Description

Thomas will accept orders for cannons until 31st July 2019. After that he will order the parts, make them and ship them about two weeks later.

Please give a shipping address that can accept the cannons in August – or contact Thomas if you want him to delay posting until September.

Vacuum cannon v1.2. It includes:

• A 1m long 1½ inch imperial PVC pressure tube with both ends lovingly smoothed off by Thomas with superfine finishing paper.
• Two tapped ⅛” BSPT (taper) female holes (one for the vacuum pump, one for fitting of a pressure gauge should you decide to buy one).
• A ⅛” BSPT (taper) male threaded nylon elbow valve. (The valve tube has a diameter of 6mm, perfect for rubber pressure tubing with 5mm internal.)*
• A ⅛” BSPT (taper) male threaded nylon plug for the second hole
• One roll of 3″ (extra wide) packing tape.
• Approximately 24 practise table tennis balls (as many as can fit in the tube).
• Safety information and tips on how to fire it.
• Sticker: “LOUD! Defend Ears!” at the firing end.
• Sticker: “the.physicsteachingpodcast.com” on the barrel.
• UK, EU, American and UAE postage calculates fine, but if you are in another country and make an order without contacting us then we will have to refund you less the PayPal charges we incur. Sorry.

Don’t forget that they are relatively easy to make: check out Thomas’ blog post about how to build one or check out the CLEAPPS links below.

Safety

CLEAPSS have a very thourough section on safety in their own description of how to make a cannon (you’ll need to be a member to access it). They also have a video about how to make one. Please seek it out an read it. It tallies with our own thoughts after our test firing, namely:

• The cannon is LOUD, hearing protection should be worn (we put a sticker on the cannon to remind you of this)
• There is a slim chance that debris from the tape cold fly out backwards in the event of a misfire, so eye protection is a good idea.
• The cannon shoots a ping-pong ball at close to Mach 1. Nobody should stand at or even near the business end, and safety screens should be used.
• Really, really only use a ping-pong ball.

If you purchase this you must take responsibility for firing it and make your own risk assessment.

*A ⅛” BSPT (taper) male threaded shrader valve (mentioned in the CLEAPSS document) should screw perfectly in to this hole.

By purchasing a cannon you are making a small donation to the podcasting costs, for which we thank you. We do all the postage at cost.