Step 3: Firing

Picture of Firing
Safety first: Lighting the mortar without a stand (like I did in the first shot of the video) is asking for trouble. A simple and fast stand can be made from PVC pipe and coat hanger as demonstrated in the photo. If no stand materials are available at least lean the mortar against something (bench, rock, etc.) so it isn't at risk of falling when you are trying to light it.

Tip: 3" PVC pipe will fit perfectly around Pringles cans with just the right amount of duct tape on them. A hole can be drilled through the PVC and cans for lighting. This provides extra structural reinforcement to the cans lessening the chances of a blowout.

Tip 2: Use a barbecue lighter, or like in the video a quick & easy torch (made by bending coat hanger around paper towel). This will put distance between your fingers and the bottom of the tube, in case of a blowout.

Generic safety stuff: Use adequate eye, ear, nut-sack, and various other body part protection.

To prepare for firing: Set up the mortar in a large open area where you have little risk of hitting someone. Squirt about 1-2 teaspoons of lighter fluid down the barrel of the mortar, making sure to aim for the bottom can. Spray a little extra through the hole in the bottom, to help aid in lighting, or, if using hairspray, you can spray hairspray down the mouth of the barrel for a few seconds. Drop the tennis ball down the barrel. The mortar is now loaded, and from now on no one should pass in front of it.

To fire: Wait about two minutes after pouring, to give the chamber enough time to fill up with the evaporating lighter fluid (Pouring the perfect amount of fluid, and waiting till exactly the right time to light are the two things to master when it comes to tennis ball mortars). Light the barbecue lighter or torch, and hold it close to the hole on the bottom. If all goes well you should hear a loud bang, and see the ball sail off into the distance.
jxmorris123 years ago
When I light my mortar, a small flame appears by the hole (nothing explodes). This is without lighter fluid. What is the reason for the lack of combustion?
I want to use it for airsoft and I wanted to know if anyone knows how to make the tennis balls explode and shoot BBS everywhere.
Any ideas?
just wrap the BBs in aluminium foil or place a paper ball underneath it
ElQuirko5 years ago
Doesn't work with hairspray - at least, not for me.
Alternative fuel source, propane and oxygen in small balloons. It requires that you use PVC because of the smooth inside of the barrel but its far more reliable than lighter fluid albeit a bit more expensive, and if you have leftover balloons you can scare the neighbors by turning them into loud explosions!
thedog4587 years ago
hey really good Instructable. now this is gona be a really dumb question but do u have to use the lighter fluid?(coz where I live they don't sell it) :(
are u serious?? where on earth do you live???
Tetranitrate (author)  thedog4587 years ago
Yeah, you kinda do need the lighter fluid. Where do you live that they don't sell it, North Korea?
I got a garage shop ballistics book, and it says that hairspray can work too, which makes sense. Would the whole thing just blow up?
lol no I live no coober pedy. but thanks any way.
ben0801966 years ago
ok i finaly got it to work, but my tube cuaght on fire and i connot usa it any more the out side is ok but the inside is burnt
ben0801966 years ago
i did just as the instuctions say and i couldnt get it to worj except for 1 time and it went about 10 yards
i wonder if you could turn this into a shoulder mounted cannon?
FLairsoft6 years ago
looks like ive found my airsoft team a workable paint/vinegar and baking soda greande mortar. Would you be able to convert the combustion process into a air propellent?? (pyrotechices is discouraged becasue od one rather nasty incident) Co2 or a bike pump maybe??
Crazy Kid6 years ago
i built one out of tennis ball cans and it blew up from all the pressure and caught of fire
jaghk Crazy Kid6 years ago
guys can we use a metal tube? wdnt that be safer?
Crazy Kid jaghk6 years ago
no you have to have the holes so the pressure comes out fast it trys to find the fastest root
jaghk Crazy Kid6 years ago
Thanks! But if we drilled a holes in the metal? sorry if I am being too dogmatic on this...
andrew137 years ago
Ya think you can put airsoft BBs in it?
i made this into a RPG-7 out of this its sick as hell PS heres a real RPG-7
here it is rough model not quite done as of yet
Photo 1.jpgPhoto 3.jpg
what did you use for the grip?
an mm's tube
Dang, that thing looks fun to play w/!
ya totaly
maby if you shacke the liquid it could makevapour easier too and if u head it up using blueice you can heat that up and then it will make it combustable hint: put the blue ice around the propelant cartage and let it head up awesome for shooting and if you play airsoft you can use it to make covering fire
lolz i have the stuff to make it my parents are strict though so i cant make one but i can make a modle
greenupkid7 years ago
hey use pvc pipes and pipe glue it works better and shoots farther
Scythica7 years ago
i made this and fired it using a storm drain as a bunker i worked once but then the mortar court fire lol i tred it at a mates again but we re-enforced it and used a more power put propelent (Av gas (jet fuel) vapour)and we fired tennis balls filled with very fun stuff if you want to know what those fun stuff was email me and i'll be glad to share
cost me about 20$ to make, where i live pringles are like 3.00$ a bottle because right now the only way to get in and out is by plane.
behonu7 years ago
Back in the day me and the boys built one of these out of six coffee cans. Chip cans are a little...er...cuter...
...ha ha ha...that video was great....
PYRO7217 years ago
dude make shells out of paper or cardboard and put airsoft bbs in them and you have a morter, just dont kill your friends.
can u shoot other stuff out of it like paintgrenades for example or will it explode in the barrel???
i love this thing! i almost lit my neighbors house on fire with it though.... when i shot it the ball came out on fire and landed on their roof! (thank god it rolled off)
hey you can soak the ball in water and it'll still shoot
what is the aproximant distance?is accuracy good?
jmc10298 years ago
Fun instructable... Explosions and Flying objects ... What's not to like!
dwhicks018 years ago
If you would like the mortar to fly further, use a stronger cannon. My suggestion would be using soup cans, they are much sturdier than Pringles cans. Also, use a thin peice of wood as a stronghold to help keep the cans straight. Just use a canopener to make the hollow cylinder structure. Also, this requires less tape and people are more likely to have a few things of canned food than Pringles.