CHEAP aluminum tubing for bike trailers, etc, etc, etc

Discussion in 'Spare Parts, Tools & Product Developement' started by Esteban, Nov 29, 2007.

  1. Esteban

    Esteban Active Member

    I was in a local Salvation Army thrift store, recently, looking at their old bikes for parts. They had a large stack of crutches , [ you know , when you break a leg ] . Anyway, I am thinking about ways to use the aluminum tubing for making bike trailers, pannier racks, etc. The price was good enough! They said I could have them ALL for $0.75/pr. The aluminum scrap in them is about worth that.
    Just thought I would throw this idea out for suggestions/comments.
     

  2. mickey

    mickey Guest

    Good thinking.
     
  3. az cra-z

    az cra-z Guest

    Now if I could think of a way to get a bunch of crutches home without looking like I did a raid on the old folks' home....
     
  4. Dockspa1

    Dockspa1 Guest

    I have cut up a crutch and found them to be very thin walled. On the one I cut up, you could bend it with your knee and of course it would cave in and kink. Don't mean to sound negative but don't want anyone to get hurt either.
     
  5. Esteban

    Esteban Active Member

    Yes, they are thin-walled, but that's what keeps them so light.Join 2 cut pieces by slipping in a wooden dowel into each piece & clamp, or scrwe together. Used as side railings, etc., for a trailer, or 2 rails at 90° angles for the bottom, would seem to work fine, as long as the hauling weight was kept down. Still will need stronger materials for framework , though.
    Still tinkering !
     
    Last edited by a moderator: Dec 18, 2015
  6. Dockspa1

    Dockspa1 Guest

    Your right about that, they are light. I guess you could alumina tig them. I just wouldn't trust them on anything that holds a person directly, unless their walking on them in a vertical position. I have an aluminum childs trailer and the wall thickness is a lot thicker than the crutch material. Maybe I just have a cheap crutch.
    Doc
     
  7. Sianelle

    Sianelle Guest

    Look around for dead lawn furniture thrown out in the hard rubbish collection. Most of the time the bends in the tubing just seem to be in the right place when it comes to building utility type devices for attaching to bicycles.
     
  8. kevbo

    kevbo Guest

    I picked a Burley kid trailer up off craig's list a while back. It is built with very thin walled Al tubing, but darned if it doesn't take some abuse. It only weighs about 20#, and a huge share of that is in the wheels.

    Good tip on the crutches.
     
  9. Dockspa1

    Dockspa1 Guest

    Kevbo, what kind of axle does it have or are there just stubs for the two wheels.
    Doc
     
  10. Danny3xd

    Danny3xd Member

    Wheel chairs

    Only vaguely related and if this is far off topic, forgive me. Very often there are old wheel chairs on craigs list for free. I just picked one up. It is surgical grade, thick walled stainless steel. After a lil "noxon", elbow grease, disassembly and rope forming a "cargo" style net, it is pretty! I still have not figured out how to marry it to the bike. Am thinking a small universal joint near the tensioner. (so far, it is on it's back. So if you were to sit in it in it's original configuration, you would be looking up at the sky with your feet towards the bike)
     
  11. DougC

    DougC Guest

    If you live near any major city, look in the phone book for metals suppliers, call them up and ask if they have any drops (or scraps) to sell in the sizes you are wanting.

    The scraps are a bother to store and inventory; many places will sell them cheap for cash, sometimes for not much more than scrap-metal value.
    ~
     
  12. kevbo

    kevbo Guest

    It uses regular (almost*) 20" bicycle front wheels and axles, supported both inboard and outboard by the frame. The dropouts are aluminum angle stock bolted to the bottom of the frame, and slotted for the axles.

    Here is a DIY trailer plan that uses pretty similar wheel mounting. (but with flat plate dropouts instead of angle)


    *The wheels are slightly dished, to put the tires a little farther outboard for stability, and to make it harder for a kid to push the fabric sides of the enclosure against the tires.
     
  13. Dockspa1

    Dockspa1 Guest

    Wow Kevbo,
    That gives me all kinds of ideas. Thanks for the link. Looks like all thinwall conduit. The benders can be expensive though. Like most single axle trailors, you will have to center the weight distribution over the wheels. Of course, I would have to put a cooler in it ahem, for cold groceries, don't ya know!
    Doc
     
  14. Esteban

    Esteban Active Member

    Our local hardware store will bend tubing for you for a very small cost,, or I have seen pretty neat conduit bending SLOWLY done between trees !!LOL
     
  15. Abeagle

    Abeagle Guest

    One tip on bending tubing is wrap the area you want to bend with insulated copper wire (at least 12 gauge or larger). The wire needs to be wraped tight and kept tight, with no room between wraps, it should be extended on both sides well past the area you want to bend. Bend slowly, I have used this method on 1/2 inch elec. conduit.
     
  16. ibdennyak

    ibdennyak Guest

    Agreed.....electrical conduit benders are a handy accesory. The wrapping method helps to keep it from collapsing. Another old fabrication technique I learned from an old fabricator is to fill the tubing with processed sand. (silica sand etc that has been sized and graded rather than beach sand) Pack it tightly, and it keeps the tubing from kinking. Another little technique that might be useful here it to bend PVC conduit. I've used it for like surrey top bows etc. I think a piece of 2" bent and slit in half would make a nice fender. The trick is to heat up a 50/50 mixture of water and antifreeze. Put the conduit in it until it becomes pliable. Bend it, and when it cools, it will retain its shape. It can be neated with a propane torch, but it is hard to keep from scorching one area, and another area is still too cool. Be careful with the antifreeze though around children and pets. It tastes sweet, but is very poisonous.

    Denny

    Ooops, almost forgot the original reason for posting. If you have a large sturdy table, you can make a lobuck bending table by screwing or bolting hardwood templates to it, with another block for a stop. Then just bend the conduit around the template after filling it with sand. You will want to cut your template a little smaller to allow for springback. About 1/2 inch on a 6 inch radius.
     
    Last edited by a moderator: Dec 8, 2007
  17. fetor56

    fetor56 Guest

    Neat trick about the 50/50 mixture of water and antifreeze....i'll have to remember that.
     
  18. stude13

    stude13 Active Member

    bed rail are cheap good angle iron
     
  19. Dockspa1

    Dockspa1 Guest

    So I guess Abeagle, that 12 guage wire sorta works like the smaller spring benders for smaller copper tubing, huh?Cool!
    Doc
     
  20. SimpleSimon

    SimpleSimon Active Member

    Lots of ways to bend tubing. For simple bends of thinwall conduit, I have in the past simply plugged one end, filled the tube with sand (bouncing it as you fill, to pack it well), driven a wooden plug in the other end, and bent it between two fixed posts. A very simple jig can be made to bend conduit and most thinwall tubing from plywood and two chunks of strap or angle iron.

    Take a sheet of 3/4" plywood, cut it into two 4' x 4' squares. Find the center of one square (draw two diagonals using a good straight edge, where they cross is the center), put a 3/8" hole through at the center, insert a 3/8" x 2" carriage bolt, drive it home.

    Take the other half, and cut from it whatever radius circle you want for your corners (the smaller the radius, the tighter the corner, the harder it is to make the bend) - you'll need two circles for each desired radius, one the same diameter as the radius of the larger circle. Drill 3/8" holes at the center of each circle. Take your strap iron, drill a pair of 3/8" holes the radius of the pair of wooden circles apart, plus the diameter of your tubing, in each of two equal length pieces (which need to be at least one foot longer than 2.5X the radius of the curve you are making), and a third hole near the other end.

    E.g. - if you want a 1' radius bend in 3/4" EMT tubing, the holes in the strap iron need to be 1' + 6" + 3/4" = 18 3/4" inches apart, on centers. I reccomend 1/8" x 1 1/2" flat steel bar stock, minimum, which needs to be a minimum of 2.5' long.

    Drop one bar on the center pivot in the 4' square, and put a shim piece the same thickness as your bar stock down, tangent to the desired circle, put the 1' radius circle on the pivot bolt, slide another carriage bolt thru the hole at 18 3/4" (pivot pin for the smaller circle), then put that circle on the pin. Place the other bar on the pins, and washer/lock washer, double nut it in place snugly, but not so tightly it prevents either wheel from turning.

    Next step is to put an at least 6" carriage bolt thru the holes at the free end of the bars (put a 3/4" spacer between the bars the bolt slides thru), put on a comfortable sized handle drilled for the long bolt to pass thru, and you are ready to bend tubing.

    Affix the EMT to the shim plate, tangent to the larger circle, and sliding between the two pieces of bar, and between the two wooden circles. Best way I've found is to use two or more U conduit mounts, screwed down hard. You want the tail stock of your tube to be fixed in place.

    Then grab the handle, and pull - hard. In my experience this jig works best screwed to a solid wall, as high as you can comfortably mount it. Pulling on that handle while the jig is horizontal is a good way to ruin your back. Vertical, your weight does the work.
     

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