The cup piston has to be much wider than the barrel or it doesn't work. In this configuration it has to travel back the entire length of the cup to reveal the barrel.

I actually don't know what you try to achieve with a cup shaped burst disk.

Not exactly what you have in mind but the ejection system might be of interest.

http://www.spudfiles.com/forums/deus-ex ... t7864.html

I've had that problem just recently with an old router. It seemed that the router wasn't able to keep up the connection to the ISP, only a hard reset made it reconnect and then disconnected again after several minutes.
End of story...I replaced the router and now it works as it should.

Have a look at this FX launcher from spudtech.com if you need design ideas... http://www.spudtech.com/images/products/Thunderpipe%20Twins.jpg edit: On the topic of special effects and sawdust explosions... [youtube]http://www.youtube.com/watch?v=IvPL7KC1DEA&playnext=1&list=PL3A180C2F62E4BC85&feature...

There is nothing coming up when typing in "hhhh 0001 two hands cannon".
Maybe you should just copy and paste the address of the video....

Most of the cannons in that video have been discussed on spudfiles before (except the powder cannons), also the video itself.
Maybe the walking link library (aka JSR) will provide more informations later....


Edit:
apperently he did already

I think this design could be improved with a balanced piston. There is too much stress on the trigger mechanism in my opinion.

We know this guy is not from this world....
Some members already had "fun" with him.


edit:
Here is the thread...
http://www.spudfiles.com/forums/how-to- ... 24021.html

I used to be a spud gunner but then I took a pressure chamber to the knee (that really happened to me) .
Many of us have a story like that to share, it only makes you more aware of the dangers in this hobby.

Yea these hose barbs are hard to find, many people asked about it. Much easier to find are brass solder fittings.

I don't know if you guys have noticed but there also seems to be a recoil absorbing system involved. You can see it in the very first shot in the video. The shoulder stock and the receiver move apart from each other. The gun returns into default position rather slow after a shot, which indicates som...

There are these throwing toys that might use the same principle.

[youtube][/youtube]

Some years ago I've build one myself. I cut the middle part out of a plastic bottle and weighted one end.
Worked like a charm.

A fellow YouTuber posted on one of my videos that he has build an air gun that is capable of 2000 fps. I told him that this figure is more than unlikely but he insisted on that number. His calculations are like this.... 300 fps pellet gun penetrates 9 pages homemade gun penetrates 92 pages = 10x as ...

I get the 30$ "price tag" now but if you do a simple google search you will see that key chain bottle opener are not really a niche product. Don't get me wrong, I really value well made, high quality products but is there a market for that kind of product nowadays? The system of bottle caps is also ...

Looks good but the overall design is nothing new, I have known these bottleopeners for years.



The quality of your product is in a much higher league though but 30€ seems a little overpriced IMO.