Bending C Channel - Tips, Tricks, Simple and Elegant, Complex but Cheap?

Knowing what size material you're trying to bend would be helpful. I've bent smaller 1/2" x 1/2" x 1/16" in a home made rotary draw bender and got really good results on either axis but I did use a sacrificial close fitting filler piece to support it during bending.

We are talking trailers here so 3" and/or 4" steel channel. For small stuff like you are talking about I might just make some single use dies out of scrap aluminum. I have a lot of it.

OK you're building a trailer and I saw boat and assumed it was the Al boat you're working on, my bad. Still with a 20 ton press I would expect the first bending requirement to be doable given you can get supports and constraints into your press similar to a hydraulic pipe bender, bending that section depth wise is likely to be another matter. What about fabricating from box section and galvanising it if you're worried about rust. Galvanising is a cheap bulk process if you have a galvaniser locally and IIRC in non salt environment can be good for 70 years and more, less in salt environment but still a good time.

From what I have seen no matter what you do moisture gets inside tube frames, and it rusts out from the inside. I've repaired a few commercially built tube frame trailers and seen many more with the same problem.

The boat I am working on right now is likely around 1000lbs with outboard. A little more with fuel, and rigging. It has a rusted out factory tube frame trailer. I welded scabs on it to keep the cross members from breaking many year ago for the previous owner. In return he colluded with my wife to give me my first auto dark welding helmet for my birthday. Thank you Gary. That made a world of difference in my welding over the years.

My last glass boat was closer to 3500 and came on a 4" C-channel frame trailer.

All fresh water for me, but I've seen what happens to trailers used in salt. Its not pretty.

I would prefer not to pie cut and weld, but if I have to I have to. I DO NOT want to use tube.

We are talking trailers here so 3" and/or 4" steel channel. For small stuff like you are talking about I might just make some single use dies out of scrap aluminum. I have a lot of it. Bob La Londe

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If you can fit it between the press uprights the long way bending it toward the opening should be fairly simple, but bending from flange to flange has the problem that it's not symmetrical and will try to twist. I straightened

8' lengths of 3" and 4" channel in both directions with much less than 20 tons.

I'd notch and stick weld, or for a road vehicle have a pro do it. Much of my sawmill is welded 3" channel.

Today I made car underbody rust repair parts from 22 gauge galvanized. The curved corners were bent on a 3-in-1 brake by reversing the dies square top edge down and pressing the sheet metal to the intended radius with a round rod under the dies.

This is what I used for the properties of C channel.

The pieces of C3x4.1 and C4x5.4 I bought tended to measure less than the table gives. Their calculated values for Ix and Iy weren't different enough to change the design, as I needed to use what I had. The low values of Iy reflect a tendency to twist at a loading that Ix indicates should be acceptable.

If you can weld here, you should also be allowed to heat to red in a coal forge and then bend.

Joe Gwinn

I'd be fabbing, not bending, Cut the flanges off the channel where you need to bend and cut plate to the required curve and weld it on. Grind the joints, prime and paint. A WHOLE LOT easier than stretching and shrinking the flanges to make a bend

The only way to use tube for a boat trailer is to hot dip galvanize it and make sure all the tubes are "connected" with adequate size holes to let the zinc circulate throughout. Iven a channel steel trailer I would want to galvanize - even for fresh water.