You won't burn a hole in the 8.8 tube...Do make sure you get good heat on it though...Build a good puddle. The 100 is marginal for what you need to do, but take your time, burn in good and you will be fine.

 

ya heat is good. But do one side at a time so it will cool. The things like to warp. I like to use a Torch like map gas to get hot.

By one side I mean one side of the perch and then move to the other perch

 

A 100? Better to use your wife's blow dryer - it's hotter.

Use it to tack them in place, then get someone with a real welder to finish it.

The tubes are about 3/16 - yes you can burn through with it if you try, but burning a hole and welding properly are 2 different things.

But it's your life - and maybe a few others.

 

A 100? Better to use your wife's blow dryer - it's hotter.

You're kind of scaring me a little here. I will be doing some structural work on my CJ5 this summer. I have a 110 MIG. If this will not be sufficient, then what size MIG would you recommend. I'm going to box the frame, and beef up certain areas.
Not trying to steal the post here. This just seemed pertinent.
Thanks
David

 

Im not trying to jack a post here but a fabricator at work heard complaining about my new mig not being hot enough to weld some quarter inch. He told me to heat it with a torch and then weld it. He also said not to get it red hot and just to warm it a bit. RRhich can you or any other welders here confirm this????

 

If you have a small welder or the work is very cold warming it up allways helps.

Oh and a Note: the tubs on my 8.8 are 1/4

 

As far as heating it with a torch - it should help - a little. Never tried it except on cast iron, pre-heated it, kept it hot afterwards for a slow cool down. Sometimes it worked, sometimes not. He He - funny - welded a cast thing once torch preheated, torch afterwards for a slow cool down. Looked good I was proud of myself! It was just sitting there cool enough to touch - BANG - pieces exploded everywhere!

Remember - welding is not dribbling filler on a joint. Welding is getting BOTH surfaces hot enough so the metal FLOWS and merges together. BOTH surfaces have to be heated above the melting point to do that. The thicker the material, the faster heat is carried away from the joint.

That's one reason why aluminum is hard to weld.

When welding - WATCH THE PUDDLE - NOT THE DRIPS! Move the puddle along - you can see how it's penetrating. Use magnifier glasses if needed - I do.

Yes, you can use a toy welder to weld heavy stuff - even make it look good. But put it under strain and you find out it's a cold joint - not strong at all. Similar to a cold solder joint! Usually one side pulls off, leaving the bead stuck to the other side. Look close when you see that, you can see how the weld didn't melt together.

Heat is the key - fast and lots of it - but too much heat for too long is bad too. It burns/boils the carbon out of the steel - carbon is partly what makes it strong (like burning holes.)
It has to get to temperature, melt together, then cool, but not too fast either. Too fast freezes the carbon in the wrong spots - called Markesite - brittle. Not good to quench with water - too fast.

Try something - make a weld and let it cool in air.
Make another and quick bury it in sand (cools slower.)
Quench another with water.

Now try drilling a small hole through each of those welds.

water quench - very hard - breaks your drill.
air - hard but drillable.
sand - almost like butter.
----- there - a quick lesson in heat treating!

Always err on the safe side.

Not fun if the perch breaks or falls off - it can even be deadly!

 

Heat is the key - fast and lots of it - but too much heat for too long is bad too. It burns/boils the carbon out of the steel - carbon is partly what makes it strong (like burning holes.)
It has to get to temperature, melt together, then cool, but not too fast either. Too fast freezes the carbon in the wrong spots - called Markesite - brittle. Not good to quench with water - too fast.

I think the term you are looking for is martensite, formed out of austenite when it cools too fast. Generally not too much of a problem with low alloy steels since their carbon content is generally on the low side.

110 welders: The reason 110 welders are "frowned" upon is when welding thicker steels you are normally pushing the unit to it's max, and duty cycle can be as low as 2 minutes out of 10 before you start shutting the machine down. You are pushing the unit to it's max because in order to get X output you require X input and with a 110 unit that requires twice as much input as would be required on a 220 machine. That's one of the reasons businesses in welding prefer 220/440 machines. Let's say you've got a 110 machine who maxes out at around 140 amps. If your machine requires say 40 amps input to achieve that then a 220 machine would only require 20 amps in and a 440 machine only 10 amps. These are just generalizations as all machines vary somewhat but you get the drift. They are much more efficient and require less input to get a given output. Cheaper to operate.

You can weld thicker steel with a 110 machine but it becomes a "production" issue so to speak. Let's say you are using .030 wire. You can't put enough heat into the wire for a long enough period to heat up your base material enough to get really good penetration. By the time you do you are probably pushing the duty cycle of the machine to it's shutdown point. The solution? Start dropping down your wire size until you CAN put enough heat into things to get good fusion. The problem is you're going to end up with a bead of weld so small it will take you a month of sundays of stacking weld in order to get a decent fillet on your piece. It CAN be done, it just becomes an issue of poor return for your effort.

What size machine/how many amps do you figure it would take to use .062 wire on a hunk of steel a foot or more thick?

 

Don't use the 110 v welder, its not up to the job. I thinks its more than an issue of duty cycle. As for preheating, unless you do some testing on another piece of axle tube, which seems unlikely, how will you really know whether the bead simply looked pretty, or actually had proper penetration and fusion? You can't judge a mig weld by appearance alone, so don't be fooled by that. It takes a lot of heat to start a proper puddle in the middle of piece of heavy tubing. You'd be better off to tack it and take it to someone with the proper equipment. If I didn't have a big enough mig welder, I'd use a 220 v stick welder and some 7018.

 

I agree with TiminMb.
Better safe than sorry.

CJ Dave is the welding expert around here, if you can catch him here he will give you EXACTLY what you need in the way of information and requirments.

 

Wow ..didnt expect so many responses....I think RRich convinced me with one word....DEADLY!. Think I'll just tack it in place and let a pro do the rest. I'd hate for the axle to come loose on the highway.

 

I used a Hobart 140 mig on my bumper and brackets that I made. The brackets are 3/16 and the bumper was 1/4 and the welds looked good so I decided to test the first bracket and hit it realy hard with a BFH and the weld stuck to the 3/16 but peeled off of the 1/4 so I ended up using the old Lincoln stick welder. The welds aren't that pretty, but I don't think think they will brake away either. My hobart is suppose to be able to weld 1/4 inch but I geuss I don't have a clue on how to do it. Planning on taking some classes and my uncle is comming out next month and said he would show me some pointers.

 

Maybe the volume of responses were overkill, but this issue of critical welds and a combination of possibly inappropriate equipment for the job and or inexperienced welders seems to come up over and over again. I read one post on an atv forum a few months back where a fellow borrowed a small mig welder from a relative and as a first time project built his own trailer hitch through a process of trial and error, saying he repeatedly ground out and welded over his beads, getting better and better as he finished the job. I applaud the DIYer, but we all have to know our limits.

 

Failed welds

This is what can happen if the spring perch welds let loose. I was climbing a step-like hill when it went. Fortunately nothing bad happened other than breaking the u-joint strap bolts. I drove home front wheel drive and welded them better the second time.

 

TRY IT!
Try welding a couple of 1/4" pieces together - not just running a bead along one . Weld about 3/4" - 1" together. Do the best job you possibly can with it.

Then put it in as vice and break it apart - it'll be easier than you'd think.

Do another this time after learning what you just learned.

Now cut across the weld - a grinder or chop saw works best, but you can use a blade type saw.
Have a close look at the cut - you can actually see how it melted into the base metal. See how it barely melted the base metals.

Now soak that cut piece in acid - muriatic - pool acid, sulfuric acid - battery acid - most any acid.
Look at it again.

Don't believe us - look for yourself.

Even the toys have a long enough duty cycle to weld an inch!

Using a toy welder is like a flea looking at an elephant with rape on his mind!