Octania

Like brake or fuel lines

I bought the fancy semi-expensive tubing bender

First try went OK
2nd bend kinked as bad as bending around the alternator pulley
3rd also kinked

It's the semi-good type bender:
http://www.ebay.com/itm/Heavy-Duty-T...item35cb017aed

What am I doing wrong?
Tests were on 5/16 new tube in green, from the store.

Jetstarjim

It's kind of an acquired skill to a degree, so you'll likely ruin a piece or two until you get the hang of how much pressure to use and placement of the line. I've always found those coated straight flared pieces to be difficult to bend, and generally use the rolls, which seems to be a little softer and easier to work with.

drop top olds

Sometimes using a bench vise with special jaws that surround the tube will provide extra support and prevent kinking. It is a challenge to use the moderately priced tube benders and avoid the "kinks".

Stevec

Just last week I redid all my brake lines 3/16 and 1/4.
Take your time and buy plenty of extra tubing,it does get easier the more you do them.

I actually did some over 2-3 times just because towards the end I was making some nice clean bends and the first couple I did looked like sh*t and I didn't want to leave them like that.

Paladin31

It is perhaps binding on the follower... often will spritz the bender w/ WD40. Nice & smooth then. Also keep pulling around the perimeter of the block with the follower handle to help guide it to hold the tube in the groove.
Brett

1970supremevert

I have actually used the pole that basketball hoop is mounted on & water pump pulleys , nice tip with the wd 40

jag1886

I have a bender like that it works well with practice and don't get the tubing in the wrong size slot, it will kink every time.

Octania

We have a winner
I believe that I inadvertently put the 5/16 tubing in the 3/8 slot for the bends that failed.

Lube can't possibly hurt.

TripDeuces

I have the same bender but never had a problem. You can even make nice clean 180's with it. I've never used lubricant with it but can't see how that would hurt so give it a try. There is a bit of skill involved but it's more of a 'feel' I'd call it. Just make sure the end is locked in place and if the tubing has a seam in it I'd never place the seam on either the long or short bend but 90* to either one. Sometimes I will place the stationary handle in a vice and just pull the chuck handle in a slow steady motion. You're actually forcing the tubing into the channel and then dragging the chuck over it. Sometimes it helps if you push from the back side keeping the 'heel' of the chuck on the tubing making it do all the work. Also make sure the the correct slot is used.

TripDeuces

Also...........making it longer than you need is a good thing. As long as you have the correct shape you can always go back and cut it to the proper length. If you try and finesse it and make it utterly perfect with the exact size it makes it a whole lot tougher physically and mentally. Just make sure to account for the flare if flaring it because that will make it about a 1/16 inch shorter and install the flare nut first.