motorcycle frame

[dedfish]

Pardon me this might be a bit wordy...

I have started a new project chopping a old Suzuki GS450. This will be my first project where the welds need to be strong AND look good. It is also something that I will not have many chances to practice doing before I actually have to do the real thing. I might have 1 or 2 practice attempts with the materials I have. In the past either my welds didn't have to be so pretty or I had plenty of time to practice to get it dialed in correctly. So I'm coming here looking for advice from people that may have done this before or something similar hoping to gain as much knowledge as I can before I start.

So here's the situation. I'm extending the downtubes on this stock frame by 1 1/2". I've cut out 2 1/2" and I will be replacing that with 4" extensions. The stock frame is very thin, 1 1/8" outside diameter with a 1" inside diameter and is probably made out of ERW tubing as it definitely has a seam. The extensions are DOM tubing but with a thicker wall, 1 1/8" outside diameter and a .875 inside. I made slugs out of solid 1018 mild steel and turned them down so they would fit inside the extensions and stock frame. The extensions and stock frame will be drilled for rosette welding to the slugs and the seam where the extensions meet the frame will be beveled.

My question to you folks is what settings would you start with to accomplish this using a Hobart 187?

Here are some pictures to illustrate what I am talking about.

Downtubes on frame cut:


Extensions with the slugs sleeved in. Extensions are now drilled for rosette welding to slugs but that is not pictured:

[dedfish]

Ok...I'll start the discussion. I think I'm going to start with 3/50 for the settings. Discuss!

[Tinymx]

The slugs look good! Just go by the chart on the door of the welder for the thickness of the slugs. Just be sure to clean and bevel the frame tubes also.

[Ferntj]

The slugs look good! Just go by the chart on the door of the welder for the thickness of the slugs. Just be sure to clean and bevel the frame tubes also.

I think you mean the thickness of the extensions, the slugs are solid between 1 inch and 7/8 thick. I think you would want to set something higher than the thick wall tube settings since the slug will draw a lot of heat out of the area.

Make adjustments after your test weld and walk away form the project if you fail your test.

[Hotfoot]

Have you stretched a frame before? I suggest hauling in a couple junkers to practice on first. Its not only the welds (which are VERY important), but the resulting alignment and geometry

I call your 'Rosette Welds' "Plug Welds", but call' em whatever, they are the same. I am no expert, but offer these suggestions with about the same authority as the kibbetzers encountered at any Swap Meet or car Show (the guys I refer to as "The Judges")

Be sure to clean out the inside of the tubes (a round wire brush should do it) to get those as clean as possible.

Just like Ferntj suggests, a setting higher than the tube's thickness, but you don't have a lot to play with here. The trick will be to get a good 'melt' going on the slug in the center of each hole, letting it migrate outwards to the tube at those plugs. The same setting should accomplish your edge welds...

I assume that motor is going to be removed first for access, to permit one continuous weld around the tube.

[Dan]

Considering the slug is a fairly healthy chunk of solid stock, I wouldn't recommend using short circuit transfer or a self shielded fluxcore for producing the plug welds. TIG would be my recommendation.


BTW, its hard to discus machine settings of 3/50 without including such info as what diameter wire your running, and whether you're running solid or fluxcore wire. If you're running solid wire which shielding gas are you using?