Learning to MIG Weld. Advice Needed

Def get with the welding instructor if you can, any advice you can get over the internet isn't going to be enough to get someone with no experience to produce welds I would trust on something you do more than 35 mph on. And I would sway that only a very good MIG welder should be trusted with a hardtail. TIG welding would be my first choice though, even though it's harder to do, the welds shouldn't have to be ground down or compromised in any way to make them look good.
 
Already spoke to the instructor and he is going to give me pointers when I visit the school. But really, all he talked about was just getting some metal and practicing, so I don't know how much he will help in the end other than checking to make sure i have good penetration and welds.

Like I said in my original post. I will never weld a hard tail. I will only leave that to the professionals like G&L choppers who already hard tailed the frame. I only need to weld on the fender, fender struts, pedals, brake tabs, chain tensioner, etc.
 
While my first choice would also be TIG, any competent welder could do as good a job with MIG as TIG. The difference, when done by a pro, would be cosmetic for all intents and purposes. There are shortcomings with the TIG that you don't have to contend with when using a MIG. TIG is the best for new, clean metal worked on the bench, but MIG is far better in down-and-dirty conditions. Also, a skilled welder with steady hands can run a MIG bead that will need very little touch-up.

I think people tend to forget that there were chops done in the '60s that were arc welded together that are still in use today. You can have all the high tech equipment that you want, it's the person doing the welding that determines the quality and durability of the finished product. Arc, MIG or TIG: they're just tools to accomplish the same job. KNOWLEDGE and EXPERIENCE are what keep your ass off the asphalt.

That being said, Sig stated at the beginning of the thread that he would have the tail done by a pro, something I always encourage. I also absolutely encourage getting a MIG welder and welding your own tabs, brackets, battery box, etc, etc. Everything you can do to make the build more your own.

The biggest problem with MIG welding is that in inexperienced hands a MIG can be deadly. It is easy to run a bead that LOOKS good and solid, with very little actual penetration. IF YOU DON'T UNDERSTAND WHAT THAT REALLY MEANS YOU SHOULDN'T BE WELDING YOUR HARDTAIL ON IN YOUR GARAGE. Take it to someone who isn't going to get you killed.
 
Teebs said:
...with very little actual penetration...
Click to expand...

story of my life, hur hur hur. :doh:

what do you mean by deadly? in the sense of bad welds getting you killed or *zap zap* kinda deadly. either way, also test you welds; means anything from hitting it with your best hammer or chucking the thing across the room, you want to make sure your welds have strong penetration.
 
My main problem with MIG welding is that there are far too many people who make decent looking beads that I wouldn't trust on a bike. 95% of the people who come into my shop and take a weld test, calling themselves a welder, can lay down a MIG bead. Out of the 95%, I can flunk a quarter of them with a visual inspection, and flunk most of the remaining applicants with a bend or break test. Maybe 3-5 out of a hundred will come in, lay down a good bead that has proper penetration and is actually a sound weld.

I'd say out of the people who come in to apply for a position where TIG is mostly used, I get an 80 or so percentage pass. And the ones who fail do so miserably. There are a ton of what I call "backyard welders" who think they can weld because they have a 110 MIG machine at home that they use to tack crap together for home or car repairs. But typically, someone who has TIG experience is higher up on the welder food chain, so to speak. You don't see many guys buy a $1500-$4000 welding machine for tacking crap together unless they know what they're doing.

Of course, your always gonna get the guys with the ego that think they are masters of every process because they used that 110V MIG to weld an angle brace onto a farm implement or something. Those are the ones who are funny to watch take the TIG test. By the time they're done, the tungsten is all balled up and contaminated, and the weld bead (if you can call it that) has more tungsten in it than weld metal.
 
650Jarrett,

I'd say we're on exactly the same page.

I learned to arc weld as a kid to weld up broken farm implements, broken motorcycles, broken vehicles, etc. I took up MIG welding in my teens and refined my ability in art school. I learned to TIG weld as part of a fellowship I was granted during art school. That gave me access to a plasma cutter and TIG setup, and WOW. Just the ability to experiment welding with different metals was worth all of the work to get that fellowship.

Twins, what I mean by deadly is exactly what both myself and 650Jarrett already stated. An inexperienced welder using a MIG can lay down what may look like a beautiful bead to most people, and underneath it has no strength and is just waiting to come apart.

A word about "testing" by hitting it with a hammer, throwing it against the wall, etc. This is NOT a reliable test method. Hit it with a hammer 10 times, and the 11th will be the one that snaps a poor weld. More importantly, when dealing with motorcycle frames, vibration and harmonics have a serious impact. A weak weld that can't be seen under a pretty bead may develop cracks due to vibration, and we all know how much the XS vibrates.
 
ahh, good point about the vibrations.

I learned how to weld when I was working at a place that made oversized industrial tanks, random, but I didn't worry much about long term vibrations. I'll leave the advice giving to the mechanic welders lol. :bike:
 
Teebs said:
The biggest problem with MIG welding is that in inexperienced hands a MIG can be deadly. It is easy to run a bead that LOOKS good and solid, with very little actual penetration. IF YOU DON'T UNDERSTAND WHAT THAT REALLY MEANS YOU SHOULDN'T BE WELDING YOUR HARDTAIL ON IN YOUR GARAGE. Take it to someone who isn't going to get you killed.
Click to expand...

Ha, you said penetration. I understand penetration to be when the molten metal that is created when welding is created all the way through the materials being welded. Thus ensuring a good bond. I could talk about the other penetration that I know of, but I don't think that would be appropriate here.

I have to say, I have never met a group that values their work as much as welders do. I believe everyone should take as much pride in getting good results in whatever work they do. However, I have to agree that MIG, ARC, and TIG welding are just tools for accomplishing the same job. If I had a TIG welder I could get for free, I'd be using that. But I got a MIG welder for free from my brother. So MIG is what I am using and will be using.

So its practice, practice, and more practice for me. I will post more pics using better metal and with more practice. Thanks for all the advice. :thumbsup:
 
like the OP, I needed to learn MIG welding (was given the machine by my Dad) to add mount brackets and stuff to a frame I had professionally hardtailed and raked. The thing, for me that's making it most difficult is welding in the weird positions and locations that are required, while working on a frame that has the engine in and wheels on. There's just no real way to turn the thing to gain optimal positioning. So I'm doing what I can like this and planning on going over/revisiting every weld when I take it apart after this mock up, for paint.
Will grind every weld way down (except the couple that are already really decent) and see if they need another bead. Maybe grind a tiny "ditch" where things are joined, to lay a nice even, clean bead there.
That's the plan. With engine out, forks off, wheels off, etc - i.e. bare frame only, I can turn the thing, stand it up against a wall, lean it over, whatever, in order to be able to position my body in such a way as to be able to make much better welds.

I have found that to be real important. Access to area to be welded, as well as cleanliness of material.

Its been weird trying to fill small gaps with welding wire.

An auto darkening helmet helped IMMENSELY.
lo recommendo.....
 
hi Gary, that's basically what's happening...but they are "big" tack welds. I want to at least be able to ride it gently down my street prior to disassembly. (make sure I like the ergo's and all and don't need to make any major changes)

thx for advice....
 
Lets throw this out and see what the gurus say. I try to run my arc as hot as I can, skirting burn through and drop out by as small of margins as I can. I prefer to melt base metal and weld a bit wait for it to solidify and weld some more. This is probably only practical with a gas shield but way back in the day production welding I think I ran my arc hotter than anyone else in the department. For me a quick guide for penetration effectiveness is how far out the color bands have spread on the base metal.
 
High heat input can create a strong join while weakening the steel adjacent to the weld. The softened metal to each side of the weld loses tensile strength. Ultimately, this means that while you may have achieved a good weld, you may have weakened the overall strength of the material.

What specific type of steel were you using? What alloy in the sticks? What was your travel speed? Weld size? Steel thickness and condition, hardness, notch toughness? Cooling rate? Quenching? All of these variables and more play a part in weld strength.

Ultimately though, I'm not going to say you're "wrong". Experience goes a long way, so do talent, skill and intelligence. After years of learning and doing, I think one develops a "feel" for it. I know I don't use a formula to determine the perfect combination of heat, travel speed etc before I start welding (and the formulas do exist; welding is a complex science.)

All that said, I am not a professional welder. I am a sculptor who knows a bit about welding. In the end, it is best to err on the side of caution, especially when welding something that travels at high speed, has no shock absorption capacity, and vibrates like mad.

There are young people full of their own sense of immortality out there who are taking up welding for the first time to weld two halves of a bike together. There are members of this forum who have little riding and welding experience who are welding their frame and to top it all off are buying non-DOT approved Biltwell novelty helmets because the style goes well with their bike... :banghead:

The truth is though, that it's entirely up to them to put themselves at risk. I do it nearly every time I'm on a bike. I ride without a helmet and drive too fast, but I do it with full knowledge of the risk and do everything I can to minimize the chances of injuring other people. So, personal risk is not what really concerns me.

What happens when the hobbyist becomes bored with the current bike, or needs the cash and decides to sell it? Will they warn the buyer that the frame was welded together in their garage by someone who has no welding certification at all, and no real experience? Or will they forget to mention it, or decide not to tell them so they can get the highest price? Will they let that person drive off, unaware of the potential for death or worse? (Because in a bike accident there is definitely worse.)

:laugh: OK, soapbox aside; have your frame welded by a pro.
 
I pretty much HAVE to run mine on "D" - highest setting in this little Weldpak 100. When I 1st started, I "sacrificed" a brand new trailer fender for the cause, and just ran bead after bead. Loooooooooooong ass beads, even. What I found (and was told by others) is that by then looking underneath the fender, it was easy to see by discoloration where I'd gotten nice penetration and where I'd just laid a bead of ugly metal boogers. (lol, so to speak.) Ruined the fender! good experience tho.
 
Teebs said:
What happens when the hobbyist becomes bored with the current bike, or needs the cash and decides to sell it? Will they warn the buyer that the frame was welded together in their garage by someone who has no welding certification at all, and no real experience? Or will they forget to mention it, or decide not to tell them so they can get the highest price? Will they let that person drive off, unaware of the potential for death or worse? (Because in a bike accident there is definitely worse.)

:laugh: OK, soapbox aside; have your frame welded by a pro.
Click to expand...

not sure bout others, but I'd mention the HELL out of it, and the bill of sale would have "sold as-is" and "not intended for highway use" on it. Oh yeah. Then let the new buyer deal with the bike KNOWING that they should keep an eye on the welds.
:)
 
There is something to that, but it isn't all of it. One can tell by discoloration to some extent, but what happens when that nice strong bead is surrounded by weaker metal due to overheating? It will develop cracks on one or both sides of the weld.

As far as your Weldpak 100, it's a great welder for doing steel sheet and thin-walled tubing, but I'd definitely think twice about frame-welding with it. (Not that you are.) .120 DOM is outside the upper limit of that particular welder (good for welding tabs etc, but not good enough for welding sections of tubing together or gussets to the frame.

The trouble with my earlier scenario is that I've already seen it happen on this and other forums. In some cases I know for a fact that there was no disclosure of the nature of the frame. How many? Who knows? It will end up being quite a few, and I think it's a fairly sure bet that at least a few people will die as a result.
 
thas'all Im a doin', man. :D
But what's .120 DOM? 1/8 in is .125...is that near what is meant by you?
thanks
 
Using thousandths of an inch is easier than using fractions in many cases. You can buy .134 DOM, which is 134 thousandths and can only be rounded down to 67 five-hundredths. If I ask a supplier for 1 and 1/4" 134 DOM, they know I want 1.25" outside diameter, 0.134" wall thickness drawn-over-mandrel (DOM) electrical-resistance-welded (ERW) steel tubing (NOT the pipe they sell in Home Depot!) In the case of 1/8", I have yet to see it in DOM tubing.

I used .120 because it is the standard wall thickness for custom bike applications when using ERW DOM tubing.

I'm happy to share the knowledge as others have done for me.
 

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