Compound(s) - Used after you wetsand to remove the sand scratchs. There are a number of products on the market, some are "all-in-ones" a single use compound that cuts and rubs.. Transtar makes one I beleive. I dont have experience with them and simply list them to make the reader aware. I use and highly recommend 3m's 3 stage system. It consists of a cutting compound, a rubbing/swirl mark remover and a final glaze. Very good results, easy to use. Cleanup can be a butt-hole though. Proper preperation which I'll discuss later will cut down on cleanup considerably though.

 

Buffer - If you dont have a good buffer stop right here and get one. Dont even bother using a POS, its not worth your time. A variable speed buffer is VERY VERY important. Some poeple like air powered, some like electric. For my own part, I prefer the electric over the air powered.

 

White Pad - This is the cutting pad for your buffer, its a more aggressive pad than the black and is designed for use only with the cutting compound. Not the polishing. They come in two types, foam and wool. Wool is the meaner of two. It cuts faster, making shorter work of the job but has a higher chance to burn through and will leave more swirl marks in the finish. Foam is my personal choise, cuts a little slower, but its easier to get the swirl marks out as they arent nearly as bad and its a safer pad. Less chance of a burn through. Its worth it to go the extra mile and buy a good pad.

 

Black Pad - Less aggressive pad for use with the rubbing compound. As far as I know they come in foam only. Same as before, quality, buy a good pad.

 

Soap - Keep a small bottle of car wash with you. You use it in the spray bottle and bucket and such to slightly lubricate the surface. Keeps the paper from digging in as you sand and makes an easier job of it.

Masking Tape and Fine Line Masking Tape - Used to protect body lines and edges.

Lint Free Rags/Clothes Safe for Finishs - Used for a number of things. Dont just use paper towels, they can actually put little marks on clear coats. be careful bout using random household rags as well, they leave lint that can get caught in the buffer and leave swirls.

 

 

Once you have everything you need its time to prep the car. This step is another one I see alot of poeple ignore. Skimping here can result in big trouble later as well as a much longer clean-up time. Clean the crap out of the car. Wash it very thoroughly. You want to remove anything from the finish that can potentially scratch or damage it. Now look over the car and try to work out a plan for sanding and buffing. Look for things that dont need to be sanded and mask them off. Think of it from a buffing and sight point of veiw. Can you see that indentation? Does it need to be buffed at all? CAN you buff it? Take the indents in a Z's doors for example. When no handle is present their quite visible but once you put a door handle in you cant see much of them at all. Their also difficult to get a buffer in to without risking burn-throughs on the raised edges.. So, why buff them? More work with no return. Mask em off. I also go along ALL the edges on a car, every damn one and mask them along their entirety with the fine line masking tape listed above. I use fine line because it leaves less of an edge to butt up against when sanding and buffing. Do the same for any sharp body lines or other edges on the car. These are the most likely places to burn through and should be protected. Dont worry about it effecting the over-all finish. You'll be masking such a miniscule portion with the fine line tape it makes no difference in the finished product. Now use the regular masking tape to mask off crevices between body panels, around the door jams, any and every place you dont want to get compound as you cut and rub. That stuff will get everywhere as you work and its a turd to clean up once it hardens. It can literally take hours to completely clean a car that wasnt prepped correctly. Spend an hour prepping and save yourself countless hours cleaning and fixing burn throughs.

 

A quick note on sandpaper.. I personally use 1500grit. Now, the 3m cutting compound I use is rated to remove 1200 and up sand scratchs so you can use 1200 if you so desire. Hell if your extremely careful, or just plain crazy like my teacher you can get 800 grit then go over the area with 1200. I like 1500 grit because its (to me anyway) a safe medum between cutting too quickly and risking burn-throughs and cutting too slowly and being safer. If your worried about burning through due to inexperience or if the clear on the car is thin, 2000grit works quite well and is a fine paper to use. Just takes a little longer.

 

Ok, its time to start sanding. Get your wetsand blocks, squeegy, bucket, sandpaper, sponge and spray bottle ready. Wet the car down with a hose, or lacking that your sponge. Also, put a small dab of car wash in the spray bottle and bucket, just a small amount. It acts as a lubricating agent as you sand and makes life alot easier for you. Wrap your paper around your wetsand block. Now, make sure its wrapped tightly and that the paper is completely clean. Also make sure it doesnt have any kinks or ridges in it from being bent or other-wise damaged. These can show through as you sand and cause you trouble, or at the least a less than perfect finish. Wet the crap of your block and paper and re-wet the panel you'll be working on. Start sanding. As I sand I like to sand front to back at about a 15 degree angle. This cuts well and goes along with the sight lines of the car. As you work keep even pressure on the sanding block, but dont smash it down. I dont use much more than the weight of my hand when sanding most times. Keep the spray bottle in one hand and spray the surface of the panel as you sand, this pushs the sanded out clear out of the way and keeps the surface and your block wet. I frequently pull the block away and dip it in the bucket. I also use the spray bottle to periodicaly spray the sandpaper itself off to make sure no little dirt nibs or other gremlins get into the grit and cause damage. As you go wipe the panels clean from time to time with your sponge and squeegy the panel off, keep a close eye on your panel. You'll be able to see the o-peel gradually disappear as you go and keeping track of exactly what your doing by frequently wiping and drying the panel is very important. Sanding blind is a waste of time and a risk of damage, nothing more. Swap out paper as often as you think is required. I use one half sheet of paper for every panel generally. You'll be able to tell when the paper just isnt cutting as well as it used to. Remember, dont sand where you dont need to/want to/cant buff. Watch what you do, keep your paper, water and car clean, keep track of what your doing and in no time (ok, well, after millions of mind numbing hours) you'll have a thoroughly sanded, orange peel-less, ready-to-be-buffed finish.

 

After the car is wetsanded to your satisfaction clean it up again. Get all the sanding debri off the car, it'll appear as a milky pasty crud. Clean the hell out of it and dry the car completely. Replace any masking tape that didnt survive the wetsanding process. Wipe the car down with one of your rags.

 

Grab your buffer and put your white pad on it. Now grab your cutting compond. We buy it by the gallon at school so I bought one of those cylinder ketchup bottles from Wal-Mart like you see at picnics and put the compound in it. Makes it easy to squeeze out onto the surface. Make sure to shake the compond well before you use it. Squeeze a small amount onto the panel your working on and use your buffer on the lowest speed setting to spread it around the area your buffing. Do fairly small areas at a time. I usualy visually divide a panel in two sections or more sections and do one section at a time. Once you have the compound spread around, turn the speed up and start to buff it out. Work in small areas, moving the buffer constantly. Dont apply too much pressure, but at the same time dont go too lightly or the compound wont do its job. Its hard to explain just how hard to press and exactly how to move the buffer, so i would suggest starting on a large flat panel like the hood, this should give you a solid, low-risk area to get used to the buffer. As you work you'll be able to see the finish buff out from a hazy, ugly mess to a shingy, glossy finish and as you go you'll get the hang of how to use the buffer properly. Its all about feel really. Compounds have a rated RPM their recommended to be used at and if your buffer comes with some manner of RPM guide, use the recommended speed.. Mine did not, so I have to guess.. lol. Really though, you can easily tell when your going too slow or not putting enough pressure down as the finish will still look dull or hazy after you buff it out. If this is the case, just put some more compound down and buff it again. Frequently wipe the surface off with a rag as you go so you can easily see your progress and so you remove the little bits of compound that get slung all over creation by the buffer. Oh, also, I tend to use one half of the pad at a time. I hold the buffer at very very slightly angle, just enough to keep the back half off the car. This keeps me from accidentally hitting an edge or body line with the back of the pad and causing damage. On large flat or open areas I lay it flush thought.

 

A quick note on edges.. You should have yours taped off, but even still, always buff with the edge, not against it. By this I mean make sure the buffer is spinning in the same direction as the edge. Lets say your standing in front of your car and your about to buff the hood. Lets assume your buffer turns clockwise (mine does) you can buff the right side of the hood with the top of the pad but when you go to buff the left side you'll need to use the bottom of the pad. I hope that makes sense.. I'll try to take some pictures at some point.

 

As you buff keep an eye on what your doing, work in small areas and dont be afraid to use generous amounts of compound. Do the whole car in each compond step at a time. Cut the whole care before moving on to rub, rub the whole car before moving on to glaze. Try not to get over confident or careless. Pay close attention as you go and be very careful. Between each step of the process look over the car carefully and make sure you didnt miss and sand scratchs. It sucks to think your done cutting and move on to rubbing only to realize you missed a spot and have to go back.

 

When you have the whole car cut, go over it with a cloth and wipe off all the excess compound that you can and swap out to your black pad. Repeat the above procedure for the rubbing compound. You should see the finish get deeper and even more glossy, as well as a complete removal of the swirl marks. If you go over an area and the swirl marks are still present, go back over it until they arent. Wipe off as you go.. Essentially just repeat what you did for the cutting compound.

 

Now grab yor rags and your final glaze. Final glaze is interesting stuff. It acts much like a wax by even further deepening and glossing the finish and protecting it from crud and chemicals. A freshly painted car SHOULD NOT BE WAXED. The paint will continue to dry and cure over a number of weeks and for this to happen properly the solvents have to evaporate out of the finish.. Wax will create a seal that will not allow this to happen, final glaze however is designed specificly to protect, shine and still allow the finish to cure correctly. The 3m final glaze that I use is applied by hand, just like wax. Buff it on with a clean cloth in a circular motion, buff it out with a clean cloth in a circular motion.

 

A quick note on buffing and rubbing pad care.. After use, clean them off completely. Spray them down with water and get all the compound out of them. Squeeze them out so their just lightly damp and store them, each to its own, in a zip-lock bag. This will keep them supple and pliable until their next use.

 

Un-mask the car and clean up any compound that managed to get where it doesnt belong. For hardened compound q-tips and rags with a small amount of wax and grease remover on them works well to break it up. Windex with amonia also works.

 

Wash the car good and proper with your car wash, sponge etc, dry it off and sit back, smile and revel in your glory. Buy yourself something nice, you deserve it.

 

If anyone has additions, issues, improvements or anything, I will gladly edit them in with full credit to the contributer. I hope I was thorough and didnt forget anything, its 5:30 am and I havent slept in a while, so Im a little muddled.. ha.

[V8_DatZun]

great write-up. thanks for the time and effort.

[mikeatrpi]

Thanks Mus, nice write-up. I appreciate it because I'll be doing this in the spring!