Improving a Harbor freight pipe bender

[Frank S]

Hi Frank,
When you fill the tube with sand and seal the tube to be bent. What do you use to seal the end of the tube with? Do you weld a cap on or use another method?

Pack it as tight as possible then weld a cap on the end.
Remember though even being filled and packed as tight as you can get it, you can still put a kink in the bend if you try and rush things. It is best to practice a couple of times to get the feel for how the tube is going to react. The better you prepare your jig or bending dies for the desired radius the more you will be satisfied with the results