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Pinball Rehab

pinball repair and restoration

Painting Reference Painting Reference Hot

In this article I will try to clarify the confusing world that is paint selection and application.  Hopefully by the end you will be able to answer the question of why black is not always black.  If you've ever tried to match black paint on a cabinet or backbox you know just what I'm talking about.

Let me say up front that some of the terms for types of paint that should be standard, are not.  In some cases the usage of the term has changed over time and in other cases it appears marketing is determining the terminology rather than engineering.

Paint Choices

The first choice you have in paint is water (also called latex) or alkyd (oil) based. 

If there was a peoples choice award for paint, latex would win.  While in the past oil based paints would be considered the technical winner, two things have happened.  Due to EPA regulations and manufacturing cost limitations oil based paint is not as good as it used to be.  While at the same time water based paints have continued to  improve.

While in the past enamel meant an oil based paint, it now refers to any high-gloss, hard finish paint.  Enamels are formulated with higher concentrations of resin as they are intended to be subjected to more wear and tear.  If you are planning on clear coating the playfield enamel paints will need to be scuffed up to get proper adhesion.

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Painting Reference

Enamel paint (whether water or oil based) is glossier and has a harder finish.  While urethane paint (water or oil based) will beat enamel on both counts, it is hard to get it to adhere to some surfaces and has a tendency to form bubbles when brushed on.  Therefore it requires more surface preparation and expertise.

One last type of paint I should mention is lacquer.  The problem with lacquer is that it is a "hot" paint and can bubble or lift many other types of paint, especially if the paint has not cured long enough or applied in thick coats.  It is generally best to stay away from lacquer unless you know what you're doing.

Automotive clear coat is also a hot paint.

If you're still confused about whether a paint is water or oil based just check the clean-up instructions.  Water based paints will clean with soap and water and oil based with mineral spirits or paint thinner.

Water Based Paints

The three most common choices in water based paint are acrylic, enamel and urethane.  Note: Enamel and urethane are also available as oil based.  The difference between the three is the medium the pigment is suspended in.  For example, acrylic paint consists of pigment suspended in an acrylic polymer emulsion.

Latex paint is fast drying (meaning less time to flow), easy to clean up (if you make a mistake you can remove it and start over).  It can be diluted with water although it is preferable to thin with an additive which will help overcome some of Latex's shortcomings. 

I typically use acrylic paint when doing playfield touch-ups.  For airbrushing I prefer Createx and for touch-up with a brush I use either Testors acrylic or Createx. For cabinet work I usually use a custom blended latex, or enamel if I need the higher glossiness.

When using acrylic paint on a playfield always plan on applying a clear coat for improved durability.  For spot clears you can use a water based enamel or urethane.  If you're doing the entire playfield, automotive clear is recommended.

A lot of pinball hobbyists use acrylic hobby (or artist) paint to do touch-up work, but I do not recommend this solution.  Although they offer a variety of color options they do not flow well, do not cover well, will fade over time and have a very low gloss.  If you insist, Liquitex is by far the best of the hobby acrylics (technically it's an artist acrylic).  I would generally stay away from most store brands, but the best of the "one dollar" hobby paints are Americana or Palmer. 

Note: Even water based paints include a thinner and different manufacturers use different blends so it's best to pick one brand of paint and stick with it for each specific job.

Oil Based Paints

Oil based paint requires a solvent for cleanup and take longer to dry than water based, which provides better flow and reduces brush strokes.  Oil based paints also provide a tougher finish and better coverage although they do require a little more cleanup effort than water based.

The only time I use an oil based paint is on cabinet decals where I need more gloss than a latex enamel provides.

Do Oil and Water Mix

There is a lot of contradictory information about whether you can put latex over oil based paint, or vice versa.

According to Rohm and Haas, a Dow Chemical Company: "Generally you can use one over the other. Some manufacturers of latex products will recommend a primer when going over oil-based paint."

If you plan on using automotive clear over oil based paints, while it can be done, it is a little tricky and should really be avoided.  It is best to use water based paints, thinned with water, if you p.an on using automotive clear coat.

Paint Pens

While paint pens are extremely handy for doing touch-up work, they come with a huge caveat.  Either an oil based topcoat, or a water based topcoat that is thinned with solvents, will cause the paint to run.  Therefore I avoid them, but if you must, use only a water based topcoat that is thinned with water. 

Never use Sharpies or other permanent markers, they will bleed.

You can safely draw fine lines with either the Kemper Fluid Writer Pen or the Grafix Original Incredible Nib.  Both of these products use your paint and provide a vehicle for dispensing it in a controlled manner.  The Kemper product does very fine lines and the Grafix product does fine/medium lines. 

The following information is excerpted from a discussion on Pinside.com relating to paint pens and automotive clear coat.

Drano:  "I've been using these Molotow acrylic markers for a while and they work very well.  The 1mm black is great for tracing key lines around inserts and has saved me tons of time with Frisket and airbrush.  It dries nice and flat.  I've also tried a few other colors, but the black and white seem to be the most useful.

I have not gotten any bleeding at all with the black, but I did a test with red and blue and did notice some bleeding on heavier applications of clear.  In the future I would apply a thin coating to seal and then wait to do a heavier application."

Lowrent did an opacity test on the various paint pens (see Image 11).   "Just so you know, lithography film is the most opaque you can get.  At noon when the sun is the shiniest, you can barely see it through this film.  Here are the values I get in Photoshop (relative to my scanner, just to give an idea)"

Litho : 100%
Sharpie : 71%-87% blueish
Molotov : 91% uniform black
Liquitex : 69%-91% black
Waterslide : 89% black

Rody: "I have extensive experience with high end painting and clears.  if you would like a paint pen that is 100% compatible with auto clears, you need to check out the Posca products.  Water based with good coverage.   Myself and others in the custom bicycle industry have used these for fine line work with excellent results for many years."

Paint Sheen

From less glossy, or flat, to more glossy: Flat -> Eggshell -> Satin -> Semi-Gloss -> Gloss.  Although eggshell and satin tend to be used interchangeably, satin is typically a bit shinier than eggshell. So which one is the correct choice for your pinball machine?

Unfortunately there is no set answer.  I will typically start with a semi-gloss and then go from there, although I'm restoring a Data East Hook and the cabinet paint is much closer to an eggshell.  It is also worth mentioning that just as paint will fade over time, it will also lose some of its gloss.

The type of paint will also affect the glossiness.  Oil based paint will have more sheen than the equivalent water based paint.  In other words, a semi-gloss oil based paint will be pretty close to a gloss water based paint.  You will also find variance in glossiness between different brands and types of paints. 

The method used to apply the paint will also affect the sheen.  Paint that is brushed or rolled on will have less gloss than the same paint sprayed on.  And of course the finish of the underlying wood will affect the glossiness.  If the surface is rough you will never get a glossy finish.

Here's a couple of tricks to modify the gloss of applied paint.  If you want a glossier look just apply a coat or two of gloss or semi-gloss clear over the area.  To reduce the sheen you can sand the area with 400-600 grit sandpaper.

Also with colors like cabinet black you can mix a couple of paints to achieve the correct sheen.  I'm doing a Bram Stokers Dracula right now and a 50/50 mix of Testors acrylic black gloss and semi-gloss gave me the perfect match.  You can also add acrylic gloss medium to latex paints to increase the gloss.

Application

Several choices are available when it comes to applying paint: brush, roller or air.  I'll tell you right up front I'm a believer in using an air gun or air brush whenever possible.  You will get better coverage and eliminate any possibility of brush marks.  Having said that, an air application is not always feasible.

When it comes to brushes, buy the best and spend the time to properly maintain it so it lasts a while.  Brush quality makes a huge difference when it comes to both coverage and brush marks.  In the case of paint brushes you will spend at least $10 for a good brush (I prefer Purdy).  For artist brushes most of the hobby or crafts stores now provide several grades of brushes ranging from basic to professional.  Again I buy the best brush I can.

Ninety percent of the time the above will meet your painting needs, but when painting a large area (like the back of the cabinet or backbox) there are a couple of other options.  Some people recommend a roller with very fine nap for these situations.  I haven't tried this since I use an air gun, but it would help eliminate brush marks and give good coverage.

Another trick in avoiding brush marks is to apply the paint with a high quality brush or roller and then smooth with a cheap foam brush.  Do a small area at a time if using this method.

One last note, multiple thin coats are always better than fewer thick coats.

Manufacturer's instructions

While in general it is very good advice to read and follow the manufacturer's instructions when painting, I have two issues with most of the labeling.  A lot of manufacturers will say you can apply additional coats within a set amount of time (2 hours, for example) or after a period of time (usually 24 hours).  While this is fine, going beyond two coats will typically cause problems.

If you apply more than two coats using the quick re-coat method the lower layers will take a few days to completely harden.  If you place the painted piece on anything hard during that period it will likely dimple or make an impression on the painted surface.

My next issue is with the hardening time, which is commonly listed as 2-3 days, and is not the same as the curing time.  While latex paint may feel hard to the touch in a couple of days, it takes at least two weeks to completely cure.  During that time you don't want to have anything touching the paint, use any cleaners or abuse the surface (think of a pinball beating on a playfield).

Also pay special attention to any recommendation for sanding between coats and the re-coat time, since it can vary greatly between types of paint.

Additives

Thanks to the clean air act and manufacturing cost constraints a lot of the solvents have been removed.  This leaves us with paint choices that just don't perform as required.  The solution is a paint conditioner (personally I like Floetrol and never paint without it).  The conditioner will help reduce brush marks and improve coverage.  It will also help the flow in an air application and unlike water it does not dilute the color of the paint.

Patience

The most common problem I see with beginner/intermediate painters is a lack of patience for the process.  This is not like painting a room where you start in the morning and are done by the end of the day.  Both water and oil based paints can take up to a month to fully cure.

Not including curing time, it takes at least a week to touch-up a playfield.  Latex, for example, will need to rest for 2 - 3 days before you can sand it prior to the next coat.  So if you do two quick-coats of paint, wait two days to sand, do two more quick-coats, wait two days to sand, do two clear quick-coats and wait two days for finishing sanding, you're at a week. 

And you still need to let the paint cure for a minimum of three weeks, and more is better.

Painter's Tip

A common phrase used by painters is "paint to the corners."  If you paint half of a wall, even with the same paint you used a few years ago to paint the wall, there will be a visible line between the two areas.  If you paint to an inside or outside corner, even if you're several shades off, no one will ever notice.

In the case pinball this approach will usually translate to "paint to the border."  Since black is often used as an outline, paint the entire colored area up to the black outline  If you need any touch-up on the black when you're done it's easy to match.  Of course you can get away doing a smaller area if you exactly match the paint color, but that's not always easy.

The other approach is to use an air brush to feather out the paint, but that takes a good bit of skill.

Primer

Bright colors like yellow and red are very difficult to get to cover well and match the original colors (which where likely ink rather than paint).  You can use a white primer to brighten up the color.

Ink

One last note worth mentioning is that many cabinets, playfields and plastics where silk-screened using ink rather than paint.  While it's hard to know exactly which brand might have been used, Pantone has been the largest producer of inks for many years.  So in many cases if you really want to stay original the proper selection would be ink rather than paint.