Paintball Sensitivity to Temperature

[tomcat]

It would be interesting (and usefull) to know how sensitive different brands of paintballs are to temperature. I pose this question because I think that some paintballs become useless and VERY brittle below certain temperatures.

It would be good to see a drop test (or other tests) done on "same batch "paintballs at different temps; and different brands. I am most interested to see the dry shell versions tested but all brands would be the best.

As an example.

Temps tested: 32F, 50F, 80F

It would then be good to see if paintballs reduced to lower temps are just as brittle (if they are) when returned to room temp or equiv to see if they are no longer useable or work better!!

Evern size could be checked!

[flanders]

well for the most part all cold weather paintballs are marketed as so

most higher end tourny paintballs are ment to be damaged during freezing so no one will cheat, that and they just aren't ment for those temperatures.

evil marbs and some dianlo paint are ment for higher tempratures for shurt periods of time ie during shooting high speed shooting cause heat in the barrel and paintballs expand which is why back players use a larger boar barrel

[tomcat]

Acurate and verified data

Flanders,

that is very interesting. I have never heard any of that before. Where did you get that information. I would also like to read the original source.

I would still like to see the above experiment done. It would help me and I am sure that a lot of other people would like to know.

I am looking for more than just theory and hearsay. I want accountable facts. That is why I pose the question in this forum.

Thanks.

[flanders]

Re: Acurate and verified data

which part the tourny balls

or the thing about paint expanding

i go the tourny balls by running my own test in my own freezer over night

and the expanding balls ive herd numerus times but ther was one in particualer

in barrel selection article on paintball.com

[Redkey]

flanders... have you ever felt the barrel of a marker get warm after using a high rate of fire?

Every time you shoot a ball down the barrel you're also sending a large blast of expanding gas down the barrel as well. I'm sure than any heat generated by friction between the ball and the barrel will be carried way by the blast of air. Also... when you compress a gas it gets hot... when you allow it to expand it cools... which, in theory, would have a cooling effect on the barrel.

Now, to back up your statement about balls expanding due to heat. I would suggest looking up the thermal expansion coefficient for gelatin shell and the paint. Then, calculate the amount of expansion that will take place as the ball warms. You'll also want to look at the heat flow characteristics of the shell and fill to see how much heat they can absorb in the couple milliseconds they are travelling down the barrel.

I'm looking forward to the answer.

Also... how does someone cheat by freezing a paintball?

[flanders]

no i havn't

but it takes longer to cool metal then it does to heat it

and just to prove that im not lying to u im about to go find that article

http://paintball.com/features/article.cfm?aid=1108 it talks about boar size how back player need a larger boar do to larger amounts of paint flingage it may not be precisly do to heat

[Redkey]

oh, this is the article where he says the balls are 3-4 inches apart in the barrel. Sigh... lets do some more math... first we'll assume that all balls have the same rate of acceleration. Also... lets assume the player is shooting 20 balls a second. This means there is 1/20 of a second between each shot. In 1/20 of a second a ball travelling 300 ft/sec will travel 15 feet. Now... lets assume the player is shooting 100 balls a second. The shots are 1/100 seconds apart... a ball travelling 300 fps will go three feet in 1/100 of a second.

So... is it possible to the balls 3-4 inches apart in the barrel of a *properly* functioning marker? I don't think so.

[DarrylHadfield]

Originally posted by Redkey
Also... how does someone cheat by freezing a paintball? [/B]

I'd heard (and have seen) that people will dump a case of paint in the freezer to chill the fill. As it chills, the fill turns into more of a gel than a liquid. When that happens, the paintball tends to have more of a 'solid' composition, and as such should fly somewhat truer.

I was playing last sunday with Chronic (which is a damn dense fill to begin with!) - it was 18 F outside, and my paint was getting pretty chilled. It seemed to me that things were flying a bit better than other days. Granted, there's the added consideration of the air that it's flowing through being more dense, but I'm sure you get my point.

Darryl

[tr0n]

Back 4 (lol, I'll never forget this one) years ago a kid got thrown out of a field I used to go to from hitting me in the mask with frozen paint and breaking my lens. I'm lucky I got hit in the mask, it probably would have hurt pretty bad, considering it made a thin crack all the way down and across my lens...

It scared the crap out of me hearing the marble-like balls whacking up against my bunker. I was going to raise my gun up and get hit out (cause I just thought I was screwed and whoever was shooting at me was running REALLY hot) but I thought it might dent/scratch my gun, so I lifted my head up just a bit to take one in the mask, lol...

Well yeah, a second later WHACK it knocked my head back a little and my lens was cracked. The ref ran over to get me out of the bunker and saw what had happened, and they checked everyone's hopper and found the kid.

[ckyguy]

acceleration

redkey, i haven't done the math yet, and probably won't anytime soon, but you might want to consider how fast balls excelerate in the barrel because they dont just straight from 0 fps to 300 fps, they gradually get to that point throughout the barrel maybe making it possible to have more than one ball in the barrel at once.

keep in mind this is just off the top of my head and i'm not sure if it would be possible to have a ball 3-4 inches apart in the barrel or not, but i am pretty sure that shooting whatever bps, the paint wouldn't be spaced how you said until they were out of the barrel, paintball.com was specifically talking about inside the barrel where paint isn't traveling at 300 fps the entire way.

[Urban]

On the subject of paintball accelleration I had a brief conversation with John Sosta about this.

Part of the development process for the Emag involved measuring how quickly the paintballs accellerated from 0 to 300 fps. Using a barrel made up of inch long sections they measured the distance it took for a paintball to read 300fps over a chronograph. An Impulse does it in 4 inches, the Emag took 5 or 6 inches, and one of the popular markers (I forget which one) took nearly 10 inches to accellerate a paintball to 300fps.

My brain hurts when I get into math like this during the working day but with those figures someone should be able to work out at what rate you'd need to be firing, assuming a forcefeed system that could theoretically keep up and consistant accelleration from ball to ball, to get balls 4 inches apart in the barrel.

Urban

[Wat]

back to temp and paintball. I find that humidty has a much bigger effect on paintball performance than heat. I really love playing in august when the paint gets bouncy. Once went to a field where the proball was bouncing of hardwood bunkers at 20 feet. Man, those were some painful bruises and welts.

Actually, i wonder if temperature effects fill viscosity which effects how it breaks.

[bjjb99]

Re: acceleration

Originally posted by ckyguy
redkey, i haven't done the math yet, and probably won't anytime soon, but you might want to consider how fast balls excelerate in the barrel because they dont just straight from 0 fps to 300 fps, they gradually get to that point throughout the barrel maybe making it possible to have more than one ball in the barrel at once.

Tell ya what... I'll do the math. :)

Let's assume the ball is under constant acceleration while it is in the barrel. In reality the acceleration starts out big and decreases as the ball travels down the barrel, but let's assume it's constant throughout just to make the math easier.

Let's assume a nice 12 inch long barrel, and a 300 fps exit velocity. For constant acceleration from a standstill, the following equation
applies:

X = 0.5 * V * t, where

X = distance travelled (1 foot),
V = final velocity (300 fps), and
t = time over which the object moved distance X.

Solving for t and plugging in numbers, we get the following:

t = X / (0.5 * V)
t = 1 / (0.5 * 300)
t = 1/150

It takes 1/150th of a second for a ball to move the entire length of the 12 inch long barrel if it starts from a standstill and experiences constant acceleration to a final velocity of 300 fps upon exiting the barrel. This is about 6.7 milliseconds (0.0067 seconds) If you want two balls in the barrel simultaneously (one ball just exiting the muzzle and one just entering the breech), you're going to have to have a fire rate greater than 150 balls per second.

Good luck.

Now let's look at the fire rate to get two ball spaced 4 inches apart inside this 12 inch long barrel, assuming each ball is constantly accelerated to 300 fps. We know it takes 1/150th of a second for the ball to reach the end of the 12 inch long barrel, and so we can use the standard equation for distance travelled under constant acceleration:

X = 0.5 * a * t^2, where

X = the distance travelled (1 foot)
t = the time required to travel distance X (1/150th of a second), and
a = the acceleration of the paintball.

Solving for a and plugging in numbers gives us the following:

a = X * 2 / t^2
a = 1 * 2 / (1/150)^2
a = 2 * 150^2
a = 45000 ft/second^2

Now that we know that, we can find out how long it takes for a ball to travel 4 inches down the barrel if it starts at a standstill.

X = 0.5 * a * t^2
X = 4 inches (1/3 foot)
a = 45000 ft/second^2
t = how long to travel 4 inches

t^2 = 2 * X / a
t = sqrt(2 * X / a)
t = sqrt(2 * (1/3) / 45000)
t = 3.85 milliseconds (0.00385 seconds)

So, in order for two balls to be within 4 inches of each other in a properly functioning marker, you would have to have a fire rate in excess of 259 balls per second.

As before, good luck.

The only way you're going to have two balls spaced 3-4 inches apart inside a barrel during firing is if the first ball has become stuck in there, at which point you've just double fed your marker and are making a gooey paintball mess.

BJJB

{edited from original post to add fire rate for 4 inch spacing}

[paintposse]

i think that you barrel getting hot can be true. But only on a barrel that isnt honed very well. Barrrels now are honed to almost perfection and are friction less.