We built a couple air-powered marshmallow launchers and are interested in other groups that built them. We're constantly being asked how to make marshmallow guns, so we thought we'd post the plans online. If you're looking for a smaller, less dangerous option, Instructables has marshmallow gun plans. Please contact us to report how your launcher worked or if you need help building it . A scout is helpful, right?
What We Did
At the November 2005 Fall Cub Scout-Boy Scout campout, our programming included a Marshmallow Launcher Range. The Boy Scouts set up a full target range for the Cubs to launch marshmallows from Air-powered, highly accurate, PVC shooters (click image on the right to zoom). Each scout got a chance to shoot marshmallows toward the targets and see how many holes they could make in the plates.
We found that the range is about 100 feet with a marshmallow. Other, heavier items will travel farther.
The marshmallow launchers are powered by an air chamber(rather than more dangerous gas/fuel powered), so they'll need to be pumped up with a bike pump or an air compressor. The small marshmallow launchers that use bite-size marshmallows like a blow gun are fun too.
Before you read the plans, please note that we are not responsible when you get hurt .
Supplies (available at your local hardware store)
1 6 ft. piece of 1in. PVC pipe
1 1in. valve (trigger)
1 1in. in to out elbow
1 1in. PVC cap
1 standard tire valve (for a car from an auto parts store).
PVC glue and primer
Several bags of the big marshmallows
An air supply (compressor or pump). Limit the pressure is using a compressor. Otherwise, we found about ten pumps works well.
Instructions to build the Marshmallow Gun
Cut the 6ft piece of PVC into approximately 4ft and 2ft pieces. The 2ft piece will be the air chamber, the 4ft piece will be the turret.
Glue the turret into the 1in. PVC valve. We kept the assembly vertical with the valve on top for a few minutes to ensure that the glue didn't drip into the valve and lock it.
Next, glue the 2ft piece of PVC pipe into the other end of the valve. Same process of keeping the valve above the glue till it dries.
Now you can begin the tire valve assembly. First, drill a hole the size of the tire valve you purchased into the flat end of the PVC cap. There are two sizes (maybe more), but the package will tell you the size. You might need to slightly increase the size of the hole in order to get the tire valve into it. Finally, using a pliers or visa grips, insert the tire valve into the hole and pull it through. Obviously, the valve stem should be coming through the top of the cap. This will be hard; if you make the hole in the cap too big, though, you'll have a leaky valve.
Now glue the cap onto the "in" side of the elbow and let ti dry.
Finally, you can glue the "out" side of the elbow to the end of the 2ft piece to complete the air chamber. This glue joint is the only one where you really want to pay attention to the orientation of the elbow because you'll want to reach the air valve easily while having access to the trigger (PVC valve) - especially if you are mounting the turret as we did.
There is one optional step, which is to take a short (6 in.) piece of 1/2in PVC and mount it to the end of the turret as your heat-seeking scope. We added a pine needle down the center of it for more accuracy.
Using the Marshmallow Launcher
Close the trigger, locking the air chamber.
Load a single large marshmallow into the turret. Depending on temperature, you may need to roll the marshmallow in your hands to help it slide down the turret a little better. When they get cold, they slide down better (building this using 1 1/2 in PVC might fit the marshmallows better, but we didn't try it).
Pump up the air chamber. Using a hand pump, it's probably impossible to over pump it. If you have a compressor, pay attention to the MAX PSI ratings of the PVC. WE ARE NOT RESPONSIBLE WHEN YOU GET HURT.
Finally, keeping the launcher down range at all times, aim your launcher and flip the trigger (PVC valve). The trick is to flip the valve as quickly as possible for maximum velocity.
Reload and repeat.
We are currently looking at modifying the design to use a 1in to 2in adapter to create a 2 in. air chamber, creating a venturi for the air to exhaust, potentially increasing velocity. We'll update this page with more information.
If you build this and would like to share your experience or modifications, please contact us with details.
December 11, 2006 - Mike from Giant Database added a 6 inch piece of copper pipe bolted to the red trigger valve , making it a lot easier for younger scouts to trigger the marshmallow launcher. Nice Mod!
We've heard other people call these things marshmallow shooters, marshmallow guns, marshmallow blasters, and marshmallow launchers. As far as we know, they are all the same.
Here are some additional pictures from the Marshmallow range we set up at camp.