Potato gun igniter...

[personman]

Hey, I made a potato gun a while back out of PVC but I could never get it to work (I was using hairspray) and I just came up with the idea of launching my school adjenda out of it, so I tried to make it work with the bbq grill igniter that I was trying to get it to work with before.. its not working, ive tried deoderant(main ingrediant: butane) and hairspray both.. so I think its the igniter and its not giving off a good spark, and I just came up with the idea of using a 9v battery.. well the spark is miniscule and I dont know what to do.. is there a way I can make a bigger spark? I thought of using a spark plug too but I dont have one readily available..
Here is what I have setup so far, yes I know, the wires will be longer..

[personman]

Here is my gun..
Do you guys think my barrel is too long for anything to get out?:confused:

[pbguy888]

One of my friends is an engineer and makes alot of these. We shot some last weekend and we allways use the spray deodorent. His sn on aim is - doobykeebler1 tell him Andy said he could help with your spud chucker and he will be happy to.

[personman]

I think I set my igniter up wrong :o
I will talk to him..

Meanwhile I will fiddle with my lighter..
I have my eye on this (http://www.mscdirect.com/IWCatSectionView.process?Keyword=Y&RestartFlow=t&Merchant_Id=1&p_section_Id=2000379&Section_Id=2000379&p_product_type_Id=1297&ShowProductList=t&p_att_type_id_0=21344&p_att_value_id_0=341261&p_search_flag_0=1&SelectedAtt.length=1&pbegin=0&pcount=15&NameVector%5B0%5D.Name=Type&NameVector%5B0%5D.Value=Pencil+Flame+Porpane+Torch +Kit&NameVector.length=1&View.x.x=114&View.x.y=5&View.x=View+Products) just in case ;)

[sneakyhacker420]

get a glow plug for a nitro RC car... they heat up quick, and if they can ignite Nitro-Methane fuel, they can ignite hairspray...

you'll also wanna try the compressed butane for jet lighters, that stuff is HELLA FLAMABLE


btw, barrel looks a bit big for a spud gun IMO (too large of a diameter)


edit: at sears or your local hardware store, they should sell replacement BBQ starters which make a fairly large spark to ignite the propane... they cost around $6-8 usually



just ask sneaky... he likes to burn alot of shiznit :D

[KILLMORE]

your barrel isnt too long but may be too wide. You need a pretty good seal too get good distance out of potatoes or whatever else. I have a roll flint in mine for an igniter,
You can pick them for like a dollar and they are very reliable.

[Thordic]

Your barrel is too wide and your chamber is too small.


You want a 6" or 8" chamber, about 10" long, and a 2" barrel, about 2.5' - 3' long for a combustion spud gun.

You aren't going to get any velocity the way you have it set up now.

[personman]

Ok I understand about the size, but I cant even get it to light.
And sneaky, did u even read my first post? I've already tried a bbq lighter and it doesnt work. I just played around with it and set it up rigth but I still cant get it to light..

Whats roll flint? Is it something I can get at home depot? If It is I might as well just go by home depot and build another launcher.. I dont have a Nitro RC car, and I dont know where to get parts for one.

I am making a spark with the lighter but its still not lighting the spray on fire.. Is that most likely because of the chamber being too small and spray escaping out the barrel?

[mirthvader]

I made one that works on compressed air. 100 psi and away you go. Uses a lawn sprinkler valve for firing. Works awesome.

[SlipknotX556]

Potato guns, im to lazy to make something like that. If I want something to fly, I tape it to an airplane with 2 bottle rockets, light them, away it goes.

[personman]

You power the compressed air ones with bicycle pumps?

See, I like things like building stuff but I make a lot of mistakes.. and I mean lots of mistakes, so something where I have to drill a perfect hole into something then get it to glue right wont work.. what kind of sprinkler valve would I need? Maybe I'm just better off at reading directions from a site or something..

[ubooze]

Hey, use a tazer. Believe me, THAT will spark good enought.

I saw a video online of someguys tazer equiped spud gun, and he had wires running from the tazer's tips to screws/bolts/nails that were exactly level with one on the left side of the chamber and one on the right, with enough distance to allow for it to send the spark where it is supposed to.

.........................___
......................../.....\
(Tazer lead in) ---- S ----(Tazer wire out back to tazer)
........................\___/

S= spark

some reason the normal spaces wouldn't show, so just ignore the periods

[mirthvader]

I power mine with one of those 12V electric tire pumps. Hook it into the car and away you go. You can use a bicycle pump but it takes a long time. If you want to make yours work, you need to cut the barrel off after about 18". Add a reducer and 1.5" pipe on the end. Your combustion chamber is probably too big and leaking like hell trying to plug that sucker. If I can find the directions for mine, I will send them to you. It was easy to make.

[rhetor22]

hehe, 9volts isn't nearly enough to spark very far at all. That bbq lighter is probably making around 5,000volts.

Try rigging something up with a disposable flash camera. I have an idea that will make a much, much larger spark than the bbq lighter, but its really hard to explain.

You would need to have a metal probe in there connected to one wire of the flash, and a another probe that you could slide towards the first. Once the probes touch you'll have a nice big spark, and if that doesn't light it, then you just need more air in there.


Try going back to the bbq lighter and dont put so much hairspray in there. Fire needs air!

[personman]

I'm just going to build another firgnn launcher from this guide:
http://www.spudtech.com/content.asp?id=5

Thanks alot though guys, I'll put up pics tommorow when I test out my launcher (I might even attempt a video but I have no where to upload it..)

Oohh its going to be fun watching my ajenda fly across my back yard.. I might even set it on fire before I launch it.. lol soak it in lighter fluid, push it down the barrel, load up the launcher, drop a match down the barrel and then aim, and FIREEE ahahahahahahahha

Thanks again..

Edit: I'll keep your idea in mind, rhetor, just in case :D :insert evil smily here:

[einhander619]

I too have compressed air potato gun actuated by a sprinkler valve, and let me tell you, the performance is unreal! It will put a 2" chunk through plywood or over 500 yards away, your choice. Unless you're going to use propane, I wouldn't bother with a combustion gun. Here's a link that I think you might find useful and very entertaining.spudtech.com (http://www.spudtech.com)

[Tyril]

My friend and I made one a couple of summers ago, and we found that by far the best method of ignition was the grill igniter. The secret is in the mounting, however. We used two un-finished steel screws each pointing inward at about 30 degrees. This allowed us to easily screw one in farther if on one day the spark was not gapping, since screwing it in lessened the amount of space between the two pieces of metal.

Man, those things are fun. I've gotta built a nice ABS one this summer.... or even steel powered by ether =) I've heard stories of those things firing over a mile when burning ether!

have fun, and don't kill yourself,

-mike

[personman]

Well, I just came back from home depot with all the parts I need except 2..

The guy there said he had built potato launchers before and he seemed to know what he was doing, and he said I would be better off to use like a camping igniter that you twist and flint rubbs against a wheel and makes sparks. (im pretty sure thats what killmore was describing)
The guy saw the instructions for the cannon and said the chamber was too small so he lopped off a big piece of 4" pvc and a piece of 2" pvc and gave me the parts for the cap..
They were out of 4 to 2 reducers though, and he told me not to go with a bushing because it wasnt nearly as stable. So its going to be a pretty simple cannon, which is good I guess because not many things can go wrong.

[KILLMORE]

Personman,

A roll flint is a a brass rod with a flint on the end that sparks when spun. You can pick them up at Wal mart or prabably home depot. Just ask for a lantern flint and you should have no problem. Easy to use and less complicated than a compressed air design, you cant go wrong.

[KILLMORE]

didnt see your latest post

[personman]

Well it took some dremel work to make the igniter work like how I wanted to, and I snapped off the knob that makes one of the flint things spring loaded for pressure (lucakkly it was screwed in all the way when I snaped it) and I had to figure out some things about how to do it, but I made it, and it looks nice and clean ( from the outside atleast) its drying right now and then im leaving for oklahoma tommorow morning so ill test it when I get to oklahoma.. that will be pimp..
Here is a pic..

[personman]

Inside of the cap

[personman]

This thing gives off alot of sparks! If I cant get it to light with this I might as well give up :p

Ouside of the cap, just twist that little knob and BAM ;)

[mirthvader]

Be careful with that thing. Reason I went with air is that I can control the pressure. I know it's never going higher than 100 psi. With gas, you never know.

[personman]

Well, my grandparents have 40 or so acres of farmland in oklahoma, andi m about to go there so I should have plenty of room to fire the cannon.. I can even try to pluck off chickens from a distance ;)

Nahh they dont have any chickens.. :(

[BTAutoMag]

wheres butterfingers when you need him:)

[Sinnet]

my friends and i have a 3 inch gun, its about 15 feet long... we use spray deodorant and a kitchen torch to fire it, although we have a stun gun coming from ebay...

started firing big potatoes... then carved a wooden shell, and now we've got a mold made for concrete ones, havent tried them yet though

[mirthvader]

When I said be careful, I didn't mean with aiming the gun. The problem with hair spray or that type of firing system is you have no control of pressure in the barrel. You are using pipe made to withstand a certain pressure. Put a little too much propellant or have a problem with a plugged barrel and the pressure can rise quickly and blow your gun up causing death and dismemberment. Oh wait, I'm starting to sound like a parent. Never mind.

[OKJEFF4]

I recommend the CA ones also. Mine has a guage, and I screw in a 12oz tank. I've got a reg to hook up with it too. It has interchangeable barrels too, so I can shoot ping-pong balls (through a mason jar) or I can shoot a potato or pop can full of cement. Where in OK are you going?

[_Spork_1]

buy a grill button igniter, it sets off a spark when you click the button, just drill a hole into the chamber for it and it works like a charm

also, get a bigger chamber,you'll get no distance on that thing

[personman]

Ahhhh spork diddnt read the thread.

Anyway, I'm in oklahoma and yesterday I tried it out and its not working too well.. I shot an orange and an apple out of it but it only went like 40 feet.. we went to the store and picked out some potatoes and maybe they will work good.. I think one of my problems is like lubracation because I spark the right guard and you hear this like phsssssp and you open it up and the potato is like half way down the barrel.. maybe my barrel is a little too long, or maybe its not lubed up, or not a very good fit. Anyhow, im going to try again today.

[FalconGuy016]

Im likin this one...

[OKJEFF4]

Where in Oklahoma are you?