General welding questions that dont fit in TIG, MIG, Stick, or Certification etc.
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mikelove316
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Hello all !

So as a newbie welder I finally landed my first welding job outside my regular day job.
Is kind of a big deal because this first job sets the tone for the rest of my welding side hustle so I’m a little nervous but confident I can to it . The job is to weld up a new hitch attachment for a motorcycle rack that goes on the back of a car . My friend says that when he loads his bike up the weight of the bike drops it pretty low and it sometimes bottoms out while he’s driving around or if he goes over speed bumps it scraps the bottom . I told him I’d do it for free just for practice but he said he wouldn’t feel right taking it for free . So he will pay for the welding anyway any advice?
homeboy
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Personally as a "newbie welder" I wouldn't touch it. If this in in fact supporting the weight of the rack and motorcycle attached to the vehicle this is entirely different than welding something static vs. live loading. The live loading on something like this could far exceed the actual weight by many times with shock loading, bouncing over bumps etc. Liability is a huge issue. Detatched motorcycles and carriers bouncing thru windsheilds is frowned upon! By changing the mounting points there may be additional bracing /supports also required which will require some type of structural knowledge. :shock:
cj737
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Does he tow the bike "inline" with the vehicle, or parallel to the rear of the vehicle? If inline, he needs to worry about mechanical issues and your "trailer" lift needs to be stout to deal with the weight so far away from the receiver.

I'm going to assume parallel, unless your pal is a masochist. I would fabricate a 90* lift to raise the platform, gusseted. That will add extra strength and rigidity to the bend. For the trailer bed, I would use 2"x2"x3/16" angle, and I'd run those front to back, every 2' across the bed. Weld them to the frame of the platform, from the underside. Should hold the world.

Its the same method and setup I made for a buddy's Job-Box to hang from his trailer hitch on his new welding truck (a surprise gift for him). I bought 2x2x.25 HRST for the hitch insert and lift. His box weighs about 250# and is 5' wide. Less than a bike, but equally important ;) Doesn't move an inch.

PS - I did also weld small "dots" on the hitch insert to tighten up the fit within the receiver. 2 small beads on 2 adjoining sides. Flap Disked to fit under just enough tension.
mikelove316
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Here’s a pic
Last edited by mikelove316 on Thu Feb 15, 2018 8:01 pm, edited 1 time in total.
mikelove316
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Side view
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MarkL
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A hitch riser might accomplish the goal without any welding.
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mikelove316
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yea that looks like it will do the job exactly . hmm well there goes that job but would it be to far a stretch just to weld something like that ??
cj737
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And you need some triangulation from platform back to hitch to add rigidity.
MarkL
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mikelove316 wrote:... would it be to far a stretch just to weld something like that ??
No, they sell the parts to do the fabrication yourself, or you can probably buy them locally and save on shipping.
Lincoln Square Wave 200
Lincoln 225 AC/DC
Harris Oxy/Acetylene torch
mikelove316
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thanks for all your advice every one , very helpful . I think I will Just go for it . you got to start somewhere right
tweake
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i would also look at checking to see if you can mount the bike closer to the car. its sticking a mile out and looks way to long (ie lighten it up as well).
the further out it is the more leverage it applies to the suspension and the lower the rear of the car will be.
also be careful of blocking number plates and lights. not sure on your laws but it pays never to give police an excuse.

edit: btw how heavy is the bike?
tweak it until it breaks
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