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Welding equipment

The Tesseract

TRIBE Member
I want to make a low-rider or chopper bike frame.

I have to get materials first, but I imagine that will be harder than the actual welding equipment.


Which is easier? WIG or TIG?
and more importantly... which is stronger?
 
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adorablehomeboy

TRIBE Promoter
Originally posted by The Tesseract
I want to make a low-rider or chopper bike frame.

I have to get materials first, but I imagine that will be harder than the actual welding equipment.


Which is easier? WIG or TIG?
and more importantly... which is stronger?

Ok, sorry for posting in this old thread but I was among the first batch of graduates to complete the Welding Specialization within my engineering program at UW.

I am assuming you have little or knowledge or welding or materials, so please excuse me if I sound rude - I'm trying not to.

WIG is TIG Welding.

Welding will be a skilled trade soon in Canada, because it is NOT easy. AND, you are going to be fitting some pretty weird angles I assume making the frame. If you can actually get this thing to hold, after some dynamic loading caused by you riding it it's going to break, while you are riding it....

Find out what other bike frames are made of...

You want it to look nice and be tough (as in the best combination of strength and ductility)? You'll want a brushed titanium or chrome moly steel.

Titanium will be expensive as hell, and chrome moly will be too. Welding both are different. Titanium has to be cleaned and welded right away, and completed gas shielded when welded. Chrome moly or other types of steel you have to be careful about the cooling rate, you could end up with a brittle joint, liquation cracking, stress cracking etc....

I could go on but I'm not too brushed up on this stuff but I can be quickly, my focus is on QA.

So I don't know how much welding and fitting experience you have, but if you are welding something structural please be careful!!!

(materials - try Metal Supermarkets)
 

Temper Tantrum

TRIBE Member
I knew someone once who wanted to be an arc welder in a small town in southern ontario.

but then he changed his mind

and decided on the Ethiopian navy.

SMRT

~allie~
 
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The Tesseract

TRIBE Member
Originally posted by adorablehomeboy
WIG is TIG Welding.
I know, i realized my mistake after
W is just the german designation for it
Wolfram/Tungsten = same shit
What i really meant was MIG


Originally posted by adorablehomeboy
Welding will be a skilled trade soon in Canada, because it is NOT easy. AND, you are going to be fitting some pretty weird angles I assume making the frame. If you can actually get this thing to hold, after some dynamic loading caused by you riding it it's going to break, while you are riding it....

Find out what other bike frames are made of...

The bike would be a completely road (more or less) frame, and so would be made from double butted aluminum. I'm sure i can get that stuff no problem, thanks to a source of mine.

Originally posted by adorablehomeboy
You want it to look nice and be tough (as in the best combination of strength and ductility)? You'll want a brushed titanium or chrome moly steel.
Nope... just regular 6000 or 7000 series aluminium... 6061 or 7005
If not, Hi-ten steel.

Originally posted by adorablehomeboy
Titanium will be expensive as hell, and chrome moly will be too.
Titanium is not that expensive... but it's not exactly easy to obtain either. It's only when parts get smaller does the material go up in price. Bulk order of Ti is actually cheap... at about $10-15/lbs
Chromium Molydenite Steel is around $6-8/lbs

Originally posted by adorablehomeboy
Welding both are different. Titanium has to be cleaned and welded right away, and completed gas shielded when welded. Chrome moly or other types of steel you have to be careful about the cooling rate, you could end up with a brittle joint, liquation cracking, stress cracking etc....

more shit i know...

Originally posted by adorablehomeboy
So I don't know how much welding and fitting experience you have, but if you are welding something structural please be careful!!

I did welding in Grade 10 (or was it 11?)
granted, that was about 10 years ago... I still remember how to do it. It was easier than sodering... i remember that for sure.
 

Noodles0

TRIBE Member
if ur welding aluminum ur gonna want to use TIG !!! its a little tricky tho so make sure u go slow and dont get too happy with the foot trigger...
 

depraved

TRIBE Member
Originally posted by The Tesseract
I did welding in Grade 10 (or was it 11?)
granted, that was about 10 years ago... I still remember how to do it. It was easier than sodering... i remember that for sure.

My experience after having taken a cpl courses at community college is that TIG welding is hard to do well. Give the job to somebody who knows what they're doing or you'll be disappointed with the results.
 

defazman

TRIBE Member
Yep, if you're doing a bike frame you'll want to do TIG welding, so make sure to get a welder with at least 220V. Most bike frames are done with a 5356 filler metal, so you dont need the 6061 or 7XXX alloys.

A friend of mine is a nationally ranked mountain biker who also makes his own bikes. He had the welding on a frame professionally done (aluminum is its own monster, not the same as welding steel), and the frame still cracked on him, causing injury and a concusion.

from www.lincolnelectric.com

TIG Welding Aluminum
Source: adapted from New Lessons in Arc Welding The Lincoln Electric Company, 1990



Although many metals are TIG welded, the metal most frequently associated with the process is aluminum, especially with metals of a smaller thickness. Many other processes, of course, can join aluminum, but in the lighter gauges the most applicable process is TIG. The popularity of aluminum in automotive applications has brought TIG welding to a new golden age. Mechanically strong and visually appealing, TIG welding is the number one process chosen by professional welders for professional racing teams, and the avid auto enthusiast or hobbyist.

That Confusing Thing About Aluminum
The process is well suited for aluminum, but there are a few characteristics of the metal that bring up points that must be considered if this material is to be welded with consistent ease and quality.

The pure metal has a melting point less than 1200ºF and does not exhibit the color changes before melting so characteristic of most metals. For this reason, aluminum does not tell you when it is hot or ready to melt. The oxide or "skin" that forms so rapidly on its surface has a melting point almost three times as high (3200º+F). To add to this confusion, aluminum even boils at a lower temperature (2880ºF) than this oxide melts. The oxide is also heavier than aluminum and, when melted, tends to sink or be trapped in the molten aluminum. For these reasons, it is easy to see why as much as possible of this oxide "skin" must be removed before welding. Luckily, the reverse polarity half of the AC arc does an outstanding job of cleaning off quantities of this oxide ahead of the weld!

That Aluminum is Hot!
Aluminum is an excellent conductor of heat. It requires large heat inputs when welding is begun, since much heat is lost in heating the surrounding base metal. After welding has progressed a while, much of this heat has moved ahead of the arc and pre-heated the base metal to a temperature requiring less welding current than the original cold plate. If the weld is continued farther on to the end of the two plates where there is nowhere for this pre-heat to go, it can pile up to such a degree as to make welding difficult unless the current is decreased. This explains why a foot or hand Amptrol™ (current control) is recommended with your Square Wave TIG 175 PRO or Square Wave TIG 275 – it enables you to easily change the current while simultaneously welding.

Some aluminum alloys exhibit “hot short” tendencies and are crack sensitive. This means that at the range of temperatures where the liquid alloy is slushy (part solid and part liquid) or just turned solid, it has not quite enough tensile strength to resist the shrinkage stresses that are occurring from cooling and transformation. The proper choice of filler metal and welding procedures along with smaller beads can help eliminate many problems of this kind. Some experts recommend backstepping the first inch or so of each aluminum weld before finishing in the normal direction.

Filling the Gap
The metal produced in the weld pool is a combination of filler and parent metals that must have the strength, ductility, freedom from cracking, and the corrosion resistance required by the application. See table below for recommended filler metals for various aluminum alloys.

Maximum rate of deposition is obtained with filler wire or rod of the largest practical diameter while welding at the maximum practical welding current. Wire diameter best suited for a specific application depends upon the current that can be used to make the weld. In turn, the current is governed by the available power supply, joint design, alloy type and thickness, and the welding position.

Recommendations are for plate of "0" temper.
Ductility of weldments of these base metals is not appreciably affected by filler metal.
elongation of these base metals is generally lower than that of other alloys listed.
For welded joints in 6061 and 6063 requiring maximum electrical conductivity use 4043
filler metal. However, if both strength and conductivity are required, use 5356 filler
metal and increase the weld reinforcement to compensate for the lower conductivity of
5356.

A Quality Deposit
Good weld quality is obtained only if the filler wire is clean and of high quality. If the wire is not clean, a large amount of contaminant may be introduced into the weld pool, because of the relatively large surface area of the filler wire with respect to the amount of weld metal being deposited.

Contaminants on the filler wire are most often an oil or a hydrated oxide. The heat of the welding releases the hydrogen from these sources, causing porosity in the weld. Lincoln ER4043 and Lincoln ER5356 aluminum welding wire is manufactured under rigorous control to exacting standards and is packaged to prevent contamination during storage. Since filler wire is alloyed, or diluted, with the base metal in the weld pool, the compositions of both the filler wire and the base metal affect the quality of the weld.

The Three Cs: Clean, Clean and CLEAN!


Pieces to be welded are usually formed, sheared, sawed, or machined prior to the welding operation. Complete removal of all lubricants from these operations is a prerequisite for high-quality welds. Particular care must be taken to remove all oil, other hydrocarbons, and loose particles from sawed or seared edges prior to welding. Sheared edges should be clean and smooth – not ragged. For ease of cleaning, lubricants used in fabrication should be promptly removed.

To reduce the possibility of porosity and dross in welds, cleanliness of the welding surfaces cannot be overemphasized. Hydrogen can cause porosity, and oxygen can cause dross in welds. Oxides, greases, and oil films contain oxygen and hydrogen that, if left on the edges to be welded, will cause unsound welds with poor mechanical and electrical properties. Cleaning should be done just prior to welding. A summary of general cleaning procedures is given in the table below.

COMMON METHODS FOR CLEANING ALUMINUM SURFACES
FOR WELDING

Type of Cleaning
Compounds
Removed Welding Surfaces Only Complete Piece
Oil, grease,
moisture, and
dust. (Use any
method listed.)
Wipe with mild alkaline solution and dry.
Wipe with hydrocarbon solvent,
such as acetone or alcohol.
Wipe with proprietary solvents.
Dip edges, using any of above.
Vapor degrease.
Spray degrease.
Steam degrease.
Immerse in alkaline solvent.
Immerse in proprietary solvents.

Oxides
(Use any method
listed.) Dip edge in strong alkaline solution,
then water, then nitric acid.
Finish with water rinse and dry.
Wipe with proprietary deoxidizers.
Remove mechanically, such as by
wire-brushing, filing, or
grinding. For critical applications,
scrape all joints and
adjacent surfaces immediately
prior to welding.
Immerse in strong alkaline solution,
then water, then nitric acid.
Finish with water rinse and dry.
Immerse in proprietary solutions
 
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