staledale Posted November 17, 2002 Share Posted November 17, 2002 After using a friends car trailer about 6 times this year, and a lot last year I've decided to build my own. They make them with 3" channel iron. Would there be any advanage to using a 2x3 tubing instead? Any idea's on making it lighter but stronger. I've got blueprints, just wondered. Thanks Quote Link to comment Share on other sites More sharing options...
denny411 Posted November 17, 2002 Share Posted November 17, 2002 The tubing could be lighter than the channel, but 3" channel really isn`t that heavy anyway. I can`t really say which would be stronger. Depending on what type of welder you have, the box would be thinner and easier to get penetration. The channel would be cheaper to buy than the box. Quote Link to comment Share on other sites More sharing options...
yo2001 Posted November 17, 2002 Share Posted November 17, 2002 It's kind of hard ro make a good parpendicular joint with tube unless you got a equipment to cut the tube in an inverted moon shape. ) Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 17, 2002 Share Posted November 17, 2002 You could buy a tube notcher for about 30 bucks which I understand makes perfect tubular perpendicular welds. I have never used one myself however. Steve Quote Link to comment Share on other sites More sharing options...
Guest greimann Posted November 17, 2002 Share Posted November 17, 2002 Without spraining a brain muscle by digging into the books on moments of inertia and modulus of elasticity, my seat of the pant feel is that a section of square tubing should have a higher bending moment ( less deflection )than channel of equal height. Trailer manufacturers use channel because it is easier to fabricate with and run tail light wires in. Square tubing adds another level of complexity in manufacture that is not cost effective for a dumb 'ole trailer Quote Link to comment Share on other sites More sharing options...
denny411 Posted November 17, 2002 Share Posted November 17, 2002 I also think the added cost of box tubing vs. channel is also a factor with trailer manufactureres. Quote Link to comment Share on other sites More sharing options...
staledale Posted November 17, 2002 Author Share Posted November 17, 2002 Thanks guys, I get ideas Friday nite and this is the best place to check them out. I'll have to go to my local corner metal store and get a cost per ft. vs. weight per ft. vs strength per ft. and compare them. Thanks again. Quote Link to comment Share on other sites More sharing options...
Guest AlsoRanFPrepared Posted November 17, 2002 Share Posted November 17, 2002 A trailer is not something that you should be too concerned about weight on. Even if the difference between the box and the channel will make the trailer weigh say 300 pounds less that is not enough to worry about. If the weight of the trailer itself is an issue when you are towing a car on it you should likely seriously look into the tow vehicle. True, the box will have a better area moment of inertia if it is the same height width and thickness as the channel. However, this shape (channel) may be the most cost effective means to achieve the necesssary strength. Given the location of the neutral axis on the channel being closer to the closed end, and given the loads that this structure will see, the bending stresses seen at the top surface may be smaller than for a comparable sized box. This is where the engineering comes in. Do the math. Determine the loads, calculate the stresses, account for fatigue and apply a large safety factor. The tubing will no doubt cost more as trailer manufacturers would build them in tubing if it was cheaper. If you already have blueprints there is no sense re-engineering someone elses work. -Mark Quote Link to comment Share on other sites More sharing options...
Dan Juday Posted November 17, 2002 Share Posted November 17, 2002 Hey Mark alsoransomewhereinthemiddleofKansas, I like your sig. But if Sam Clemmons said it , he got it from a jew named Solomon. Proverb 17:28 "Even a fool is thought wise if he keeps silent, and decerning if he holds his tongue." NIV Oh ya, and a little wisdom on that trailer thing from an OLD guy. Build it stronger than you think you need it to be and don't worry about a few extra pounds. Years down the road you'll, undoubtedly, want to move something much heavier on it. Quote Link to comment Share on other sites More sharing options...
JKDGabe Posted November 17, 2002 Share Posted November 17, 2002 One more thing to consider is that you can't (cost effectively) coat the inside of the tubing. The channel will be easier to paint completely. It's inevitable that moisture gets trapped inside tubing. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted November 17, 2002 Share Posted November 17, 2002 I would use the channel rather than the tubing. It will be near impossible to paint the inside of the tubing. Unless you plan on getting everything plated, at which point it will be cheaper to buy a manufactured trailer. Also why use a tubing notcher on a trailer? Just butt the square cut pipe to the other and fill in the gap with several passes of the welder. I wouldn't do a roll cage this way, but I did a workbench and believe me it is plenty strong. And yes, Mark Twain was very well versed on the bible. He referenced it frequently in his writings (and was a frequent critic of it too). Doesn't make his phrasing of it in the English vernacular any less quotable. His famous quote that applies to Hybrid Z is "Necessity is the mother of taking chances." Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 17, 2002 Share Posted November 17, 2002 Square tubing for about every thing on the trailer frame. Use channel or angle in non critical areas. Check around and you may find a very good used one for what material and labor will cost to build one.(Ol Sam also said something like this:"why should I serve in heaven when I can rule in hell") Quote Link to comment Share on other sites More sharing options...
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