Vintage M-69 Puckering versus Modern Day OTP Rings

pinefd

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There has been some controversy in one or two other threads about the dimples/puckering found in some of the OTP M-69 rings on the market today, and whether this puckering is a characteristic of the vintage rings that these OTP rings are trying to imitate.

I received an email from none other than Uncle Lou, who was kind enough to give some input into this matter. The following was taken verbatim from the email:

"Now in regards to your question about "Dimples or Puckering" (hence, deformation) in original M-69 Gibson pickup surrounds, my immediate response is yes, they all had them to some degree. Now if you'll bear with me I'll explain how I know this. First of all, with the exceptions of Vic DaPra and Perry Margouleff, nobody had handled, examined, or sold more PAF equipped vintage guitars than me. And where there are PAF's, you'll find black or cream M-69's holding them onto the guitar. So it's safe to say I know what I'm talking about after nearly 30 years of doing this. Secondly, besides seeing all those original M-69's in context (mounted on the guitars they left Kalamazoo with), I've also had no less than 2 dozen "orphaned" sets of cream M-69's and scores of black sets as well. And finally, I spent about a year in the research and development phase, working with an "old school" injection mold maker, to produce what have come to be known as "Uncle Lou Tips". So in addition to my vintage guitar & parts expertise, I now know something about the injection mold process.

There are several factors that can be attributed to the amount of
deformation in plastic injection molded products such as:

"Material Type"...nearly all plastics shrink during cooling but at different
rates and amounts.

"Machinery"...older machines don't mix materials as thoroughly as newer
machines giving a varied end result.

"Cycle Time"...the amount of time between the injection of hot material to
the time it's ejected from the mold.

"Finished Product Thickness"...thicker products take longer to cool. Eject
too soon and you get deformities, wait too long and the company
losses money...time is money right? It's up to the mold maker to find the
perfect balance of cooling time vs. an acceptable amount of
deformity.

I've seen this first hand with my buttons, some have noticeable amounts of deformation whilst others have nearly none at all...exactly like original
buttons since mine were produced with vintage machinery.

Now with regards to color, that's kind'a tough to describe...how blue is the
sky today? But I will say the original cream plastic that Gibson used during the 50's has a "buttery cream" hue to it...not light yellow or white, but closer to beige. I'm not real good at 'describing' color; I just know it
when I see it. You also have to take into account what conditions the cream plastic parts were subject to over the last 50 years such as direct
sunlight, sweaty grime, and nicotine as found in smoky bars or chain-smoker homes. But what you never want to see on alleged 50's cream plastic is a pinkish hue, which is what Gibson started using in the late 60's.

Anyway, I hope this information helps quell a lot of speculation by all the
armchair experts. If you're really bored and have some time to kill, I'll
tell you all about the very first version of M-69's that came out around the
early part of '57, before the mold was altered to its "flawed state" that
everyone is familiar with. I actually have one set of these that I keep for
historical purposes, only a handful of people even know they ever existed."


I hope this helps clear up the matter once and for all, and that we can all now agree that dimples were in fact a normal occurance on vintage rings, and that the same "flaws" that showed up on them are now showing up on the OTP rings as well. Therefore, dimpled or not dimpled, they are vintage correct (as long as the color is right!).

Thanks for listening (reading).


Frank
 

markguitar

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Cool Frank! Maybe this would get more views in the Historic area since those are most of the guys buying the reissue rings.
 

decoy205

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forgive my ignorance but I still don't really understand what "puckering" is on the rings. Can you post a photo circling this?

BTW thanks Frank very cool!
 

pinefd

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forgive my ignorance but I still don't really understand what "puckering" is on the rings. Can you post a photo circling this?

BTW thanks Frank very cool!
You're welcome Decoy!

And here's what's meant by the term puckering...the indentations on both sides of this "face" of the ring:




Frank
 

decoy205

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You're welcome Decoy!

And here's what's meant by the term puckering...the indentations on both sides of this "face" of the ring:




Frank
Ooooooooooooooooo
ok now i get it. I really didn't understand what everyone was talkin about. :laugh2:

Thanks for clearing that up!
 
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You're welcome Decoy!

And here's what's meant by the term puckering...the indentations on both sides of this "face" of the ring:




Frank
In the Injection Molding field, we call that "Sinking", usually caused by insufficent pack or hold pressure, insufficient cooling time, excessive mold temperature, etc.

Looking at the picture, the first thing I would do if I were the one molding it would be to check and make sure the damned mold heater was turned on and at the correct temperature, because that looks a lot like insufficient cooling to me. Then I would increase the second stage pressure in order to fill the mold more completely. I might even increase the injection velocity, which would allow me to give it a little more hold or cooling time without actually slowing the machine down.

I do this crap everyday, we would get red-tagged by Quality Assurance in a heartbeat for a part that looked like that!!
 




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