How To Make Your Pinball Machine Cabinet Look Like New
This discussion assumes some modest wood working and painting ability. A lot can be done by the hobbyist without a great deal of experience.
First Step: Identify the Damage
Surface damage such as shown on the two photos that follow are easily repaired with fillers. And the corner damage is no problem either.
This type of wood damage on the head / backbox is easy to fill and sand smooth.
If the wood is irreparably damaged (water or physical), it maybe best to get a new blank cabinet and start over, unless you have a lot of wood working experience. But minor damage can be repaired through different types of wood fillers.
The plywood used on cabinets are different thin layers glued together. Once it gets wet enough to separate, it is difficult if not impossible to repair with fillers, no matter how strong. And the damage is usually deeper than it looks.
The bottom board in the cabinet is usually a type of particle board. It takes only a little bit of water for it to foam up and weaken. It cannot be repaired. A good cabinet maker can cut a new piece and replace it.
Types of Wood Fillers
1) For edge damage repair, you will need a very hard filler, otherwise it will be damaged again through everyday use. Typical wood fillers will not last. The only type of filler that we have found that is hard enough and sands well is Bondo Fiberglass Resin.
Other manufacturers may make equivalent products but we have not tried them. It is available at many hardware stores, auto supply shops and Amazon.
2) There are many different wood fillers that can be used to repair areas that are not corners.
For spot damage, we used Bondo All Purpose Putty. If an area requires more support, we have used epoxy wood fillers. But these putty products should not be used in corners or any area that are under stress. They are not hard products.
Prepping the Wood
Lead vs. Not Lead Paint
Lead was used in paints but was banned in the USA starting in 1978. However, in commercial applications, it was used after that period.
Do Pinball Cabinets Have Lead Paint?
We cannot get a straight answer on this. We know people who have done tons of cabinets and tested and never found lead. And others that say always assume lead. If you want to be safe, assume lead. That means doing any sanding in a paint booth or outside (be aware of wind and your neighbors). Or don’t sand (nearly impossible).
If you plan to sand, either get a lead paint test kit or just assume the worst and get a high quality mask that pulls and seals tight and is rated for lead paint work.
Removing the (Paint or Decal?)
Decal Cabinets
If your cabinet has decals / artwork, it is usually better to remove it with a scraper first. We find that Citrus Strip does a great job of softening the artwork up.
We then remove it with plastic scrapers so as not to damage the wood.
At this point, skip down to Repair the Wood.
Painted Cabinets
If your cabinet is painted, you have to sand. See note above about a warning for potential lead paint.
Do not use a belt sander! Belt sanders are great and can remove a lot of paint quickly. But they are difficult to control and keep flat. Any tilt and you have gouged the wood and now have to do wood repair. Just don’t use one.
Use an Orbital Sander
We like using 1/4 sheet sanders. It is easy and cheaper to buy sheets of sandpaper, then split them to fit this sander. Make certain to select one that has an ‘orbital’ or ‘random’ setting (most do). Done properly, this will result in a finished surface ready to work on.
Another type of orbital sander is random orbital sander that uses 5″ sheets. These are more expensive to purchase and operate – the sanding sheets are more expensive. They also cannot get into corners as well. But they are extremely popular and work well.
Sandpaper Grit
We start out with 180 grit sandpaper to see how it goes. Sometimes, we find that we have to go down to 120 grit sandpaper. But be careful about going down to too low of a number.
The lower the number, the coarser the grit and the faster the work will go. But the wood will also be damaged more. So it will take more sanding with finer and finer sandpaper to get the wood nice and smooth.
After removing most of the paint, stop sanding and move onto Repair the Wood.
Repair the Wood
Sometimes the wood just has to be replaced. Other times, large pieces can be cut out and inserted into the side. Usually, the fiberglass resin and wood putty can do the job.
Severe Damage
We have a few examples of complete wood replacement. In one case, the side of the cabinet got wet and the plywood came unglued and separated. We got our cabinet expert to remove the one side of this Data East cabinet and make a replacement piece.
We also have a bottom piece that got damaged. This wood is especially vulnerable to water damage. Once wet, it cannot be repaired. Cheaper pressboard can be used, but it is better to use plywood.
All of these pieces were built with finished birch plywood. If you are lucky, the bottom can be removed and used as a template. In this, the bottom was so weak that it could not be easily removed in one piece.
Using Bondo Fiberglass Resin, a lot of the wood can be repaired. Anything that is plywood can be worked on – but not that particle board bottom.
If there is a deep hole, clean it out and then insert a wood dowel with wood glue down below the surface by ~1/4 inch or so. This will then get filled with resin later.
Using Fiberglass Resin
This stuff is great for repairing cracks or damaged edges. Be sure to follow the instructions on the container. Wear disposable gloves.
Note that some kinds of gloves can be dissolved by the resin.
This is a two-part (like epoxy, but it is apparently not epoxy) resin. When it is mixed together, it generates heat. We have used drink plastic cups to mix it in, but it has to be applied quickly. The heat generated will be so much that the plastic will melt dumping the goop on the floor and your shoes (don’t ask). Never use foam cups.
Prep the area by cleaning it of any loose material, sawdust, dirt and oils. If repairing a long crack, you should clamp it after application. Wipe down with Naphtha or isopropyl alcohol.
Taping Off / Repairing Edges
If repairing any areas with holes which could cause the liquid to drain, it must be taped off. This includes the edges. We use blue painters tape. Occasionally, we find a hole in the edge of plywood that seems to drain forever. We push wood filler down into those holes.
The edges / corners of cabinets take on a beating. This is your chance to fix those up. Bondo is strong and will not easily chip.
But it must adhere to the wood. To make sure this is possible, the repair area must be clean and free of lose materials. The Bondo must also be able to ‘grip’ onto something. A jagged edge is best. If the edge is slight, it maybe advantageous to make it worse!
Mix the resin and apply it quickly. It hardens fast. If applying to a hole, add more than needed as it can sink with time (see use of dowel above). Always apply a little too much and sand it off later.
If repairing a long crack, be sure to clamp it before the resin hardens. This will insure that the crack is properly repaired like it was before the crack appeared.
Use a spare piece of wood between the clamp and the cabinet to prevent damage to the cabinet.
Removing the Tape and Sanding
Using the painter’s tape is quick and easy. After the resin hardens, carefully remove the tape. Let the resin fix following the instructions.
Inspect the resin and look for any areas that are not filled enough. We frequently find that we have to do a second application of resin to fill areas where the resin drained unexpectedly.
If repairing long cracks in the plywood, wait extra time for the resin to harden. The deeper the fill, the longer it seems for the resin to harden. Waiting overnight is advisable.
The resin will never be flat. Plus, you might have drips that need to be sanded.
We like the flat sheet sander for edges. It just seems to be easier to get an edge.
Note, do not leave a sharp edge after sanding. Create a rounded corner. After getting the two sides flat, briefly go over the edge at 45 degrees. Start small until you get a ‘natural feeling round.
When sanding the flat surfaces, sand to the point where you are removing the hardened resin AND the wood next to it. If your sander is not touching the wood, then it is not flat and will look terrible later.
Final Sanding
Once any repair (resin or wood filler) is sanded to the point where it is also sanding the wood right next to it, slowly move up to a finer grit. We know people that stop at 220 grit. But we go to 400 (because we can).
Be sure to clean between sanding. Use a vacuum and follow with a brush. We sometimes use tack paper between sanding, especially towards the higher finishing grits.
Obsess over the finish. Minor imperfections will show through paint or side art.
Possible Additional Step
We had a pinball cabinet expert recommend that, after sanding is completed, we should paint the cabinet with shellac to make it even smoother.
We tried it. It was difficult to tell if it helped, but it was easy to do.
External Links
Epoxy vs. Bondo Resin – Which is better?
What Sandpaper Grits to Use – A beginner’s guide to picking sandpaper.
Sandpaper Grit Chart – How to choose sandpaper.
How to get the Perfect Wood Finish – What mistakes to avoid.
Cleaning the Wood Between Sanding – What to use.