so heres the scenario i've got the hf kninko-matic bender and i'm trying to bend 1" sch 40 for bumpers but its just kinking bad. its kinking on the side against the die and "flat spotting" on the other. the die has alittle gap on the sides of the pipe, but i know my pipe/die sizes match. i've lubed everything good.

heres my idea... fill with cold water, seal and cap both ends, then heat pipe to room temp, thus creating hydrulic pressure inside the pipe to prevent kinking. what you guy think?

i've tried using sand and it still kinks, may not be enough in the pipe? has sand worked for anyone?(personal experience, not "i've heard so and so")

I think that you will probably injure or kill yourself if you do that. I have seen hastelloy schd 80 pipe burst just due to the fact that both ends got valved off and it sat in the sun. And that is not even considering the added stress of bending it. The die should be tight. Keep taking it back to HF until you get a good set of dies. That or order some shim stock, and shim the dies.

Later,
Jason

I have heard of using sand

I have used sand and it helps a lot and will not explode on you.

Make the bend in 3 spots rather then 1.

For each mark bend a third of the bend.

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If you are bending 1 1/4 pipe, then thats what I would space each spot.

Does that all make sense?

if sand didn't work for you i highly doubt water will do anything better.




...unless you could fill the tube with water and freeze it where you are going to bend it so it is effectively a solid bar. i have no idea how you would do that with out splitting the tube in the freezing process.

for those who have used sand...

how full did it have to be, packed in?

how did you cap it? tape or welded? ie. how strong does it be?

I've use sand all the time and it works OK. I cap 1 end w/flat stk tacked in a couple of spots. Tacked enuff so I could knock it off w/a hammer(some times i have to grind). Fill w/sand tap the pipe on the ground to compact it a little and then fill to the top. Then tack another piece of flat stk on end then bend. Do all your bends b4 knocking off flat stk. It doesn't have to be jam packed..

Are you sure your using the right die? Pipe size is measured on the ID. 1" schd 40 will have 1.315 od, 3/4 pipe will have 1.05 od. Tube is measured on the od.

so heres the scenario i've got the hf kninko-matic bender and i'm trying to bend 1" sch 40 for bumpers but its just kinking bad. its kinking on the side against the die and "flat spotting" on the other. the die has alittle gap on the sides of the pipe, but i know my pipe/die sizes match. i've lubed everything good.

heres my idea... fill with cold water, seal and cap both ends, then heat pipe to room temp, thus creating hydrulic pressure inside the pipe to prevent kinking. what you guy think?

i've tried using sand and it still kinks, may not be enough in the pipe? has sand worked for anyone?(personal experience, not "i've heard so and so")


What size is the die? How tight are you trying to bend it?

i'm using a 1" die and 1" sch40. i'm trying to bed some 45's and some 90's for bumpers. the pipe starts to kink at about 22* and is ruined by 45*. it would be a "v" by the time i got a 90* bend!

I think that you will probably injure or kill yourself if you do that. I have seen hastelloy schd 80 pipe burst just due to the fact that both ends got valved off and it sat in the sun. And that is not even considering the added stress of bending it. The die should be tight. Keep taking it back to HF until you get a good set of dies. That or order some shim stock, and shim the dies.

Later,
Jason

googled it, 1" sch 40 has a burst rating of 15171psi and a working pressure of 3793psi

I've bent pipe 90* in that size w/sand in it w/no problems. So the OD of your
pipe is 1 5/16"?

I've bent pipe 90* in that size w/sand in it w/no problems. So the OD of your
pipe is 1 5/16"?

i'm using the home depot chinese pipe, what were you using when you bent your 90s?

i'm using a 1" die and 1" sch40. i'm trying to bed some 45's and some 90's for bumpers. the pipe starts to kink at about 22* and is ruined by 45*. it would be a "v" by the time i got a 90* bend!

Do you have a ram bender or a rotary draw bender? This is critical:

If you have a rotary draw bender, what is the CLR (center line radius) of the die?

If it is smaller that a 3.5" CLR you could have problems trying to get a good looking bend.

The tighter the bend, the thicker your material has to be. The thinner the material, the larger the radius needs to be. There has to be enough tube wall thickness to support the bend without collapsing, rippling or kinking the tube. Moving to a larger die usually helps with this problem.

i'm using the home depot chinese pipe, what were you using when you bent your 90s?

I was using used sch 40 1" ID 1 5/16 approx OD and some sort of Harbor Freight style hyd bender. We paid like $89.00 for it. I think I had the rollers closer to the center.
Nothing special!

quite possibly its the type of the pipe you're using and not the bender or method of bending.

A buddy of mine had this problem build his bumpers & sliders. He had a few sticks of pipe that bent perfectly with no kinking. But then he ran out and got some more pipe, but it was a slightly different type that kinks very easily. If you're interested send me a PM and I will ask my friend what markings where on the pipe that bent better. I do remember the good stuff had a smoother finish/coating on it though and had a bit of a redish tint to it (not rust tho) where as the crappy stuff was the starndard black finish.

i got this aaron


we have 2 different types of pipe we get up here.


one is the cheep ass black stuff. Probably like what you get from home depot.
it is cheeper to make, therefor the company makes mre money off of it. BUT the quality just isnt there.

we also have pipe with a glossy dark maroonish coloring on it. Both types of pipe have the same markings on them (a53a sched 40) but the maroonish pipe bend much nicer and doesnt kink at all

i took a sample to a local steel place and they told me the steel comes from different plants in China. i have him making some calls for me and ill get you more infoon it when i get it. he said its a fluke to get the good stuff and when it comes in it gets bought up quickly because people realize its better quality.

ill see if i can dig up some pics for yah

move the rollers as far out as they can go. i bent my bumpers & sliders with 1 1/4 sch. 40 without filling with sand and they were fine. the closer i moved the rollers to the center the more it jacked up the pipe.

I've allways been able to get decent bends out of 1/2", 1" and 1 1/2" pipe up to 90*. However, I've never been successfull with 3/4" or 1 1/4" pipe. I've tried packing sand in and no luck it just kinks over.

I'd bet quality of pipe has something to do with it. Water ain't gonna work.

Kevo

it seems that quality of the pipe has somthing to do with it, because people get such varying results with the exact same tool, setup the exact same way:confused:

is it true that the steel quality of sch 40 pipe is regulated?

i might get the ol' chop saw out and just angle cut all my corners, might look cool with bumoers with pointed "bends".

Might be something to the pipe quality... I sometimes run into batches of rigid conduit that will kink pretty bad. Keep in mind its pretty nice radii on our stuff too.

Might be something to the pipe quality... I sometimes run into batches of rigid conduit that will kink pretty bad. Keep in mind its pretty nice radii on our stuff too.


I have tube bender but have the HF bender and have bent 3/4 90* easily and nicely. You may try to fill it with Salt just because it can be desolved to get it out after packing. I would bet it is the pipe not the bender

it seems that quality of the pipe has somthing to do with it, because people get such varying results with the exact same tool, setup the exact same way:confused:

is it true that the steel quality of sch 40 pipe is regulated?


It is regulated in that the manufacturer certifies that the end product meets the mechanical, metallurgical and dimensional properties required by the standard it is built to (ASTM A53, ASME SA53, API 5L etc.)

In my experience any pipe procured from China is suspect and many industrial users of pipe will not allow any Chinese produced product to be used.

[

i might get the ol' chop saw out and just angle cut all my corners, might look cool with bumoers with pointed "bends".[/QUOTE]


Another aproach is to get some weld-o-let 90* and 45* Then its just straight cuts and zip them up.

Fill it with sand as has been said. Then go to a steel supplier and buy some real pipe, not lowes or home depot. Go slow and keep pressure on the top of the pipe in the die so that it doesn't come out of the die. On the rollers, take a piece of 1.5" pipe and cut ~2" off, cut that in half, then flatten it/sand it out some/or cut some more of the sides off so that a piece of 1.5" pipe will fit inside it--like a saddle of sorts or a follower on a rotary bender. Weld each half to each roller. It stops the rollers from denting the pipe altogether and also helps keep the pipe from kinking as bad. Seems like a lot of work but it really isnt. Keep practicing and you'll get the hang of it. Might also try smoothing your (shittily cast) die out as well.

Fill with water, put in the freezer.

Go to a steel supplier and good pipe. The HD and Lowe's stuff is junk. The good stuff from suppliers will come in 20' sticks with no threaded ends. It is night and day better quality. I wouldn't try to go anything past the 3rd hole personally.

i scrolled through quickly, so forgive me if this was posted before, but adjust you top stops out to the next hole, it will have a longer bend, but the kinks will be less.

I dont have any tips for you..... but where can I find some more pics of your rig?:D

I dont have any tips for you..... but where can I find some more pics of your rig?:D

this is my tracker, hitchless, and bumperless

this is my tracker, hitchless, and bumperless


cool thats it for pics? whats the wheel base?


Thought of one tip... there as this post about bending tube by hand... you just need a long bar for leverage and some thing to wrap it around.

I searched.. but i will see if i can dig it up.

Ok found it but I need some more pics of your setup:flipoff2:






























http://metals.about.com/gi/dynamic/offsite.htm?site=http://www.metalgeek.com/archives/2005/05/01/000047.php

I would not use water, I see too many things going wrong that way.

I have the HF bender as well. I have actually been able to bend tighter bends than 90º with sch 40 1.25 pipe.

The trick is in both filling the pipe with moist sand (packed) and patience.

Typically with other benders you could set your angle and go to town.With the HF bender you have to make "smaller" bends and on larger radius'. By this I mean (similar to the suggestin of marking the radius into thirds) start with your stationary points spread as far as they will go, and as flat. start your bend until you feel some resistence. STOP! adjust the stationary points in one position and repeat. Stopping at a minute amount of resistence.

Using the rule of thirds you were given early move the pipe in the bender. Once you run out of postions to make adjustments then begin adjusting one side while having the other side stationary in about the middle postion.

This method takes time but it can be done.

Another method that works somewhat but takes a lot of more care as well is to heat up the pipe as you bend it. It takes less force to bend so you have to watch what you are doing extremely close, but it does work.

The key is to pack the moist sand in. I tape it so that on the tighter radius bends, it will rip the tape on it's own rather than splitting the welded seam of the pipe (actually seen a caped pipe do that)

If you don't mind the extra weight, leave the sand in the tube making sure your have that tube sealed extremely well and you have a strong piece of metal. Almost making it a solid piece.

i filled it with wet sand, it was only wet because it's what i had around.

Duct tape one end, pack the sand in there pretty well, just by setting the pipe vertically and tapping the end against the concrete.

i also took a piece of scrap pipe and sliced it in half longitundinaly, then put the halfs between the pipe and the rollers, keeps the rollers from digging into the pipe.

I tried bending 1-1/4 x .049 chromo tubing on a protools 105 bender @ 4.5" CLR.

It was kinking like crazy. We tried sand and other similar stuff. Only thing that made a difference was putting a very thick coating of heavy grease on everything. The kinking was greatly reduced.

Go here and download the "Sand Bending.zip" file
http://www.locost7.info/mirror/tools.php

There is some good info there and the sand bending article if very informative.

Go to a steel supplier and good pipe. The HD and Lowe's stuff is junk. The good stuff from suppliers will come in 20' sticks with no threaded ends. It is night and day better quality. I wouldn't try to go anything past the 3rd hole personally.

Pat's 100% right. Get your pipe from a real supply house; the HD/Lowes stuff is complete crap. You want pipe mfg'd by Sharon Tube or Wheately. I went through the same thing you did; switching material was the key.

Pat's 100% right. Get your pipe from a real supply house; the HD/Lowes stuff is complete crap. You want pipe mfg'd by Sharon Tube or Wheately. I went through the same thing you did; switching material was the key.


Same here... never a problem bending decent pipe. Bends very smoothly - no sand, water, etc.

I do space out the rollers to their max, even for small diameters, and I do the sleeve over the rollers trick, otherwise, no problems with the HF bender using decent quality pipe.

Home Depot was the worst... Regular plumbing supply shop the best -- USA made pipe... I also shop their "drops" pile, which for my local plumbing supply means all the stuff that is slightly bent in 20 foot lengths! Last time out, I got half a trailer load for free... :smokin: Plumbed air lines in the shop with the 1" stuff and use the rest for exos.

ok, i've had the same problems with the HF benders that ya'll are having....the problem ISN'T the pipe it IS the die.....In the center if the die (which would be the center of the bend) sometimes the pipe doesn't fit tight because of the die being worn or it being manufactured incorrectly.. to correct this , use the weld /grind method on the inner sides/upper inner lip of the die untill the pipe fits snugly (you may have to slightly tap it once to fully seat) just make sure the pipe still lays in the bottom of the valley of the die and ther is no space anywhere around the pipe in the die...basically, the tighter the die fits, the better the bend. i dont use sand, water, etc. and i get perfect bends over 90* anytime i need them. yes, overtime you may have to repeat the weld/ grind method.

my die did not fit tight at all and the pipe would "pancake" until it did hit the sides of the die. i bet that was my problem. this is good info for next time because i just did the "angle cut" method for my bumpers.