Author Topic: Stern Thincoat - Dimples & Craters  (Read 40880 times)

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Offline Strangeways

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Re: Stern Thincoat - Dimples & Craters
« Reply #105 on: July 04, 2015, 12:32:13 PM »
Had the crew from HRP down during the week and we spent some time looking at the dimpling issue. The immediate reaction was that "it is not right". As with all restorer's that have seen TWD LE - None of us could put our name on such a poor clearcoat. We agree that the playfield would have to be re cleared if either HRP or APR was responsible for such a bad job.

At this point, we tried a couple of tests, and one really took us by surprise. As mentioned earlier in this thread, to create a dimple on a clearcoat is s simple as rolling a ball off the flipper bat. Drop the ball from a height of two or three flipper bats (the height of a ramp), and you have a crater. The idea was to rule out the wood. So we reverse the playfield and exposed the underside of the playfield. We picked a spot and attempted to create a dimple. Didn't happen. We could not create a dimple. The wood was too strong. The only way to create a dimple was to almost "throw" the ball on the underside on the playfield.

From this simple test - we ruled out the wood. The only possible exception - One side of the timber is "pressed" to be harder - like the topmost ply is more compressed than the underside. THEN - The timber is "flipper" and the art is screened to the wrong side. This is a possible theory. There is no doubt that one side of this playfield appears to be harder. This is the ONLY reason to point to the wood being "too soft".

Back to the topside - This title has a very busy and colorful playfield. The possibility that because there are so many colours and "screenprinting" passes, that the playfield simply has too much colour layers. This would make the paint soft. So if the playfield wood is rock hard, then the paint layers allow dimpling. But this can be protected by a reasonable clearcoat.

Enough experts that apply clearcoats to playfields arrive at the same conclusion. The clearcoat is too thin, uneven in patches and is "too soft". It appears that the factory clearcoat material is of a very poor standard and not applied correctly. Again, a simple test on a freshly clearcoated playfield proves this is the case. A ST TNG with a professional clearcoat was used as a test. The only way to create the smaller dimples was to drop the ball from the height of three flipper bats. Then four flipper bats then five. We now have three visible tiny dimples than can only been seen while holding the playfield up to the light. We placed the playfield aside for 30 minutes. We reviewed the playfield and looked as hard as we could and only found 1 dimple that was slightly visible. The others had "self healed". These playfields will dimple over time, but never as badly as what we see on some Stern playfields.

It seems the dimpling issues can easily be addressed by Stern in the factory. No one should be accepting the "just play the damn thing and it will all blend in". That might have applied to the 5% of home users. But that 5% is now 20%. Next year 50%, the year after 80%. Imagine buying a $500,000 Ferrari and finding out that the auto body clear was thin and of poor quality. You go back to the dealership and you are told "keep driving down dirt roads - it will all blend in and level out".. I guess that's the first and last Ferrari that owner will buy.

The theory is that an extra $50 of material - or a better clearcoat product + one or two more passes under the gun - and extra 5 minutes on the line - could remedy this situation - or at least prevent NIB $11,000 machines from having moonscapes. That's the bottom line.

We invite Stern to send us two playfields and we can provide a better solution ;

1 - Factory cleared playfield. We will test the dimpling and then re clear using a superior product that is used on all HRP and APR restorations. Then run the same tests.
1 - Factory uncleared playfield. We will clear using a superior product and then run the same tests.

Now moving forward - if Stern believe this is all just a whinging pinhead with an axe to grind, I'd like to point out the following - I've spoken to TWO pinball manufacturers who are going to be using the same clearcoat approach as professional restorers. Clearly, this is now the acceptable standard.

Without a doubt, dimpling is part of EVERY game with a ball flaying around off ramps etc etc.. Steel ball VS wood = Steel ball wins. We all know that. We need to find a way to minimize this effect on $10,000 pinball machines. If it was done 20 years ago, it should be able to be achieved in 2015.
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