Today I welded the entire front triangle together.
First, BB and seatstay were prepped, BB was drilled for airhole, and was tacked using the BB failure jig and then finally welded:
BB/seatube and headtube were set up in set up frame jig. Downtube and top tube were tested for fit, and breather holes were marked out and drilled. Breather holes allow argon to flow throughout inside of entire frame. Tubes were reinstalled in jig, tacked and some welding was done. Since tacking was done off of the metal table, welding wire needed to be attached to steel part of jig (or frame) to keep the piece grounded. Tacks were initially applied on all obtuse angles, and then acute angles.
Frame was taken out of jig, and was then welded on the table. For each tiny weld made, I rotated from the four welds (Top tube/head tube Drive side to BB/seat tube non drive side, to Seat tube/ top tube drive side... etc) This helps keep the frame aligned and helps keep the frame from pulling itself apart and making it impossible to weld the other sides.
All of the welds weld a mitered tube to a thicker non mitered tube. The head tube, Bottom Bracket and seat tube collar make it alot easier to weld the two tubes together. The one exception to this rule is where the Down tube meets the seat tube, which butts two thin walled tubes together. You can see the results of applying the same welding force to that joint...yikes.
I've gotten alot better at patching holes, (and avoiding them in the first place), but after only making the hole bigger in my first attempt to patch it, I deferred to Jim's expertise in remedying the situation and filling it so I could finish the BB/seattube/downtube welding.
Seeing how most of the people new to welding did the exact same thing, I didn't feel too bad about it.
All better and finished:
Finished head tube:
The other side:
omg... finished front triangle:
While not finish prepped, I may have found a future worthy portfolio shot:
Already, I've got framebuilding groupies vying to help make my portfolio as attractive as possible:
Assos bib model, you can lend two hands...
Alright, enough "bike porn" of sexy welds for one day... check back tomorrow for chain stays.
Short Technical Section:
1. Tubing used for this Titanium frame is all single gauge 3/2.5 Titanium Tubing. Titanium is never found in its pure form in the environment. Instead, the metal must be extracted from other compounds, such as rutile ore and ilmenite. This extraction process is difficult and expensive, and is one of the reasons why titanium is so costly.
3/2.5 Ti means means there is 3% Aluminum and 2.5% Vanadium in the tubing with the remainder being Titanium. Filler wire is 6/4 Titanium (6% aluminum, 4% Vanadium, rest Titanium). 6/4 Ti is alot stiffer, so theoretically the welds are actually some of the strongest points on the bike. 6/4 Ti can not be used for frame tubing as it is only produced in sheet form, and would have to be welded along its seam after being rolled.
For more information about Titanium, see Seven Cycles site for some really good information about Ti-
http://www.sevencycles.com/buildingbike/techsupplement/ti.php
2. It took me some time, but I finally understand the concept behind welding (and helps begin explain Friday's fiasco)
A) The welding torch is angled along two orientations. It faces the direction your moving, with the filler coming from the opposite direction.
B) Welding a thinner, mitered tube to a thicker non-mitered tube, you want to focus the weld blast more on the thicker tube. This is done by angling the torch below 45 degrees rotated around the mitered tube's axis:
Alot of the skill involved with welding depends on maintain this angle as you rotate around the mitered joint. Just moving your hand in the direction of the weld leads you to aim the torch tangent to the mitered joint instead of rotating it around the mitered joint's axis.
If this diagram was real welding, you might aim the torch slightly towards yourself at the angle show, and flick your wrist upward as you traveled down the side of the tube.
It also helps to begin your welding "puddle" on the thicker surface and weld not directly on the joint but favoring the thicker, non mitered tube.
Also, keep your your tungsten tips sharp and free of Ti.
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