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Author Topic: Urethane's early roll characteristics  (Read 1592 times)

bowler100

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Urethane's early roll characteristics
« on: April 05, 2020, 06:21:16 AM »
Urethane does not have any significant microscopic peaks unlike any resin ball and yet it seems to want to read the front of the lane more so than any resin. What is it about the urethane material that causes this early-rolling effect even with good head oil?

 

bonez44s

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Re: Urethane's early roll characteristics
« Reply #1 on: April 05, 2020, 08:29:17 AM »
Most of the people I see throwing them keep them 500 or 1000 grit. Thus the early roll

2handedrook12

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Re: Urethane's early roll characteristics
« Reply #2 on: April 05, 2020, 03:04:04 PM »
Most of the people I see throwing them keep them 500 or 1000 grit. Thus the early roll
but urethane is earlier than reactive at the same surface.
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MI 2 AZ

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Re: Urethane's early roll characteristics
« Reply #3 on: April 05, 2020, 04:51:48 PM »
Back in the day when resin balls first came out they were called 'reactive' urethane balls. I remember reading that the term 'reactive' meant that the balls were more sensitive to friction or the lack of it when compared to the previous urethane balls.  They would supposedly skid more in the oil and react more violently upon encountering the dry or friction area of the lane.  So it may be that the resin balls use a modified urethane with some other additives that create that type of reaction besides having the microscopic pores that allow them to absorb more oil than urethanes.
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avabob

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Re: Urethane's early roll characteristics
« Reply #4 on: April 05, 2020, 05:14:49 PM »
It is correct,  the first resin balls were urethane enhanced with a reactive resin additive.  To understand the result you have to understand a bit about
Coefficient of Friction.  The COF between a ball and Lane surface decreases as the amount of oil increases.  Prior to the addition of resin, sanding increased the COF on both the oiled and drier portion of the lane.  What resin additives did was increase the COF on the dry without increasing it on the oil.  Thus a polished pearl reactive would react stronger in the dry than a non reactive in the dry wuth 5he same surface prep.

Today there are so many different shell materials that it is hard to tell what is going on except for non resin urethane that still responds to surface adjustments in both the heads and coming off the oil