Angle or C Channel for trailer?

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OK, First post here asking for some insight.I built this trailer about 2 years ago....Its built with 2x3x1/8 tubing, measures 5'x10' with a Dexter 3500# axle. I routinely have this trailer over loaded either with firewood, or logs for milling. I am currently in the process of starting another trailer, 5'x12', and putting two axles under it. I see allot of 16' landscape trailers built with 2x3x3/16 angle with a GVW of 7000#. Ive had experience putting tractors and skid loaders on trailers built with angle, but for some reason it leaves a bad taste in my mouth.Here is my question...Is 4" 6.2# p/f C Channel overkill for the trailer Id like to build? Would 5.4# p/f work? Or is Angle just fine for a trailer of this size?Also...just a little off topic...I borrowed a friends Lincoln 3200HD and did some test welds. This isn't my first time welding, but it is my first time using a welder this small. I'm still up in the air about getting the Pro Mig 175. Here are some test welds to see if the Lincoln was up to the task.Here is a horizontal weld in some 1/4" tube...Vertical weld in some 4" 6.2 C ChannelAnd some misc. Welds finishing off a corner.Keep in mind these are just test welds. I was using .030 wire and 75/25 mix.Flame away! Attached Images
Reply:Looks good from here..getting back to the question in the post..if all you have to work with is c channel or angle?c channel all the way.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Thats what Im thinking.Do you think I need to spring for the 6.4, or will the 5.2 do for what I need? I guess Im only talking about a 54# difference in total weight between the two.....54 being the number of feet I need for the frame perimeter and tounge.
Reply:Originally Posted by OpieThats what Im thinking.Do you think I need to spring for the 6.4, or will the 5.2 do for what I need? I guess Im only talking about a 54# difference in total weight between the two.....54 being the number of feet I need for the frame perimeter and tounge.
Reply:Depends on how you want to build the trailer. If you want a single rail for a frame, it will need to be tube or C-channel. Most of the angle trailers I see are designed into a full length truss type arrangement with a lower and upper rail and uprights welded between them. This gives the frame much more strength than the individual angles.
Reply:Hello Opie,Are you using Garden furniture as a welding table?  or is it just for the photo.Actually it does not seem like a bad idea just stiffen it up a bit and maybe some wheels.
Reply:Originally Posted by IcabodHello Opie,Are you using Garden furniture as a welding table?  or is it just for the photo.Actually it does not seem like a bad idea just stiffen it up a bit and maybe some wheels.
Reply:Over overbuild?  No such thing.
Reply:I used channel on my 6x12. I ran 4 pieces of channel for the front part. Two making the "A" and then two in the center about 4" apart. I wanted something I didn't have to work on every time I hauled something heavy. I used 5200# axles from Northern. A friend bought a 6x12 from a local trailer supply and about once a month he comes over for me to fix something.
Reply:Allright, thanks for the help guys....Ill post up some pictures when I get it completed. Might be a month or two as this is going to be a "no rush" project. My last one was a rush because I was using the space and welder at work.....Nothing like welding for 4 hours at a time after putting in a 12 hour day doing my real job.
Reply:OK, small update...I can get 4x4x1/4 angle for next to nothing, "read" free, so thats what Im going to use for the perimeter frame and tounge. Ill have to purchase some 2x2x1/4 for the rest of it.Here is a mock up I did on a smaller scale to see how the 110 welder would do with 1/4 angle.I know Ive read quite a bit here that it takes allot of prep to get a 110 welder to succesfully weld 1/4...its true. I could probably done more beveling on some of those joints.  I got good penetration the way its done in the pics....Please dont hesitate to criticize. Ive got the volts on max, wire speed is around 6-6.5, .030 wire and 75/25 gas. Attached Images
Reply:For what It is worth, I don't think the 110V machine is capable of making safe welds on the 1/4in angle.  Looking at the first four pictures you can look under the weld and see The weld is not penetrating.  The weld in the last picture "look" okay, though it is two edges coming togther.Do a test try welding one lap joint as in the first for drawing.  But do only one side. The try breaking it apart by twisting it up.  I would suspect that the weld will break away from the lower angle (larger surface).The volume of welds might make it safe. However I don't think the individual welds with that machine are effective.Also, as Zap frequently points your welds are not finished properly, since you have a dimple.I'd go with flux core, if I had to use a 110v machine.Good luck, glad your willing to seek advice.
Reply:Thanks for the tips. I do have a roll of flux core, Ill give that a try on a couple joints.I did take that piece and a 4# sledge and did my best to break it apart and had no luck. I bent the angle all to heck. Also, I wasnt getting nice cherry red on the opposite side of the weld, but I was getting a dull red, more than enough to notice.What if I preheat my joints? I think I read on here that 200 degrees of preheat makes a world of difference?Last edited by Opie; 01-22-2007 at 04:40 AM.
Reply:A couple of points in no particular order.If you destructively tested your welds with a BFH and they didn't break, then they are fine.But the little ending crater isn't right, as said above.  And I like to see the weld wetting/melting the edge of the stock a little better.  You fillets look like they are putting a lot of metal onto the surface of the flat face and not getting an even weld pool melting the edge of the other workpiece.  If the material is 1/4 inch thick, then the fillet should be up 1/4 inch on the edge (to the top edge of the edge piece) and 1/4 inch 'out' onto the flat face of the other workpiece.  It looks more like you have 3/16 'up' on the edge and maybe 1/2 inch 'out' onto the face.  Generally, the two legs of a fillet weld should be equal in size for workpieces of equal thickness.Fluxcore wire generally lets you weld thicker materials than solidcore wire, on the same machine. When you are trying to weld a thickness at/over the 'max' for a machine, preheat and workpiece prep can usually let you safely go a little past the machine's rated limit.  How much past that rated limit depends though.For 1/4 inch material and using a 110V machine in the 130-140A class, I'd probably say to use the 0.035 fluxcore wire.  The heat is just a little bit more with that wire than 0.030 solidcore wire.And if you can get 4x4x1/4 angle for pretty much free, why bother going out and buying 2x2 angle?  Make it all out of 4x4 angle!  But making it out of the C-channel would be a better approach, because the C-channel is stronger and stiffer and will flex and twist less than the angle would (comparing comparable thicknesses and exterior nominal sizes).Lincoln's 135A-class 110V machines are rated to do 1/4 inch mild steel with 0.035 fluxcore wire.  You're not even exceeding the machine's rated/listed capabilities with that thickness of workpiece.
Reply:Originally Posted by MoonRiseA couple of points in no particular order.If you destructively tested your welds with a BFH and they didn't break, then they are fine.But the little ending crater isn't right, as said above.  And I like to see the weld wetting/melting the edge of the stock a little better.  You fillets look like they are putting a lot of metal onto the surface of the flat face and not getting an even weld pool melting the edge of the other workpiece.  If the material is 1/4 inch thick, then the fillet should be up 1/4 inch on the edge (to the top edge of the edge piece) and 1/4 inch 'out' onto the flat face of the other workpiece.  It looks more like you have 3/16 'up' on the edge and maybe 1/2 inch 'out' onto the face.  Generally, the two legs of a fillet weld should be equal in size for workpieces of equal thickness.Fluxcore wire generally lets you weld thicker materials than solidcore wire, on the same machine. When you are trying to weld a thickness at/over the 'max' for a machine, preheat and workpiece prep can usually let you safely go a little past the machine's rated limit.  How much past that rated limit depends though.For 1/4 inch material and using a 110V machine in the 130-140A class, I'd probably say to use the 0.035 fluxcore wire.  The heat is just a little bit more with that wire than 0.030 solidcore wire.And if you can get 4x4x1/4 angle for pretty much free, why bother going out and buying 2x2 angle?  Make it all out of 4x4 angle!  But making it out of the C-channel would be a better approach, because the C-channel is stronger and stiffer and will flex and twist less than the angle would (comparing comparable thicknesses and exterior nominal sizes).Lincoln's 135A-class 110V machines are rated to do 1/4 inch mild steel with 0.035 fluxcore wire.  You're not even exceeding the machine's rated/listed capabilities with that thickness of workpiece.
Reply:Hey, you never asked us to spend your money!BTW, the Lincoln PowerMig 175 still calls for using fluxcore wire on 1/4 inch stock, except that machine's door-chart setting calls for 0.045 NR-211-MP Innershield fluxcore wire and multipass welding.  The chart stops the 0.030 solid wire workpiece thickness at 10 gauge.And about the weld fillet dimensions, once you make the fillet's legs as big as the stock thickness you don't really get all that much more strength by piling on filler metal.  If you have enough heat to melt 1/4 inch steel, making a fillet leg 1/2 inch long on 1/4 inch stock is just caulking the surface.The crater is the little dimple that you had at the end of your weld beads.  Anytime you have a crack or seam or undercut or depression in a weld, you have made or introduced a starting point for a failure down the line.  So try not to put a failure starting point in your welds.
Reply:BTW, all this talk about penetration brings me back to my original question....4" C Channel at 5.4#/ft or 6.2#/ft.The 5.4 has a vertical wall thickness of around 3/16, the 6.2 has a vertical wall thickness of 1/4 roughly. Just did a little recon yesterday on some landscape trailers.....entire trailer is built with different size angle, but all the angle was 3/16 thick. Am I right in assuming that 5.4 C Channel will be almost twice as strong as 2x2x3/16 angle?
Reply:I have never built a trailer but have seen the direct results of C channel used for framing on a travel trailer. Granted, the main premise for travel trailer manufacturers is to save weight where they can. This unfortunately includes the frame. a friend of mine has a 30 foot fifth wheel only 5 years old. He was loading up to go on a trip at Christmas and saw his slide-out look crooked. He looked underneath and saw the leaf spring shackle weld forward of the tire had broken loose from the channel frame. Damage was quite extensive withthe C channel ripping nearly in half. Its all due to too light of material ( c channel) being welded to a 1/4 inch plate for the shackle bracket. The welder overheated the thin frame. It held for a whiile but once it failed, boy did it fail.For my money I would use 1/4 2X4 angle or even small I-Beam for the bottom frame rails especially if you ever intend to overload it. Over engineering never hurt anybody.
Reply:One way to check penitration is to cut across your weld and see how far you are burning in. If you have a band saw that would be best for the cut.  We have built a couple trailers here for work, we used tube in of ours...I am based here in California so corosion is not realy a major factor like where the roads are salted. My boss designed and built them, he used to build trailers for Wesco a company that builds Transfer trailers, grain hoppers and such.  Truly I would take my digital camera out and snap a bunch of pics of trailers in your area. Maybe go to a rental yard and snap some pics of their heavy haulers.  With anything you are going to be driving around you need to be shure it is going to be right. You will be trusting your life and the life's of others on your design and fab skills. I am not taking away from your skill, your welds look good and strong, but you have to be shure. I will try to take some pics of our trailers today for you."If you live in Sacramento you have seen my work."
Reply:Ok got some pics for you. Trailer out side frame is 2"x4" .125 wall, cross braces are 2"x2".083 the tounge and digonals going back are all .250 wall. The tounge is 4"x4" and the diagonals are 2"x4". the trailer weighs in at 1900lbs. and my boss has haulled 2-1/2 tons of hay on it with no problems. Also as you can see it has brakes.Hope this helps"If you live in Sacramento you have seen my work."
Reply:Jonnie, thanks for the pics.OK, I got most of my steel yesterday, and started coping my corner joints tonight. I ended up getting the thicker C Channel, and a bit of 2x2x1/4 angle. Im going to document the entire build with pics, so I should have some pics to share. Im hoping to get started and finished this weekend.
Reply:Originally Posted by MoonRiseOver overbuild?  No such thing.