Cutting dom and other questions.

[nniemczyk]

Hi to everyone.
I recently bought a Hobart 140 mig and have a few questions. My first fab project is a stinger for my bumper.

My questions are

-Is welding to a bumper with a winch ok, i realy dont want to fry my winch.

- The stinger is 1/8 inch wall dom. My bumper is 1/4 inch think what are the best wire speed and volts to use so i dont cut the stinger in half?

- What is the best way to cut the stinger, it is not precut at an angle, is there some kind of equation to find the angle to cut dom at?

I dont know very much about fab work but want to learn so any help is greatly appreciate.

Thank you for your time and help.

[nniemczyk]

anyone?
10 char

[whateg0]

If this stinger is to be functional, you need a bigger welder. The HH140 does not have the umph to weld to that bumper in such a way that it would be likely to support a vehicle when it needs to.

As far as cutting the tubing, I'm not sure what you are asking. Cut it like you would anything else. Is the bumper round? What is special that makes you wonder how to cut it?

As long as you are grounded to the bumper, and not passing welding current through the winch, there should not be any problem. If you aren't sure, remove the winch, or disconnect it.

Dave

[Scott Young]

can you post a drawing or picture of what you are wanting to do? There are several ways to do what I think you are wanting to do and then again I may be thinking in the wrong direction. Can't say as you didn't post a picture of what it is you are wanting to do!

Need more info.

[SidecarFlip]

Mating angles have to be extrapolated using that ugly word mathematics.

I agree, the 140 don't have the gonads for structurally secure welds in your instance and...

as far as wire speed and amperage, that's a matter of experience and consulting the base line chart under the side lid, if your Mig had the oooomoph in the first place. It's marginal at best.

[brucer]

depending on the size of your front bumper..
you could bend the stinger you currently have so you could cut 4 holes through the bumper, then slide the stinger completely through the bumper and weld it on both sides....

if all you have access to is your 140amp welder, i would preheat first.. i wouldnt weld it with anything less than a 180amp actually and thats too small but thats as big as i've got... 200-250amp would be idea..

[whateg0]

...i wouldnt weld it with anything less than a 180amp actually and thats too small ...

180A isn't enough for a 1/4" thick bumper?

[brucer]

well i guess i shouldve reworded it,i wouldnt say too small, just on the light side..

i think 200amp would be better..

[FabDave]

First thing is invest in a mangnetic angle finder.They sell cheap ones at lowes or home depot. Have someone help you hold the stinger up to the bumper at the angle you want it at and put the angle finder on it to see what angle you need to make your cut at. Once you get your angle then you can set your chop box at the angle and make your cuts. My stinger is at 30degrees but it all depends on the length of the stinger and your roof line. I agree a 140 is a bit small but can be done if you preheat the steel. My first jeep,,,the cage and stinger was welded with a 140 and handled a few flops on the side and the rock rails took a **** of a beating and never broke a weld but i wouldn't take a chance like that. Looking back,,i could of really got hurt or killed if i flipped and something broke loose and speared me or got crushed.
Also when welding the stinger to the bumper,,,make sure your heat favors the thicker steel to get the best penetration when welding it up. Hope this helps

[Scott Young]

With a bevel a 180 class gmaw welder can weld 3/8 easily. 1/4 inch is a walk in the park. At one of the shops, I welded at we had a Lincoln 175 plus (if my memory serves me right), I don't know why it ended up there, but it was used as a tacking unit so all the larger units would be tied up. in the over flow it ended up be used more than tacking. I was impressed with it. I welded 1/4 in many times. I wouldnt want to push it all day like the wall and floor units but for a hobby unit they are good.

[tenfingers]

What I used to do was all the joint prep, cutting, beveling, rust removal and tack it all together. I then took it to a weld shop and had them do the finish welding.

Before you do this, take your drawings of what you plan to do to the shop and ask if they are willing to do this. (Some won't)

The shop I ended up at was very helpfull showing me exactly how they wanted the prep work done. They also gave me pointers on sequence to weld to take into account weld shrinkage to keep corners square, and frames flat.