Wet-Sanding (Colour Sanding)

Discussion in 'Compounds, Polishes, Paint Cleaners, and Glazes' started by togwt, Mar 24, 2010.

  1. togwt

    togwt Nuba Guru

    Wet-Sanding (Colour Sanding)

    Recommended Products

    In the interest of full disclosure, I am in no way affiliated with, employed by, have any vested interest, or in any way receive compensation from the sale or distribution of the product lines reviewed or the company that manufactures or markets it. The product endorsement is entirely unbiased and the product “Does what it says on the tin”

    Results Obtained

    These articles are not intended to warrant or guarantee any results with any of the products mentioned. No endorsement of companies or their products mentioned is intended, nor is criticism implied of similar companies or their products not mentioned. The author does not provide, nor guarantee and is not responsible or liable for any third-party products or services. Brand, product and company names used throughout these articles are trademarks of their respective companies and are used for product identification purposes only.

    Proper Technique

    The detailing methods set out here have been adapted for special use and may not be the same as those recommended by the product manufacturer, and you may experience different results from those stated. When in doubt always use common sense. A sound understanding of the proper technique and the correct process will produce excellent results even with a mediocre product. A quality product used without the proper surface preparation or application technique will never obtain a satisfactory result. Using the proper methodology (surface preparation, using a quality product, along with the correct application technique) will ensure an excellent result.

    Skill Level / Experience

    Some methods described may be beyond the capabilities of the average detailer or enthusiast; in this case we strongly encourage the reader to consult a professional detailer or body shop concerning the matters discussed herein.

    Liability

    The information contained herein is believed to be true and accurate; however we make no guarantees concerning the veracity of any statement. The writer assumes no responsibility, expressed or implied, due to misuse or misinterpretation of the information or methods used, or for any vehicle damage or injury that may occur due to the suggestions and information offered.

    Accuracy of Content

    I strive to present complete and accurate information. To be of real practical use, a subject like automotive detailing requires a great deal of research, and updating as new products or technologies becomes available, so the articles are updated on a regular basis as necessary from current research. From time to time there may be information that contains typographical errors, inaccuracies, or omissions (because I’m human). These are unintended and TOGWT™ reserves the right to correct any errors, inaccuracies or omissions and to change or update information at any time without prior notice.

    Product Quality and Technique

    Proceed with this in mind; the products you use constitute a very small factor in the equation. Methodology and technique constitute 95%; the reasoning behind the choice of quality products is to eliminate any limiting factors, thus enabling you to place emphasis on technique used. There is no `one correct way' to apply a product; the way detailing products are customized are what each individual finds give them their desired results.

    Aesthetics

    The aesthetics- of a vehicles appearance is very subjective to say the least, the only best wax or sealant that really matters is what looks 'best' to you. In the final analysis it all come down to; 85% preparation, 5% product, 7% application methodology and the balance is in the ‘guy’ of the beholder

    Research

    Research others opinions and products, test them and then make an objective decision based upon factual information not marketing hype or brand loyalty. I have always thought that the more facts and information you have at hand the easier it is to judge what information you are being given. After all, how can you fully understand and properly use any product unless you have all the facts?

    Detailing products

    No endorsement of companies or their products mentioned is intended, nor is criticism implied of similar companies or their products not mentioned. The author does not provide any guarantee of results and is not responsible or liable for any third-party products or services. Brand, product and company names used throughout these articles are trademarks of their respective companies and are used for product identification purposes only.

    Car care chemicals are the most misunderstood component auto detailing, they should work on their real merits, not ‘smoke and mirrors'. Proceed with this in mind; the products you use constitute a very small factor in the equation.

    Methodology and technique constitute 95%; the reasoning behind the choice of quality products is to eliminate any limiting factors, thus enabling you to place emphasis on technique used. Most importantly - choose carefully whose advice you listen to, and more importantly what advice you act upon, so I would strongly suggest that you verify any information that I or anyone else shares with you.

    Disclaimer

    The information contained herein is believed to be true and accurate; however we make no guarantees concerning the veracity of any statement. Use of any information on this page is at the reader's own risk. The detailing methods set out here have been adapted for special use and may not be the same as those recommended by the product manufacturer, and you may experience different results from those stated. When in doubt always use common sense

    Article Revisions / Updates

    The advent of new materials like detailing clay, micro fibre, polymer coating, nano-particle technologies and new micro abrasives are examples of why it’s so important to monitor the industries new products, chemical technologies and ideas that are constantly being introduced, as are the techniques for applying them, hence all of the in-depth articles will be up-dated and revised on a regular basis


    Colour Sanding / Polishing:

    Years ago it was called colour sanding because automotive paints were single-stage (primer and a colour coat) and when the finish faded from ultra violet radiation (UVR) exposure, sanding off the oxidized paint thereby exposing the underlying paint would bring back the paint surface colour. Then, as now, most sanding was done wet so the terms colour sanding, wet sanding and as all these process involves a sanding block, block sanding all became interchangeable whether you were sanding for colour or for a level surface.

    I am never too keen to colour sand factory paint, but any aftermarket paint is a great candidate. Don't start with less than 1500 grit finishing paper unless you have lots of material to work with or some serious imperfections. Block wet sanding (finishing paper and a sanding block) is the most effective tool for paint defect removal only because you can sand the paint surface flat until the defects are removed. Non- diminishing abrasives and a flat foam pad are similar in application.

    This kind of work should only be undertaken by a very experienced enthusiast or a professional detailer; experienced in colour-sanding (wet-sanding) / paint renovation, more so than detailing, someone who uses a paint thickness gauge (PTG) to measure and document the vehicles paint. This is a technique that takes a lot of 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

    Preppin Weapon Sanding Block

    Made out of high impact ABS plastic & is constructed in an ergonomic shape for complete comfort when sanding. The tough rubber pad that is firm for wet or dry use. Perfect for wet sanding as it's made from stainless steel and plastic and it floats in a bucket. It also has the best paper clamping system I've ever experienced and it's flat.

    • High-impact ABS plastic, tough rubber pad that is firm for wet or dry use.
    • Ergonomic shape for complete comfort when sanding.
    • Stainless steel lever action clips to grip & pull the sandpaper tight.
    • Tapered edges allow you to get into corners
    • 2-34"W x 7-3/4" L

    Paint Removed by Polishing

    Using a medium abrasive polish and a rotary polisher will remove approximately 0. 1 Mil (3µ Microns) from the paint surface (typically 4 passes at 1500-1800 RPM) but there are many variables such as polish/compound and speed / pressure used that may affect the paint removed) There comes a point when you must judge wither removing a scratch will compromise the clear coat and if so you’ll have to ‘live’ with the imperfection.
    If you have reservations about the amount of paint surface removed or the amount of paint coating remaining the use of a paint thickness gauge (PTG) is arbitrary
    These numbers are offered as a guide only, as there are too many variables to provide any more than an approximation.

    Clear Coat Thickness

    Modern clear coat paint finishes are so good today that they lull people into thinking that vehicle paint has protection and shine when in reality there is not really much there. Most vehicle paint film systems (127 - 178 µ) comprise a Primer coat of 2Mil (50 µ) a Colour coat of 1-2Mil (25 -50 µ) and Clear coat 2-3Mil (50 - 75 µ)

    Removing more that 0.5 mil (12µ) of clear coat will cause premature paint film failure as UV protection percolates to the top of the clear coat. The half-life of paint UV protection is 5 years (exponential decay) the half-life of a quantity whose value decreases with time is the interval required for the quantity to decay to half of its initial value

    For these reasons all car manufacturers now specify that the paint thickness be measured in 0.1mil, or 1/1000th of an inch before and after any wet sanding or buffing. The following are the maximum allowable clear coat reductions the major USA car manufacturers will allow; Chrysler- 0.5 Mil, Ford – 0.3 Mil, GM – 0.5 Mil

    Paint thickness gauge - PosiTest DFT Combo; Measures paint on any metal; including steel and aluminium, a popular choice given many cars have both steel and aluminium. It automatically recognizes the material and takes a measurement-

    Sanding Prep-

    Wash paint surface thoroughly to remove any surface contamination, fill a spray bottle with paint cleaner/ degreaser (DuPont PrepSol II™ to remove old wax and soluble contaminates, spray onto a 100% cotton micro fibre towel (DF Towels - DF Concours products) and clean the surface. If you don’t wipe the surface before you sand you will not remove the contaminants, you will force (sand) them into the paint surface The secret to a Concours d'elegance winning paint finish is colour-sanding (before wet-sanding paint show vehicle owners often have an extra 2.5 Mil to 3.0 Mil of clear applied).

    The paint sections / panels that are difficult and involve risk are usually those that are close to the edges of a panel (as this is where the paint is usually thinnest) or highly contoured areas. Flat areas like the trunk, hood or roof involve minimal risk.

    Orange peel - it is possible to wet-sand orange peel, but if you try to eliminate it completely you risk severely compromising the paint thickness. Wet-sanding levels the paint (and removes orange peel, harsh acidic or alkaline marks, etc) it removes approximately 0. 1 Mil (3µ Microns) of paint from the vehicle using 2000 -grit finishing paper. As a point of reference a sheet of Saran wrap measures 0.95 Mil

    A digital paint thickness gauge will allow you to measure the film thickness of the paint system which includes the e-coat, primer, base coat (colour) and clear

    Wet or Dry Sanding

    If possible, it is always better to use a lubricant. This will extend the life of the finishing paper greatly and keep the material from loading. It will also keep heat generation to a minimum. There are many types of lubricants, but generally water is best. It is best to work using a light mist or spray. Flooding the work surface or work piece is not recommended as it will cause the abrasive to skate across the surface, making less contact and removing less material

    Methodology
    1. Put a drop or two of Woolite® liquid in a clean bucket and fill it with clean water.
    2. You will need 6-inch x 4-inch sheets of Nikkens™ 2000, 2500 and 3000 - grit finishing paper (1000 and 1500 grit is also available, but they are usually used on single stage paint systems, you can start with any grade of finishing paper according to the condition of your paint film surface, but as always use the least abrasive first) next cut or tear three or four pieces of the finishing papers in half and place them in the bucket also.
    3. Leave them in the bucket of water for about 20 -30 minutes to soften their edges. These papers have a latex rubber impregnated paper backing that is waterproof and this prevents the finishing paper from breaking-down into pulp from over soaking. Keep the surface wet at all times and sand in short strokes, applying light to moderate pressure with the sanding block held flat. After going over the finish with 2000- proceed to 2500- and then switch to 3000-grit finishing paper and sand once more.
    4. While you're waiting for the paper to soften, wash your vehicle too completely to remove any grit or dust, and then gently dry it with clean terry cloth towels. Next, take a tack rag and wipe over the paint surfaces one final time to make sure the paint is absolutely clean. A small particle of grit can make deep scratches in even the hardest finish. If you're working outdoors, wet down the surrounding area to keep dust under control, and keep a garden hose running with a trickle of water on the surface at all times.
    5. Wrap a piece of the softened Nikkens™ 2000 - grit finishing paper (or whatever grade your paint surface requires) around a Unigrit Sanding Block (see also alternative products) if you're going to be working broad, flat surfaces. Otherwise, you can just fold the sandpaper in thirds. Keep wetting the surface of the vehicle in the area where you're sanding and keep it wet while you work. Place your hand flat on the sanding block / finishing paper at all times and start sanding in short, crisscross strokes.
    6. Don’t apply too much pressure to the sanding block; by flexing the metal you’ll sand through the clear on the spots contacting the block before the low spots disappear.
    7. Avoid applying excessive pressure; by flexing the metal you’ll sand through the clear on the spots contacting the block before the low spots disappear.
    8. Always keep the sanding block flat or you’ll gouge the paint surface and never sand with just your fingertips, as you'll create grooves if you do.
    9. Only move the finishing paper and block about 4 - inches back and forth, if you do make a scratch, it will be a short one and easier to buff out. Using shorter, quicker strokes requires about the same amount of time as the longer sweeps most people are used to. Besides, you shouldn't worry about time and have a lot of patient when colour-sanding.
    10. As the finishing paper skims over the surface it will remove the highest points in the paint, causing them to dull, the lower spots will still have a shine; once the high spots have been removed keep working until the paint is level.
    11. A clean rubber squeegee (3M™ Wetordry™ Rubber Squeegee, P/N 05517, 2 -inches x 4 -inches) is the best tool for checking your progress. Swipe the squeegee across the sanded surface periodically to clear it of water. Only when you have the surface completely free of any suggestion of orange peel or imperfections are you ready for the next step.
    12. Proceed to the next level of grit and repeat the process until all the coarser scratches are eliminated and finish with 3000 - grit finishing paper in order to remove all of the very fine scratches, only when the paint has a consistently level, smooth, satin finish should you continue to the polishing stage.
    13. By finishing with 2000 – 3000 grit finishing paper, less buffing will be needed to get a flawless finish.

    Alternative –
    a) Four Star Professional Abrasive Enhancing Gel, extends sandpaper life and adds lubrication - non-toxic, use instead of water
    b) 3M™ Trizact™ Hookit™ II Clearcoat Sanding Disc - P1500 (PN 02069)- large area wet-sanding, runs damp, long lasting, excellent for texture matching and sanding contours, removes nibs and other defects, leaves a very refined finish
    c) Micro-Mesh Regular finishing papers (silicon carbide grit with standard backing) - The standard grade of Micro-Mesh used for the majority of operations on plastics, paints, wood and most metals and polymers. It is used to produce a uniformly smooth surface and bring the surface to a high gloss finish. Available in grades 1500 to 12000 (30 to 2 microns)
    d) Unigrit finishing papers -http://bit.ly/6cW2TP
    Bi-directional sanding- if you are sanding in a \\\ pattern with the 2000, then sand in a /// pattern with the 2500, once all your lines are opposite then you know you have completely covered the area. (See also Polishing, Spit Shining, Colour, Depth and Clarity, Legal Stuff, Wet Sanding / Polishing)

    Notes:
    1. Aluminium Oxide exhibits a high degree of friability. This means that when heat and pressure are applied it fragments. This is highly desirable because when it creates new sharp edges, this self-renewing property allows aluminium oxide to last longer than most other finish papers.
    2. Finishing paper quality - cheaper paper will induce deeper sanding scratches, which will be more difficult to remove
    3. Wet-sanding can also be done using a random orbital polisher that has a short eccentric offset (typically 5/16 – inch)


    Going through the grits

    What does this mean?” It’s a very similar idea to ‘Least aggressive first’ it refers to the process of using different grit finishing papers of progressively finer grit or foam / wool pads with progressively denser pads to get a smooth finish (i.e. using finishing papers 500 grit increments will yield flatter results - 1000 > 1500 > 2000 > 2500 > 3000)

    By going through the grits each progressive piece of grit finishing paper or pad removes the scratches from that previously used. Always start with the least abrasive combination, i.e. a machine polish and the least aggressive foam / wool pad. If that combination doesn't remove the imperfections, using the same machine polish and change to a more aggressive pad, if the surface imperfections remain, then step-up the abrasive polish and use the least next level (abrasive)only when the paint has a consistently level, smooth, satin finish should you continue to the polishing stage.

    Using a PC

    1500 >2000> 3000 grit 3M Perfect-It Trizact speed 3 -4.Remove sanding scratches with a suitable finishing polish, or use a 4-inch Purple Foamed Wool pad and M105; followed by M105 on an LC Orange foam pad and finally M205 with an LC White foam pad.

    Final polishing

    First step is to completely remove all the sand scratch marks. Subsequent polishing steps will involve polishing for maximum gloss and then finessing (jewelling) for maximum clarity. You can't be in a hurry in any polishing step or you risk missing some imperfections. It needs to be flawless.

    Material data sheets (MSDS)

    Material Safety Data Sheet (MSDS) is required under the OSHA Hazard Communication Standard. The MSDS is a detailed informational document prepared by the manufacturer or importer of a hazardous chemical. It describes the physical and chemical properties of the product. MSDS’s contain useful information such as flash point, toxicity, procedures for spills and leaks, and storage guidelines.
    Information included in a Material Safety Data Sheet aids in the selection of safe products, helps you understand the potential health and physical hazards of a chemical and describes how to respond effectively to exposure situations. Although there is an effort currently underway to standardize MSDS’s the quality of individual MSDS’s vary. A MSDS may be useful but it cannot substitute for prudent practices and comprehensive risk management.

    An MSDS should be available for every chemical you use. Read these and follow the recommendations for safe use and disposal of the material. The target audience for information in a MSDS is the occupation worker who may be exposed to chemicals at work. However, much of the information is also relevant to consumers.
    Read the manufacturers application instructions and then obtain and read the MSDS sheet to ascertain the chemicals used. Although it should be said that an MSDS is a document that contains details of the hazards associated with a particular chemical and provides information regarding its safe use. The MSDS is required to state the chemical's risks, safety and impact on the environment.

    An MSDS is a fact sheet developed by manufacturers describing the chemical properties of a product. Material Safety Data Sheets include brand-specific information such as physical data (solid, liquid, colour, melting point, flash point, etc.), health effects, first aid, reactivity, storage, handling, disposal, personal protection and spill/leak procedures.

    How to Read a Material Safety Data Sheet (MSDS) How to Read a Material Safety Data Sheet | CMHC

    Chemical Information (MSDS) A-Z- The Most Complete Free Material Safety Data Sheet (MSDS) list of chemical information on the Internet

    Definitions of Terms Used in Material Safety Data Sheets (MSDS) - Definition of Terms Used in Material Safety Data Sheets (MSDS's)

    Chemical Abstracts Service (CAS)

    Each CAS registry number (often referred to as CAS #) is a unique numeric identifier that designates only one substance; it has no specific chemical significance, but is a link to a wealth of information about a specific chemical substance. Since CAS Registry Numbers are not dependent upon any system of chemical nomenclature, they can provide a reliable common link between the various nomenclatures terms used to describe substances. And serve as an international resource for chemical substance identifiers used by scientists, industry, and regulatory bodies

    Environmental Commitment

    You should never assume that aqueous solutions can be disposed of untreated via the storm drainage system. Pending regulations are in place (Clean Water Act and Ground Water Pollution) to limit the amount of contaminated water that is allowed to be discharged into storm water systems (i.e. street vehicle washing)
    Always responsibly dispose of all non-biodegradable materials from your vehicle cleaning in a responsible manner. Waste run-off must be disposed of in accordance with federal, state and local environmental control regulations.

    Personal Protective Equipment (PPE)

    Protection from Potential Health Hazards
    1. Warning: Always use ground fault protection interruption (GFPI) when using any electrical device around water
    2. Eye Protection: I would strongly advise the wearing of safety glasses or visor when operating any machine polisher.
    3. Ear Protection; the constant pitch of a polishing machine could affect your hearing so wearing ear plugs would be wise to protect you from hearing loss.
    4. Hand Protection; Gloves- with the verity of chemicals a detailer uses on a daily basis wearing chemical-resistant gloves resist penetration and permeation, and will provide protection against dermatitis and chemical burns. Gloves can provide protection, but they must be chosen with care, the proper selection matched to the hazard is critical. Chemical-resistant gloves resist penetration and permeation, and cam protect against dermatitis, chemical burns and corrosion.
    5. Respiratory Protection (N95): Materials such as aluminium oxide (Aluminium oxide is on EPA's TRI list if it is a fibrous form) or silicon carbide (Nuisance particulate-Accumulation in lungs) used in polishes and compounds, and powdered fillers (Crystalline silica poses a serious inhalation hazard because it can cause silicosis) and Isocyanate clear coat residue represent a hazard to your lungs and may cause respiratory distress. Use a NIOSH-approved half face respirator equipped with a combination filter cartridge should be worn while using them
    6. Consult the current 3M Respiratory Selection Guide for additional information or call 1-800-243-4630 for 3M technical assistance.
    7. Material Safety Data Sheets: Use a ring binder or other filing system to ensure the appropriate MSDS is always available to identify hazardous substances
    8. Work Hygienic Practices: Rinse cloves under running water before removing them
    9. Protect yourself, work safe. As in all things, allow common sense to prevail and proceed with due caution


    Information resource

    1. PERFECT-IT 3000 Training Class
    2. Eastwood Technical Library - Eastwood Company Home Page
    3. Glasurit, Advice on Paint and Paintwork Defects - Glasurit
    4. Colour Sanding and Polishing - Welcome to System One APS
    5. Eastwood Technical Library - Eastwood Company Home Page
    6. Automotive Detailing Inside & Out; a Knowledge Base for the Perfectionist, by Jon Miller
    7. TOGWT™ Series of Detailing Articles, by Jon Miller

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    Detailing Articles

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  2. slanguage

    slanguage OD On Detailing

    Thanks Jon :thumb:

    I need to read the entire article later, when I have more time. It was what I was looking for though.
     
  3. Twisted007

    Twisted007 Banned

    good write up of info. this should help out alot of people.
     
  4. GDAL

    GDAL Guest

    great info ... I was waiting for this one.

    One question though ... which wet-sanding method do you prefer? wet-sanding at an angle or wet-sanding back and forth horizontally?
     
  5. togwt

    togwt Nuba Guru

    Perhaps I need more coffee; but I'm not sure I understand the question
     
  6. GDAL

    GDAL Guest


    which wetstanding method do you prefer? wet-sanding back and forth or wet-sanding at an angle (either // or \\)?
     
  7. togwt

    togwt Nuba Guru

    OK now I understand.

    My preference is /// \\\ overlapped as you can tell what's been sanded
     

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