The rear fork is completed according to the plans.
My son helped by grinding a bunch of the metal clean.
One thing I discovered it that the plans are for 26″ wheels, meaning that my 700c wheels are slightly too large. Good thing I was planning to use my son’s old 650c wheels!
For my next project, I modified the plans to use 17″ forks, which are more than large enough for full sized 700c wheels. I even made some paper templates, as I found that aligning everything by hand / eye was a pain in the butt. As you can see, the dropouts have to be manually aligned to the rear fork. Ensuring this is straight is way harder than it seems.
The paper templates (bad picture) are life-size, showing the correct angle of the forks to ensure proper welding. I added a middle rectangle which represents the wheel. This can be used to ensure that the wheel is perpendicular to the top bar of the fork.
My poor welder is at the Welder Doctor, so I used my down-time to cut and sand some more pieces for future projects. Here are some aluminum parts for a future build! Even though none of it is put together, it was a cool experience to lay them out into the correct shape. Hey! I might actually finish building something after all!
Here is some dirty (left) and clean (right) aluminum.
Funny side story. I was going to tease my son and jokingly tell him that he did such a great job sanding the steel, that I can no longer tell the difference between the steel and the aluminum. A moment later, I reach onto my pile to pull out a piece of steel, and I pick up a piece of aluminum instead. So the joke’s on me!
The bottom two metal pieces in the picture below are steel (rounded corners). The others are aluminum.
Once my welder is out of the shop, it’s back to bike building!
I’ve learned some interesting things about metals since I started educating myself about welding. This is especially true because I started by reading and then doing.
Which one of these nuts is the old one? You might be surprised to know that I received these two nuts at the same time, and that they were identical at the time. The one one right hasn’t been left outside in the rain for a month. It got its look from being exposed to extreme heat in a nitrogen and oxygen rich environment.
I already knew that “rust” is formally called “iron oxide,” but I’d never given the term much thought. I figured metal rusts when it gets old. If you get metal wet, it’ll start to decay (rust) away. Except aluminum, which doesn’t rust. Imagine my surprise then when I discovered that I could coat a shiny metal with rust in just a matter of seconds!
So here are some things I’ve learned about oxidation, and I’ll use the term “rust” interchangeably to show how it can be confusing.
Iron rust is from exposure to oxygen, not moisture
Metals can oxidize instantly; rusty doesn’t mean old
Aluminum (and “stainless” steel if I recall correctly) does in fact rust or oxidize
Aluminum rust (aluminum oxide) is silver colored instead of orange, and it doesn’t eat away at the metal the way iron oxide does. Instead, it actually protects the metal from deteriorating in the elements
Both iron and aluminum oxides have to be removed from the metal before TIG welding. This is especially difficult with aluminum because you can’t necessarily see it.
The TIG welding process (the one I use) utilizes a shielding gas. While welding, Argon (one of the noble gasses) is blown on the hot metal to keep out nitrogen and oxygen rich natural atmosphere from oxidizing the metal. The bolt on the right in the picture above was welded without this gas, and you can see the results.
I’ve just fabricated the arms that will hold the rear dropouts, which, in turn, hold the wheels on:
This is part of a larger piece that I still need to finish, so normally this wouldn’t be enough to justify a whole blog post. But, it’s my very first fabricated part with my new welder, so I want to brag!
The steel tubes are cut at a 45° angle:
Another piece of tubing is cut and ground as flat as possible, then welded onto the end:
Some work on the grinder to remove all my ugly welding:
A Before and After shot:
Both pieces ground down:
Here is a closeup of the finished piece. What I’m most proud of is that, unlike something that is affixed or glued, there is no line where the cap was attached. The weld makes the entire thing a single piece of metal. Neato!
I put ads on several online forums asking for people’s junk bikes. A couple guys from the Woodlands Bike Social replied, so now I have one and a half donor bikes!
Bike Number One is a steel framed Magna donated by John.
It has some nice looking shocks on the fork.
The straight handlebars may come in useful as well.
There will be plenty of opportunities to make good with this frame. In fact, the only thing broken about the bike is that the bottom bracket has a stripped crank bolt!
Bike Number 1.5 is an interesting contraption donated by Leo:
It attaches to the back of a mountain bike, converting it into a tandem. The front sprocket attaches to your mountain bike’s chain, replacing its back wheel the crank actually has two identically sized chainrings.
This allows a second person to pedal, sending the power to the rear of the frame, where you’ve moved your bike’s back tire. Very interesting, and made of heavy duty aluminum as far as I can tell.
One project I’d like to make eventually is a pedal-powered generator. This device looks like it’s got the perfect gearing setup.
Leo also said he used to build bikes and finally stopped because he’d built more than enough for him to use. With that, he gave me a box full of miscellaneous parts, including chain rings and trigger shifters. One day I’ll be satisfied and pass my own box of parts onto another hobbyist.
I assembled it all and played around a little with some scrap aluminum and steel I had lying around. It was already late at night by the time I got started, so I didn’t do any actual welding. That is, I didn’t want to open up my new box of filler rod and try legitimate TIG welding. Instead, I melted the metal and played around with pushing the puddle around.
The aluminum was just like I expected from watching YouTube videos. The AC makes a very distinct buzzing noise. The steel was a different story. When I switched to DCEN (Direct Current, Electrode Negative) mode and struck an arc, I was amazed. TIG welding on steel is so quiet! My only experience with welding thus far is playing around with a wire-fed MIG welder from Home Depot as seen below:
Here I’m really just making sparks and welding random pieces of steel together. It’s loud, sparky, and smokey (I know, I know – flux coated wire). But the TIG arc on DC, if it made any noise, was drowned out by the welder fan and the flowing argon.
I didn’t use any filler rod on the steel either. I won’t have time to mess with it for the next week or so, but so far everything seems to be working great!
Some melted steel:
The patch of goo on the right is a pile of leftover slag from my Home Depot welder fun that I melted with the new TIG torch.
Here is the ugly melted aluminum.
I’m aware that the two pieces aren’t joined properly and that the weld penetration isn’t deep. This was just a little bit of playing around with my new toy on the day I received it. By the looks of the weld, I contaminated my tungsten a bit. Time to practice practice practice!
I took a trip to Rose Steel today to look at their stock. The staff was very friendly and helpful, and their prices seemed very fair. I bought:
For bike frames:
24 feet of 16 gauge (1/16″) 1.5 inch square steel tubing
24 feet of 1/8″ thick 1.5 inch 6063 aluminum tubing
For wheel dropouts and misc load-bearing small parts:
4 feet of 2″ wide 1/8″ thick steel flat bar
They cut the tubes into 8 foot sections. Because Houston Metro is such a large area, driving to the place was a little bit of a hike. Within reason, I was trying to buy as much material as I’d need to tide me over for awhile. I figure this is enough metal to make at least two complete bike frames out of each material, but time will tell!