Restoring Playfields with Magic Erasers - The Tests

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Using Mr. Clean's Magic Erasers for cleaning pinball machine playfields was first mentioned on the rec.games.pinball newsgroup in March of 2004.  The early reports were mixed - some people were impressed with their performance, others said they did little or nothing.  So I was determined to try them out for myself, and this page describes the results of my tests.
     

Mr. Clean's Magic Erasers are available at grocery stores, large retailers like Wal-Mart, and home improvement chains like Home Depot.  I've seen them in packages of two and four, priced about a dollar per pad.

During my initial experiment, I used almost all of just one pad to completely rub down a standard size pinball machine playfield. 

The manufacturer recommends wetting the Magic Erasers with water, but water and playfields should never mix.  So for these tests, I used isopropyl alcohol.

I did two separate tests.  First I used a Magic Eraser to clean a Close Encounters pinball machine playfield to see how well it would do removing dirt and swirl marks.  This got me curious as to how abrasive the Magic Eraser pads really are, and if they work differently than wet/dry sandpaper.  So I took a very worn, scrap playfield (a Bally Playboy that will be getting an overlay), marked off four separate areas and compared the Magic Eraser to three different grits of wet/dry sandpaper (400, 800 and 1500).

Executive Summary

For those of you not reading the entire page, here are my conclusions.

The Magic Eraser removed at least 90% of the swirl marks.  The cracks were still visible in many cases, but for the most part, the dirt was removed.
 
Compared to sandpaper, the Magic Eraser is roughly equivalent to 1500 grit wet/dry sandpaper in abrasiveness, but it is more effective at removing embedded dirt than sandpaper.
 
I highly recommend Magic Erasers for cleaning any lacquered playfield as long as the existing finish can handle the abrasive action of the wetted pad.  I did not perform any tests on modern clearcoated playfields.

Details of these tests are below.

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Cleaning a Close Encounters

I used my first Magic Eraser to clean a Gottlieb Close Encounters that was very dirty and had moderate ball swirling. I first cleaned off the major crud with Novus 2 and then got to work with the Magic Eraser, wetted with 92% isopropyl alcohol.

Easily 90% of the swirl marks were removed or cleaned out, and I probably could have done better if I kept going. But I didn't want to wear through the topcoat and although I used up an entire eraser on the playfield, I had no wear-through spots. Here are some thoughts:

The pads look to be simple abrasives - there is no chemical component to the cleaning action. However, the liquid (water or alcohol) plays an important part.
 
As the pad wears down, the fine particles get dissolved in the alcohol, so I'd say that's the magic juice that helps pull the dirt out of the swirlies.
 
Aside from the effect of the dissolved particles, the pad itself sands off the topcoat fairly aggressively.
 
I was keeping the pad fairly wet, and I periodically mopped off the playfield with a paper towel. What came up on the paper towel was a nice tan color, which told me that lots of dirt and yellowed topcoat was being removed. The lacquer topcoat is many times thicker than the layer of ink underneath, and at the rate that the topcoat was being removed, the ink wouldn't stand a chance if all of the topcoat gets taken off. So if you ever see color on the pad, STOP.
 
After cleaning up with some plain alcohol, it's clear that the Magic Erasers work by not only removing the topcoat but by cleaning dirt out of the remaining cracks in the topcoat. You can still see many of the cracks, but most of them are now dirt-free.
 
The playfield finish is dulled to a uniform sheen that I'd estimate is that of 800 or 1000 grit wet/dry sandpaper. If I were to just polish this out (which I'm not), I would start with 1000, then 1500 sandpaper and then go to Novus 2. This applies to an old lacquer finish, which is thicker and softer than Diamondplate style clear (which may need a different approach).
 
So what you're left with is a playfield with a good percentage of the existing clearcoat removed, and with hollow cracks that will eventually fill with dirt, dried wax or other kinds of crud. So I think that any time an old lacquered playfield gets a major Magic Eraser treatment, it should also get re-cleared. The Magic Eraser also did a great job cleaning all the crud out of the shooter lane, except near the bottom where the finish had already been worn down to bare wood (that small spot will get sanded out with 220 grit).
 
I'll be re-lacquering this Close Encounters after doing some minor paint touch-ups around the pop bumpers and inserts with water-based acrylics. The new clearcoat will restore the protective layer over the artwork, protect the touch-ups from wear or chipping, and give a nice thick surface to polish out.

Magic Erasers are simply great for restoring old playfields. Just keep in mind that unlike Novus 2, you can  remove significant amounts of material with these things. This serious abrasion will also lift any hanging pieces, and after the crud has been cleaned out of the chips and cracks, it would be wise to do something to keep the dirt out. I don't think polishing with Novus 2 and/or any kind of wax would be sufficient, although it may look great over the shot term.

And now for the pictures.  You can see from the close-ups how well the Magic Eraser does cleaning a fairly dirty playfield.  It also took off enough of the oxidized lacquer topcoat to make the playfield noticeably brighter.  The before and after photographs were taken under similar lighting conditions and with the same camera (a 5 megapixel Nikon Coolpix 5000).  Some of the close-ups show that the cracks in the playfield topcoat are still substantially there, but much of the dirt in the cracks has been removed by the Magic Eraser.

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Before

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After

Before

After

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Click on any of the pictures above to open a larger view in a new window.

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How Abrasive are Magic Erasers?

After that first successful experiment, I was curious just how abrasive these cleaning pads really are.  Some other users had worn through to the artwork while trying them out, and others said that they had no effect at all.  So far, they were "just right" since they had removed most of the dirt and dreaded swirl marks, without any collateral damage at all.

It was clear that the Magic Erasers were removing something, since the liquid residue was a different color than the pad (white) or the alcohol (clear).  Lacquered playfields have a fairly thick layer of lacquer over the artwork layer, which is a very thin layer of silk screened inks.  When you sand or polish a playfield, you are usually just affecting the top layer of clear.  In fact, the layer of artwork is so thin, that if it is ever exposed, it is extremely easy to damage.  There is usually a base layer of white ink, so the first sign of wear-through of the ink layer is a lightening of the color to white.  Beyond that, bare wood will be exposed.

Swirl marks are a very common flaw in older playfields.  They are caused by microscopic cracks in the top coat that then become filled with black dirt.  These cracks are usually circular arcs or they run along the grain of the wood.  Or both.  Swirl marks have defaced many a playfield, so anything that helps reduce their deleterious effects would be quite welcomed.  The problem with most swirl marks is that the cracks usually run all the way down through the top clear layer down to the ink.  So if a simple abrasive is used to sand off the clear, the swirl marks will disappear only when the entire top coat has been sanded off.  And since this is a practical impossibility, you're left with some combination of swirl marks left behind and artwork damage.

So the purpose of this test was twofold.  First, to get an idea of how quickly a Magic Eraser removed a lacquer topcoat compared to regular wet/dry sandpaper.  Second, to verify what I noticed when cleaning the Close Encounters playfield: that they remove dirt from swirl mark cracks, without necessarily removing the cracks themselves.  I also wanted an idea of what happens if you just go too far with a Magic Eraser, so that I could avoid doing that in the future.

The playfield that I chose for this experiment was a pretty wasted Bally Playboy.  There were multiple spots worn through to the wood, plenty of dirt and it was covered with swirl marks.  I plan on installing an overlay on this playfield, so a little more damage wouldn't matter at all.

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4-Pack of Magic Erasers and 92% Isopropyl Alcohol

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The starting point

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Playfield after quick clean-up with Novus 2 - Didn't do much, did it?

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Close-ups of the areas to be cleaned

Now I split the center of the playfield into four areas.  The bottom right section would get the Magic Eraser,  The other three areas got different grits of wet/dry sandpaper: 400 grit for the top right, 800 grit for the bottom left, and 1500 grit for the top left.  Each area was rubbed wet with isopropyl alcohol for approximately 90 seconds and the results were evaluated.  No further sanding was done after an area started to wear through.  The pictures below were taken without a flash, so the white spots in the artwork are wear-through, not glare from a flash.

Initial Condition

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 1500 Grit

400 Grit

800 Grit

Magic Eraser

 

First Pass - 90 seconds

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1500 Grit
Some reduction of swirl marks
400 Grit
Worn through after 60 seconds
800 Grit
Worn through after 90 seconds
Magic Eraser
Swirl marks greatly reduced

 

Second Pass - 3 Minutes

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1500 Grit
Minor improvement
 
  Magic Eraser
Even more swirlies removed

 

Third Pass - 4.5 Minutes

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1500 Grit
Worn through - some swirlies remain
 
  Magic Eraser
Starting to crack along woodgrain

 

Final Pass - 6 Minutes

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Magic Eraser
Finally worn through

 

The pictures below show the effectiveness of swirl mark removal up to the point of total topcoat removal.  

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Magic Eraser close-up

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400 grit close-up

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800 grit close-up

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1500 grit close up

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Conclusions

It's clear that the Magic Eraser removes swirl marks much more effectively than wet/dry sandpaper, and its abrasiveness is similar to 1500 grit wet/dry sandpaper.  This test playfield was heavily worn to begin with, so there wasn't much of the topcoat there from the outset.  Even with the worn topcoat on this playfield, it took over five minutes of rubbing the same spot to get down to the artwork, and the majority of the swirl marks were removed long before then.  With all of the sandpapered areas, the swirl marks were still there until the topcoat was almost completely removed.

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Before

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After

If that's not magic, it's damn close to it.  For all the time that I've been in this hobby, one question that has come up repeatedly is "how do I deal with swirl marks on my playfield".  And the answer had always been "clean it as best you can and learn to live with them".  Now there is finally a better answer to offer.

Each pinball machine manufacturer used their own topcoat formulation, so these results may vary based on the brand and age of the game.  Up until approximately 1990, all playfields had a lacquer-based topcoat, so these should all react similarly.  1990 saw the introduction of automotive-style clearcoats, which are both thinner and tougher than lacquer.  The tests that I performed here don't apply to these playfields, so in those cases, "your mileage may vary".

The Magic Erasers work in two different ways.  The main part of the pad works like very fine sandpaper to uniformly remove the topcoat, and the dissolved grains of the pad (in combination with a liquid like alcohol) help to clean the dirt out of the fine cracks of the top coat.  

One potential problem that I foresee is a recurrence of visible swirl marks if nothing is done to seal the now-empty cracks in the topcoat.  Perhaps a good coat of wax would be sufficient, but in my opinion it would be better to apply additional layers of topcoat, if at all practical.  I prefer using acrylic lacquer, but a waterborne urethane or automotive clear would work as well, if not better.  Lacquer is my  preference because it is the original finish.  Lacquer goes on "hot", which means that the new lacquer bonds to the old lacquer as one layer.  Urethanes and auto clears seem to be more popular, and that is fine - this is a matter of religious importance to some.  Regardless of the type of clear, Magic Erasers do a great job of preparing a playfield for its new finish.  Along with the swirl marks and dirt, any traces of old wax and other cleaners are removed, and the surface is roughed up just enough to accept the new finish.

Hopefully, this page will expand with new uses and techniques for these Magic Erasers.  If you have any additional information, links to useful information or just comments that you'd like to share, you can get in touch with me here.

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Picture Gallery & Links

Here are links to other sites that have pictures and information pertaining to Magic Erasers

Mr. Clean's Magic Eraser home site - from the manufacturer
pdx_pinball's Cyclone - before and after
Pinball Magic's ball swirl info page

Here are before and after pictures of a Stern Seawitch sent to me from Q Frost, showing how effectively a Magic Eraser removed heavy swirl marks from the playfield.


Before


After

Here's a before and after comparison of a Big Indian playfield (1974 EM).


Before


After

Above, it's clear that virtually all of the dirt was removed from the swirl marks, and that the cracks
are still present but devoid of black crud.  This photo should also demonstrate that after
cleaning, the cracks are still there and will probably re-appear as black swirl marks
unless the cracks are filled, either with wax or by re-clearing the playfield.

Below are before and after pictures from a Williams EM playfield, courtesy of Chris (greenacarina).
Note that the dirt is almost completely removed from the divots in the playfield that had chipped the playfield ink, and that the Magic Eraser treatment did not enlarge the size of the area of missing ink.  Note also that where the ink had already been worn down to the white undercoat, that the Magic Eraser was abrasive enough to remove the ink that was unprotected by the lacquer clear coat.


Before


After

 

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Original material Copyright 2004 - Mark Clayton
All rights reserved

 

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