How to bend 1/4" pipe without kinking?

Madhatter

Madhatter

Sr Member
Hi everyone

I am going crazy trying to get 1/4 inch pipe to bend at a 90 degree angle without it crimping. I have tried a pipe bender, pipe bending springs,filling it with sand, heating it then try to bend it all of the above in one go and all with the same result: kinked bends. How can I get a 90 degree bend without the middle of the bend caving in on itself? I need to essentially make a U bend. It has to be a tube to run the power wires up through the middle

edit: forgot to mention it's brass tube Im trying to bend
 
Madhatter
Perhaps you can use a solid styrene rod in it. Afterwards use a chemical to eat the styrene away. Brass is a rather difficult metal to make a tight bend successfully. Thin wall brass would be easier, but I find brass doesn't stretch or wrinkle easy.

Does it need to be a brass tube? What kind of strength or rigidity do you need?


TazMan2000
 
I guess it doesn't have to be brass - it's just what I have on hand. It's for my Star destroyer build. I want the tube to come out the bottom of the base, go up 90 degrees, go straight and then back in on another 90 degrees to go back into the model. I need 2 of them - one for the front and one for the rear, although if I could get away with just 1 I would, but I think the weight of the SD would require 2

Edit: this is a long winded way of saying I want to side mount it
 
Last edited:
If it's brass, get the trick instrument makers use: fill pipe with soapy water, plug the 2 ends (rubber plug if possible) put pipe in freezer for 36 hours (to make sure all of your water is frozen solid), remove from freezer and bend it: voilà...a perfect bended tube with no kink!
 
joberg said:
If it's brass, get the trick instrument makers use: fill pipe with soapy water, plug the 2 ends (rubber plug if possible) put pipe in freezer for 36 hours (to make sure all of your water is frozen solid), remove from freezer and bend it: voilà...a perfect bended tube with no kink!
Click to expand...

This is amazing!!! I thought this thread would be interesting
 
Madhatter said:
I guess it doesn't have to be brass - it's just what I have on hand. It's for my Star destroyer build. I want the tube to come out the bottom of the base, go up 90 degrees, go straight and then back in on another 90 degrees to go back into the model. I need 2 of them - one for the front and one for the rear, although if I could get away with just 1 I would, but I think the weight of the SD would require 2

Edit: this is a long winded way of saying I want to side mount it
Click to expand...

I was thinking you could 3d print it in halves, but if it requires the strength to support something...

TazMan2000
 
I'm not sure how I'd go getting a smaller pipe out from the inside, but I'll give that freezing trick a go and see how that works out.
Any other ideas on how to side mount a SD?
 
joberg said:
If it's brass, get the trick instrument makers use: fill pipe with soapy water, plug the 2 ends (rubber plug if possible) put pipe in freezer for 36 hours (to make sure all of your water is frozen solid), remove from freezer and bend it: voilà...a perfect bended tube with no kink!
Click to expand...

It's true. I saw it on Mr. Roger's Neighborhood when he visited a place where they made trumpets.

Looking on YouTube now though, found something a little different:
 
the brass you are using sounds like it is too thick. Usually packed sand or frozen soapy water works well.

A 3D print, as mentioned, before is probably your best best for a crisp-looking bend.

Maybe bend a 1/4" rod of solid metal, then drill a hole to make a communication from one end to the other. Drill the hole shifted to the inside of the bend.

You have two mechanics working against each other: strong/thick enough to hold up a star destroyer and tight bend
 
Every piece of metal pipe has a bend radius limitation. The trumpet video was like a 10D bend and didn't use frozen soapy water but a malleable metal, to try and keep the pipe round. I've seen million dollar pipeline bending machines work and they have supports to keep the cross section of the pipe as round as possible. They stretch one side and compress the other, but there is only so much stretching and compressing a pipe can take before failure.

TazMan2000
 
Have you tried Bismuth?, it melts at 70C/160F and you melt it, pour it in, bend then melt it and pour it out.
Google Bismuth bending, I've used Woods Metal, which is an alloy of it
 
this topic comes up pretty consistently on this forum. i've seen the "fill with sand" and "freeze water" posted many times but i have only seen one poster here who claims they've actually had good results. was it good results with a 1/4" hobby store brass tube at an extreme tight 90 degree angle? nobody really knows and having tried the sand method personally, i remain skeptical....

good luck and tell us if it works.
i'm with taz on this one
 
Last edited:
You might not have much success trying to get a really tight bend, but if a larger radius will work then this could do the job:

1601195949490.png


LORESO Tube Bender, 3 In 1 for 1/4" 5/16" 3/8" 0-180 Degrees Tubing Bending Tools- Manual Tubing Bender for Copper, Brass, Aluminum and Thin Steel Pipes - - Amazon.com

LORESO Tube Bender, 3 In 1 for 1/4" 5/16" 3/8" 0-180 Degrees Tubing Bending Tools- Manual Tubing Bender for Copper, Brass, Aluminum and Thin Steel Pipes - - Amazon.com
www.amazon.com
 
Some good info in this thread:

Bending brass tubing

Tried bending brass tubing. Failed! This is the brass tubing from the hobby supply that telescopes. 9/32 (.281) tubing. Anneled it. Filled it with bismuth. When i try to bend it, it cracks the tubing right off. When i try with the tube empty, the tubing just folds right up. Should i try some...
www.homemodelenginemachinist.com www.homemodelenginemachinist.com
 
star-art said:
You might not have much success trying to get a really tight bend, but if a larger radius will work then this could do the job:

View attachment 1352975

LORESO Tube Bender, 3 In 1 for 1/4" 5/16" 3/8" 0-180 Degrees Tubing Bending Tools- Manual Tubing Bender for Copper, Brass, Aluminum and Thin Steel Pipes - - Amazon.com

LORESO Tube Bender, 3 In 1 for 1/4" 5/16" 3/8" 0-180 Degrees Tubing Bending Tools- Manual Tubing Bender for Copper, Brass, Aluminum and Thin Steel Pipes - - Amazon.com
www.amazon.com
Click to expand...

that's the same bender I have already. I may have to look at a different metal to use - something a little less prone to breaking
 
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