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Build a cheap semi trailer

Gadgetman ยท 2009-04-30 21:25

Im sure there are farmers among us that wish they had another hay or multi purpose trailer. Been sitting on this project waiting for a big rainy spell,so here we go. We got ahold of these railroad container trailers from some online brochure for around 2k per. The frames are weak,as the containers they carry are self supporting. But, everything else is there and the frame makes a good templet to hang your steel. We done the calculations for the steel needed to give us the strength we need. This will be another liquid fertilizer nurse trailer when I'm done. We started out today on it. They come 48' long,we only wanted 40'. So we cut 30" off the back,and 5' out of the center. Joined the frame back together,straighted out any kinks in the I-beam flanges,and straighted the lenght of the frame itself. Ready to start slapping on some steel. Will post pics and explainations as I go. Sorry for the quality,using my cellphone.

Replies24
  1. #1Gadgetman2009-04-30 21:31

    This is basically what I'm building,but better. Our first trailer we built several yrs ago ended up heavier than we wanted,so we put a pencil to this one. Should be able to trim 2,000-3,000 lbs. and still carry a safety factor of 1.4

  2. #2Iron Horse2009-04-30 21:49

    They will make good trailers . Did you decide against cutting the suspension off and wheeling it forward and re-welding it ? You would not have had a join in the middle then .

  3. #3Gadgetman2009-04-30 21:56

    With the way I'm going to be adding steel,it won't matter. You will see. There isn't a lot of stress at this point,so it's really a handy way of shortening it.

  4. #4Iron Horse2009-04-30 22:02

    In OZ , if you make a join mid wheelbase it needs to have an engineers certificate . If you wheel the suspension forwards and cut the excess off the rear it does not .

  5. #5Gadgetman2009-04-30 22:14

    Iron horse, this isn't my first rodeo. I do this stuff for a living,have for more than 25 yrs. And, the numbers I'm using came from an engineer. That section will be stronger than anything in front of it.

  6. #6td25c2009-04-30 22:53

    Look's great Gadgetman.In the US ,we cut & lengthen truck & trailer frames often if the wheelbase dosent suit us.Driveshafts are not a problem either.

  7. #7Gadgetman2009-04-30 23:07

    Yup yup, that rig in my avatar was lengthened 4'. Grosses over 70,000lbs.,bounces thru ditches,waterways,terraces,and runs down the road at 42 mph. Works just fine,

  8. #8Gadgetman2009-05-01 23:41

    No pics today, Had to do some redesigning of the reinforcement for the lower to upper deck transition. These frames are tighter from the kingpin back,not allowing me to add steel underneath that area. Trucks hooked up to this would of had to slide their 5thwheels back to keep from rubbing in turns. Instead I choose to side plate thru that section. This will keep the bending moment rating where it needs to be. So, we had to cut the landing gear off to open up that area. Plazzed out 4 1/4" side plates and welded them in place.

  9. #9Gadgetman2009-05-05 21:47

    Got sidetracked yesterday getting this setup ready. Our customers wanted us to inoculate the beans we are selling. We scavanged thru the scrapyard and came up with an old dry spreader hopper (which we made a stand for),and an old fertilizer conveyor. The conveyor was all froze up,and was geared way too fast. Dropped a new 1100 rpm motor on it,geared it down to about 4' per second,replaced all the bearings,and came up a way to lift it up and pull it around. The beans come in 2,500lb bulk bags which we hoisted up with a spear attachment on the loader. The beans zig-zag thru the green box while the chemical is sprayed on. System worked pretty well for a last min. effort. My mobile toolcrib while working on outdoor projects. That old ford had a rusted out flatbed just a few months ago. Got a good deal on that service bed,it's been nice to have around.

  10. #10td25c2009-05-05 22:02

    Thats quick thinking and a neet setup Gadgetman.The mobile tool crib looks great to.I never herd a service truck called a mobile tool crib.Mobile tool crib's are handy for sure.Keep us posted on the 09 planting season.

  11. #11Gadgetman2009-05-05 22:07

    Did start hanging some steel today. Added a 4x4x1/4 sq. tubing above the upper deck frame,then sideplated that to the lower frame. Also added a 1/2x6 top flange the full length,and hung a 5x8 I-beam beneath the main frame for a total of 20" of web. The original beam was a piddley 4x12 with 1/4" flanges and a 3/16" web,about 1/2 the strength we need.

  12. #12Gadgetman2009-05-05 22:26

    Dang, shoulda posted that in the other thread, lol :Banghead Yea, I have a torch in one compartment,and a compressor in another. There's top lids that open up,one of those contains a 25 pack of every bolt size from 1/4"x1" to 3/4"x8".

  13. #13Gadgetman2009-05-06 23:37

    Spent most of the day welding all this up. Still a few hrs. to go yet. Migged all the new metal,but had to go with 6011's anywhere paint residue remained. The mig does not like Union Pacific yellow....at all. Must be a catylized polyurethane. Also started making the tank saddles out of 1 1/2 x 12 jr. channel. 8 of them to make,so a jig was in order.

  14. #14hvy 1ton2009-05-07 00:48

    I've decided that one could weld a 2x4 back together with 6011. I haven't ever had a problem welding with 6011, at least as far as surface prep. If there is a bunch more metal to burn, you might try out a spool of dual shield wire. I haven't tried it in heavy paint before, but it is close to 6011 in rusty metal. It is a bit of a pain b/c its flux core and CO2, but your gonna be chipping anyway and gas is cheap right.

  15. #15Gadgetman2009-05-07 20:44

    Yea, we'll go thru 200 lbs. per yr of 6011 in this eviroment. Not much chipping,just hit it with a wire wheel,slag blows right off. Frame is done (200' of welds later),ready for the landing gear,fenders,bumper,and tank saddles. This frame is structurally ready for our 85,000 lb. gross load, short of a few X-braces that will go in after the 4" plumbing we'll be running later. A few pics showing how it ties together. It's almost 3 times as strong now. The bending moment is the greatest about 6' back from the transition,tapering down to almost nuetral in front of the axles. So the frame splice isn't an issue now. The railroad can get away with such a lite frame,because the containers themselfs are the main structure. The axles are rated high enough. Metal used 1-4'x8' sheet of 1/4", 80' of 1/2"x6" flat,and 2-25' 5"x8" I-beam (1/4" web/3/8" flange). The rest depends on the application,tanks,flatbead,etc.

  16. #16Gadgetman2010-01-03 11:51

    Forgot to post the finished pics on this project. Been using this trailer for awhile now. It's top dress season again for wheat,and it's often filled to the gills.

  17. #17td25c2010-01-03 13:09

    Another job well done Gadgetman!

  18. #18JDOFMEMI2010-01-03 13:36

    Good looking rig you built. Did the weight come out like you wanted?

  19. #19Gadgetman2010-01-03 16:56

    Frame did, but you know how these things go. Save a ton in steel,so you can carry 50 gals. more fuel for the floaters and 600 gals. worth of chemical totes. lol That's what the lil hopper and meters are for on this one, inducting chemicals as we load the spray rigs. Beats jugging over the top,or hauling hot mixes to a field that's too muddy to run.

  20. #20bill53622010-01-03 17:28

    Nice job gadgetman, how did you prep the frame before you painted it. I recall that you said the paint was pretty tough how well did it clean up for the new paint.

  21. #21Gadgetman2010-01-03 20:09

    After fitting everything we stripped it all back down to the frame for sandblasting. Shown here hooked up for the 50 mile trip to the blaster. Even pulled the inside rims off for access to everything. All surfaces are cleaned down to bare metal before painting. I try to avoid two flat surfaces of metal contacting each other,unless I enclose it with welds. Your not able to paint these surfaces,which in our enviroment is guaranteed to rust out. In the case of the two I-beams stacked and the heavy top flange added, I didn't want continious welds running the full length of the frame. So we ran welds every 6" or so,then filled the seam with a paintable silicone after the sandblasting was done. This has been working well for us.

  22. #22blyne32010-01-29 09:26

    looks great!

  23. #23robin yates uk2012-05-29 05:45

    your work looks very professional and you sound like a guy who does stuff right.Great set of pics.Thanks for an interesting post

  24. #24watglen2012-06-20 23:00

    nice work! I have a question, how much trouble do you have with cracking on the cross bracing welds? I imagine there are some tricks involved with allowing the frame to flex and twist without the braces fatiguing and cracking??? ken