Question for metalurgists and welders, Professional or amateur.

[fixit3546]

Getting ready, in the coming months, to to turn an old CB360 into a bobber.

My question is why do i have to use a tig welder to modify the frame, or do I.

I have a mig welder and an AC stick welder that I think will work ok, I haven't gas welded in several years; but I can do that if need be, But i'm thinking the mig welder will suffice.

 

I'm asking this question because I want to completly replace the tail section, and I want to do it myself.

 

I'll take any other advice you may have as well, I've never done this sort of thing before. Not on this scale anyway.

 

The closest I've come is when i was younger i blew up the motor in my MT 125 and i wanted to ride. so i had an SL 125 motor in another bike, I swaped them. The bike was a lot better in these hills with the sl engine because it was a 4 cycle, more lugging power. not as fast as the MT though.

 

The other thing i did was to build a three wheeler of sorts by matting a gocart to an old MX 250. I cut the rear off the gocart and removed the tripple trees from the MX250. welded the bike to the rear of the gocart. that was one wild ride.

 

Don would like this, I named the buggy the "FREEBIRD".

[hipshot]

ok, you asked , so here it is.

mig welding, uses gas and wire, to weld two pieces together.

the two pieces are held together, only by the weld.

mig on the other hand, is like "brazing". it litterally melts the two pieces together.by creating a puddle, and adding only enough "stick" to keep the puddle "alive", you infact, make one piece out of two.

mig is slower, by far, than tig, but much more durable, and generally leaves a better looking "meld"!

just jt

[Gary N.]

Hipshot, I think you got some of your facts backwords.

 

Mig or wire feed welding is used for many types of production welding because its fast and strong. At the hand of an experienced operator it is as good as most other types of welding. It does require adding metal to a puddle like other type of welding. Most of the small 120 volt machines are only good for light duty work like body metal etc. but higher output machines are available for heavier jobs. My 120 volt mig welder will do 1/8" material for short duty cycles. Mig can also be used for alloy welding like stainless and aluminum with the right wire and shielding gas.

 

Tig, also known as heli-arc uses shielding gas and tungston carbide arc that is controlled by the operator to start the puddle and the filler is added by hand kind of like gas welding. Tig is also very strong and generally a nicer looking weld. It too can be used for alloy welding. Tig takes a little more practice to get the hang of.

 

Brazing is not welding at all. It's more like soldering. Don't even think of using this method on your frame.

 

As far as welding on the bike frame goes I wouldn't be affraid to use mig as long as your machine will run hot enough. Tubing is harder to weld with a stick machine but it can be done. If you have tig machine or access to one and somebody who can run it, that would be a good way to go. It makes a good strong pretty weld that doesn't require a lot of grinding afterwards. Gas welding is also an option.

[Squidley]

Jim,

 

Mig welding the frame will be fine, thats how they come from the factory as it's all automated and done with robots for the most part. The biggest things you need to do is make sure the pieces your welding are clean steel. I would also heat them up a bit prior to striking the arc as mig wire will flow better if it's started on a preheated surface. As mentioned use a good machine to do this with plenty of power. I would NOT use a 110 vac welder or a flux core to do this, Use a 220 vac unit as it will give better current for a better weld and better penetration.

 

If you have problems or other questions give me a shout, I just happen to be a welder by trade

[FreezyRider]

What Squidley said!

 

I was a welder/welder foreman for 14 years, working with tubing, sheet metal, and heavy steel. Did everything except Tig, my specialty was Mig. Don't use one of the low voltage welders....they are "hobby" duty only and won't produce a good weld.

 

BTW, a good, experienced human being can produce a stronger weld than any robotic welder I ever saw. We had them in one plant I worked in, and they cannot correct "on the fly" for any little unexpected differences in steel or in wire.

 

Good luck,

 

Joe

[Gearhead]

I'm not a professional, but I play one on TV... :-)

 

Seriously - just my humble opinion - the gage of steel in bike frame tubing is not terribly thick, I would think. My Hobart 135 120V MIG can make a nice, strong weld easily on 1/8" and the tubing is surely thinner than that. I use CO2 / Argon mix gas.

 

Jeremy

[Gary N.]

I'm not a professional, but I play one on TV... :-)

 

Seriously - just my humble opinion - the gage of steel in bike frame tubing is not terribly thick, I would think. My Hobart 135 120V MIG can make a nice, strong weld easily on 1/8" and the tubing is surely thinner than that. I use CO2 / Argon mix gas.

 

Jeremy

 

I agree with you, as long as you don't try and do to much at once. At 135 amps the duty cycle on these machines is very short. A lot of the 120 V machines can only put out 80 or 90 amps and I would be nervous using one of those. Squidley's suggestion to heat the metal first is a good one too.

[Yammer Dan]

With all this welding talk how hard would it be to reinforce a 83 frame to prevent it breaking? Could it be done without stripping it down and turning it over as randya did? Randya what do you think? Squid how hard is it weld in tight places like that?

[Squidley]

With all this welding talk how hard would it be to reinforce a 83 frame to prevent it breaking? Could it be done without stripping it down and turning it over as randya did? Randya what do you think? Squid how hard is it weld in tight places like that?

 

Dan,

 

I dont believe that a quality weld can be accomplished other than the way Randy did it (upside down). #1 it would have to be perfectly clean to make sure of good penetration and # 2 it is difficult at best to weld with the MIG upside down from the underneath. That area is very tight and it really should be done while flipped as Randy did.

[BOO]

Excellent Post guys!!!

Jerry

[Venturous Randy]

Dan, I absolutely have to agree with squidley. The trick is to be able to see in all of the little areas that give solid continuity in the weld. Also, I believe I could have my bike turned upside within an hours work. You would need to take the rear wheel and differential off, rear bags and trunk, rear fender and seat. Once you are this far, there are only four bolts that hold the rear frame section on. Just unplug all the electricals to the back. Once the rear frame is off the gas tank is easy to take out. I think I also had the carbs off, but if you drained them, you might not have to take them off. Drain the oil and disconnect the radiator overflow bottle. You would also need to take off the windshield trim and windshield.

At this point, the trick is to pull the bike over back wards. You will need several pieces of wood to put under the handlebars where they make the turn down and some blocks under the rear area.

I pressure washed the bottom good and did the weld. Of course on mine, I also had to pull the towers back in place that the lower shock mount suspension pieces mounted to. I definitely suggest putting in the bracing that I did with the 3/8th rod. To me, this is the most critical part of all.

For those not familiar with my re weld job, I will see if I can find some pictures.

[Squidley]

That is some excellent welds Randy I doubt I could have done any better. This should help out folks that have this problem...Good job Buddy!

[Venturous Randy]

I will also add a couple of broken frame pictures. This is what you are trying to avoid in the future.

randya

[Venturous Randy]

Thanks squidly, but I have to give the welding credit to an old friend that has built many a racecar, from prostock to blown rails. He is the reason I considered doing this fix in the first place.

randya

[fixit3546]

Fellas, I appreiate your input. Think i have what i needed to know now.

 

We striped the bike down to the motor and frame this evening and got some ideas as to which way we want to go with it, I think we may stretch it a foot or so and build a hard tail section for it. not sure about the stretch.

 

the next phase in the project will be to rewire it and start the motor. I've never heard it run and i think before we get a lot tied up in it the motor has to be checked out.

 

it is a 1976 CB 360 T if you are wondering.

[Yammer Dan]

With a 83 I guess thats something I'm going to have to plan on.

[concours]

Either your MIG (Metalic Inert Gas) welder or stick (SMAW)welder will be just fine for the low carbon steel tubing frame on the bike. The TIG (Tungsten Inert Gas) method has no advantage in strength in this application. Pay NO attention to the crack monkeys on American Chopper. Myself and many other fabricators cringe when the start in the antics. I offer 30 years fabricating and welding experience, ASME section 8 (pressure vessel) and section III (nuclear) and FAA certified.

[Eck]

As Boo stated....good post boys.....!!!!!!!!!

After reading these postings,,I must say, I did learn something here.

Thanks all !!!!

[chabicheka]

Either your MIG (Metalic Inert Gas) welder or stick (SMAW)welder will be just fine for the low carbon steel tubing frame on the bike. The TIG (Tungsten Inert Gas) method has no advantage in strength in this application. Pay NO attention to the crack monkeys on American Chopper. Myself and many other fabricators cringe when the start in the antics. I offer 30 years fabricating and welding experience, ASME section 8 (pressure vessel) and section III (nuclear) and FAA certified.

 

just as i was about to jump into this discussion..........having had a lot of experience with my radio shack $ 12.99 soldering iron, Concours had to butt in with this post........well fine! i will keep all my experience to myself and just amuse myself reading you all "experts" posts.

[hipshot]

Hipshot, I think you got some of your facts backwords.

 

Mig or wire feed welding is used for many types of production welding because its fast and strong. At the hand of an experienced operator it is as good as most other types of welding. It does require adding metal to a puddle like other type of welding. Most of the small 120 volt machines are only good for light duty work like body metal etc. but higher output machines are available for heavier jobs. My 120 volt mig welder will do 1/8" material for short duty cycles. Mig can also be used for alloy welding like stainless and aluminum with the right wire and shielding gas.

 

Tig, also known as heli-arc uses shielding gas and tungston carbide arc that is controlled by the operator to start the puddle and the filler is added by hand kind of like gas welding. Tig is also very strong and generally a nicer looking weld. It too can be used for alloy welding. Tig takes a little more practice to get the hang of.

 

Brazing is not welding at all. It's more like soldering. Don't even think of using this method on your frame.

 

As far as welding on the bike frame goes I wouldn't be affraid to use mig as long as your machine will run hot enough. Tubing is harder to weld with a stick machine but it can be done. If you have tig machine or access to one and somebody who can run it, that would be a good way to go. It makes a good strong pretty weld that doesn't require a lot of grinding afterwards. Gas welding is also an option.

 

yessir! i stand corrected!!!

i got my procedures reversed!

 

 

just jt

[Mean Dog]

Man!

It is amazing what you can learn here! This is a great post and I give it 5 stars. I did a repair job for a guy that had totaled the front of a Ford Fiesta, the guy had sentimental value in the crazy thing and wanted me to chop the front end of another good bodied car and weld it from the windshield forward on his body. I told him I could buy the whole donor car and put his drivetrain in it cheaper than what he wanted to do but, he would not hear of it. He paid me a great deal of money to chop the two in half with a plasma cutter and mig weld the two of them together. He was happy, I got rich, good trade in my book! http://www-freesmileys.com/images/36_1_36.gif

 

Dog

[Black Owl]

Excellent thread with some great info. Guess no one does gas welding any more. In my younger days I was a certified Oxy welder and did many a frame repair and modifications with Oxy welds.

 

Have been considering taking a welding course at the local CC to get up to speed on arc welding......

[Snarley Bill]

i've got a millermatic 185 and it does an awesome job.as brad said ,upside down welding is a little rough and tight places are often hard to get to because you can't get close enough to keep the weld covered with the shielding gas.the only thing i use my stick welder for anymore is in the wind and places i can't get real clean.

[a1bummer]

Good sound advise from all. I needn't even bother to add any input.

[tooldood]

Fixit

It sounds like you throw together a meet-n-eat and you can get a whole bunch of welders at your beck and call!!! WILL WELD FOR FOOD!