How to bend 1/4" pipe without kinking?

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Madhatter

Well-Known 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
 

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TazMan2000

Master Member
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
 

Madhatter

Well-Known Member
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
 
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joberg

Master Member
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!
 

Chaank

Sr Member
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!

This is amazing!!! I thought this thread would be interesting
 

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TazMan2000

Master Member
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

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

TazMan2000
 

Madhatter

Well-Known Member
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?
 

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JCalhoun

New Member
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!

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:
 

JPH

Sr Member
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
 

TazMan2000

Master Member
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
 

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ajaxjones

Member
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
 

modelcitizen

Sr Member
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
 
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star-art

Sr Member
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


 

star-art

Sr Member
Some good info in this thread:

 

Madhatter

Well-Known Member
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


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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