Playfield construction

 

What would be the best way to make a playfield? There are so many ways to do this.

Playfield constructions

In general there seems to be two approaches

1. Plywood with print on top and a thin protective coating op top. Inserts are glued in the playfield for lights
2. Plywood or mdf with thick plastic plastic sheet that is printed on the back.

Opt. 1) plywood with inserts and coating

Approach 1) plywood with inserts and coating is the most common way to make playfields.

The playfield is first drilled/milled. Then the inserts are all glued in and everything is sanded, sealed and printed. Finally it is covered with some car grade clear top coat. 

Topcoats

The biggest issues for a DIY using 2 component clearcoat are that this stuff is poisonous, so you need a spraying boot with good dust masks etc. Also you need a good sprayer and compressor. And there is lot of sanding involved between every clearcoat layer. But this can be outsourced to a car painter.

An alternative clearcoat approach for DIY is using self leveling compound. This is normally used by artist to make there artworks shiny. This can applied in a single thick coat. Because it is self leveling property it creates a very smooth surface. For this you don’t seed sprayboots or sprayers so it done with less investments. I know one diy that has used this on his playfield successfully, but have not seen reports how good this holds up.

A other diy only way is to cover the whole playfield with mylar or thin polyester sheet.

Prints

The prints can be done in various ways:

- Silkscreen printing. This is the main way playfield where made in the past. You need to make a lot of silkscreens: one for every color printed.

- Direct print on wood/plastic with dye’s. This seems to be the common way most playfield are produced nowadays. For DIY is this also nowadays a usable approach, because the dye printers are quite common now. If the dye printer can not print white, the playfield first has to be sprayed white. Any insert need to be masked to prevent it being painted.

- Vinyl overlay glued on wood/plastic substrate. Typical only used for the outside of a pinball cabinet. Some people have used this approach also for there one diy playfields.

- Paper poster glued down: have not see anyone using this way.

- Decals: Typical only used for small area’s like inserts or small repairs. Possible worth a try if you can cover larger area’s without distorting the very thin decal

 

Opt. 2) Playfield with thick plastic sheet

The playfield with thick plastic is only used in a couple of pinball machines For example it is used in Elektra, Bushido, Canasta.

The playfield looks like this:

(picture from pinside user Star_Grazer)

The wood is either plywood or MDF.  MDF is more difficult to screw in, but it surfaces are normally very smooth. The wood has only holes, and maybe a sealer, but not other paints.

The plastic sheet has the graphics on the bottom/reverse side, so the graphics are fully protect against damage. The surface of the plastic is fully smooth, so no sanding or coating is needed. Likey a wax coat can be used to protect  the plastic better against scratches.

No inserts need to be glued. The shape the hole in the wood defines the insert outline. So this gies a huge flexibility and allows to choose any ‘insert’ shape and size as you like. There will likely be light bleed from the hole to the surrounding playfield. The bleeding can be reduced by making wide black area’s around the “inserts”.

Because you need to have access to a cnc to mill the wood, the plastic sheets can also be milled on the same machine . Instead a cnc a laser cutter can also be used. A laser cutter has the advantage that it create much nicer edges  in the plastic then what a mill can make, but cannot cut all types of plastic. If you have a powerfull enough lasercutter, you could even cut the wooden playfield with it. Any charring on the wood in fine and not visible. Because the holes are black, it is possible that that even helps reducing light bleed.

I looked around , but I could not find information on the web what the actual thicknesses used for the wood and plastics. If standard pinball mechs are used, then the total thickness of both wood and plastic need to be 1/2 inch or about 12mm.  Thus you could use 9mm wood and 3mm plastic.  If the thickness is less critical, then use of 12mm ply or mdf with 3mm plastic to make a stiffer playfield.

The type of plastic. This is also unclear what the excising machines are using for this. The most likely options are:

-  Plexiglass (PMMA, acrylic glass). This is very transparent and reasonable stiff material.

- PETG is a more flexible material. Lot of times used for transparent playfield parts and ramps.

- Polycarbonate. This is the strongest material (and the most expensive). Can not be lasercut due to poisonous vapours escaping. It scratches easy. 

print

The print can use the same approaches as for the plywood print. If the decal or vinyl approach is used, then these need to have holes cut in the same places as the plastic sheet to pass though any pinball mechs.

After the colors & black are added to the plastic, it has to be coated with white to create better colors. Possible the wood can also be painted white to help reflacting the light.

The places where the ‘insert’ are present can either be coated white too, or covered with a diffusor layer. This will help spreading the light from LED , so the insert is lighted evenly.  The diffusor layer could be a layer of thin sime (transparent) white plastic. Not to thick, otherwise it creates more light bleed.

 

The firepower playfield

After looking though all the options I think I go for the wood/plastic sheet sandwich approach. No messing with paints and sanding. No cupping of inserts. Always a very smooth playfield. Drawback is that it needs 2 milling sessions.

I will do some test to see if the 9mm wood and 3mm plastic sandwich is this is stiff enough for a playfield. Otherwise I will use 12mm wood and 2 or 3mm plastic. Because I print my own playfield mechs, the thicker playfield is no issue. I just have to correct my drawings.

For the first test will use plexiglass with wax.

For printing: I will get some quotes for dye printing on plexiglass and vinyl prints and view some examples how the colors will look. I will also try how decals work on plexiglass. Further some testing what type of diffusor layer is the nicest for the ‘inserts’

So plenty of things that need experimenting. I will keep you posted.