Compressed air is the most common way to shoot t-shirts and other objects from a cannon. If you want to fire marshmallows, then a low-tech solution is the best option. Air from your lungs can easily push a small marshmallow out of a homemade gun. The most important aspect is the design of the gun. You can use a variety of materials for this purpose. However, a PVC pipe marshmallow gun may be the best option.
A PVC pipe marshmallow gun is similar to how a basic blowgun works. You will blow into a mouthpiece to send a marshmallow out the end of the barrel. The design of the gun will need to include grips or handles to make it look more realistic. However, the assembly will require a bit of thought.
Making a PVC pipe marshmallow gun will require the right type of PVC pipe. The best type of PVC for the gun you will build has a 1/2-inch diameter. If you use anything bigger, then smaller marshmallows might simply fall out of the gun. You should also be able to fit two or more marshmallows in the gun. If you want to fire a larger marshmallow, then an extension for your PVC pipe marshmallow gun is necessary.
There are many design options to consider when making a PVC pipe marshmallow gun. For example, you may choose to make a marshmallow gun look like any old fashioned machine gun used by gangsters. This is something to consider based on the result you want to achieve.
Connecting the parts for your PVC pipe marshmallow gun will require various adapters. These adapters are easy to find at a local home improvement store. This is also where you will find all the PVC pipe needed for this project. You may also want to paint the gun once you have the assembly completed.
The basic steps to make a PVC marshmallow gun are found at instructables.com here…