How to Bend Tubing





Introduction: How to Bend Tubing

Here, I show a quick and dirty method to bend aluminum tubing. I am documenting how I built a new bow rail for my sailboat.

Step 1: Build the Jig

Here, I trace the curve that I want on some scrap lumber. This scrap will be used to build the bending jig. I'm just using a couple of old 2x4's. Your wood should be somewhat thicker than the diameter of the tube you wish to bend.

Step 2: Cut the Lumber

Just cut out the traced jig. Use a bandsaw if you have one. I don't so, I just used a jigsaw. Cut the jig to be little smaller than the desired curve. This will allow for the spring action of the tubing.

Since I used two pieces of 2x4, I made a little gusset to hold the two together (2nd pic).

Hint: Add a little bevel inward on the bottom of the cut. This will keep the tubing from popping off of the jig when bending.

Step 3: Don't Bend Like This.

If you do this, then you will almost certainly get a kink in the tubing.

Step 4: Ready to Bend

Here, you can see that I take a piece of scrap (from the earlier cut) and attach it to the table to complete the jig.

You will want to bend from one side only while ensuring the tubing is supported wile bending. While bending, try to keep the pressure against the jig instead of the tubing.

You may want to practice with some cheap amluminum conduit to get the hang of it. When you are ready, get the polished stuff.

Have fun.

Step 5: Mounted on the Boat :-)



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    71 Discussions

    That liquid foam no more gaps stuff in a spray pack works well too. It dries real quick & my aluminum pipes don't flatten/kink when I bend them. if you need to get rid of the foam when your done bending,,,then just start pouring small amounts of acetone in one end & it will eventually dissolve.

    Fill it with sand and close both ends (corks do a great job here). It has always worked perfectly for me.

    +1 on filling with sand-it appears in old school DIY magazines I have.

    Here is another tip that may help you. Pack the tube with sand before starting the bend. This provides some support from inside and helps prevent it collapsing. One other thing I dont think that trailer is large enough to carry a compac 16 !

    Hey.. I LOVE your boat. I built my own sail boat. Love sailing and boat building...I also love to Cycle... I am in the process of making a Bicycle trailer and needed to bend some conduit. Can't see buying a conduit bender to use only once..Thanks for this info..Chief Redelk

    I have been looking for alternatives to buying conduit benders (they are not cheap...and I  Would doing a jig like this, but for a small 3 or 4 inch radius work for 1/2" conduit? or would it kink?

    3 replies

    I use a spring to bent PVC Conduit. For long pipes I attach a rope on the one end and shove it down the pvc until it is in place. My spring was inexpensive. Hope this helps.


     I think it should work ok.

    Just pull very hard and go slow. You keep the conduit very tight against the jig.

     I was thinking if it does kink, to try and make a groove in the edge of the half circle part to match the conduit (thinking to maybe mount the full circle into the drill press and use it as a makeshift lathe)

    If you are super concerned with getting a smooth rail, fill the rail with sand and close both ends. When you bend the tube it won't kink or deform.

    I have had a little experience bending tubing, as I was a band director who "dabbled" in instrument making in my early years.

    I successfully bent brass tubing using molten lead (which I reheated and removed later) inside the tubing. If you are not trying a real tight curve, then this should keep kinks from forming.

    Another way I have seen, but never tried, is to freeze water in the tubes, and then bend them. (Saw this on T.V.) I imagine you could place your pipe into a freezer, as long as it will fit.