If you're working on HVAC or dust collector piping and you need to convert a female end to a male fitting, the traditional solution is to stop what you're doing, run out to the home center and buy a crimper made for the purpose, and watch your $30 investment sit in a drawer the rest of your life. Some tips advocate deforming the perimeter with a pair of needlenose pliers, possibly resulting in an ugly, uneven, ill- fitting job. Try this easy, no cost method instead for a more professional looking and better fitting joint.
Step 1: Crimp With Style
Grab a pair of wide mouth pliers and tape two cutoff brads to the lower jaw and one centered between on the upper. Now you have a reasonable facsimile of a proper crimper tool, and for 2 or 3 crimp jobs you just saved some serious time and money.
To use, just orbit the tool around the mouth of the opening trying for an even, undulating result. You should get enough shrinkage to fully and securely insert the new male connector end into the next female section.