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Paintball Fill Viscosity....


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#51 drg

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Posted 05 April 2012 - 09:03 PM

I've always loved the term thixotropic ;)
Every time I pour ketchup I think about it.

A while back the original proball was designed around the idea of being very small and very heavy. IIRC it marked very very well too. I wonder how it specced out?

Edited by drg, 05 April 2012 - 09:05 PM.

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#52 vinti6674

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Posted 10 April 2012 - 12:37 AM




Chemstry is cool stuff. I have no idea what actual chemicals are used in paint - but here's an example from the kitchen - corn startch is a thickener, but it's light. mixing equal volumes of dirt and water or corn starch and water would end up with a situation where the mud is heavier but the corn starch mix is thicker.

As to the ASTM standards - it's 3.5 grams. I've never weighed balls heavier than 3.2g - so I don't know that there is a problem exceeding it. I have measured balls down to the mid 2-gram weight. That's a HUGE difference in mass - and the ones closer to the max ASTM weight will certainly shoot further and be deflected less by wind.

maybe UV Halo can chime in - I think he did some calcs on this.

Yes, the higher the weight, for the size does equal higher sectional density - that makes a very big difference, it may be why the better paintballs are smaller...


I just conducted some analysis of rntlee's paintball data. Here's the processed data (sorted by sectional density):

Brand Avg Diam / Weight / SD / 'eccentricity'
Visible Impact .670 / 3.40g / .0167 / .030
DXS Triumph .665 / 3.32g / .0166 / .030
Xball .678 / 3.44g / .0165 / .015
DXS Field .670 / 3.36g / .0165 / .030
Marbs .670 / 3.08g / .0151 / .030
Evil .679 / 3.08g / .0147 / .010

SD = Sectional Density, higher numbers are better
eccentricity = difference between the cross seam diameter and the seam diameter, smaller numbers are better.

I find it a bit interesting that the least dense paint in the roundup was the roundest. I also found it interesting that the heaviest paint was second largest.

I strongly suspect that shrinking paint sizes have little if nothing to do with trying to improve things for us.

^^^ Thank you for this great data....I need to spend some time thinking about it before I comment

Disagree. Smaller paint sizes are better. Consider eccentricity and mass (not density) as constant and the only free variable is size. Smaller is better. This analysis really isn't critiquing the optimization of a paintball, but rather it exploits the tolerances needed as size decreases. As we get smaller the paint cant be produced through current means because there is a clear direct relationship between size and eccentricity. No more half a** production on the paint as it gets smaller industry.

#53 brycelarson

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Posted 10 April 2012 - 07:30 AM

Disagree. Smaller paint sizes are better. Consider eccentricity and mass (not density) as constant and the only free variable is size. Smaller is better. This analysis really isn't critiquing the optimization of a paintball, but rather it exploits the tolerances needed as size decreases. As we get smaller the paint cant be produced through current means because there is a clear direct relationship between size and eccentricity. No more half a** production on the paint as it gets smaller industry.


Why is smaller paint better? Why should we consider eccentricity and mass a constant? If all paint were the same mass then smaller would be better - since it would mean higher density - bit it's not.

As far as I know all major paint manufacturers use the same method to make the paint - and all involve tumbling it while it hardens. This means that they're guessing at the shrinkage %. Obviously they're good at guessing - but final size doesn't have a direct correlation to mechanical process.

What evidence are you using to prove that smaller means better eccentricity?

#54 vinti6674

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Posted 10 April 2012 - 10:34 AM


Disagree. Smaller paint sizes are better. Consider eccentricity and mass (not density) as constant and the only free variable is size. Smaller is better. This analysis really isn't critiquing the optimization of a paintball, but rather it exploits the tolerances needed as size decreases. As we get smaller the paint cant be produced through current means because there is a clear direct relationship between size and eccentricity. No more half a** production on the paint as it gets smaller industry.


Why is smaller paint better? Why should we consider eccentricity and mass a constant? If all paint were the same mass then smaller would be better - since it would mean higher density - bit it's not.

As far as I know all major paint manufacturers use the same method to make the paint - and all involve tumbling it while it hardens. This means that they're guessing at the shrinkage %. Obviously they're good at guessing - but final size doesn't have a direct correlation to mechanical process.

What evidence are you using to prove that smaller means better eccentricity?

Maybe I wasn't clear.
You sort of encouraged my point
As paint gets smaller ideally keeping the mass constant means a denser fill. The fill should be changed.
Eccentricity does have have a direct relationship to decreasing paintball size. look at the data.
As the paint gets smaller the eccentricity increases.
This is because of manufacturing of the paintball.
To eliminate the increasing eccentricity as the paint size gets smaller: Change the method.

#55 brycelarson

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Posted 10 April 2012 - 10:45 AM

Maybe I wasn't clear.
You sort of encouraged my point
As paint gets smaller ideally keeping the mass constant means a denser fill. The fill should be changed.
Eccentricity does have have a direct relationship to decreasing paintball size. look at the data.
As the paint gets smaller the eccentricity increases.
This is because of manufacturing of the paintball.
To eliminate the increasing eccentricity as the paint size gets smaller: Change the method.


We can't really use that one data set to make blanket determinations like you are trying to make in this case. Paint, like produce, is a commodity that has a shelf life. It's storage situation and age will drastically effect it's shape.

Why would manufacture technique effect shape based on size?

I'll repeat what I do all the time - before we determine WHY something we need to determine IF something. In this case we don't have enough evidence to determine IF smaller paint is more or less round than bigger paint. Since we don't then trying to determine WHY is irrelevant.

#56 your_colourful_elimination

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Posted 18 September 2013 - 06:34 AM

I suspected as much given the roundness of the Evil. How did the X-ball perform? How were the seams?

Here's a few comparison pics of the groups for reference.

Worst to best as in your list:

TM-7VisibleImpact.jpg

TM-7Xball.jpg

Tm-7Evil.jpg



I was able to bring the poor performers up to roughly the same performance as Evil by scraping their seams smooth...so the fill itself doesn't seem to contribute much spread at the distance I was shooting here (75').

Rntlee, what are the dimensions of the target and or the diameter of your circle (only shown on 2 pics) ?

This thread is valuable but let's not forget we ballers aren't shooting things out of cowboy's hands or guaranteed headshots at stationary standing men. 12 x 12" is a reasonable spread at 75'.




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