Search found 33 matches

by cometboy
Tue Jan 22, 2013 6:39 pm
Forum: Pneumatic Cannons
Topic: Copper Marble Cannon
Replies: 84
Views: 29028

Brian,

Video could be done but my hobby does not support a 30,000$ (new) price for a good color high speed camera.

In any case, what you gain in multiple pictures you lose in resolution. Like any engineering issue it's all about compromise.

I had a friend who has intermittent access to a high ...
by cometboy
Sun Jan 20, 2013 8:41 pm
Forum: Pneumatic Cannons
Topic: Copper Marble Cannon
Replies: 84
Views: 29028

I have slowly been putting together a higher pressure set-up for the steel bearing throwing cannon and got a speed reading a little while ago.

At about 200psi the speed is 680fps, much higher than the ~120psi/520fps from the standard air compressor. I don't have any pictures shot at the higher ...
by cometboy
Tue Jan 01, 2013 9:47 am
Forum: Pneumatic Cannons
Topic: Copper Marble Cannon
Replies: 84
Views: 29028

Mr Crowley, al-xg

Thank you for the explanation.

As far as the banana, in my experience if you shoot a lot of stuff, some pictures turn out. Maybe one in five. And out of those that turn out, a few turn out good.

The banana shot above is good.

It's the high speed version of "spray and pray ...
by cometboy
Mon Dec 31, 2012 8:03 pm
Forum: Pneumatic Cannons
Topic: Copper Marble Cannon
Replies: 84
Views: 29028

I realized I can post the animation also.

<a href="http://picasion.com/" rel="nofollow"><img src="http://i.picasion.com/pic63/b8e071e4c2ef7d0ce86f4c6c7e2dc2de.gif" width="300" height="191" alt="make gif"></a>

I promise I won't spam the forums too badly.

Cheers.
by cometboy
Mon Dec 31, 2012 5:20 pm
Forum: Pneumatic Cannons
Topic: Copper Marble Cannon
Replies: 84
Views: 29028

So I tried hooking up the refrigerator compressor today.

It seems to work.

It doesn't like back pressure, refuses to start.

I ran it up to 200psi and shot a few bearings. Much faster, I don't have velocity numbers but it goes through ~100% more plywood, about 1".

I am not going to take any ...
by cometboy
Sat Dec 29, 2012 9:48 am
Forum: Pneumatic Cannons
Topic: Copper Marble Cannon
Replies: 84
Views: 29028

jack,

I'd love to do film but the cameras are really expensive. About 30K$ for reasonable quality. Too much for this photographer.

My first air cannon was a 70psi PVC unit. I shot limes, ping-pong balls, Christmas bulbs filled with gelatin etc.

http://www.flickr.com/photos/8763834@N02/sets ...
by cometboy
Fri Dec 28, 2012 4:00 pm
Forum: Pneumatic Cannons
Topic: Copper Marble Cannon
Replies: 84
Views: 29028

All,

A few more images.

I should be getting parts for my compressor in a few weeks so I can work on the higher pressure. I don't think I'll be going to 300psi but we shall see.

<a href="http://www.flickr.com/photos/8763834@N02/8316443888/" title="Non-Mayan Chocolate Apocalypse by alan_sailer, on ...
by cometboy
Wed Dec 26, 2012 8:50 pm
Forum: Pneumatic Cannons
Topic: Copper Marble Cannon
Replies: 84
Views: 29028

To Whomever,

I said that I would post a few images once I got my new cannon up and running.

It's at low pressure, I am still working to get my refrigerator compressor running. I bought a bare compressor, no starting parts, so.....

I also had a problem with the unit triggering too easily. This ...
by cometboy
Fri Dec 21, 2012 6:54 pm
Forum: Pneumatic Cannons
Topic: Copper Marble Cannon
Replies: 84
Views: 29028

Technician,

I see where you are coming from.

As an optical chrono it might work.

I would be worried that flash jitter ie variations from flash to flash would be a big source of error. Especially compared to your quartz xtal time base.

I am most often coming from a "How do I make a good photo ...
by cometboy
Fri Dec 21, 2012 4:03 pm
Forum: Pneumatic Cannons
Topic: Copper Marble Cannon
Replies: 84
Views: 29028

I'll look into the reflectors.

You idea has merit. But as far as I understand it, you would get a bunch of shots of a projectile traveling through the air.

A great technical achievement, but I have doubts that it would be visually interesting.

The impact is when things really start happening ...
by cometboy
Fri Dec 21, 2012 12:17 pm
Forum: Pneumatic Cannons
Topic: Copper Marble Cannon
Replies: 84
Views: 29028

Jack,

I plan to go slowly as I do not really know what I am doing. And I may never go to 300psi since my present 129psi/540fps has a fair amount of power. 1/2" plywood penetration is impressive to me.

Technician1002,

The lenses sound like a difficult part of your idea. Look up Cranz-Shardin ...
by cometboy
Fri Dec 21, 2012 9:37 am
Forum: Pneumatic Cannons
Topic: Copper Marble Cannon
Replies: 84
Views: 29028

Jack,

You know your stuff for sure.

When I searched I didn't find much at all.

I will read these and figure out what to do. And when I get some "damage" pictures I promise to post them.

Cheers.
by cometboy
Thu Dec 20, 2012 1:10 pm
Forum: Pneumatic Cannons
Topic: Copper Marble Cannon
Replies: 84
Views: 29028

Jack,

Just knowing that the valve is supposed to be sensitive is a great step towards a solution.

Thank you.

Off topic, but I bough ta refrigerator compressor that has none of the starting parts. I know it needs a PTC start relay and a run cap, but other than that.....

Any resources?

I am ...
by cometboy
Thu Dec 20, 2012 12:34 pm
Forum: Pneumatic Cannons
Topic: Copper Marble Cannon
Replies: 84
Views: 29028

3/4" Valve

It has been a long time since I posted. I am sorry if this makes me a bad SpudFiles contributor, but as I have mentioned before my primary interest is taking high speed photographs.

I have built up a second copper air cannon that I want to use for shooting small (~11mm) steel bearings.

The ...
by cometboy
Fri Dec 23, 2011 9:31 pm
Forum: Pneumatic Cannons
Topic: Copper Marble Cannon
Replies: 84
Views: 29028

ramses,

Jasper (she) got me started. When I saw that it was possible to build a fast flash, I built one.

Cheers.