Automatic Vacuum-Powered Paint Marker

Just a quick throw-together, showing how to take the vacuum-powered launchers to another level of performance. This one is based on a paint-ball set-up, scale up or down to suit this approach to your version of danger!

Step 1 Putting pieces together

I just couldn't wait for Tippman to put out the rumoured auto-loading propane powered marker. So I am thinking of how else to not use refillable tanks, as it's a pain to get them refilled. Here I've started the second version, and I'm thinking up the third before I'm done with this one. Oh well....

Comments

[AnarchistAsian]

nice, but since there's a hole, you lose a lot of energy...

[Shadetree Engineer]

Oh yeah, big loss for sure! I did some serious research to see what it would take to scale this up to 300 FPS and self-powered. My next prototype will do away with the flap at the end of the barrel, which uses up a bit of velocity. It would also recirculate the airflow (Active Muzzle Brake), both pushing & pulling each paint. That would help keep exit noise down. I think it would take a 13 horsepower motor to do it! The calculations I went through kept referring to losses. I believe that besides the friction of the airflow & heating losses in the power-train, just keeping the air in motion between shots, even with full-auto, will use more energy in addition to what's needed to move each paint. Now if a person is interested in building a paintball tank and they can handle the extra weight, this is still a workable approach. But my interest is in surprise shots.

[AnarchistAsian]

well... the design itself is uhh... pretty interesting, but not practical...

Really, if you have a vacuum pump to pull the paintballs, you might as well just have an air pump to push them...

you could reverse the motor on the vacuum, and put it on the other end, then you'd have way less energy loss...

[Shadetree Engineer]

I would never have called this experiment a practical design, but I was trying to get away from CO2 or HPA systems. As a result of my efforts, I am becoming quite impressed with just how much energy is available from CO2 or HPA. If I connect the exhaust of the vacuum cleaner to the breech end of the barrel, and keep the hopper sealed, then I wouldn't need the flap at the end of the barrel. That would probably give slightly better performance, but I don't think that approach will make the fan work more efficiently. However, eliminating the 90Ú air-box from the muzzle end of the barrel should make a noticeably small improvement, more than just removing the flap. All the formulas for designing a fan have something like an 80% assumed efficiency, providing the design is well thought out. Which is why I wouldn't want to build the fan. I noticed that the highest capacity 3-stage HVLP air sources are much better than any vacuum cleaner. Those provide about the right flow velocity, and maybe the right pressure. But I don't think one of those can get as high as 95% efficiency.

[AnarchistAsian]

really, pumps/vacuums aren't good for airguns... build up of energy to be released quickly is the best way to go...

[Shadetree Engineer]

I understand your point. I just want to explore the possibility that what is 'best' is dependent on expectations of performance. To have a marker that is easy to carry by hand, is the kind of expectation that will rule in favor of a high-pressure storage being released in small discrete charges per paint. Now what I built here was a fun project, and easy to do. If I want to scale it up to something more serious, well maybe I'm just crazy...

[AnarchistAsian]

hmmm... maybe i'll try this sometime...

[Shadetree Engineer]

If you do, I would recommend getting a 3-stage HVLP turbine. Let me know how it works, thanks.

[AnarchistAsian]

oh, i was thinking i'd use my vacuum cleaner or something, lol.

[Pumpkin$]

I have a ancient crossman 707 air gun that fires 22. pellets. the first paintball gun is modeled after that.

[Shadetree Engineer]

Very cool gun! I had never heard of it until just now. A google search turns up on the first page, this: Crosman 707

They mention that the first 'paint marker' was intended to mark trees and cattle using an oil-based paint. The .68 caliber may have been simply because that's the size of the ball-end mill that was laying on the bench when it came time to make the first molds.

I don't suppose you are too tempted to connect a shop vac up to your 707?

[Pumpkin$]

not yet.... i moved so i'm waiting for it to catch up

[Pumpkin$]

well....... maybe but it's a little too valuable to me

[Shadetree Engineer]

I have moved up to prototype 1.2, mainly I reconfigured the muzzle assembly to a side-by-side setup. The previous results were wrong, the hopper only holds a bit over 185 paints. Which means that my corrected BPS was actually 9 with a 22 second total to empty the hopper. But I didn't actually count the balls into the hopper, so it's just approximate. The side-by-side version was a bit slower, at 33 seconds overall. I counted exactly 185 for that. The hopper really does not keep up with this thing! I forgot to add that my air source is 120 volts, 8 amps. So it pulls 960 watts and generates exactly 7 inches Hg static using an automotive vacuum/fuel pump gauge. I probably could find the velocity by using my video recorder and shoot along a measuring tape, then use the frame rate to estimate the speed. I'm thinking about using an 8' length of pipe to hold a single row of balls for future testing. Eventually I'll just have to get one of those electric hoppers...

[GorillazMiko]

Nice job, looks cool, looks awesome actually. Looks pretty dangerous, I might have to show this to my friend, he loves this kind of stuff. (added to favorites)

[receiver545]

dude i love those ORIGIN paintballs those have hard shells and they hurt and there expensive those.