Bending tube the cheap way

So, lets see what we need Sand (I use play sand, its free if you go to a local playground, just make sure you don’t have a beard…)
Baking dish (ask the wive) Oven
Duck tape (every biker has this stuff laying around)
Funnel (every biker has this stuff laying around to)
Barbecue (Or some bricks in a circle will do as well)
Cheap conduct pipe bender(you can find these in your hardware store for less than 50$)
Tubing

Preparing the sand:
Sand has always some moist in it and this prevents it from flowing smooth. This will create air pockets if you push it in a tube.
Thats why we put some in a dish and bake it for 30 minutes or until its desert dry.

Cut your tube always a bit longer then necessary. Debur it!

Seal one end with duck tape.

And use the funnel to add sand. Don’t do this all in one time. Put some in and stomp it down, repeat until completely full.


Now carefully without spilling seal the open side.

Heat it up. Doesn’t matter how you can make a campfire or lay it on a stove. I always use the barbecue. (side note: don’t ever use carburetor quick start fluid to start a BBQ. It will just blow it in an orbit around earth!)

Put it in your bender. Make sure you use a dice with the snuggest fit. If your using welded tube turn the weld line to a quarter as in the picture.

Take a step back and look at the result.

In the last pic you can see why all these steps are necessary. The top tube is bended as in the tutorial, the middle is bended without heat, and the bottom one without heat or sand.

As you can see the top one has the smoothest bend.

PVKM

Comments

  1. Ted says:

    Looks like this is the first article to come out of the contest. We should be able to build out a good tech-library.

  2. the main reason for removing the moisture in the sand, is to keep steam out of the equation. steam under pressure can obviously cause catastrophic results. a quick google search will explain it better than i can, but as long as the sand has been dried previous to use you will be okay. great tech either way.

  3. PVKM says:

    Cool it got posted!

    The steam thing is true, tho sealing the pipe with ductape prefents it to blow up. The tape will burst before the pipe can. On the other side its still strong enough not to break from the pressure of the sand while bending.

  4. Eric says:

    Looks like it works… how hot are you heating that tubing? No quenching right? I don’t know how extensive your knowledge of metal working is but these are huge factors in the final outcome of a structural member.

    I love the backyard Mcguyver style goin down on here! It may not be the best method but it is definitely the cheapest… just watch that heat and how fast you let it cool if this is going to be a structural member of the frame.

    Nothing would be worse than hearing of a bro takin a nap cause his bike broke.

    Live Lightly

  5. PVKM says:

    Its not cherry red hot and I’m not throwing it in water to harden it. Just let it cool on its own.

    Its true about that backyard Mcguyver style tho I think its more a “how they did it in the old days when all these modern machinery wasn’t available” style. Even Ron Covell does it that way. People have been chopping there bikes for ages without the proper tools.

    Things brake off of factory bikes as well. Google that BBC bike where the neck broke off! 3 years ago I totaled a car that just came from inspection. It went straight to the highway barrier. After investigation they’ve found out the left front wheel axel just broke off?!?

    As with any form of transportation, have a quick visual check before you head out and if something feels wrong while driving don’t go like “oh it will hold until I’m home”.

    Sorry for the long post and Eric I’m not flaming you or anything bro.

    Cheers,
    Tim

  6. myron says:

    I like the “oldschool ” technique ,,,,, I especially like the ” doing it for cheap” part. I’ve got 2 questions ; 1) If building a frame from scratch,, what size tubeing would you use, and where would you buy it ?, and 2) Could you use a torch of some kind for your heat source ?
    I ‘m new to this whole bike building , but I’ve worked in mach. shops for many years bending and stamping metal, so I know I’ve got some skills. I’m happy I found this site with people to share common interests
    thanx Myron

  7. PVKM says:

    1.25″ x 0.120″ ERW is fine for most frames. If your going to use a high power +200HP engine I’ll go bigger.
    Don’t use thin wall conduct tubing and DOM tubing isn’t really necessary.
    If your chopping an XS frame, use the same diameter tubing as the frame and always use slugs to make your connections.
    Tubing can be found at your local steel supply shop and sizes are all common.
    And yes torches will do depending on which kind. If you use a butane torch instead of oxyacetylene it just takes longer to heat up.

    Get an account on a chopper forum and start a project, take lots of pics and ask advice during the progress. Good luck.

    Cheers,
    Tim

  8. Nik says:

    shouldn’t you be using seamless tubing because of the strength and if it don’t matter whats the strength differences

  9. PVKM says:

    Seamless is better because its dimensions are more precise.
    The seam in ERW tubing is always a weak spot.
    So why don’t we all use seamless? Well, because its more expensive and for 99% of motorcycle frames ERW will do just fine. There’s not one production bike with a steel frame that uses seamless. Its all ERW, from Honda to Harley Davidson.
    If your building a high end custom with twice the torque a regular engine has so the limits of your frame are getting closer, use seamless.
    For all else use ERW.
    If you have money to spend use chromoly. Its always seamless but it weighs less tho it has the same strength as regular steel. Less weight means more power.

    Cheers,
    Tim

  10. Jeff says:

    Actually I believe the sand may help slow down the cooling of the metal … another little trick is a fireproof ceramic insulation as a blanket. Wrap up the tube after your done and let her come down on her own. You can also use a fairly cheep infra-red point and shoot thermometer to keep an eye on temperatures. I’ll take a look and see what a good target temperature would be to work the metal without loosing strength.

  11. Wooley says:

    I bend my pipe cold filled with sand although your probably using thicker tubing than I. Is that red bender the $50 one? Great info by-the-way