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Choose high-quality abrasives that can help drive productivity throughout your process
Quality paint jobs start from the beginning.
Common sanding scratches that cause rework
A closer look at common imperfections that could appear during the sanding process or after the repair is complete.
Get all the gritty details behind better paint jobs. Download the infographic (PDF, 141 KB).
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Deep inline scratches while sanding fillerAs you prepare to spray primer, it is important to completely remove any 80 or 180 grit scratches.
Avoid these imperfections by:
- Knowing the grit or grit range for each step of the sanding process
- Using guide coat to help highlight sand scratches and any high or low spots
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Inconsistent scratch profile during blend panel prepSanding today's ultrafine metallics with yesterday's process could lead to inconsistent scratches.
Avoid these inconsistencies by:
- Removing paint build up and dirt nibs
- Using proper sanding techniques (hand sanding, then DA sanding)
- Utilizing dust extraction to vacuum remaining dust on the panel
Get tips to identify and avoid inconsistent scratch profile.
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Unwanted pigtails during surface prepPrevent the formation of 'pigtails' or sprial-shaped scratches that can compromise the quality of the final finish.
Avoid these marks by:
- Regularly replacing abrasive discs when they show signs of wear or clogging
- Using quality abrasives and the proper grit selection
- Implementing consistent sanding techniques and processes
Resources to achieve smooth surfaces, sharper results
The gritty details behind better paint jobs.
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Related resources: Paint and surface prep SOPs.Relevant Standard Operation Procedures available to help further refine your prep process.
Maximize your refinish hours—tips to identify and avoid scratches
Failure to address or avoid these type of sand scratches could lead to possible rework or a complete repaint. Let's take a close look at how they are caused, identified, and tips on how to avoid them.
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Removing deep inline scratches while sanding filler
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- When sanding filler or glaze with coarser grades on a repair panel, creating consistent inline scratches are key. Missing any of these scratches could result in potential rework.
- How are these imperfections caused?
- At the start of the sanding process, many jobs will require the use of coarse grit abrasives (typically 80 grit, working upwards through the grades) to sand down and feather out filler and glaze.
- How are these imperfections identified?
- Blocking with a coarse grade abrasive can leave deep scratches on a surface that resemble semi-straight lines put in from each pass. There are helpful tools like powders or guide coats that drop down into the scratches and help make them more visible during each step of the sanding process. Identifying these scratches on a panel can not only help visually show us what the scratch profile looks like, but it can also tell us that we still have some work to do.
- How can these imperfections be avoided?
- Many times, it’s easy to overlook some of these deep scratches you may have put in early in the sanding process. As you change sandpaper grits, applying guide coat before each sanding step can help you easily identify these scratches along the way. It’s important to make sure you keep working to fully remove these deep scratches before you spray primer.
- Get the job done with these 3M products:
- 3M™ Cubitron™ 2 Abrasives (80+ to 320+ grit)
- 3M™ Blue Abrasives (80 to 320 grit)
- 3M™ Clean Sanding System for dust extraction
- 3M™ Hookit™ Dust Extraction Flex Blocks
- 3M™ Dry Guide Coat
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Avoiding inconsistent scratch profiling during blending
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- There are undoubtedly some challenging colors on the market today that present even greater complexity for shops. The repair process must be adapted to properly color match some of these complex colors, preventing a repeat of the repair. While there are steps on the paint side one can take to more easily reproduce these colors, taking certain precautions during the sanding process can increase chances of a high-quality result.
- How are these imperfections caused?
- Basecoat metallics are finer than they’ve ever been, requiring a finer and very consistent scratch profile. Technicians today are having to sand finer than they ever have before. Too deep of a scratch, improper removal of paint build up, or even inadequate removal of dust on the panel could all impact the quality of the job.
- How are these imperfections identified?
- While it may be difficult to see these inconsistent scratches with the naked eye, useful tools like dust extraction systems and following sanding best practices can help bring these issues to light before it’s too late.
- How can these imperfections be avoided?
- OEMs require a certain mil thickness for coatings, resulting in paint having to be smooth after one or two coats - making it crucial to have fine, consistent scratches for an optimal surface for the basecoat to land. Always be sure to check your paint company’s recommendations for the appropriate grade abrasive to use and when to use it. Be sure to remove any bumps on the surface and ensure there is no picture framing around the panel. A properly blended panel requires a combination of both hand sanding around curves, body lines, and arches and DA sanding for the final sand, removing those inline scratches put in from hand sanding.
- Get the job done with these 3M products:
- 3M™ Cubitron™ 2 Hookit™ Clean Sanding Abrasive Disc 737U (800+ to 1000+ grit)
- 3M™ Hookit™ Flexible Abrasive Foam Disc (800 to 2000 grit)
- 3M™ Clean Sanding System for dust extraction
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Escape from unwanted pigtails during surface prep
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- Prepping the surface for paint requires careful attention. Concerning issues like “pigtails” can start to form, which could compromise the quality of the final finish.
- How are these imperfections caused?
- Pigtails may start to appear on a surface during the sanding process as result of a variety of factors. Sandpaper loading, incorrect grit selection, and inconsistent sanding techniques (uneven pressure or sanding pattern) are some of the main reasons why these imperfections may result.
- How are these imperfections identified?
- Pigtails are fortunately fairly easy to identify. Unwanted swirl-like marks or scratches that resemble “pigtails” may appear on surfaces and should prompt technicians to course correct before spraying.
- How can these imperfections be avoided?
- There are certain preventative measures that can be taken to help avoid these unwanted pigtails from forming. One of the main factors causing these imperfections is clogged or loaded sandpaper. It is important not use abrasive past the life of the disc or sheet. Failure to keep the surface clean can introduce dirt and other contaminants. Transitioning too quickly to a finer grit abrasive can also create pigtails but starting with a finer grade sandpaper may not remove imperfections initially put in, so knowing the correct grit sequence is key. While you might be able to cover up some imperfections when spraying some solid colors, you could start to see these pigtails again when spraying a metallic color. Having a consistent surface prep process no matter what color you plan to spray, can help prevent rework in the end.
- Get the job done with these 3M products:
- 3M™ Cubitron™ 2 Hookit™ Clean Sanding Abrasive Disc 737U (80+ to 320+ grit)
- 3M™ Hookit™ Blue Abrasive Disc 321U (80 to 320 grit)
- 3M™ Hookit™ Flexible Abrasive Foam Disc
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Top picks: 3M high-performance abrasives for the job
Our best abrasives that can help get you to the finish line faster.
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3M™ Cubitron™ AbrasivesFeaturing at least 30% fast cut and at least 40% longer life than other traditional ceramic abrasives.
Explore 3M Cubitron™ 2 Abrasive Discs
Explore 3M Cubitron™ 2 Abrasive Sheet Rolls
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3M™ Blue AbrasivesFeaturing an engineered ceramic mineral blend for best-in-class performance at a mid-tier price point.
Explore 3M Blue Abrasive Discs
Explore 3M Blue Sheet Rolls
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Advance your skills with 3M | Online and in-person training
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Explore in-person training at 3M Skills Development Center
3M instructors will lead attendees through the course primarily using practical “hands-on” sessions that reinforce and demonstrate key concepts, supported by occasional classroom theory and discussion. Held at our state-of-the art training facility.
Explore our classes and register
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Where can I find more information about the proper grit sequence to help remove deep inline scratches?
See our comprehensive brochure (PDF, 3.55 MB) that includes a chart that notes the proper recommended grades for use. Also, see our related Standard Operating Procedures for Panel Repair and Paint Prep (PDF, 1.05 MB) and Feather, Prime, Block (PDF, 707 KB).
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Which product will help me achieve a more consistent scratch profile during blend panel prep?
Our 3M™ Cubitron™ II Abrasives feature 3M Precision-Shaped Grain that continuously fractures to form sharp points and edges — slicing cleaner, faster, staying cooler and lasting many times longer. This can help technicians achieve a more uniform scratch profile.
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Which products can help with pigtails?
Choosing high-quality abrasives that promote longer life like our 3M™ Cubitron™ II Abrasives or 3M™ Blue Abrasives, can defer the loading or clogging of discs. It is important to replace abrasive discs as soon as they show any sign or wear or clogging.
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What new abrasive products do you have to offer that can help me achieve a better repair?
We recently launched finer grades 500+ to 1000+ to our premium line of discs and sheet rolls – 3M™ Cubitron™ II Abrasives. Their long-lasting triangular shaped grain and multi-hole pattern for superior dust extraction make the discs ideal for a long disc life. These abrasives feature at least 30% faster cut and at least 30% longer life than traditional ceramic abrasives. The wide range of available grades offer discs for coarse body work up to fine sanding of blending areas.
Our abrasive grain technology continues to evolve with the introduction of 3M Cubitron 3 Cut-Off Wheels. Cut faster with less heat and fewer changeouts with 3M™ Cubitron™ 3 Cut-Off Wheels for collision repair. We have engineered these cutoff wheels to continuously fracture to form sharp points, run cool and optimize mineral breakdown to allow fast cutting and long-lasting performance. These Cut-Off Wheels feature 40% more life than our Cubitron™ II Cut-Off Wheels which allows technicians to remove up to 40% more material than our previous generation, all while cutting smoother than the leading competition.
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How can I get more information about the featured products above?
See our comprehensive brochure (PDF, 3.55 MB) that includes our complete offering featured above, as well as additional supporting products and tools to help boost your day-to-day productivity. Explore our online catalog for product details and specs.
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Where can I go for more training or resources to help avoid these common pain points during the prep process?
3M has a variety of ways to access more resources. We are committed to providing the tools you need to invest in your team and help shape the future of the industry.
The 3M™ Skills Development Center3M™ Skills Development Center in St. Paul, MN, is our state-of-the-art training facility that allows our industry experts to deliver more hands-on training, teaching body shop staff the most updated processes from real-world experts, OEMs, and accredited partners. We also have online, on-demand virtual courses, webinars, white papers, articles, and videos focused on fulfilling the learning needs of individual technicians. Our library also includes 20+ SOP-focused modules and 6 multi-module learning tracks. Sign in or registerSign in or register and explore today.
We also have two related Standard Operating Procedures for Panel Repair and Paint Prep (PDF, 1.05 MB) and Feather, Prime, Block (PDF, 707 KB).
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Where can I find more information about dust extraction solutions?
We offer the 3M™ Clean Sanding System, a complete sanding solution for efficiently moving through your essential surface preparation and finishing work. The system includes our dust extractor, pneumatic and/or electric random orbital sanders, mobile workstation, wide selection of quality abrasives, and personal protective equipment.
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What other abrasive solutions do you have to help drive productivity in my shop?
We have a full range of high-quality abrasive solutions specifically designed for automotive applications. It’s all part of a complete and always expanding selection of 3M abrasive discs, abrasive sheets, cut-off wheels, belts and much more for increased productivity at every stage of body repair.
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What solutions does 3M have for inventory management?
Help advance your collision repair business with 3M™ RepairStack™ Performance Solutions. Accurately track and organize all your 3M and non-3M materials, automate re-ordering from your preferred distributors, and help improve efficiency by eliminating manual inventory management.
