[James2]

Hi all- new here, great forum. Been watching Jody’s videos and going to start learning TIG.

I have a 2” receiver hitch tube I’m going to weld to the frame of my car. It’s 2.5” square tube, and I measured the wall thickness at about .220”. I bought a piece of 2.5” square tube to weld as the crossmember. The wall thickness on the crossmember is .120” wall. I did this because I thought .250” wall was too much. The main frame rails on the car are 3”x2” rectangular tubing and I think the wall thickness is .083”. It could be .120” wall but I don’t think so... but also don’t have a way of checking.

So, it’ll be a T-shaped configuration, with the .120” wall 2.5” tube welded across the two frame rails (.083” wall). Then, the receiver tube (.220” wall) will be welded to that crossmember in the middle. There are two other small diameter diagonals and another crossmember also, for additional support.

Should I bevel the .220 wall receiver tube where it meets the 2.5” .120” wall Square tubing? And do more than one pass? Will my Maxstar 140 scratch start machine handle this weld? If so, what settings/ techniques do I need to use?

Thanks in advance.

[G-ManBart]

A trailer hitch isn't exactly the sort of project I'd consider a good choice if you're still learning TIG and asking those sorts of questions. Do you have experience with other kinds of welding?

I'm far from an expert, but I think you'd want a machine with more output. At the very least you should get some similar thickness scrap and try a few of the critical weld joints, then section them and see what sort of penetration you got.

If I'm not completely mistaken, can't your machine also stick weld? That might be a better option.

[Oscar]

..... I’m going to weld ....

I think you need to take just a couple steps back before you make your decision on this. I know you want to weld this, but it doesn't mean you should/could. If you machine can only produce 140A on TIG, then no, I don't think you shouldn't attempt this, at least not without producing a few scrap parts (exactly replicating what you are planning to do) and cutting-&-etching to verify you have your skills/technique down. Very few people will give you detailed instructions when it comes to welding on something that will be driving down the road. I'm not a welding expert either, but it's not just a question of 'if your machine will handle it'. What you have on your hands is an entire problem consisting of mechanical engineering and welding procedure mixed in together.

[cj737]

To weld the cross tube to the frame rails you will be fine with machine. You’re limited by the amperage the frame rails will take. Weld all four edges with 3/32 filler.

The receiver tube will be radiused, so there’s no beveling needed. But you will need 2 passes at max amperage. Go slow and use 1/8” filler if you have. Weld all four edges. Let it cool a bit, then repeat.

This is not a DOT-certified weld or hitch, so use due care with what you’re doing and towing. Lives can depend on your handiwork.

[JayWal]

I believe the Maxstar is a tig only machine, the torch is built into the case. Otherwise I'd agree stick would be a better option.

140 amps definitely on the low end for this. The question remains tho, what's your skill level as a welder. Welding a part on a table is much different than scrunched up underneath a car trying to weld a solid vertical, trying to get your head in a portion where you can actually see what you're doing and still be able to feed rod.

It is doable, but I'd definitely weld as much on a table as you can. Like the reciever to the cross piece, and add all the bracing and gussets in position. And clean the crap out of every piece. Get rid of all the millscale and decrease everything with acetone. Take your time and do it right, as CJ said, people could get hurt or worse if those welds fail.

Sent from my SM-G970W using Tapatalk

[G-ManBart]

I believe the Maxstar is a tig only machine, the torch is built into the case. Otherwise I'd agree stick would be a better option.

140 amps definitely on the low end for this. The question remains tho, what's your skill level as a welder. Welding a part on a table is much different than scrunched up underneath a car trying to weld a solid vertical, trying to get your head in a portion where you can actually see what you're doing and still be able to feed rod.

It is doable, but I'd definitely weld as much on a table as you can. Like the reciever to the cross piece, and add all the bracing and gussets in position. And clean the crap out of every piece. Get rid of all the millscale and decrease everything with acetone. Take your time and do it right, as CJ said, people could get hurt or worse if those welds fail.

Sent from my SM-G970W using Tapatalk

I check Miller's website and the manuals show it as stick capable and the pictures show a machine with DINSE fittings.

I'm sort of shocked anyone thinks this might be doable for someone who has to ask such basic questions. I sure don't want that rig in front of me when I'm driving down the road...

[James2]

Thanks for the input. That’s correct, the Maxstar 140 does stick as well as TIG.

I have MIG experience and some TIG but it’s been awhile since I’ve used MIG. Don’t have my MIG machine here so I was going to just use my TIG. Haven’t been fabbing much.

Point taken about the risks. This won’t be a heavy road use hitch, will be pulling a small 4x6 trailer once a year with this car. My truck hauls the race trailer. Nonetheless, it will be welded properly by me or a welding shop. Just figured I might get some tips here.

The receiver tube is straight cut, but will meet the crossmember tube where it is radiused at the top and bottom of the joint. The sides will be flush.

Everything I’ve read/watched says 1 amp per .001” of material thickness up to about 1/4”. And when welding different thickness pieces, the weld size is determined by the thinner piece. And so I figured the 140 should be able to handle this job. I’ve welded 1/8” wall before with this machine but not 1/4” or thereabouts.

[VA-Sawyer]

You might try drilling a hole or two in the frame to see how hard the material is. A number of modern vehicles are using higher strength steel alloys to reduce weight. Some of them do not respond well to welding. I have seen warnings in service manuals about welding not allowed. Just a heads up.

[cj737]

Thanks for the input. That’s correct, the Maxstar 140 does stick as well as TIG.

I have MIG experience and some TIG but it’s been awhile since I’ve used MIG. Don’t have my MIG machine here so I was going to just use my TIG. Haven’t been fabbing much.

I would NOT MIG weld this. MIG in this application is only used by "pros" with a verifiable procedure. It would be extremely easy to weld this with what looks like a good weld only to discover it zero penetration. There's a recent thread on here with exactly that situation on a piece of heavy equipment.

TIG it. If you have reasonable experience and can verify the penetration, you will likely be just fine. Tack it all up to put some heat into it first before you weld it. And make sure its bright shiny metal clean before you light up.

[Oscar]

Everything I’ve read/watched says 1 amp per .001” of material thickness up to about 1/4”.

Yes, but that is not a rule, it is a general rule of thumb. That is where practical welding comes into play, because a lot of it depends on actual joint configuration and the overall size of the part. Nothing can replace knowledge gained from experience. For example. I actually tried 200A into a ¼" T-joint, and it wasn't nearly enough power for what I would consider sufficient weld reinforcement. Yet on an outside corner joint, 200A would actually fare quite well and might be more than what would be needed. My point is that you need to be able to properly distinguish general rules-of-thumb vs actual real life requirements. Until you actually go out and try things, you won't really know.

"the weld size is determined by the thinner piece."

Yes, but the total heat/power is not. From my understanding, the part that I feel you are mis-interpreting from that statement is that you still need to fuse into the thicker piece, which means raw POWER. The weld size is then controlled by you, the operator using technique and filler metal deposition. Ever heard the phrase "focus your heat on the thicker piece, and then wash/fill the puddle into the thinner piece"? It goes something along those lines, and I tend to agree with it. Again, this is just my perspective, but I think it applies here.

For example. Say I want to weld ¼" to 1/16". I personally would want to use more than just 62A because that won't do diddly squat to the ¼" piece. Just my take on it.

[LanceR]

Frame rails? Do any modern cars have true frame rails? All I've seen since the demise of the Ford Crown Victoria/Mercury Marquis/Lincoln Town Car (AKA the Ford Panther platform) died off ten years ago is stamped sheet steel. Without factory weld nuts, bolt holes/slots or some such I would be scared to death of being involved with welding on a hitch.

Factory hitches made for installation on cars are pretty uncommon not just due to most cars having very limited towing capability but due to most cars being unsuitable to support a hitch of any size let alone a 2" hitch.

What make, model and year is the car. And what is it's rated tow capacity?


Lance

[Granddaddy]

Frame rails? Do any modern cars have true frame rails? All I've seen since the demise of the Ford Crown Victoria/Mercury Marquis/Lincoln Town Car (AKA the Ford Panther platform) died off ten years ago is stamped sheet steel. Without factory weld nuts, bolt holes/slots or some such I would be scared to death of being involved with welding on a hitch.

Factory hitches made for installation on cars are pretty uncommon not just due to most cars having very limited towing capability but due to most cars being unsuitable to support a hitch of any size let alone a 2" hitch.

What make, model and year is the car. And what is it's rated tow capacity?


Lance

and on top of that what metal is there will melt away at a much lower temp and also requires more skill or experience. I have to agree a trailer hitch is not the place to be learning what someone or their machine is capable of, it is someone else's life that you are gambling with.

[Granddaddy]

Frame rails? Do any modern cars have true frame rails? All I've seen since the demise of the Ford Crown Victoria/Mercury Marquis/Lincoln Town Car (AKA the Ford Panther platform) died off ten years ago is stamped sheet steel. Without factory weld nuts, bolt holes/slots or some such I would be scared to death of being involved with welding on a hitch.

Factory hitches made for installation on cars are pretty uncommon not just due to most cars having very limited towing capability but due to most cars being unsuitable to support a hitch of any size let alone a 2" hitch.

What make, model and year is the car. And what is it's rated tow capacity?


Lance

and on top of that what metal is there will melt away at a much lower temp and also requires more skill or experience. I have to agree a trailer hitch is not the place to be learning what someone or their machine is capable of, it is someone else's life that you are gambling with.