Input requested: turning angle iron into rectangular tubing

The bed iron tends to be very hard and brittle, feels like it is .4% carbon range. The HAZ is likely to be quite nasty. This translates to a
much lower fatigue resistance for the welded up angle iron compared to mild tube.
I'd suggest using new tube of whatever thickness you need. My local supplier sells 10' lengths of the common sizes for around $.55 a pound, take your choice.
New stuff also has the advantage of clean, no paint, no rust, long lengths, all those nice things!
Andrew H. Wakefield wrote:

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Hi RoyJ. I tend to agree with you, but I did not at first. I needed to fabricate a bracket for a large vise out of 1/4 or 3/8 steel bar. There were no bed frames or junk steel on the street, so I went to the local surplus. They did not have what I needed in stock. They did have a lot of aluminum and stainless, and it was pricey. This was really annoying, since it was a long drive, and I only have the use of a car every once in a while.
I did find a whole bunch of rusty, thin, non-square angle iron behind a dumpster. It was the wrong size and shape, but I did have an anvil, forge and arc welder. First, I cold folded the angle by thirds, and welded the seams shut. Then, I heated it good and hot, and forged the brackets, meanwhile folding it another time (6 layers), hot punching 5/16 holes, and forge welding them together. Finally finished up by arc welding the final end folded seams. The brackets looked and worked great!
In retrospect, this was a waste of time. I thought (incorrectly) that since my arc welding skills needed a lot of improvement, this would beat wasting rod on the beginner's exercise of laying beads down on plate. Indeed, the improvement in my welds was pretty impressive, and when I was done, they looked like the ones in the book. But, there was one detail that I did not take into account. Surface prep. The welds came out looking bad (which really did not matter, since the forging makes the layers stick together enough to keep the contraption together) unless I cleaned the metal of paint, rust and pitting. Otherwise, I got this annoying porosity problem which masqueraded as poor skill. Alright, alright, skill was poor, but that's another point. I tried using an angle grinder, but it hurt my ears and my sensibilities. Then, I tried a dremel, but it was also made an annoying noise, and blew disgusting dust all over the place. Finally, I recalled two pieces of advice. I read on the web once that if you get a sickly sweet taste in your mouth while grinding painted scrap, you are getting lead poisoned. Second, a master blacksmith once told me that he never grinds with an angle grinder or belt sander, since he likes to hear the birds sing. So, I used sandpaper. This gave me plenty of time to understand how I was wasting my life by doing something I did not like. And the ratio of time being spent sanding versus welding was pretty high, making the cost of instruction likewise high.
There were some homeless guys on the corner, and I thought of paying them $5/hr to sand the metal, but it would have been better to buy clean stock from onlinemetals, or buy the stock at the local hardware store. If you can find clean angle iron, it would probably be worth it for the welding practice, which I feel you may desire, but in that case, real square tubing may be available at about the same price.
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I would box it up leaving the edges to form a small vee for your weld. Weld up your angle in lengths running a one inch weld every six inches along the corners. Now that you have you "tubing" cut it to the lengths you need. I would weld at the corners of your structure so that there is a continuous weld at least four inches from every connection of the tubing. Since you figure your load is maximum of 300 put a six hundred pound static load on it then pull and twist it to see if you have any permanent deformation. You are looking for it to bend. Those are the areas you will need to reinforce. Paint your rack with a good quality enamel. Regularly look for failure of the paint film which will indicate cracking or deformation during service. Randy

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Nice info on using a load to indicate reinforcement places. Thanks.

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Well, I knew if I tried hard enough I would get a conversation going :) Many thanks for lots of helpful input; you have given me much to ponder.
At this point, I believe the next step is to work out the design, and then I can see where I am. (I still would love to see anyone else's design -- surely someone out there has made a rack or two?? I am looking for something that is relatively easy to put on and take off.) I will post ideas and developments on the design as I try out some ideas, to get your feedback.
Meanwhile, I am leaning towards buying the tubing, but may also look at the suggestion made by a couple of you just to use angle iron without forming it into tubing. One question I should have asked sooner: What thickness of tubing would you buy for this project? Is 1/8" overkill? 1/16" (.0625") seems a little too light to me, so that's where I was thinking the 1/10" material might be about right. Yes? No?
Thanks again,
Andy

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Good, good. I am currently modifying a utility trailer into a canoe trailer myself, and after some thought and experimentation, have come to the following conclusions:
a) Although a hobby welder myself, I always buy new tubing & other metal rather than scavenging or cobbling together stuff which might work--at least for projects like a rack or trailer that others are going to see. The time and money saved on metal prep alone is worth it in my experience. Furthermore, people are more likely to ask you where you bought your project with an envious look than they are to edge away from it nervously. (Cleaning up the welds and slapping on a couple coats of paint helps enormously, too.) b) For my canoe rack, I am going with 2" square tubing x .100" because while the .0625" material is cheaper, lighter, and easier to cut/fit, I have a lot more burn-through when using 7018-AC 3/32" rod on my tig/stick machine. (I am sure a better weldor would not use this as a deciding factor, but...) Plus, it is easier and more reliable to weld on tie-down rings made of chain links, handles, and other bits when the base metal is a bit thicker. The same could be said of .125" but have you carried a 20' length of that stuff around? I suspect you can save that for heavier jobs...
Good luck.
Lawrence

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Good, good. I am currently modifying a utility trailer into a canoe trailer myself, and after some thought and experimentation, have come to the following conclusions:
a) Although a hobby welder myself, I always buy new tubing & other metal rather than scavenging or cobbling together stuff which might work--at least for projects like a rack or trailer that others are going to see. The time and money saved on metal prep alone is worth it in my experience. Furthermore, people are more likely to ask you where you bought your project with an envious look than they are to edge away from it nervously. (Cleaning up the welds and slapping on a couple coats of paint helps enormously, too.) b) For my canoe rack, I am going with 2" square tubing x .100" because while the .0625" material is cheaper, lighter, and easier to cut/fit, I have a lot more burn-through when using 7018-AC 3/32" rod on my tig/stick machine. (I am sure a better weldor would not use this as a deciding factor, but...) Plus, it is easier and more reliable to weld on tie-down rings made of chain links, handles, and other bits when the base metal is a bit thicker. The same could be said of .125" but have you carried a 20' length of that stuff around? I suspect you can save that for heavier jobs...
Good luck.
Lawrence

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Good, good. I am currently modifying a utility trailer into a canoe trailer myself, and after some thought and experimentation, have come to the following conclusions:
a) Although a hobby welder myself, I always buy new tubing & other metal rather than scavenging or cobbling together stuff which might work--at least for projects like a rack or trailer that others are going to see. The time and money saved on metal prep alone is worth it in my experience. Furthermore, people are more likely to ask you where you bought your project with an envious look than they are to edge away from it nervously. (Cleaning up the welds and slapping on a couple coats of paint helps enormously, too.) b) For my canoe rack, I am going with 2" square tubing x .100" because while the .0625" material is cheaper, lighter, and easier to cut/fit, I have a lot more burn-through when using 7018-AC 3/32" rod on my tig/stick machine. (I am sure a better weldor would not use this as a deciding factor, but...) Plus, it is easier and more reliable to weld on tie-down rings made of chain links, handles, and other bits when the base metal is a bit thicker. The same could be said of .125" but have you carried a 20' length of that stuff around? I suspect you can save that for heavier jobs...
Good luck.
Lawrence

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Andrew H. Wakefield wrote:

Just using the angle can be a pretty good solution. On spans, have the tip down and the flat up ("L" rotated 180 degrees). On cantilevers, tip up. This keeps the tip out of compression, and avoids reducing the strength.
Another benefit of just angle is that you can easily bolt through some of the connections and give a little extra comfort, if that makes you feel better about the design.
As for the thickness of bought tubing - you probably wouldn't have strength problems with thin tubing, but it would be harder to weld without melting through. Keep in mind that (especially with tube) that you gain more strength and stiffness by going to a deeper (taller) section than with a thicker wall.
Rich
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On Sun, 15 Aug 2004 16:28:54 -0400, "Andrew H. Wakefield"

Go for it. I've done a lot of using bed frame angle, and other parts off the frame. Even a couple headache racks and a couple lifters. Still have one of those in the shop. Powered by a hospital hand jacked cylinder. It does what we need, but the foot print is too big, so my buddy wants to put it up for sale. We believe it will hold together for a long time. Just remembe to be SURE the metal is clean if there is to be anyone on or under it. Lou Hinshaw
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Postscript after reading some replies. Bemember that the world is full of people whomight not know a damn' thing about what you are doing but who can yak for hours about why it won't work.
That's why B. Franklin did his kite thingy in the middle of the night.
I once went to a friend to ask how much he wanted for some metal left over from his used--funiture deals. He said "If you can haul it you can have it." Next day i showed up with my one--ton and saved me and him both money. I wanted the steel, and he wanted to avoid hauling it off.
On a typical 1/2 ton headache rack, the material savings more on the order of a hundred or so for decent metal from Earl M Jorgensen Steel Co.
And I agree with you that 0.065 wall thickness is awful thin. If you are in Tulsa OK area, I can show you the lifter. Lou
On Sun, 15 Aug 2004 16:28:54 -0400, "Andrew H. Wakefield"

Go for it. I've done a lot of using bed frame angle, and other parts off the frame. Even a couple headache racks and a couple lifters. Still have one of those in the shop. Powered by a hospital hand jacked cylinder. It does what we need, but the foot print is too big, so my buddy wants to put it up for sale. We believe it will hold together for a long time. Just remembe to be SURE the metal is clean if there is to be anyone on or under it. Lou Hinshaw
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Oh, okay: 'sure, just go ahead and weld up any damn thing you want without regard to safety and time verses money.'
wrote:

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