A "How to Bend Tubing and Pipe by Hand" web site

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Jim Berquist
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re: A "How to Bend Tubing and Pipe by Hand" web si

Post by Jim Berquist » Fri Dec 02, 2005 1:55 am

Back to subject:

If you place a coil type spring inside the tube your bending it willnot kink!!

Don't leave it inside as it will most assured cause electrolisis......

Ok I can't spell

JIm
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hinote
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Re: re: A "How to Bend Tubing and Pipe by Hand" we

Post by hinote » Fri Dec 02, 2005 2:25 am

berquistj@peoplepc.com wrote:Back to subject:

If you place a coil type spring inside the tube your bending it willnot kink!!
If you buy a GOOD u-bend product, it will be mandrel-bent--and they use a series of steel balls strung along a cable and pulled back and forth inside the tube, to keep the tube from kinking or collapsing.

The interior of the tube will be coated with white grease as a giveaway.

If anybody (USA) wants some references for sources of good product, let me know.

Bill H.
Acoustic Propulsion Concepts

".......some day soon we'll be flying airplanes powered by pulsejets."

hinote
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Re: re: A "How to Bend Tubing and Pipe by Hand" we

Post by hinote » Fri Dec 02, 2005 4:09 am

hinote wrote: If you buy a GOOD u-bend product, it will be mandrel-bent
As a reminder, here's a cropped version of the recently-posted image of my M8E SS engine, at the Avenal test site.

The point here is that part of the nice appearance of this engine is because I utilized a professionally formed u-bend of 304 stainless.

This part isn't cheap at something like $45--but I think it's worth the bucks.

Bill H.
Acoustic Propulsion Concepts

".......some day soon we'll be flying airplanes powered by pulsejets."
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paul skinner
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Re: re: A "How to Bend Tubing and Pipe by Hand" we

Post by paul skinner » Fri Dec 02, 2005 2:34 pm

hinote wrote:
berquistj@peoplepc.com wrote:Back to subject:

If you place a coil type spring inside the tube your bending it willnot kink!!
If you buy a GOOD u-bend product, it will be mandrel-bent--and they use a series of steel balls strung along a cable and pulled back and forth inside the tube, to keep the tube from kinking or collapsing.

The interior of the tube will be coated with white grease as a giveaway.

If anybody (USA) wants some references for sources of good product, let me know.

Bill H.
Acoustic Propulsion Concepts

".......some day soon we'll be flying airplanes powered by pulsejets."
I never thought of that. Using ball bearings on a string. Good idea.

Paul.

Viv
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re: A "How to Bend Tubing and Pipe by Hand" web si

Post by Viv » Fri Dec 02, 2005 5:02 pm

Well on topic for a change, heres a very simple method of bending small (1/2" in this case) stainless tube 90 or 180 degree.

Peace of bar stock the required outer diameter then use a shaped bull nose tool to cut a groove, must be cut so that you are past the point of the curve and end up with a straight sided groove and so the side wall of the tube to be bent goes below the surface.

I don't think I am contradicting any physics books by claiming its a simple method and easy to do but will wait for any comments to find out;-)

Viv
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4.5" dia bar stock, 1/2 rounded groove
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Stuart
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Re: re: A "How to Bend Tubing and Pipe by Hand" we

Post by Stuart » Fri Dec 02, 2005 7:11 pm

hinote wrote:
If anybody (USA) wants some references for sources of good product, let me know.

Bill H.
Acoustic Propulsion Concepts

".......some day soon we'll be flying airplanes powered by pulsejets."
I think I've found some sources for up to 4.5 " mandrel bent pipe, but I would have a cow if someone could find me 6" U in thin wall.
I'm writing an automated airplane designer in java, useful later when you guys get ready to bolt a p-jet onto some wings

hinote
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Re: re: A "How to Bend Tubing and Pipe by Hand" we

Post by hinote » Fri Dec 02, 2005 8:14 pm

Stuart wrote: I think I've found some sources for up to 4.5 " mandrel bent pipe, but I would have a cow if someone could find me 6" U in thin wall.
Look through some suppliers of big diesel truck parts. 6-inch is used in the exhaust of some of them.

Here's a typical example:

http://www.grpipes.com/heavytruck.asp

Bill H.
Acoustic Propulsion Concepts

".......some day soon we'll be flying airplanes powered by pulsejets."
Last edited by hinote on Fri Dec 02, 2005 8:23 pm, edited 1 time in total.

hinote
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Re: re: A "How to Bend Tubing and Pipe by Hand" we

Post by hinote » Fri Dec 02, 2005 8:18 pm

Stuart wrote: I think I've found some sources for up to 4.5 " mandrel bent pipe, but I would have a cow if someone could find me 6" U in thin wall.
Also don't fail to consider the use of 2, 90-degree bends. They'd be really easy to weld together to form the u-bend, and you'll usually find the bend radius is tighter. You can also leave-in as much straight section as you want, in the middle of the "U".

Bill H.
Acoustic Propulsion Concepts

".......some day soon we'll be flying airplanes powered by pulsejets."

Jim Berquist
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re: A "How to Bend Tubing and Pipe by Hand" web si

Post by Jim Berquist » Sat Dec 03, 2005 1:07 am

I never heard of the U-Bend product and seems to be hard to find here in Deming...

My wife does have a string of Pearls from japan!!!!!!

HEMMMMMMMM!
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Mark
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re: A "How to Bend Tubing and Pipe by Hand" web si

Post by Mark » Sat Dec 03, 2005 1:36 am

Maybe a boiler company would have some big curvy pipe too. Imagine the effort to make this octopus.
Mark
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Bruno Ogorelec
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re: A "How to Bend Tubing and Pipe by Hand" web si

Post by Bruno Ogorelec » Sun Dec 04, 2005 7:06 am

Look at what Lockwood had to do to get a big bend fabricated. Not the clearest of pictures, but you can see what I mean.
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hinote
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Re: re: A "How to Bend Tubing and Pipe by Hand" we

Post by hinote » Sun Dec 04, 2005 7:17 pm

Bruno Ogorelec wrote:Look at what Lockwood had to do to get a big bend fabricated. Not the clearest of pictures, but you can see what I mean.
We've got poor Lockwood beat, right there!

BTW for those considering placing a u-bend in the "throat" area (the skinny pipe in the exhaust), there's a velocity node right at the back of the throat--so it's best to place it in the forward area if you have a choice. Optimum location would appear to be starting slightly aft of the foremost portion of the throat.

Bill H.
Acoustic Propulsion Concepts

".......some day soon we'll be flying airplanes powered by pulsejets."

Mark
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re: A "How to Bend Tubing and Pipe by Hand" web si

Post by Mark » Sun Dec 04, 2005 7:52 pm

Sometimes this is a good old obvious resource for finding the stuff you need, of course it takes some fishing/research to find the company that makes the exact stuff you want or need sometimes. Then too, they often have a minimum purchase price or sometimes only sell to businesses, (they don't want to bother with you). But sometimes you can end up talking to some very friendly, helpful people which is refreshing.
Mark
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