Spudzilla Pro BMF9000

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
Budarooski
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Mon Jul 06, 2009 12:05 pm

I just finished this it this past weekend. Works great, now to try MAPP gas!

It has two fans; the small one on the outside draws in fresh air, the CPU fan on the inside mixes the propane with the air.

Ignitor is a battery operated and integrated into the PVC.

[youtube][/youtube]

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Last edited by Budarooski on Mon Jul 06, 2009 12:32 pm, edited 1 time in total.
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twizi
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Mon Jul 06, 2009 12:09 pm

is this your first gun i must say wow

great first cannon

welcome to spudfiles
i expect great tings from you
dont play with airsofter with 1000$ gun and play with a 5 dollar pair of glasses
Budarooski
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Mon Jul 06, 2009 12:12 pm

It's actually my second (first was about the same, but no propane...just silver Right Guard).

My only complaint about this one is that the battery is too long for the case. When I bought the 12v 4200MaH battery, it was listed on eBay as being 20cm long, which would fit the box, but it turns out it's 22.5cm. I couldn't find a longer box after hours of Googling for one, so I had to settle for this.
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twizi
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Mon Jul 06, 2009 12:25 pm

but still second gun it still amazing
dont play with airsofter with 1000$ gun and play with a 5 dollar pair of glasses
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theBOOM
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Mon Jul 06, 2009 1:22 pm

Hey REALLY nice gun man 8)
Good job .. only thing is the barrel looks a little small for the size of your chamber maybe getting a couplers and make an extension :?:
Also you can get a ball valve to seal the chamber instead of the threaded cap, as they have a tendancy to blow off even in a normal spray and spray... you SHOULD be fine but incase it causes problems a ball valve is the way to go :wink:

Hey how did you get the electric igniter onto your handle like that? :shock:
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Moonbogg
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Mon Jul 06, 2009 2:01 pm

This is a beautiful cannon for sure! I like the inline design and the simplicity of it. Great job.
One thing I noticed is that I am not sure if the small fan is needed since when the large fan is used to vent it already brings in fresh air. As someone mentioned, a ball valve and only the large fan is a good way to go. Simply open the ball valve and kick on the fan and it will suck fresh air right through the whole gun and vent it out as well.
This is your second gun? Very impressive. Love the color scheme.
Budarooski
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Mon Jul 06, 2009 2:04 pm

Moonbogg wrote:This is a beautiful cannon for sure! I like the inline design and the simplicity of it. Great job.
One thing I noticed is that I am not sure if the small fan is needed since when the large fan is used to vent it already brings in fresh air. As someone mentioned, a ball valve and only the large fan is a good way to go. Simply open the ball valve and kick on the fan and it will suck fresh air right through the whole gun and vent it out as well.
This is your second gun? Very impressive. Love the color scheme.
Thanks for the compliment. I just bought a bottle of MAPP gas and will paint it red to go with the theme.

As for the fan, I originally built it with the small fan underneath, but quickly found it wouldn't vent out the chamber (as I kinda expected it was too small), so I added the second fan inside. Either way, I have to open a valve to add fresh air, and this setup works GREAT.
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Davidvaini
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Mon Jul 06, 2009 2:12 pm

I like this a lot.. I was gonna say that looks like a airsoft battery pack.. what type of connectors are you using for the battery?

I know it would be more cohesive if you have one large box for the battery, but have you thought about taking another little box and attach it on the end and then fill the gap with bondo or epoxy and re-paint it?


Overall very nice presentation, everything looks very solid and the paintjob is good. My only suggestion is that you incorperate some sore of bolt action loading or something so you dont have to use a stick to push it down... But since its a combustion and you have to wait in between shots longer, its not greatly important.
Budarooski
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Mon Jul 06, 2009 2:18 pm

Davidvaini wrote:I like this a lot.. I was gonna say that looks like a airsoft battery pack.. what type of connectors are you using for the battery?
It is...good call. It has a Tamiya connector on it and I can plug it into the cannon and easily unplug it to plug into my charger.
I know it would be more cohesive if you have one large box for the battery, but have you thought about taking another little box and attach it on the end and then fill the gap with bondo or epoxy and re-paint it?
I did, but after working on it for so long and finding it difficult to ever find time to work on it, I just wanted to finish it.
Overall very nice presentation, everything looks very solid and the paintjob is good. My only suggestion is that you incorperate some sore of bolt action loading or something so you dont have to use a stick to push it down... But since its a combustion and you have to wait in between shots longer, its not greatly important.
I don't mind pushing the ammo down...I put a small stop screw where the barrel and chamber meet to a) help keep the gun together, and b) avoid a "slippery" potato from falling into the chamber (has happened with my other gun). This chamber is too long and the fan is in the way for me to ever reach in and grab a loose potato.
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Moonbogg
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Mon Jul 06, 2009 2:25 pm

I want more from you! Do you have ideas or plans to build another?
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mark.f
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Mon Jul 06, 2009 2:35 pm

Very clean! The only suggestion I [had] was to simply go with one fan to vent and mix the fuel, but that's already been suggested. The extra fan isn't hurting performance or anything like that, it's just draining your battery more.

Overall A+.
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Moonbogg
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Mon Jul 06, 2009 2:38 pm

Oh...Sorry for spamming you but I had to mention another thing I liked...The LACK of a regulator! I am starting to think to hell with regulators. It keeps it cleaner, simpler and less expensive. It allows you to easily tweak the pressure and experiment on the fly. Either way is great, but what i'm saying is not having one is, IMO, just as good or better than having one.
Budarooski
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Mon Jul 06, 2009 2:38 pm

mark.f wrote:Very clean! The only suggestion I [had] was to simply go with one fan to vent and mix the fuel, but that's already been suggested. The extra fan isn't hurting performance or anything like that, it's just draining your battery more.

Overall A+.
The second fan draws (I think) something like .06AMP...something ridiculously low, and my battery is rechargable.

Thanks for the A+! :)
Budarooski
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Mon Jul 06, 2009 2:54 pm

Moonbogg wrote:Oh...Sorry for spamming you but I had to mention another thing I liked...The LACK of a regulator! I am starting to think to hell with regulators. It keeps it cleaner, simpler and less expensive. It allows you to easily tweak the pressure and experiment on the fly. Either way is great, but what i'm saying is not having one is, IMO, just as good or better than having one.
I agree...I wanted to be able to play with different psi settings to compare and contrast.

I'm going to paint my newly purchased (today at lunch) MAPP bottle red, then mount it tomorrow and see what PSI works best. Wiki says MAPP requires 4.98% Displasive Volume Percent, but then on the next page it says 4.6%, so I'm not sure what to believe. Then again, everything I read says Propane requires 4.03%, yet the second wiki page says 4.2%.
Budarooski
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Mon Jul 06, 2009 4:30 pm

theBOOM wrote:Hey REALLY nice gun man 8)
Hey how did you get the electric igniter onto your handle like that? :shock:
I started with a 1" PVC T and cut out a notch for the ignitor, then used JB Weld to smooth out the seams and hold it together. Then I sanded it all down.

To attached, I sanded (via dremel) a 1" coupler to curve one end of it so it made full contact to the chamber, then JB Welded it together. Let it drive overnight, then JB Welded it again to smooth it all out, let it dry, sanded it and then I had a boss for the handle to glue in. I makes for a smooth looking attachment.
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