Ball Swirl Info

The purpose of this document is to help you better understand , prevent, and reduce ball swirl marks.

Ball Swirl Cracks, Ugh! Many pinball machines have them and they ruin playfields.

What is a Ball Swirl Crack, AKA ball swirl mark?

It is a scratch in the playfield surface usually caused by a ball that is worn... Worn meaning it has tiny scratches, pits, rust, or other imperfections. The scratch is usually not the problem. What causes the visible mark is dirt. When the ball is moving over a scratch on the playfield it is compacting any loose dirt, wax, or dust into the crevice. Over time, the crack may expand or contract depending on temperature or humidity conditions, thus making removal of the marks nearly impossible.

I have been experimenting on my old Silverball Mania playfield to see If I can somehow remove or reduce the appearance of ball swirl cracks. I have also scoured the web (probably just like you) to find any information or products to help me. I found some information, but most of it was inconsistent.

Prevention

The first and foremost thing to do is replace the pinballs on a regular basis before signs of wear appear.

Second, frequently clean and wax the playfield. Following these steps will prevent ball swirl cracks.

Explanation - Here is a cross-section view of a typical playfield surface including the ball swirl cracks. There are typically three to four layers. The black illustrations are the ball swirl cracks.

	Layer 1 - Plywood
	Layer 2 - Screened Artwork
	Layer 3 - Clear Coat (varnish. diamond plate, lacquer, etc)
	Layer 4 - Mylar (Optional)

	Crack A - The scratch is only in the fourth layer. Easiest to remove. Just remove the mylar using the Goo Gone method or freeze spray method. Please see my links page for mylar removal techniques.
	Crack B - The scratch is only in the third layer. Fairly easy to remove. Shouldn’t damage the artwork in layer 2.
	Crack C - The scratch is in the second layer. More difficult to remove than crack # 2. Extreme care must be used when sanding or cleaning this area because the paint is very thin.
	Crack D - The scratch is in the first layer. Impossible to remove since it is down to bare wood. The only thing you can do is re-paint the area to conceal the cracks.

Over time, those cracks become distorted and the dirt is much harder to remove. The playfield will expand and contract with temperature and humidity changes. This causes the paint and clear coat to warp making the crack smaller. This is one reason why it is so hard to remove the dirt since it is now compressed in the crack. See the image below.

Cleaning and Repair - By now you should have a better understanding of ball swirl cracks. I will explain some methods to reduce the appearance of them. Remember, you will probably not be able to remove all of the ball swirl marks.

Disclaimer: Pinball Magic will not be held liable for any damages to your pinball machine caused by performing any of the techniques in this document. I do not necessarily endorse or support any of these techniques. This document is for your reference only. Thank you.

Hi-Deal playfield using Magic Eraser technique

Before After

Lucky Ace playfield after using Methanol technique

As I explained earlier, if the scratches are only in the mylar layer you can use the Goo Gone or Freeze Spray methods to remove the mylar.

Crack is in the clear coat only (Layer 3)

Method 1: A product called "Magic Eraser" by Mr. Clean helps clean the cracks. It is available at many retailer stores like Wal-Mart, etc.

I ran three tests with it on three playfields and it worked very well. Wet the sponge with Isopropyl Alcohol until damp. Grab some paper toweling or a towel for excess alcohol cleanup. Apply medium pressure to the playfield with the sponge using a small, circular motion. Wipe up the excess alcohol immediately after cleaning a 2 inch square area. When finished, let the playfield air dry for 4 hours. This method will not remove all of the dirt from the cracks, but is very effective. You may want to consider trying method 1 or 2 after this. Follow up with some Novus 2 and wax or you can clearcoat the playfield.

I've also added instructions for the Magic Erasers in Adobe PDF format. Feel free to download it below!

Magic Eraser.pdf

Method 2: Try using pure, denatured alcohol or Methanol (available at home improvement store). Be sure to pour the solvent on a cotton rag and not directly on the playfield. Start with a small, inconspicuous area. Clean with mild to moderate pressure in a circular motion while frequently turning the rag to keep the dirt from going back into the crack. This method actually “melts” the clear coat and removes the cracks. When finished let it dry for an hour, then clean the area with Novus 2 and wax it. You may want to clearcoat it. Note: This may only work on pre 1990's era games.

Method 3: Lightly sand the area starting with 600, then 800, and 1000 grit sandpaper until the cracks disappear. Clean the area with Novus 2 and wax it. You may want to clearcoat it.

Crack is in the screened artwork (Layer 2)

Use the same methods as for the clear coat cracks above. Warning: Use extra caution when sanding the artwork area. It is very easy to “burn” through to the bare wood underneath.

Crack is in the plywood surface (Layer 1)

This type of scratch is not going to look better without repainting the area. Use water-based acrylics to touch up the area. Water based acrylics are available at most craft stores and major retailers like Wal-Mart. Click here for some more information about painting playfields.

If you have a playfield with many ball swirl cracks and have cleaned them with any of the methods described above, you might want to consider clear coating it to prevent the scratches from accumulating more dirt.

I hope this document was helpful as it was intended. Please email me if you have anything to add or revise to this page. Thanks :)

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