Bicycle Trailer Hitch

Yes, its welded but I did the butcher work and prep for welding.  Then I found an extremely cool welder and he charged me $5 to weld it up.   I honestly think that all the "no weld" hitches are, for the most part, DANGEROUS............. but you have to start someplace and the fallowing caveman tactics may just point a few people in the correct direction.  If you don't think you can bite into a welding project......... just take smaller bites!
    TOOLS: hand grinder, drill/bits, Vice-Grips, hack saw, file

Step 1 Parts

 I'm not going to get into sizes because what you find can work and not everybody needs monster strength for just going to the store.

Comments

[glorybe]

It would be pretty easy to saw the tube from a bike that is ruined to accept the seat post. That way it could glide left or right without any back and fourth slop in it at all. Simply use a bit of grease to prevent wear and make certain that you have a steel seat post. Take a short length of all thread and rap it around the tube so that you have the equivalent of a u-bolt. A very simple weld should keep the all thread located forever and you can now easily attach a link to allow up and down movement. You might even take a universal drive from a decent size ratchet and socket set and well that to the tube you made from the ruined bike. Or if you wish to go one step further simply look at a universal from that socket set and make one a bit larger than you are used to seeing.

[nanoassembler]

I often use a propane torch to remove (burn) the zinc or galvanized coating from nuts, bolts, washers, nails, sheet metal, etc. BUT DO IT OUTSIDE! The fumes are DANGEROUS.

[appsman]

Throw the zinc coated part in household vinegar for a few hours (I usually leave it over night) and the coating gets cleaned off (as well as any rust). Make sure the part is completely immersed, otherwise it will corrode at the air/liquid junction. After it's done, rinse it off thoroughly with lots of water and dry it to prevent runting. Then it's fine for welding with no dangerous fumes.

[markstutzman]

If you're in a hurry, muriatic acid will strip the zinc coating off in a few minutes. Any hardware store (it's used for cleaning/etching concrete before painting) or pool supply store should have it. Note that it is more dangerous than vinegar, since it's a 31% hydrochloric acid solution...

[nanoassembler]

Great tip! I'll try it. I hope the acetic acid doesn't oxidize the metal too much.

[onrust]

You need a grinder for the project. Welding creates its own chemical field. The idea is to weld with clean metal not with something else on it.

[appsman]

Not sure what your talking about when you say "chemical field". I got the idea to use vinegar to strip galvanizing and the shiny coatings on hardware-store nuts and bolts on the Miller Welding Forum, which seems to be the best welding forum I've found. I've done this about a dozen times and the hardware always comes out very clean and ready to weld. I have never gotten any of the white cloudy smoke that occurs when you try to weld a zinc (galvanized) coating. If you're saying that the only reasonable way to remove the coating is by grinding, I'd have to say from my experience, that is wrong. Besides, how would you grind out the inside of small tube?

In reply to nanoassembler - If the part is completely immersed, the parts come out fine. I usually leave them over night and I've never had a problem soaking a part too long. My only warning is to be careful about splashes and spills. I ruined a pair of calipers because I didn't see them get a few drops of vinegar. By morning they were badly pitted.

[onrust]

I'm no welder. I was referring to the argon/weld when I said chemical field. NANOASSEMBLER mentioned concerns of oxidization.......... using a grinder eliminates those concerns on a situation neither of us had knowledge of.
How do I grind the inside? I don't, the weld takes place on the outside.

[appsman]

I don't know how you can comment if you have no welding knowledge. Your advice is close to being dangerous. Zinc poisoning is not fatal, but makes you feel like crap. You need to get the coating off the inside, as well as the outside, of the pipe because, even though you are welding only on the outside, the WHOLE pipe gets plenty hot enough to cook off the inside coating and create fumes.

[glorybe]

Zinc shakes are something to avoid and I believe that one can be seriously harmed by zinc fumes at a certain point. I'm not certain about immediate fatality or not but if it wrecks your health that is bad enough.

[nanoassembler]

Oxidation concerns me because I do not want to weaken or distort the items being welded. A grinder may work for big, low tolerance projects, but it usually does not work when you need precision. A grinder is often impractical on large pieces of sheet metal (e.g., HVAC duct). Burning the Zn (oxidizing it into ZnO fumes) does not damage nor distort the underlying item—tight tolerances are maintained—and large areas can be processed very quickly and effectively. The acetic acid bath sounds like a good alternative, as long as the part is small enough to be immersed.

[onrust]

Honestly, the best solution is to eliminate the NOXIOUS fumes all together.

[jkm]

why not weld the hitch directly to the (iron/steel) seat post?

[onrust]

The death of a bike and trailer never come together. I could just see me running around looking for a frame to fit a seat post..... no thanks. Also, your better seat posts are generally Aluminum.

[onrust]

OMG! I think those are french fries on the ground! ( step #2)