Spray Painting & Finishing

MODULE: 01

SPRAY PAINTING & FINISHING

MATERIAL TYPES Spray paint consists of a mixture of colorful paint solids and a chemical solvent thinner, which are propelled by a compressed air. Spray paint cans are referred to as “rattle cans” in the industry.

“Rattle Can” Spray Primer - automobile primer is a favorite in the design industry. The mid-gray color shows off details very well. Automobile “fller primer” is also available, which is thicker and has a higher solids content, which is better to fll in tiny pinholes. I’ve found the automobile primers to be superior quality to other types of primers on the market.

“Rattle Can” Spray Paint - most commonly available in either enamel or acrylic. Montana offers hundreds of high-quality, vibrant colors — with a versatile spray cap system for different spray effects (i.e. skinny to fat, round, fat, etc.).

HVLP Spray Primer / Paint - catalyzed primer, or “Cat” primer, hardens with an MEKP chemical catalyst. Color base coats are available in a wide variety of colors, and can be precisely color-matched by special order automotive paint shops.

Solvent - strong chemical used to temporarily thin, or remove paint from a surface (similar to nail polish remover). Acetone, Lacquer Thinner, and Mineral Spirits are the most common solvents.

Top Suppliers: Rust-Oleum™, Dupli-Color™. Spruce™. Tamiya™, Montana Cans™

COMMON USES Model making, custom airplane / car models, prototypes, DIY crafts, and everything in between. Rattle can paint quality can’t come close to HVLP (especially when painting larger objects), but is much more convenient — and doesn’t require the use of an air compressor.

SAFETY Always work in a well-ventilated space or spray booth.

PRO TIPS I’ve found (the hard way) that many major spray paint brands are based in California, and are formulated for California’s dry humidity and warm temperatures. Damply humid locations like Houston will make paint drying much more diffcult for some brands (especially in winter). Make sure to use the right materials to avoid the frustration of paint formulas not curing properly.

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Above: Degreasers and “Rattle Can” spray paints shown in process order: Prep —> Primer —> Paint. Through experience, I’ve Above: 1) With new advancements in modern paint mixing technology, many found the Rust-Oleum automobile primers to be far superior to other types of primers on the market. Don’t hesitate to splurge a crazy paint colors are coming out constantly — like the metallic paints pictured. 2) few extra bucks on quality primer — it will make a big difference in both drying times and fnish quality. Montana acrylic enamels Other popular “industry standard” primer brands. Always stick with the light gray, are a favorite in design circles, since they are available in a wide variety of high-quality vibrant colors — and dry much more no matter the brand, as this will show off surfaces the best. 3) The “Filler Primer” is quickly than other paints. They are also a favorite among sign painters, graffti artists, and hobby model makers. useful for flling in small pinholes, but will not achieve anything near the results of a professional, HVLP catalyzed primer (and will dry much slower). This particular can was purchased from an auto parts store.

2 SPRAY PAINTING & FINISHING Below: Professional HVLP gravity feed guns — Sata, DeVilbiss, and Iwata are the choice of the pros. Pro-level commercial painters geek out on spray gun technology, and will most likely own HVLP Automotive at least 2 or 3 different guns. Spray Paint Gun SPRAY NOZZLE

TOOL BASICS High Velocity, Low Pressure (HVLP) - these “gravity feed” spray guns are the top choice in commercial / industrial fnishing applications, such as bicycle frame and automotive painting. HVLP uses an air compressor to propel highly PAINT CUP concentrated paint fuids. Two major types are available — ATTACHMENT gravity feed (paint cup on top) or siphon feed (paint cup on bottom). Each gun has adjustment dials which can adjust AIR the amount of air pressure, paint fow, and size / shape of TRIGGER FLOW spray (round, horizontal fat, vertical fat). Primer has a much DIAL higher solids content vs. paint. Paints and primers need to PAINT be thinned with a solvent like Acetone before they can be of FLOW sprayable consistency. Use specially formulated Catalyzed DIAL Automotive Primer, base coat and top coat only — in this order. LVLP (Low Velocity, Low Pressure) guns also exist.

Top Suppliers: Professional brands used by expert automotive painters are Sata, DeVilbiss, and Iwata — these guns have precision machined stainless steel components and can run upwards of $1,000 a pop. They are quality built and will last a lifetime if properly cared for. Most pros prefer gravity feed guns vs. siphon feed (an older technology). Harbor Freight offers low-end spray gun packages for around $45, which are decent enough for a handful of uses — however, parts are made of brass and are much lower quality.

PRO TIPS Clean guns thoroughly after every use. If not, components AIR COMPRESSOR will become clogged and the gun will need to be replaced. HOSE CONNECTOR In 90% of scenarios, HVLP is superior to Siphon Feed guns.

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HVLP Gun Clean-up Process: 1) Fill paint reservoir with Acetone or other strong 2) Disassemble the spray nozzle, 3) After thorough brushing, leave the disassembled parts in a measuring cup solvent, then depress the trigger to purge the solvent out through the spray nozzle. This air / paint valve adjustments, and flled with Acetone or Paint Thinner, then leave to soak for an hour or more. It’s will start to wash through the internal mechanical gun parts. spring components one by one. impossible to be too clean here, since any primer or paint buildup inside the gun Once disassembled, clean the can cause clogging. If clogged, the entire unit will need to be replaced — so put inside of the gun with a small wire forth the extra effort to clean all parts properly! brush (included with most spray gun kits).

4 SPRAY PAINTING & FINISHING 1 2 3 Left: 1) Catalyzed primer thinned with Acetone, then 2) mixed with MEKP hardener. 3) Prep the surface with auto prep or alcohol. A tack cloth is Spray Painting useful for removing small specs of dust. & Finishing Below: For best results, overlap spray strokes (middle) to avoid gaps TIPS & TECHNIQUES (bottom). Careful not to Spray painting is both an art and a science — getting it right is no easy task. Many factors are involved, including proper spray too heavy, or the surface prep to proper paint mixing ratios, dust in the room, and more. For most industrial purposes, painting follows these paint will run (top). Store important steps: Surface prep —> Primer —> Wet Sanding —> Top Coat (color) —> Clear Coat. The clear coat acts as the the respirator mask in fnal gloss layer that will seal and protect the painted surface underneath. Paint fnishes are limited only by your imagination. a zip-lock bag between uses, to extend the life of (Rattle Can) Automotive / Filler Primer - spray can version of primer. Filler primer sprays on much thicker vs. standard the flter cartridges. automobile primer, but will take longer to dry. (Rattle Can) Spray Paint - these paints are most common at hardware stores, and are suitable for smaller models. The most common rattle spray paint types are Acrylic and Enamel — follow the application and drying time directions on the label, since each paint formula is different.

(HVLP) Catalyzed Primer - To mix, add MEKP catalyst to the primer, which causes the paint to harden and cure through a chemical reaction. Cut with Acetone frst, to thin out for spraying. Less Acetone = thicker and quicker set time. More Acetone = thinner and longer set time. This 2-part primer is almost like a “Sprayable Super-Glue.” (HVLP) Spray Paint - 2-3 light coats a few minutes apart (making the last coat the heaviest) achieves far better results vs. one heavy coat. Follow application and drying time directions on the label, as each paint formula is different. Adjust spray fow, volume, pressure and spray pattern shape using the HVLP gun’s adjustment dials.

PRO TIPS PRACTICE, PRACTICE, PRACTICE. Test paint a small object frst, before committing to the fnal part. Professional quality paint results are only possible in a dust-free room.

12 5 13 Left: Spray paint jigs are the best way to create “hand holds” and to speed up painting times. The parts can be held by a dowel stick or wooden pencil while the full 360º of the piece can be painted. This is also very useful for drying, since the pieces have no contact with a fat surface. Make this jig by drilling a small hole in the bottom of the part (choose a spot hidden from sight), and another hole in a scrap piece of wood or other material (the base). Parts that cannot easily be propped up this way can be hung with a hook or coat-hanger, and hung for drying (i.e. following spread). Again, custom jigs come in handy here.

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Above: (right to left) Faber Light clay sealed with a coating of Shellac. This is then followed by a primer / bondo / guide coat layer to fll any valleys or pinholes. Finally, one last coat of primer is then wet sanded and ready for fnal paint. Almost all paint projects follow this same order. Due to its oil content, clay needs to be sealed frst, otherwise paint will not fully cure. Porous materials like wood or tooling foams will need to be sealed frst with Shellac or several thick coats of HVLP primer /rattle can “Filler Primer” to make the surface smooth enough for fnal painting.

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Pro-Level Spray Painting Process: 1) PU foam model with fnished surface details 2) Shellac is sprayed or brushed onto the foam to seal large surface pores (this step is needed for porous foams or woods only) 3) First primer layer of all parts, layered on thick to create a smooth surface. 4) Primer is sanded and Bondo’d several times, until a fnal guide coat is lightly dusted over the Above: (right to left) bare unfnished Chavant clay before sealant (darker red color vs. Faber Light), gloss clay top (use a rattle-can for this). This coat is used as a guide to show which areas have been completely wet-sanded — and which after Shellac spray sealant coat, and fnal paint / clear coat (“candy coat”) at left. This is the exact same process have not — before fnal paint is applied. 5) Guide coat has been fully wet sanded off. The primer surface is now ready for painting. top automakers use when creating show-ready, painted concept cars from full-scale sculpted clay car bodies. 6) Rattle-Can base color paint coat applied as evenly as possible. 7) Once the base color dries, mask off contrast color / texture break areas with blue or green non-stick painters tape. A thick clear coat is then applied. 8) Final painted model at right — lower 6 red knob areas are painted separately, allowed to dry, then epoxy glued onto the model. MFG. LAB MASTER MAKER MODULE

Primer: Because there is no fat spot on this pair of sunglass frames, it is hard to paint without the appearance of an unsightly dry spot. To counter this, the piece is hung with fshing line tied to a spot on the object that will be unnoticeable in the fnal paint fnish (in this case, the inside of the ear-stem hinge). The frames are frst covered with 2-3 full coats of automotive rattle can primer. They are then and left to dry for at least an hour, before being wet sanded or readied for fnal paint.

Paint: 1-5) While holding onto the object by the fshing line hook (wear gloves), the sunglasses can be spun and rotated to evenly cover surfaces all over. Notice a frst light ‘mist’ coat (2&3), which is then followed by one to two medium wet coats a few minutes apart (4&5). Be careful not to apply too heavy of coats here, or the paint will run, meaning the process of primer then sanding and paint will need to be repeated all over again!

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Spraying an Irregular Object: In the case that the object being painted cannot be easily propped up using the dowel stick method, the object must be hung via a hook instead — here, a simple hanging hook was fashioned from a metal paper clip and fshing line. A special area must be set aside to spray and paint parts like these (i.e. Urban Workshop’s DIY spray booth pictured below). Keep in mind that high-quality industrial painting will need to be done in a fully enclosed, dust free indoor space with ventilation — however, spray booths don’t always need to be ultra-fancy and cost tens of thousands of dollars. Most important of all, the booth must be covered, and well ventilated (preferably outdoors).

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Drying: 1-2) After the fnal paint coat has been applied, the sunglasses are left to hang overnight. 3) Make sure your painted piece is in a place that is both covered and undisturbed, to avoid ruining. You may also want to leave a note with your name and contact info next to the piece, if this is a shared space.

Below Spread: Final paint coat in all its glory. In my experience, a good quality rattle can paint can come very close to achieving a level of fnish that is visually on par with that of a high quality HVLP spray gun. However, the key differences are the size of objects which can be painted, as well as the longevity of the fnished paint surface. Objects being handled often may start to chip or rub off vs. HVLP which is more permanent. One way to counteract this is to apply a sprayable clear coat once the color coat has been allowed to fully dry.

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Spray Painting Cheat Sheet

For most industrial purposes, painting follows these important steps (works with both Rattle Cans and HVLP Gun): 1) Surface Prep —> 2) Primer —> 3) Dry Sanding —> 4) Wet Sanding —> 5) Painting —> 6) Drying

1) Surface Prep - sand and prep every surface before each step listed. Make sure the part being painted is dust and lint free. Clean away oil & grease with a lint-free rag or tack cloth, wetted with alcohol or auto prep degreaser spray. To protect from overspray, mask off all areas of the model which are not to be painted using blue or green painter’s tape.

2) Primer - prepares the surface to be painted, essentially creating a new surface “skin” that can once again be sanded, wet sanded, or fnished with body fller. Slick surfaces should be roughened with sandpaper before priming.

3) Dry Sanding - lower-grit sandpaper with heavier tooth, for removing more material. Dry sanding is used to sculpt a material, or to roughen a surface in the pre-primer stage.

4) Wet Sanding - fner-grit quality sandpaper, used for polishing in the post-primer stage. Wet sand (with a few drops of dish soap added to water mixture) up to 600-grit sandpaper to create a glass-smooth surface ready for painting. Wet sanding is used as the last and fnal surface prep just before the fnal paint coat — always make sure to keep in mind that the fnal paint coat will pick up the exact fnish quality of the underlying surface (including oily “Cheetoh Finger” prints!)

5) Painting - once primer surface has been sanded to the desired fnish (typically 600 grit wet sand for gloss fnish, although a matte fnish can make due with lower grit — i.e. 320) and cleaned with degreaser, it is time to paint. Always paint using riser support stands and / or hangers — this will double or triple the overall paint and dry time effciency, and give more control to rotate parts and apply coats evenly. Work in a dust-free, well-ventilated area. Using overlapping paint strokes, spray 2-3 light coats a few minutes apart, making the last coat the heaviest. After a few minutes, the paint will begin to set and develop a satin “egg shell” appearance. An optional clear coat can now be applied during this “window”. The clear coat is the fnal gloss layer that will seal, protect, and improve overall gloss level of the painted surface underneath.

6) Drying - primer dries much quicker than spray paint, and will typically be dry to the touch within 1 hour. Paint typically takes 24 hours to fully dry. When drying, store parts in a safe, dust-free place where they will not be disturbed — especially when using a clear coat. Clear coat will attract microscopic dust particles in the air, so it’s a good idea to Above: Custom painted mountain bike place a cover over the entire piece. Otherwise, all of your hard work could literally be ruined overnight! frame by a pro paint shop in California. This bike frame follows the same industrial HVLP paint process covered in this book, with pin 20 striping added by hand with a brush. 9 SPRAY PAINTING & FINISHING MFG. LAB MASTER MAKER MODULE

This module is an exerpt from:

THE MAKER’S FIELD GUIDE: MASTER MAKER EDITION 230 pages of professional content, including an advanced bonus chapter on industrial design & entertainment design project builds from start to finish. Collector’s edition cover design variant.

Digital pdf downloads included with every book purchase through the website. www.themakersfieldguide.com

ABOUT THE AUTHOR

Christopher Armstrong is part industrial designer, part product developer, part brand specialist, entrepreneur and thought Leader. He has held senior leadership positions on several different Advanced R&D and Special Projects teams.

Christopher was born and raised in Houston, Texas, where he developed a love for working with his hands, while watching endless behind-the-scenes featurettes for blockbuster flms like Batman Begins and Terminator 2. After working multiple blue-collar jobs (and selling movie replicas on the side), he fnally saved up the means to later immigrate to California, where he attended the Art Center College of Design. After design school, he began his professional career working in consumer faucet design. Briefy thereafter, he served a short stint as a freelance concept designer working on Sony PlayStation Home and other video game titles with his close friend and long-time mentor, John Park.

He has since worked with over 30+ clients worldwide, designing and developing some of the most technically-advanced products in their respective industries. He continues to have an intense passion for design, technology & engineering, business, and brand building — where he helps to shape the future of companies through innovative products, brand messaging, and storytelling (only now on a much larger scale than the home garage days of his youth). He’s lectured and given talks at multiple design and concept art trade schools, including Art Center, Concept Design Academy, Red Engine School of Design, Brainstorm, and Design Engine. He currently offers corporate training in advanced design and CAD modeling.

Most recently he was responsible for designing and developing and helped to launch a full line of patented performance footwear and apparel for LIFT Aviation, where he served as Lead Designer. He also designed high-performance racing footwear for some of the most hardcore race car drivers around, under the Piloti brand name — helping to restore the cult brand to the forefront after it’s demise in the early 2000’s.

Christopher’s work has been featured in TransWorld Motocross (TWMX), Red Bulletin Magazine, AOPA Pilot, Hypebeast, Footwear News, Digital Trends, Corofot, RECOIL, Performance BMW, Octane, IDSA, and ImagineFX.

www.christopherarmstrongdesign.com [email protected] Instagram: @christopher_armstrong_