CAN'T YOU JUST COAT A PLAYFIELD WITH EPOXY? (p1)

CAN YOU TEST WOOD FOR HARDNESS? (p1)

OLD WILLIAMS PLAYFIELDS DIMPLE THE SAME (p2)

HOW COME MY PLAYFIELD IS DEAD FLAT, BUT MY OUTLANES ARE DIMPLED LIKE THE MOON? (p2)

DOES HUMIDITY CAUSE GRAINING OR RIBBING? (p1)

HOW DO I KNOW IF A PLAYFIELD IS BIRCH OR MAPLE? (p1)

WOOD HARDER THAN STEEL? (p1)

THERE IS NO SUCH THING AS 'OLD GROWTH MAPLE' PLYWOOD (p5)

CAN WE ACTUALLY MEASURE HOW MUCH DIMPLES COMPRESS THE WOOD? (p6)

WOULD A THICKER CLEARCOAT PREVENT DIMPLES? (p4)

It seems like 3 times a week some newbie is saying that new pinball playfields are junk wood and dimple like crazy.

My buddy had a Medieval Madness that has sat folded up for 12 years in his basement. Never restored, not played since he joined the army.

Take a look at the protected area (under a ramp) here:

under.jpg

And a normal, unprotected area of the playfield here:

dimples.jpg

So this should show you guys that even a lightly played Williams 90s game has millions of dimples.

After a while, you get so many dimples that all the wood fibers are as compressed as they are going to get and it "seems" smooth, but really isn't.

In the next few months, I'm going to put a good clear coat over this playfield to protect it, but that will not stop the dimpling.

The Stern playfields are still made by CCC, the same company that made most of the Williams playfields.

Once and for all: it's not new cheap wood, it's not Stern sucks, it's not crappy clear coat - it's just pinball.

My Orbitor 1 does not have any.

^ another great example.

Not just air balls, but balls that bounce off of posts and targets.

Of course balls that drop from ramps make many dimples too.

Yes, no doubt.

But the best part is; the more dimples you get, the flatter the playfield becomes.

So play the crap out of your games to compress all the wood fibers you can.

Nope.

Steel ball = harder than clear coat.

Epoxy usually yellows over the years. Too hard and the coating might crack.

And, the epoxy clear for bartops says to sand the wood with 80 grit so the epoxy has some tooth.

Stick with auto clear.

Yep, lots of NOS playfields with cupped inserts, especially if they don't have the jeweling on the backside.

They were only made to last 3 years, not 30...

The Janka test (the way we determine the hardness of wood) is measured by the force required to drive a 1/2" steel ball 1/2 way into a piece of wood.

There is no wood harder than steel, so that is why they use a steel ball as a measuring device.

Maple (the wood use to make playfields) requires 1400 lbs of force to bury the ball 1/2 way.

Australian Buloke wood requires 5000 lbs of force; so in the larger scheme of things, Maple is not that hard of a wood.

Jhardnesstest.jpg

Here's a BSD with thousands of plays, dirty as hell, wear around kickout, etc. The playfield is nearly flawless in front of the standup targets.

A quick photoshop autocontrast shows that your playfield looks to have millions of dimples.

If your playfield had a gloss finish, they would even be more evident.

dimple.jpg

That's what were all talking about, the more dimples you get, the more invisible they become.

That MM has had very little play and has been in storage for most of its life.

Because it still has good gloss, and little play, you can see thousands of dimples.

If your BSD still had it's factory gloss, it would be much easier to see.

I just repaired an all original AFM last night for a guy that is having a pinparty this weekend, and it had a very shiny playfield.

Of course, all that shine really brought out a sea of 1000000 dimples.

afm-dimple.jpg

Because someone keeps posting that WOZ playfields don't dimple; here is a pic of when the playfield is new, and then when it gets it's cherry broken.

Woz playfields dimple - just like any other manufacturer (they are made by Mirco).

graining.jpg
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Here we have a Theater of Magic, a Williams game from what many feel was the peak period of pinball craft.

Note that the dimples are behind the flipper and are actually in the outlane (click the image and really take it all in).

So all of these dimples are from balls that hopped OVER the lane guide or flipper.

The rest of the playfield looked great, because it had so many dimples it looked completely smooth.

Theater-of-Dimples.jpg

Yes, I level out all the dimples.

But, it will dimple again.

Once you get about 10000000 dimples, it will appear to be completely flat again.

1700

It only seems that way because:

1. The games are brand new, so every dimple stands out like a sore thumb. A few thousand more dimples and you will never notice them.

2. They are among the first pins to have a completely lit up playfield. They make TOM or WOZ look like most the lights are burned out.

You are kind of missing the point of this entire thread.

No matter how hard a clear coat is applied to a wooden substrate, the wood below will dimple because steel is harder than wood.

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Or if that does not make sense to you, think of it this way:

A clearcoat is 4 mils thick (.004").

If you took a piece of .004" thick steel foil, bonded it to the playfield and played a game of pinball, you would get a ton of dimples instantly. Thin steel is no match for a 1.06" diameter pinball.

Even your car hood, made of .06" thick steel (that's 15X thicker than a clearcoat), can not survive a pinball being dropped on it without denting.

Of course they dimple, all games do.

You only see the dimples better on those 2 games because they are the first fully lit pinball playfields ever made.

shrinkage.jpg

Here we have a CPR Space Shuttle playfield.

About 3 years ago I restored a dozen of these machines when reproduction playfields became available.

This game is owned by the father of an actual NASA Shuttle astronaut.

The playfield had CPR's normal 2 coats of clear, plus it got 2 coats of clear from my shop (This one got actual DiamondPlate clearcoating, you can tell by the slightly cloudy inserts).

The playfields were sanded dead flat, and then were brought up to a mirror finish.

3 years latter, this game has only 52 plays in the audits. It sits in the client's basement and seldom gets used.

If you look closely, you can see that the wavy grain of the underlying wood has become visible in the high polish of the playfield.

Why?

1. The wood has taken up additional moisture while being stored in the client's basement.

2. No one ever plays the game, so the wood fibers have never been compressed flat.

shrinkage-no.jpg

Here, on the same playfield, you can see that over the plastic inserts, there is no shrinkage, so the clearcoat maintains it's flatness.

Right.

The more layers, the better the plywood (although it makes for a crappy looking shooter lane...).

I use Baltic Birch all the time; great wood, no voids in between the plys and waterproof glue throughout.

They have tried in the past.

Unfortunately, the face ply of BB is too thin, so trying to run the board through the sander to get all the inserts flush becomes a nightmare.

In addition, the Maple of a regular playfield is harder than Birch.

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There were a few Mirco playfields floating around a few years ago that were cut from BB - you can tell by the funky shooterlane.

Baltic_Birch_shooterlane.jpg

Here is a great shot of a Shadow playfield.

Note that all these dents are in the outlanes.

Because the outlanes get very little ball bounce action, the wood fibers are never fully compressed - so every dimple stands out like a sore thumb.

Shadow-dents.jpg

No, not at all.

All games dimple the same.

They still dimple.

Whenever someone finds a NOS playfield for an EM and gets it cleared, it shows tons of dimples instantly.

I did a Fireball EM playfield for a guy over a year ago, it's dimple city now.

Here is an example of a Bally from the 1970s.

No ramps, no multiball, yet thousands of dimples evident on this lightly played specimen.

70s-dimples_(resized).jpg

Got a better picture? That one is too close up.

Looks like normal graining from those pics.

Even brand new games can exhibit this, so it's probably nothing to worry about.

1fb5387c61af6b55f44e1400b04aa5eedad5c4da_(resized).jpg

Here is another great example.

A Steel magnet core (you know, made of solid steel) is covered in dimples from the hardened steel ball.

Now tell me of ANY wood that is harder than solid steel?

Got any clearcoats that are harder than solid steel?

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look-sir-ian-mckellens-sign-at-womens-march-sums-up-message-of-protest-in-trump-era (resized).jpg

That's because it was operated for a very long time.

The billions of dimples have mashed the playfield down into a homogeneous surface.

BUT, don't take my word for it, there is a NOS MB playfield on Ebay right now. Buy it, do a playfield swap, and play it for a month.

Then we will have something to talk about, lol.

The ones with the normal shooter lanes have wood from Canada.

The ones with the many layered shooter lanes have wood from the the Baltic region of Europe, and look like this:

1caec34e529cbc45597ec7106de45eb21595197e.jpeg (resized).jpg

Every playfield (except maybe Elektra and Orbitor1) gets dimples, deep and shallow. No way around it, because a steel ball is harder than any wood known to man.

Here is a SOLID STEEL magnet core.

It already has tons of dimples on it, in just a few weeks of play.

If a piece of solid steel is getting dimpled from the hardened pinballs, what chance does a piece of wood have against dimpling????

75e22f517a4787783461d062c579859e91c2cf8f (resized).jpg

Nope.

Your car has a Clearcoat.

If I drop a pinball on it, it's going to dimple. The clearcoat cannot save it.

Clearcoat is flexible because we don't want the paint chipping off your car every time there is hail.

Pinball **restorers** who have mixed up clears with extra hardener have found out later that the clear cracks. Any auto guy could have warned them....

==========

So wise up guys, it does not take 10 pages of discussion to see that STEEL IS HARDER THAN ANY WOOD.

If you guys find some wood that is harder than steel, let me know, and I'll make a guitar out of it.....

^ You are joking right? ^

Look at the SOLID STEEL magnet core.

See how it's starting to become dimpled?

If solid steel is dimpling under those hardened steel balls, how could the maple wood fare any better ?????

What wood is harder than solid steel?

LOL

Of course the answer is that the flap is tempered spring steel.

That is the reason that when you compress a spring, it returns to it's original shape without deformation.

Let's bring some unrestored playfields to Expo, lets bring a Janka Test rig, and lets do a simple demonstration.

I have a wood moisture meter (so we can compensate for older dryer Maple) and a digital depth scale.

Then we can silence the science deniers once and for all.

Digital-Depth-Gauge-80mm-With-Magnetic-Feet-LCD-Height-Gauges-Calipers-For-Router-Tables-Woodworking-Measuring (resized).jpg

BD-2100-26-PKG-2 (resized).jpg

Bring it for science!

Exactly.

Anyone that has a playfield that does not have any dimples in it, let's actually test it.

The testing will be done under the apron, so no damage will be visible if you ever sell the game.

If we pay for his trip and his hotel room, I'm pretty sure I can get a German violin maker to come and do the unbiased testing. He uses Maple every day, so he really knows his stuff.

We will test exactly that.

It takes 1450 lbs of pressure to press a .44" steel ball, .22" deep into a piece of of Sugar Maple.

If new playfields require that same amount of pressure, then we know that it's just somebody's imagination.

If new playfields only require 60 pounds of pressure, then we will know that they are made of Balsa wood.

We have to measure our dimples using the JANKA Test.

That's how the hardness of wood is tested.

Bouncing balls is interesting, but that won't let us test these playfields that people say don't dimple.

The Janka test is used through out the entire world - we need to keep with the standard for wood testing.

That has been my experience......

Can you prove this scientifically?

You have to put profit first in a business, or like over 600 pinball companies in the last century, you go under.

It's all we got.

Stern does not make playfields.

They use outside contractors.

Same as Bally, Gottlieb & Williams used to when they were still in biz.

I use an OSHA inspected downdraft spray booth for 2PAC and they added a UV line earlier this year.

I've only ran 2 playfields with the UV cure so far, but I can foresee a point in the near future where that might be all I use.

???????????

UV lamps cure the clear instantly.

100% solids, baby!

I have a Stern Orbitor1, and not a single dimple.

They just don't make 'em like that anymore.

Still solvent based, you can smell it when you first slide the glass off in a new game.

When I sand a new game playfield to prep for clearcoating you can't miss it.

I don't know why, but my Orbitor1 and Electra have never dimpled.

There is NOTHING to debate.

Hard Maple comes from the same trees it always has. There is no sacred 'old growth Maple' because Maple dies young.

Hard Maple is a crop that is grown for 80-100 years then cut down and replaced by younger trees that produce more sap for the Maple Syrup industry.

That's why Maple is not grown in Europe, they have the wrong climate to mass produce Maple Syrup

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There is no wood harder than steel, thus ALL playfields made of wood dimple if you use steel balls.

There is no clearcoat that can prevent dimples, your car caught in a hailstorm is obvious proof.

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If you can't handle the truth, stop buying new games.

Stick to the 30 year old games that have had hundreds of millions of plays.

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There is no Old Growth Maple. Hard Maple (aka Sugar Maple) is a crop:

DSC_0885 (resized).jpg

It is that simple.

The average hardness of any piece of Sugar Maple is 1450. Sure there might be a knot or some area that is harder, but the average is what you get.

If you have ever tried to buy the maple plywood that pinball machines are made of (not the Spruce core, paper thin maple face veneer junk at the Home Center), you know that you can't walk in off the street and buy it. It's not sold or stocked ANYWHERE on earth.

The pinball playfield plywood, with it's 3/16" thick face and "lumber core" Maple core, is only made for the pinball industry, by a single manufacturer. 100% custom production.

Sugar Maple does not grow in China or Europe (there are no production scale syrup farms because the climate is wrong), so it's not like you can buy cheaper "lumber core" Maple from Asia.

A cynical person might point out that the 40 year old, very familiar theme of StarWars might just attract more plays, than the Cellphone theme of DialedIn.

Either way, a two point sample is not enough to draw any actual conclusions about anything

Not really.

There were a few made of plastic (Oribitor1), a few made with a plastic overlay layer ( New Canasta, Electra) , very few made from MDF/Bakelite (samples of Xenon exist), and a few made from Baltic Birch (one run of Metallica, one run WOZ).

Otherwise 99% of all popular games by Gottlieb, Williams and Bally were made from Maple "lumber core" plywood.

Maple is super stable (thats why most guitar necks are made from it), cheap and relatively hard (that's why the first 1/3 of a bowling ally is made from Maple).

Back in the 80s, Bally used to sell blank playfields with the shooter lane and outhole pre-cut for $35. It was described as "solid Maple", but of course, it was lumber core with all the layers being Maple.

Have you ever gone to Best Buy and looked at one of those big name, Chinese made audio receivers?

The specs say 300 watts per channel X 9 channels for a total of 2700 watts output !

Now of course, your 15amp breaker would trip at 1800 watts, assuming nothing else was plugged into the circuit.

And that would assume that the amp was 100% efficient, rather than the more typical 50% efficiency.

Would it surprise you that when people who know how to actually perform a proper industry-standard test on these amps test them, that they only deliver 40 watts per channel, before the amp shuts down, and the thermal overload light locks on?

It always makes me wonder what kind of non-industry-standard tests the manufacturer uses to get those enthusiastic results.

Then the rumors are true, Jack said he might try making playfields with Ironwood™, the only wood harder than steel.

ZZZZZZZZZZZZZZZZZZZZZZZZZ61804 (resized).jpg

HOW MUCH DOES WOOD COMPRESS FROM DIMPLES IN AN AREA WITHOUT AIRBALLS?

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Nubes like to say "My EM or SS does not have have any dimples", But just because there usually aren't airballs with an EM, that does not mean that the wood has not been compressed by the millions of balls that have traveled over the wood.

All the little micro dimples must add up over time, right?

To test the amount of compression, I needed a protected area that would not have any chance of an airball bouncing from a target or dropping off a ledge or ramp.

I also needed an area less than 12" between areas of no ball travel, because my $350 Starret combo square is only 12" long. (this thing is hardened, then ground DEAD flat).

I also needed an area that had all the paint intact, as missing paint would of course affect the measurements.

I found the perfect spot on a 40 year old Xenon playfield.

The area to be measured is UNDER the tube, so no balls could fall off a ledge, drop from a ramp or bounce off the glass.

This playfield has heavy wear, with many areas down to bare wood. It's safe to say this game has had millions of balls served over it.

IMG_20181017_201010084 (resized).jpg

Note that the Starret is sitting across an area that held 2 pop bumpers.

It's safe to say that no ball ever got under the pop bodies to compress any wood in these areas.

I also avoided any holes that may have raised wood grain around them.

You have the traditional Hard Maple Lumber Ply from CGC with a hardness of 1430

Or out of Europe, you have the Baltic Birch Ply with Maple veneer from Mirco with a hardness of 1370

So both products are very similar in hardness.

Europe does not have a Maple Syrup industry, so they don't commercially grow Hard Maple.

YOU are the person that told me that it was Birch in the middle.

Has something changed?

Seems his experiences comfortably fit right in to what all the other professional restorers are saying.

Wood playfields dimple, and clearcoat will not prevent dimpling.

The Crow and James have been testing a bunch of playfields with a Janka tester lately, trying to get enough data points to be meaningful. (testing one Whitewater, one Metallica, one AFM and one GOT is just not science).

And some titles have both a Birch and a Maple version, so you have to identify which is which for meaningful data

I gave them a few dozen unpopulated playfields from 1950 to 2004, so that will give a bunch of data points too.

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If you want to know which playfield you have, look at the edge.

The Birch ones have many small plys:

mpf16 (resized).jpg

=

and the Maple Lumber Core have fewer, thicker plys:

IMG_0609_grande (resized).JPG

If a new playfield was not "up to snuff", it didn't get the final step of having the dimples impressed on both sides.

The dimples were pressed in, on a bed of nails.

These gave the assembly line workers the starting holes for all the playfield posts, mechs, and lamp holders.

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Now, not having the dimples is not the end of the world when you are swapping a playfield, but it does cost the swapper an extra hour of work.