annealing aluminum with a plumbers torch
Close
Login to Your Account
Page 1 of 2 12 LastLast
Results 1 to 20 of 27
  1. #1
    Join Date
    Jul 2004
    Location
    Pittsburgh, PA
    Posts
    469
    Post Thanks / Like
    Likes (Given)
    29
    Likes (Received)
    63

    Default annealing aluminum with a plumbers torch

    I need to put some 90 degree bends in some home depot aluminum flat bar. i know if i try without annealing it first, it will crack. but currently my shop is sitting in a storage unit 200 miles away. Will a plane old plumbers torch get hot enough to anneal this stuff for bending?

    I was going to use the old trick of mark it up with a sharpie and heat it till the sharpie burns off. Just don't know if i have enough heat.

    butane in the plumbers torch maybe?

  2. #2
    Join Date
    Nov 2009
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    1,118
    Post Thanks / Like
    Likes (Given)
    73
    Likes (Received)
    311

    Default

    sure...

    You need to provide more information to get a better response.

  3. #3
    Join Date
    Jul 2004
    Location
    Pittsburgh, PA
    Posts
    469
    Post Thanks / Like
    Likes (Given)
    29
    Likes (Received)
    63

    Default

    what more do you need? i don't know what alloy Home Depot sells, its the 1/8th inch stuff, mostly 1/2 wide. Don't know what else to tell you. Sorry.

  4. #4
    Join Date
    Feb 2004
    Location
    Napa, CA
    Posts
    2,641
    Post Thanks / Like
    Likes (Given)
    45
    Likes (Received)
    705

    Default

    Home Depot aluminum is going to be 6061 or 6063 most likely at T651 hardness. With 1/8th flat bar you should be able to bend 90 deg cold without cracking - I've done it many times. 1/4" you would probably crack if trying for a short radius. 1/8 might crack if your bend line is along the extruded length. If you anneal it you will lose around 60% of the strength, if that matters. It cannot be re-hardened effectively in the field. If it is anodized, the anodizing will crack for sure whether annealed or not - you will see that on the outside radius but it will not affect strength noticeably.

  5. #5
    Join Date
    Jul 2004
    Location
    Pittsburgh, PA
    Posts
    469
    Post Thanks / Like
    Likes (Given)
    29
    Likes (Received)
    63

    Default

    Im just building some brackets for my bicycle. Im on location for work and had to put my shop in storage till this jobs done. Ive tried cold bending this stuff before and got to about 80 degrees before the outside shattered. Maybe it was just that batch. but i will give it a shot.

    But, if anyone knows of a small fab shop, or home shop with skills, within stones throw of downtown Harrisburg, i would gladly farm it out. I would much rather have this thing welded rather than me bolting it together but all the boys around here are scrappers, no fab shops. except one, but they do bridges so i couldn't even get the secretary to talk to me.

    but, in the mean time, i will see what i can get it to do.

  6. #6
    Join Date
    Oct 2013
    Location
    California
    Posts
    75
    Post Thanks / Like
    Likes (Given)
    12
    Likes (Received)
    62

    Default

    It totally depends how sharp you're aiming for the corner to be. A gradual 90 degree bend done on a hossfeld? No problem. I've bent heaps of 3/8" thick 6061 bar with no cracks without annealing it first. It's a different story if you're going to stick the piece in a vise and mash it with a hammer. I wouldn't put good odds on the mystery-metal + vise + hammer plan but annealing it first will at least improve your chances.

    A mapp gas torch will get us to 5300*F, I don't think any aluminum alloys require more than 1000*F. A mapp torch should have no problem heating a small piece of aluminum to the temperature you need.

  7. #7
    Join Date
    Jun 2010
    Location
    santa cruz, CA
    Posts
    821
    Post Thanks / Like
    Likes (Given)
    1994
    Likes (Received)
    719

    Default

    Hey guys...you are making it much too complicated. He asked a simple question, with a reasonable solution. The Sharpie marking works quite well for the bend that he is wanting. Same as using an oxy-acet rig to apply a layer of carbon soot to the surface, and then heat it to burn it off.

    Lee (the saw guy)

  8. Likes gary-sc, metlmunchr, kustomizer, 9100 liked this post
  9. #8
    Join Date
    Nov 2013
    Location
    Eastern Massachusetts, USA
    Posts
    6,810
    Post Thanks / Like
    Likes (Given)
    5844
    Likes (Received)
    6234

    Default

    I've never tried the sharpie trick but I have bent (or straightened) aluminum a few times by heating it until a small piece of white pine just leaves a char mark when rubbed. I learned this from an old time welder who used to have a shop near a friend's house.

  10. #9
    Join Date
    Jul 2005
    Location
    Eastern PA
    Posts
    1,122
    Post Thanks / Like
    Likes (Given)
    216
    Likes (Received)
    805

    Default

    It's 1/8 X 1/2 for a quickie bike rack. Heat the bend line until you think it's "real hot" then bend it in a vise. Works 99% of the time. If not just heat it until it's really real hot and try again. You'll get the hang of it real quick..............Bob

  11. Likes Bobw, Jrill liked this post
  12. #10
    Join Date
    Jan 2012
    Location
    Midland, Texas
    Posts
    1,618
    Post Thanks / Like
    Likes (Given)
    631
    Likes (Received)
    838

    Default

    I've bent 2024 T6 with a Burnz-O-Matic torch. Heat, quench, bend.

    For a hanging bracket for a bike, I'd suggest going to Home Depot and getting a couple of closet pole brackets.

  13. #11
    Join Date
    Dec 2008
    Location
    Portsmouth, England
    Posts
    927
    Post Thanks / Like
    Likes (Given)
    313
    Likes (Received)
    601

    Default

    Old-time, rough and ready temperature indicator for annealing aluminium - rub a bar of soap on it and heat until the soap turns brown. It works for me.

    George

  14. Likes Limy Sami, baldwin, lumley32, TheOldCar liked this post
  15. #12
    Join Date
    Jan 2007
    Location
    Norfolk, UK
    Posts
    21,183
    Post Thanks / Like
    Likes (Given)
    16560
    Likes (Received)
    17233

    Default

    Quote Originally Posted by Georgineer View Post
    Old-time, rough and ready temperature indicator for annealing aluminium - rub a bar of soap on it and heat until the soap turns brown. It works for me.

    George
    Must be a Brit thing Georgineer

    That's how I was taught at secondary school, guess what? ;- it still works.

  16. Likes baldwin, Georgineer liked this post
  17. #13
    Join Date
    Dec 2004
    Location
    uk
    Posts
    14,046
    Post Thanks / Like
    Likes (Given)
    4552
    Likes (Received)
    6723

    Default

    Just try the soap on a bit of scrap first. My mum when i was a kid use to be a Avon lady and one of our bars of soap did not work :-( My piece i had spent about 2 hours cutting out by hand with a fretsaw paid the ultimate price.

    Of cause every bar - time i have used the trick since + tried on scrap first i have yet to find another bar that did not work :-(

  18. Likes baldwin, TheOldCar liked this post
  19. #14
    Join Date
    Oct 2006
    Location
    williamsburg va
    Posts
    7,883
    Post Thanks / Like
    Likes (Given)
    839
    Likes (Received)
    1753

    Default

    Oldster has it right: soot the aluminum with a candle and bend it when the soot burns off. I haven't tried the soap method,though it likely works,too.

  20. Likes gary-sc liked this post
  21. #15
    Join Date
    Jun 2010
    Location
    milton freewater oregon
    Posts
    2,029
    Post Thanks / Like
    Likes (Given)
    3811
    Likes (Received)
    1643

    Default

    Your basic propane will bend it easy as pie. I have even been able to work borosilicate glass very slowly with one.

  22. #16
    Join Date
    Dec 2004
    Location
    uk
    Posts
    14,046
    Post Thanks / Like
    Likes (Given)
    4552
    Likes (Received)
    6723

    Default

    seeing as aluminium melts at 700 celcius or so, even a std cooker hot plate will get hot enough to anneal it.

  23. #17
    Join Date
    Nov 2004
    Location
    Birmingham, AL
    Posts
    13,335
    Post Thanks / Like
    Likes (Given)
    6617
    Likes (Received)
    2631

    Default

    Propane torch gets plenty hot. Sharpie or soot black then just heat enough to burn most off. Don't try to burn it clean or you'll end up with a puddle. DO NOT bend teh work when hot. Aluminum (especially 6061) is hot short, which means it drastically loses strength when hot. It will crumble like a warm cookie if you bend it without letting it cool back down. You can quench in water directly from the anneal without hardening or affecting it.

  24. #18
    Join Date
    Mar 2018
    Country
    UNITED STATES
    State/Province
    Arizona
    Posts
    31
    Post Thanks / Like
    Likes (Given)
    18
    Likes (Received)
    2

    Default

    Sorry to dig up an old thread, just wanted to post that teh Sharpie trick works like a charm. Cracked some 1/8" sheet trying to bend it so jumped on the interwebs and found this post. Gave it a try and worked like a charm.

  25. #19
    Join Date
    Jan 2007
    Location
    wales.uk
    Posts
    1,613
    Post Thanks / Like
    Likes (Given)
    325
    Likes (Received)
    348

    Default

    Rub with white soap bar, heat till it blackens the old fashioned way!
    Mark
    Sorry limy,and others poor reading skills must be the CoViD

  26. #20
    Join Date
    Nov 2013
    Location
    Eastern Massachusetts, USA
    Posts
    6,810
    Post Thanks / Like
    Likes (Given)
    5844
    Likes (Received)
    6234

    Default

    Annealing with a torch may or may not work. The trick to hot bend aluminum is not to overheat it because there is no color change to guide us. An old timer's trick is to take a small piece of Eastern white pine and rub it on the aluminum as you heat it. When it leaves a black smear the aluminum is at the right temperature for safe bending. I've straightened a lot of stuff that way, especially when I rode off-road motorcycles. Straightening bent levers and pedals often got the bike back in service while waiting for replacement parts to come in. After replacing the parts I usually kept the straightened parts for emergency spares.


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
  •