Problems bending ½ inch pipe

[travis_towle]

I am trying to bend ½ inch rigid – but I am getting kinks.

I have a Harbor Freight style table top hydraulic hand pump bender with spring return.

I need a 90 degree bend using the #15 / ½ or #20 / ¾ bender die.

I am using ½ inch standard black iron pipe off the shelve of home depot – and I also tried ½ inch standard galvanized iron pipe off the shelve too. Both are kinking BAD. Six months ago they worked FINE and did not kink at all – but now I am getting all kinds of kinks and it is just not working. I thought it might be because of the cold – so I tossed some of the pipe in the grill and heated up – still kinks. Then I went back to my old scrap from 6 months ago and they are bending GREAT. Problem is in the pipe. They must have changed the pipe or supplier in the last 6 months.

I WOUNDER:
IS there a difference between 1/2 PIPE and 1/2 RIGID CONDUIT = they look the same? Maybe the Real Rigid Conduit even though it cost a lot more $$$ will bend correctly?

I must use Rigid because I need to thread the pipe for my antique fittings.

Please advise.

Travis E. Towle
Topeka, Kansas

785-357-1004

[EPAUTOWELDING]

The only time I have experienced kinking is when the wall thicness of the pipe or tubing is too thin. Or maybe you have your roller pins too close. In the wrap around type benders the dies have a minimum thikness that can be bent on them. The tighter the bend the thicker the wall needs to be. Compare the thicness from your old pipe and the new one. Hope it helps......El Paso..

[ImanCarrot]

An old guy I used to know used to bend pipes by hand (yes, by hand)... what he did way fill the pipe with fine grained sand, plug both ends and basicaly bend it!... no creases... just a thought

[travis_towle]

Filling it with sand would be WAY too much time for what I do. BUT I have found the problem.

Home Depot's newer pipe has a seem inside of it. This pipe will kink everytime. The older pipe has NO seem inside and bends just fine everytime.

I bought some other pipe at an electrical store today and it bent just GREAT for me. I thought it might be because I moved the wheels out a bit, so I bought another pipe at Home Depot and tried it tonight too, and like before it kinked on me. I then cut the two pipes in the middle and miked the them to compair and they were both exactly the same thickness. The only difference between the two is the seem.

So - the seemed pipe will kink everytime no matter what and no matter where you put the seemed edge. They must make it different in a way that makes it weeker then the other non-seemed pipe.

Thanks for the help guys!


Travis E. Towle
Topeka, Kansas

785-357-1004

[greg b]

It is probably not just the seam in the tube that makes it get wrinkles it is probably more the hardness or softness and pressure applied in the right place on the tube. Over the years i have bent quite a bit of round tube in steel ,alluminium,stainless,copper and have also made a few benders from 1/4inch to 2inch and depending on the tubes hardness/or softness you need different amounts of pressure and support. On the sand bending side of things or as we called it gas bending you are quite right ,it is very slow and quite an art but very rewarding,as I found out of many years of making 1off exhaust systems for classic motor cycles in both stainless and cold drawn mild steel.Any ways enough of my blabbering while walking down memory lane good luck with that tube bending and good to see you sorted your problem.greg b.