i need to build a spud gun

[Simond001]

Ok, need tobuild a spud gun for pub competition.

I am fine with the mechanics, 2inch pipe barrel, 4 inch waste pipe for champber, hairspray propellent etc.

What i need to know is the best way to get a large spark. Preferable arcing accross the chamber.

Another option is using a spark plug, but again..how?

Appreciate any help.

[Red Firecracker]

You need to find an old gas cooker or hob. Get the piezo (?) ignitor off of that. Works a treat.

[Silent1]

Make a burst disk spud gun and use propane.

[KingRichard]

Simond001 said:

Ok, need tobuild a spud gun for pub competition.

I am fine with the mechanics, 2inch pipe barrel, 4 inch waste pipe for champber, hairspray propellent etc.

What i need to know is the best way to get a large spark. Preferable arcing accross the chamber.

Another option is using a spark plug, but again..how?

Appreciate any help.

Go old school with a flint lock... that would be cool

Or get one of those friction powered toys that use the sparks to light them up (used to have loads of cars like that as a kid), and cannibalise that. Or dismantle a zippo and use the sparking element from that?

[Ganglandboss]

Don't forget to video the finished product and put a YouTube link here!

Edit: WTF is an 'oroduct'?

Edited by Ganglandboss on Wednesday 27th August 11:28

[H2DaE]

what about those long lighter/sparker things for lighting gas hobs and barbecues? that's what all the other spud mortars seem to use

Edited by H2DaE on Wednesday 27th August 11:29

[devonshiredave]

this guy has it sussed

http://www.youtube.com/watch?v=wvpjAyHH490

We are building one too, perhaps a PH league in order

[Ganglandboss]

H2DaE said:

what about those long lighter/sparker things for lighting gas hobs and barbecues? that's what all the other spud mortars seem to use

Edited by H2DaE on Wednesday 27th August 11:29

Wikipedia says BBQ ignitors are often used!

http://en.wikipedia.org/wiki/Spud_gun

[Tuna]

Apparently the best spud guns use compressed air and a quick release valve - you can get about four or five times the air pressure that way. You can build a quick release valve out of piping, but you need to use gas pipe rather than normal drain pipe to withstand the pressure. Expect spuds to go up to half a kilometre that way.

[hairykrishna]

The coil from a microwave oven will give a high enough voltage to jump a ~1cm gap. Be careful!

[KingRichard]

Tuna said:

Apparently the best spud guns use compressed air and a quick release valve - you can get about four or five times the air pressure that way. You can build a quick release valve out of piping, but you need to use gas pipe rather than normal drain pipe to withstand the pressure. Expect spuds to go up to half a kilometre that way.

They did it with chickens on mythbusters and found that air pressure really had little to do with velocity

[SS HSV]

Very important to pick a good target

http://uk.youtube.com/watch?v=XNnEKnwsjVo&NR=1

What a tt.

[carter711]

My friend built one of these and used a electric gas cooker lighter as ignition, you can buy them all over the place.
The gun was very powerful, it put a massive dent in his old cavalier and sounded like a proper gun much to my mum's disapproval!

[Tuna]

KingRichard said:

Tuna said:

Apparently the best spud guns use compressed air and a quick release valve - you can get about four or five times the air pressure that way. You can build a quick release valve out of piping, but you need to use gas pipe rather than normal drain pipe to withstand the pressure. Expect spuds to go up to half a kilometre that way.

They did it with chickens on mythbusters and found that air pressure really had little to do with velocity

True, but volume is a factor, and the two are related.

Bottom line is that hair spray has only a limited ability to expand explosively.

I'll try to find the links..

[lawrence567]

I really want to build one of these but have no idea how - is it literally a matter of minutes to build one?

[sadako]

Get a relay, wire it so when the relay is off it energises the coil and such is stuck in a feedback loop, take the cover off the relay.

[Simond001]

I actually need to fire a leek, so the drainpipe is a reasonable diameter. Looked at compressed air but the larger bore pipes wouldnt work apparently.

I cant seem to find ignitors on ebay, or am i being thick!

[THX138]

Simond001 said:

Ok, need tobuild a spud gun for pub competition.

I am fine with the mechanics, 2inch pipe barrel, 4 inch waste pipe for champber, hairspray propellent etc.

What i need to know is the best way to get a large spark. Preferable arcing accross the chamber.

Another option is using a spark plug, but again..how?

Appreciate any help.

Go here..see the tech articles

http://spudtech.com/default.asp