SpudFiles

Waga jednej kulki w gramach

weight of one ball in grams

POLAND_SPUD wrote:

Waga jednej kulki w gramach

weight of one ball in grams

Gotcha, i guess it was the comma instead of deci-point that threw me...

This thread might best be hijacked to list the densities of most common projectiles. Then the weight can be calculated by volume alone and material selection is done by density alone.

Most materials pages list density as a ratio to the density of water.
Since a cubic centimeter of water is 1 Gram, ofen the density is listed as grams/cc or 1cc=X grams.

This is what I used when designing my launchers. For the selection of the piston the idea was if the piston was of about the same size as the projectile, if it was about the same mass, the piston and projectile would both move about the same distance in the same time when chamber pressure hit them both.

This gave me very rough modeling of the opening time on my valves. For example an apple is about the same density of water. Some float, some sink. My piston is slightly less than the density of water, it floats, but barely.

Acceleration of my piston is about the same as the acceleration of an apple that is the same size as my piston. Therefore the opening time can be calculated to be in the 1 ms or less range using GGDT.

Due to thermal expansion, the densities are often specified at a specific standard temperature near room temperature.

For starters,
Water = 1
UHMWPE = 0.945
HDPE = 0.95
Nylon = 1.15
Aluminum = 2.7
Steel = 7.86
Brass is an alloy and composition varies. 8.3 to 8.7 typically
Lead = 11.35
Depleted Uranium 19.05
Tungsten = 19.35

tech- thank you for the density of depleted uranium, i'll have to go dig mine up out of the basement now I know how to make a good round out of it

just kidding... lol

Ragnarok wrote:That sounds... excessive. For most things, I can't see the necessity in trying to get more than 99% accuracy in projectile weight.
(That said, there is a demand for ~99.9% accuracy for one thing I'm doing)

Depends in what scale you build. For 4 inch launchers, the nearest 5 grams is probably good enough. For a 2.5mm pen gun, 0.01 not enough. I agree that for most applications it's excessive though, but it's there and it's free so I'm offering my services

jackssmirkingrevenge wrote:

Ragnarok wrote:That sounds... excessive. For most things, I can't see the necessity in trying to get more than 99% accuracy in projectile weight.
(That said, there is a demand for ~99.9% accuracy for one thing I'm doing)

Depends in what scale you build. For 4 inch launchers, the nearest 5 grams is probably good enough. For a 2.5mm pen gun, 0.01 not enough. I agree that for most applications it's excessive though, but it's there and it's free so I'm offering my services

Density scales to any size. Volume may be easier to measure than small weights.

Tossing airsoft pellets into water may give an idea as to their relative density. Do they float or sink? If they float, they may be a PE material. If they sink, they may be nylon or other injectable plastic.

Most veggies are only slightly denser than water and sink, so most are only slightly more dense than water.

A close estimate based on volume would be a good ballpark value.

I threw a 1 inch bouncy ball into the sink (multicolor vending machine ball) and it floats in water, barely. so I know it's density is close to that of HEPE.

Weight can be estimated based on the volume and approximate density for any size from mini to jumbo.

tech- thank you for the density of depleted uranium, i'll have to go dig mine up out of the basement now I know how to make a good round out of it Very Happy Wink Wink Wink

I threw that into the list encase anyone is still working on a penetration contest entry and needed a really massive projectile. In my area, tungsten is much easier to get, relatively tough and nearly the same density. It's a bear to cast and machine though so the other may be a better choice if you can get it. You can get the same penetration power in a projectile of about 1/2 to 1/3 the cross section of an iron rod.

For your list, my 4 inch Poof Brand foam ball with the magnet in it tips my calorie counting scale at 2 ounces are about 57 grams.

Technician1002 wrote:Density scales to any size.

True, plus you can use alcohol or oil for less dense stuff. It does require an accurate measuring cylinder or similar to measure the displacement though, especially on a small scale (but you can use multiple projectiles and take an average too, same goes for weighing with less accurate balances).

Technician1002 wrote:

jackssmirkingrevenge wrote:

Ragnarok wrote:That sounds... excessive. For most things, I can't see the necessity in trying to get more than 99% accuracy in projectile weight.
(That said, there is a demand for ~99.9% accuracy for one thing I'm doing)

Depends in what scale you build. For 4 inch launchers, the nearest 5 grams is probably good enough. For a 2.5mm pen gun, 0.01 not enough. I agree that for most applications it's excessive though, but it's there and it's free so I'm offering my services

Density scales to any size. Volume may be easier to measure than small weights.

Tossing airsoft pellets into water may give an idea as to their relative density. Do they float or sink? If they float, they may be a PE material. If they sink, they may be nylon or other injectable plastic.

Most veggies are only slightly denser than water and sink, so most are only slightly more dense than water.

A close estimate based on volume would be a good ballpark value.

I threw a 1 inch bouncy ball into the sink (multicolor vending machine ball) and it floats in water, barely. so I know it's density is close to that of HEPE.

Weight can be estimated based on the volume and approximate density for any size from mini to jumbo.

tech- thank you for the density of depleted uranium, i'll have to go dig mine up out of the basement now I know how to make a good round out of it Very Happy Wink Wink Wink

I threw that into the list encase anyone is still working on a penetration contest entry and needed a really massive projectile. In my area, tungsten is much easier to get, relatively tough and nearly the same density. It's a bear to cast and machine though so the other may be a better choice if you can get it. You can get the same penetration power in a projectile of about 1/2 to 1/3 the cross section of an iron rod.

Normally, my bouncy balls(Don't even think about it JSR), about 1/2 float and half sink, color and finish doesn't seem to matter either way,and sometimes they are neutral, push them down 2" and they stay there...

Ok, enough about my balls...

Hm ok ! wow I guess this thread DID pick up pretty fast... I'll be adding whatever is new right now... btw someone said that I should use metric... I guess I could do it but you can simply copy and paste the weight already given in oz. and plug it in into the conversion website I linked...

hi all

first
wax is 0.9-1.0g

@jsr
is not exact the topic but can you invest 1-2euro to balance out how much fuel in a normal ligther like tokai and or bic lighter is. please

jean

jeepkahn wrote:(Don't even think about it JSR)

I say nothing!

@jsr
is not exact the topic but can you invest 1-2euro to balance out how much fuel in a normal ligther like tokai and or bic lighter is. please

Im drucking funk so clarify please, yuou wanyt ,me to weigh a full and empty lighter and compare the difrfetrence?

jackssmirkingrevenge wrote: Im drucking funk so clarify please, yuou wanyt ,me to weigh a full and empty lighter and compare the difrfetrence?

Make it easy. Butane liquid has a density of 0.573. Now all you need to know is the volume to calculate mass.

An insulin syringe and needle can be used to fill an empty lighter to find the volume.

JSR i was hopin you could weigh some stuff for me on your scale, still cant find them
plastic tack
16p nail
8p nail
Wood screws sizes 1 1/4"-3 1/2"
1" of 1-7/8" duct tape
1" of standard electric tape

Northir wrote:JSR i was hopin you could weigh some stuff for me on your scale, still cant find them
plastic tack
16p nail
8p nail
Wood screws sizes 1 1/4"-3 1/2"
1" of 1-7/8" duct tape
1" of standard electric tape

A couple weights are listed online. Nails sold by the pound have aproximations of the number of nails per pound.

http://www.iverswoodshop.com/Referance/ ... Pound.html

Divide to find the weight of each nail in lbs and convert to oz by multiplying by 16.

If the nail types confuse you, the refrence page gives a description of each type of nail in the chart.
http://www.iverswoodshop.com/Articles/Nails/Nails.html

Don't feel bad if you have to follow the link to look. I didn't know what two of the types were. I only knew common and finish.

Technician1002 wrote:An insulin syringe and needle can be used to fill an empty lighter to find the volume.

I can do it by weight to get a comparative result.

plastic tack
16p nail
8p nail
Wood screws sizes 1 1/4"-3 1/2"
1" of 1-7/8" duct tape
1" of standard electric tape

I can only do Euro/Metric equivalents