Used about 12 2" pvc pipes. Tried 1 1/2 inch, but bowed way too much. Upright 2" pvc pipe slides over 3 ft long 1 1/2 " pvc pipe imbedded in cement in each 3 gal bucket. Made mistake of not filling buckets completely full of cement,so we had to drill holes in bucket sides for water to drain out.
MINI MARSHMALLOW SHOOTERS: Made from 1/2" PVC pipe & connecters & a blast of different colors of spray paint (so everyone can keep track of their own gun), then seal w/clear primer. (See pic.) Simple to use . . . just load a mini marshmallow into the mouthpiece & give it a quick puff of air. Let the battle begin!