Rolling Thin Wall Brass Tube - Page 2
Close
Login to Your Account
Page 2 of 2 FirstFirst 12
Results 21 to 32 of 32
  1. #21
    Join Date
    Oct 2004
    Location
    Minnesota, USA
    Posts
    28
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    7

    Default

    As has been mentioned, musical instrument have many bends that are similar, conceptually, to what the OP is trying do do.

    The best example I can think of is the bell-tail on a trumpet. The tubing is ~0.6" in diameter and the 180deg. bend has a diameter of ~4-5". The wall is something like 0.030".

    You can see an example of making the bend here: YouTube
    See time: 5:10
    This is the Yamaha procedure. You can see that they are using Cerrobend or some similar low-temp alloy to make the bend. I have seen other manufacturers use water, then freezing to support the tubing for the bend. They add a little detergent to the water to make the ice weaker and less brittle. The water is a lot easier to clean up than the Cerrobend.

    My experience with instrument tubing suggest that annealing the tubing beforehand would be a good path to success.

    When making the bends, you still can get some wrinkling. These are then hammered out to smooth up the bend.

    -Jess

  2. #22
    Join Date
    Oct 2003
    Location
    East Peoria, IL, USA
    Posts
    5,407
    Post Thanks / Like
    Likes (Given)
    350
    Likes (Received)
    806

    Default

    Quote Originally Posted by jwhartley View Post
    As has been mentioned, musical instrument have many bends that are similar, conceptually, to what the OP is trying do do.

    The best example I can think of is the bell-tail on a trumpet. The tubing is ~0.6" in diameter and the 180deg. bend has a diameter of ~4-5". The wall is something like 0.030".

    You can see an example of making the bend here: YouTube
    See time: 5:10
    This is the Yamaha procedure. You can see that they are using Cerrobend or some similar low-temp alloy to make the bend. I have seen other manufacturers use water, then freezing to support the tubing for the bend. They add a little detergent to the water to make the ice weaker and less brittle. The water is a lot easier to clean up than the Cerrobend.

    My experience with instrument tubing suggest that annealing the tubing beforehand would be a good path to success.

    When making the bends, you still can get some wrinkling. These are then hammered out to smooth up the bend.

    -Jess
    what a fantastic factory tour!

  3. #23
    Join Date
    Mar 2009
    Country
    UNITED STATES
    State/Province
    California
    Posts
    5,173
    Post Thanks / Like
    Likes (Given)
    97
    Likes (Received)
    953

    Default

    I watched plenty of tube bending videos on youtube. Not the garage shop kind but the ones with automated machines rolling stainless tubing.
    Never was there one mention of using sand or frozen water. I was impressed and contacted a professional business that wanted to get a drawing
    with dimensions, etc. Probably would have cost several hundred but I'm not sure. The tightest radius they could do was something like a couple
    of inches with 7/8" OD copper.

    Using ice the bend has to be worked quickly as the ice melts. The water turns to ice and expands so a small air gap should
    be allowed for before sealing the ends. Cannot do anything too large unless there is a walk-in freezer. Burrr.

  4. #24
    Join Date
    Mar 2009
    Country
    UNITED STATES
    State/Province
    California
    Posts
    5,173
    Post Thanks / Like
    Likes (Given)
    97
    Likes (Received)
    953

    Default

    Quote Originally Posted by jwhartley View Post
    You can see an example of making the bend here: YouTube
    See time: 5:10
    This is the Yamaha procedure. You can see that they are using Cerrobend or some similar low-temp alloy to make the bend. I have seen other manufacturers use water, then freezing to support the tubing for the bend. They add a little detergent to the water to make the ice weaker and less brittle. The water is a lot easier to clean up than the Cerrobend.
    Cool video. I picked up a fact or myth about adding a little soap. The soap is used as a lubricant inside the tube as it moves in the bend process.

  5. #25
    Join Date
    Sep 2006
    Location
    Sacramento County, California
    Posts
    3,759
    Post Thanks / Like
    Likes (Given)
    2374
    Likes (Received)
    1287

    Default

    Quote Originally Posted by rons View Post
    I watched plenty of tube bending videos on youtube. Not the garage shop kind but the ones with automated machines rolling stainless tubing.
    Never was there one mention of using sand or frozen water. I was impressed and contacted a professional business that wanted to get a drawing
    with dimensions, etc. Probably would have cost several hundred but I'm not sure. The tightest radius they could do was something like a couple
    of inches with 7/8" OD copper.

    Using ice the bend has to be worked quickly as the ice melts. The water turns to ice and expands so a small air gap should
    be allowed for before sealing the ends. Cannot do anything too large unless there is a walk-in freezer. Burrr.
    Use key words "using sand to bend tubing".

    YouTube

    Use key words "using ice to bend tubing".

    YouTube

  6. #26
    Join Date
    Dec 2015
    Country
    UNITED STATES
    State/Province
    Illinois
    Posts
    437
    Post Thanks / Like
    Likes (Given)
    144
    Likes (Received)
    251

    Default

    Quote Originally Posted by rons View Post

    Using ice the bend has to be worked quickly as the ice melts. The water turns to ice and expands so a small air gap should
    be allowed for before sealing the ends. Cannot do anything too large unless there is a walk-in freezer. Burrr.
    Move north and do your bends outdoors between November and February.

  7. #27
    Join Date
    Mar 2009
    Country
    UNITED STATES
    State/Province
    California
    Posts
    5,173
    Post Thanks / Like
    Likes (Given)
    97
    Likes (Received)
    953

    Default

    Quote Originally Posted by kenton View Post
    Move north and do your bends outdoors between November and February.
    I would rather go to the local indoor ice rink.

  8. Likes kenton liked this post
  9. #28
    Join Date
    Jan 2019
    Country
    UNITED STATES
    State/Province
    Rhode Island
    Posts
    21
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    Quote Originally Posted by jwhartley View Post
    As has been mentioned, musical instrument have many bends that are similar, conceptually, to what the OP is trying do do.

    The best example I can think of is the bell-tail on a trumpet. The tubing is ~0.6" in diameter and the 180deg. bend has a diameter of ~4-5". The wall is something like 0.030".

    You can see an example of making the bend here: YouTube
    See time: 5:10
    This is the Yamaha procedure. You can see that they are using Cerrobend or some similar low-temp alloy to make the bend. I have seen other manufacturers use water, then freezing to support the tubing for the bend. They add a little detergent to the water to make the ice weaker and less brittle. The water is a lot easier to clean up than the Cerrobend.

    My experience with instrument tubing suggest that annealing the tubing beforehand would be a good path to success.

    When making the bends, you still can get some wrinkling. These are then hammered out to smooth up the bend.

    -Jess
    Thanks Jess. The soap and frozen water sounds like a promising lead, as I don't have nearly enough cerrobend (or Wood's metal) to fill the tube.

    Thanks all for the input.

  10. #29
    Join Date
    Jun 2014
    Location
    Kansas City
    Posts
    738
    Post Thanks / Like
    Likes (Given)
    102
    Likes (Received)
    469

    Default

    I used to work at a shop that had several regular jobs bending stainless steel thin wall tube in different configurations and diameters, the largest diameter was about 1 1/4”, I think. We used a pressed in aluminum mandrel or a UHMW mandrel that was several thousandths over size and frozen in dry ice for awhile to shrink. After bending in very close fitting dies in a press, the aluminum and UHMW was melted out. Freezing water in the tube with a washer welded on the ends to contain the water, only worked on the easiest bends- I don’t have much hope that the tight bend you are talking about will work

    If you were to put some kind of a stopper it the tube that is downstream from where your bend is - that way you wouldn’t need as much low temperature metal and you could melt it back out. Or use the UHMW ( I don’t remember how much the size difference is, but you could freeze a piece and see how much it shrinks- and just leave it in. Same with the aluminum, although it might be a little heavier.

  11. #30
    Join Date
    Dec 2016
    Country
    UNITED STATES
    State/Province
    Arizona
    Posts
    139
    Post Thanks / Like
    Likes (Given)
    21
    Likes (Received)
    47

    Default

    Can you substitute an 90° elbow in place of this bend? It would make things a lot easier if you can. It will be a tighter radius though if that is an issue due to the design of the bar.

    Polished Brass Flush Radius Ell 2" OD - 00-731/2 - Architectural Railings - Flush Fittings

  12. #31
    Join Date
    Mar 2011
    Location
    Providence RI
    Posts
    313
    Post Thanks / Like
    Likes (Given)
    69
    Likes (Received)
    35

    Default

    I have a fair about of experience with bending brass and you definitely need to anneal the tubing. Checking this mandrel chart you definitely need a mandrel bender and wiper to make your bend without failure. Can you up the wall thickness to 1/4"? Im local and can help you mandrel bend 1.5" tubing, but not 2".

  13. #32
    Join Date
    Jan 2019
    Country
    UNITED STATES
    State/Province
    Tennessee
    Posts
    484
    Post Thanks / Like
    Likes (Given)
    151
    Likes (Received)
    123

    Default

    Your pressure/counter die does not have required pressure (to much gap) on tangent edge. Not sure where the adjustment is on the JD, sorry. Also, high pressure grease the counter die beyond necessary, the brass is will want to guall if it catches an edge on the infeed edge.
    If brass is sticking at all to counter die it is stretching, reducing pressure at tangent.
    I open bend a fair amount of pipe, and you are pushing the limits of wall thickness without going to a mandrel or crazy linear railed counter die - but doable. Your radius after bending should be 3 5/8 on pipe if all tooling is dialed in to right (1.03 (magic bend constant) x 3.5 (die radius)).


Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •