here are plans from anoter site. are they n e good??
Posted: Sat Feb 02, 2008 7:50 pm
I'm planning on using propane.
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here are plans from anoter site. are they n e good??
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Posted: Sat Feb 02, 2008 7:51 pm
here's the barrel
Posted: Sat Feb 02, 2008 7:52 pm
just get rid of the lantern sparker and use a bbq sparker or camera flash and it will be fine.
Posted: Sat Feb 02, 2008 8:02 pm
Don't forget a chamber fan, which you should leave running during firing. Performance will suck without it, even if you do use metered propane.
Advancedspuds, while rather outdated in its understanding of spudding technology, is a great place for any beginner to start. I built my first spudgun from a (slightly modified) design that I found on advancedspuds. You may want to increase barrel size so that it meets the optimal 0.8:1 C:B volume ratio.
Advancedspuds, while rather outdated in its understanding of spudding technology, is a great place for any beginner to start. I built my first spudgun from a (slightly modified) design that I found on advancedspuds. You may want to increase barrel size so that it meets the optimal 0.8:1 C:B volume ratio.
Posted: Sat Feb 02, 2008 8:05 pm
what do u mean by 0.8:1 C:b??
what size barrel do u recomend
what size barrel do u recomend
Posted: Sat Feb 02, 2008 8:08 pm
I mean that the ratio of the chamber volume to the barrel volume should be about 0.8 : 1.
In case you didn't know, the formula for the volume of a cylinder is
(pi x radius^2 x length).
You should be able to use those to figure out your second question.
In case you didn't know, the formula for the volume of a cylinder is
(pi x radius^2 x length).
You should be able to use those to figure out your second question.
Posted: Sat Feb 02, 2008 8:27 pm
there is nothing wrong with the lantern lighter, in fact i like lantern lighters because you dont have to worry about setting gaps, but you do have to replace the flint.
Posted: Sat Feb 02, 2008 8:34 pm
It will work, but don't expect to reach the power of most of the guns here, to start I would recommend a simple sprinkler valve pneumatic.
Posted: Sun Feb 03, 2008 12:50 pm
It will work fine and is an OK first combustion gun.
Don't use the flint sparker. They work OK but it takes one hand to operate. A BBQ piezo sparker is more expensive (~$12) but are more practical and more "gun-like" since they can be easily built into a pistol grip.
It'll be a bit cheaper (and a bit safer) to not use the 4" cleanout adaptor on a 4"-3" reducer to the 3" chamber. Just get a 3" cleanout adaptor and omit the reducer.
The threaded joint for the barrel is not a particulary efficient design. It requires too many parts. Instead of the "bell reducer" just use a 3" coupler, a 3"-1.5" bushing reducer (you might have to do the 3" - 1.5" reduction using more than 1 bushing), a short piece of 1.5" pipe and the 1.5" male thread adaptor. You might get lucky and find a 1.5" male thread - spigot adaptor that'll save you the short peice of 1.5 pipe.
The best way to design and build your first gun is to decide on the chamber and barrel IDs then go to the hardware store and see what fittings they have. You might also want to get the parts for a pistol grip (1" or 3/4" pipe with a T-coupler and three caps) and a pair of screw hose clamps large enough to go around your chamber pipe and the pipe you are using for the pistol grip.
Once you have the fittings, pipe, PVC cleaner/primer and PVC glue then you can decide on the chamber and barrel lengths.
A fan will significantly boost the performance of the gun. The fan can be added later though.
Don't use the flint sparker. They work OK but it takes one hand to operate. A BBQ piezo sparker is more expensive (~$12) but are more practical and more "gun-like" since they can be easily built into a pistol grip.
It'll be a bit cheaper (and a bit safer) to not use the 4" cleanout adaptor on a 4"-3" reducer to the 3" chamber. Just get a 3" cleanout adaptor and omit the reducer.
The threaded joint for the barrel is not a particulary efficient design. It requires too many parts. Instead of the "bell reducer" just use a 3" coupler, a 3"-1.5" bushing reducer (you might have to do the 3" - 1.5" reduction using more than 1 bushing), a short piece of 1.5" pipe and the 1.5" male thread adaptor. You might get lucky and find a 1.5" male thread - spigot adaptor that'll save you the short peice of 1.5 pipe.
The best way to design and build your first gun is to decide on the chamber and barrel IDs then go to the hardware store and see what fittings they have. You might also want to get the parts for a pistol grip (1" or 3/4" pipe with a T-coupler and three caps) and a pair of screw hose clamps large enough to go around your chamber pipe and the pipe you are using for the pistol grip.
Once you have the fittings, pipe, PVC cleaner/primer and PVC glue then you can decide on the chamber and barrel lengths.
A fan will significantly boost the performance of the gun. The fan can be added later though.
Posted: Sun Feb 03, 2008 2:33 pm
If it were up to me, I'd say just use a 4" section of pipe for the chamber, and then use a reducer from there. It's a few less fittings, and the larger diameter chamber makes for a shorter gun.
And whatever everyone else said too.
Good luck, buddy
And whatever everyone else said too.
Good luck, buddy
Posted: Sun Feb 03, 2008 4:44 pm
yes, they are good. I've use them for my gun: http://www.spudfiles.com/forums/viewtop ... html#99667
Posted: Mon Feb 04, 2008 3:28 am
I will go ahead and disagree with the majority here... the lantern sparker has worked great on my last combution. go ahead and use it. just make sure that it is easy to get to when you need to change the flint. and as others have said, put a computer fan in the chamber, it really does make a huge difference.