What amperage do I need to weld a motorcycle frame?

Question

Hi guys, what amperage welder would I need to do some repairs on my motorcycle frame?

"Guys" - A general term, I am open to answers from anyone lol.

I believe my tubing has a OD of 1.160", and a wall size of 0.111" (could be some human error, I have a old caliper - not digitalized)

So I guess if the MIG welder I am looking at can handle 0.035" or 0.030" wire, then it would work regardless of amps? (the welder is 125Amps)

I need to repair the neck on my bike, as well as add some supports (I had to cut it and reposition it)

Thing is, I don't have the welder yet, I was looking at buying one, but I don't want to buy it and then it's too small and I can not do anything with it. My budget does not allow to get more than I need, wish it would lol

Yes, I have welding experience, but it's the equipment that I have will not work for the job I need.

Answer 1

A general rule-of-thumb is, one ampere for every .001" of metal thickness. (For example, 10 gauge (or 1/8") material equates to .125 decimals or 125 amps.)
Could you elaborate on what it is that you're welding?
If you're welding a gas tank tab or something onto the bike frame, your MIG/GMAW should be fine. I'm not a certified welder, but if it's a frame repair on the steering head or another critical structural component of the frame; everything I've ever read or heard says that heliarc/TIG/GTA is the best for motorcycle frames.
You might be able to find some good tips at the Miller site:
http://www.millerwelds.com/education/articles/articles70.html
or at the Chopper Builders Website:
http://64.172.168.34/neatstuff/index.html
Ride safe

Answer 2

Motorcycle Frame Neck

Answer 3

Of all the welding process available, the gas metal arc welding (GMA) and gas tungsten arc (GTA) welding processes are best suited for welding tubing of a motorcycle frame.

Drawn-over mandrel tubing is manufactured to ASTM Specification A513 Type 5, and frame fabricators often chose SAE Steel Grades 1018 and 1020. These have a yield strength of 70 ksi or 483 N/mm2. You can find them at a local metal supplier and at many online stores. Most tubing on a bike has a 11⁄8- to 11⁄2-in. OD and a 0.120-in. wall thickness, except for the steering neck tube, which is larger and thicker (perhaps 0.250 in. thick)

For tubing with a 0.120-in. wall thickness, a good welding wire is a 0.030- or 0.035-in.-diameter, S-6 hard wire (American Welding Society classification ER70S-6).

Use a 75% argon/25% CO2 shielding gas. Compared to 100% CO2, this mix yields smooth arc characteristics, better pool control, good bead wetting action, good bead control, and less spatter. It also reduces the chance of melt-through on thinner materials because it requires less voltage and lower wire feed speeds than straight CO2. Flow rates are typically around 30 ft3/h.

Shielding gas nozzles also need to be monitored, cleaned, and occasionally replaced. Depending on the nozzle size and its workload, spatter can build up and impede the proper flow of shielding gas and leave the weld pool unprotected.

Select a 1⁄16-in.-diameter tungsten (2% thoriated, 2% ceriated, or 1.5% lanthenated) for the best results with the material thickness used for motorcycle frames. A good rule is to use the smallest electrode that will carry the right amount of current and give you the proper pool size. On 0.120-in.-wall tubing, 1⁄8-in. tungsten can create a weld bead that is too wide.

Choose a 3⁄32-in. welding wire because it will melt at the optimum amperages for welding 0.120-in.-wall tubing, as well as produce a bead width that is most compatible with this wall thickness. Anything larger will require more heat to melt, which may result in melt-through.

A #6 or #7 GTAW cup is standard in this type of application. A gas lens will give you much better shielding of the whole area and allow for further tungsten extention, which will help when welding included angles. Using 100% argon, flow rates are typically 15 to 20 ft3/h, and remember that more is not better no matter what your welding process. Excessive flow rates can create turbulence and induce porosity in the weld.

Answer 4

You have better answers than I can write quickly above.
I have one question, followed by a recommendation.

Do you know how to weld?

I recommend you not weld your own frame if you do not have experience. A faulty weld in the neck can KILL YOU.

Answer 5

Make sure your battery is disconnected or out before welding on your bike.

Answer 6

I recommend getting the frame heli-arced by a pro.

Answer 7

Just out of curiosity why would you just ask the guys?