experienced welders here? question....

Rrizz · 08-01-2020, 06:11 PM

Today I discovered that the handle under my main step to pull them out was broken on one side. I own a mig welder, but am far from being experienced..
I can fix what needs fixin', but need some advice.
My first inclination was to pull the entire set of steps out, seperate them from the trailer so I don't have to be concerned about electrical problems, However, upon further inspection, they are welded way in the back to the frame. I don't want to get involved in grinding the welds off, and re-welding after my repair.
Some say I would need to disconnect the battery, and unplug my shore power prior to welding, others say as long as the ground lead is very close to where I am welding, the current will only travel from the wire to the ground, and it would not be an issue. Then there is the Inverter... is damaging that a concern I should have?
I hear from folks that you should NEVER weld on any vehicle without disconnecting the battery, but I recall In my younger days, My uncle was a line welder for Dana, who built truck frames, and also owned his own welding business for 30 years or so, and he welded the exhaust on my old beater car several times over the years, never disconnecting the battery, and we never had an issue....Maybe we were just lucky..
The break I need to fix is not in a position where I can drill it out, and throw a bolt through, or I would do that. welding is my only option. (aside from cutting the handle off, and constructing a new handle myself that can be bolted on, which is also a possibility, just alot of extra work)
Can anyone tell me the PROPER procedure?
Thanks for reading..

Papa-T · 08-01-2020, 06:22 PM

I’ve wire welded rear receivers on campers before and never I hooked the battery. Actually never really thought about it. But if your worried disconnect the battery and unhook from shore power. Better to be safe that sorry.

TexSon · 08-01-2020, 08:15 PM

I haven't welded on a trailer without disconnecting the battery, but I have welded on my Jeep a few times both ways. And haven't had any problems with the battery still connected. I imagine it is probably safer to do so to prevent overloads to the electrical systems in general. You know the saying, better safe than sorry and it is not hard to disconnect the battery.

B.O. Plenty · 08-02-2020, 07:30 PM

In the few minutes it takes to unplug and disconnect I would do it. Don't know if it matters but why take a chance?

Rrizz · 08-03-2020, 06:22 PM

No question, I will disconnect the battery and pull the shore power (I need the 30 amp to run my mig anyhow) I guess my main question is in regards to the inverter.
Its comforting to know that others have done welding on their rigs without any inverter issues.
Information isn't that easy to come by online in regards to a specific "must do" method. It seems like most discussions I have seen have both sides of the argument saying their way is the right way, and then things get heated... (no pun intended)

**Lloyd** · 08-03-2020, 06:26 PM

Rrizz
Unless you or a previous owner installed it. You don't have an inverter. It's a converter.
Probably doesn't make any difference for what you are doing tho.

Rrizz · 08-03-2020, 06:30 PM

Quote:

Originally Posted by Lloyd

Rrizz
Unless you or a previous owner installed it. You don't have an inverter. It's a converter.
Probably doesn't make any difference for what you are doing tho.

I frequently get the 2 reversed. (pun intended)

TexSon · 08-03-2020, 07:49 PM

And taking power off it will help isolate it.

priscilla101110 · 08-06-2020, 02:53 PM

Evening , I’m a certified welder for 24 yr now and using the MIG GUN is good . I always unhook power (Battery & or Shore) before Welding just for safety reasons . Grounding near the weld should be all you need to do . Of course prep work is a must to make job easier , and will make good quality work when it’s said and done .
Hope this helps ya fellow RV’r

DLG

egrum · 08-06-2020, 06:19 PM

As I see it, with 40 years teaching in the electrical trade.
Better Safe than Sorry

Having said that, car and vehicles including trailer were not filled with sensitive electronic equipment 40 years ago or even 20 years ago.

One problem would be which way is the welder set up? Positive Ground or Negative Ground? Reverse Polarity! Assuming the trailer is negative ground then a worse case situation would be Positive ground welder.

True, in either case the "Ground Clamp" should be as close as possible to the work being done.

So the 5 minutes to disconnect and re-connect the battery is SMART, that also goes without saying for shore power as well.

I also have a broken weld, (not really but that is the easiest explanation) the 90 degree bend, split on the step mount which is welded to the trailer frame, (which is aluminium, think about welding steel to aluminium). I tried adding a piece of angle iron with bolts, no luck, I tried self-threading screws, no luck. So now I live with it as I don't want to remove or cut the under-belly.

TerryH · 08-06-2020, 08:21 PM

Quote:

Originally Posted by Rrizz

Today I discovered that the handle under my main step to pull them out was broken on one side. I own a mig welder, but am far from being experienced..
I can fix what needs fixin', but need some advice.
My first inclination was to pull the entire set of steps out, seperate them from the trailer so I don't have to be concerned about electrical problems, However, upon further inspection, they are welded way in the back to the frame. I don't want to get involved in grinding the welds off, and re-welding after my repair.
Some say I would need to disconnect the battery, and unplug my shore power prior to welding, others say as long as the ground lead is very close to where I am welding, the current will only travel from the wire to the ground, and it would not be an issue. Then there is the Inverter... is damaging that a concern I should have?
I hear from folks that you should NEVER weld on any vehicle without disconnecting the battery, but I recall In my younger days, My uncle was a line welder for Dana, who built truck frames, and also owned his own welding business for 30 years or so, and he welded the exhaust on my old beater car several times over the years, never disconnecting the battery, and we never had an issue....Maybe we were just lucky..
The break I need to fix is not in a position where I can drill it out, and throw a bolt through, or I would do that. welding is my only option. (aside from cutting the handle off, and constructing a new handle myself that can be bolted on, which is also a possibility, just alot of extra work)
Can anyone tell me the PROPER procedure?
Thanks for reading..

INLAW said he welding on hitch of his 1-yo truck and EXPENSIVE MISTAKE w/ battery connected, blew his computer; safer/ easier disconnected

dkwheeler · 08-07-2020, 08:46 AM

Hi

No perfect answer

I had a hitch welded to my 5th wheel last year for a bike rack, and did disconnect the battery positive & negative. That was the end of the Jensen Stereo, never turn on again and had to replace it. My son that is a Journeyman Welder indicated they had been instructed to leave battery connected as then there is the ground needed.

Next time I would still disconnect the battery and also pull all fuses and turn off the circuit breakers.

egrum · 08-07-2020, 03:33 PM

Well in MHO (My Humble Opinion) pulling fuses and disconnecting circuit breakers is over-kill, but what ever.

Disconnecting battery is definitely a SMART choice, as the last 2 posts have indicated.

As Far as "Needing that ground" I call BS. the welder has a source and a ground which are the only things needed to complete the circuit to perform welding, otherwise how do you weld anything that is sitting on the table? or how do they weld a pipeline? hmmmm.

As I said previously I think (read guess/assume) that it has a lot to do with the polarity of the welder electrode and "ground" clamp. (reverse polarity). Welders, the guy, often use reverse polarity for welding (dont know/understand fully why 1 is better than the other), or maybe they use reverse polarity most of the time and only set the welder, machine, for normal polarity occasionally.

What ever way it is, I think that reverse polarity would be the worst culprit, as the negative of the battery connected to the frame of the vehicle, and now the welder, reverse polarity, "ground Clamp" which would actually be the Positive output of the welder, with VERY VERY large current capabilities (>70 amps) feeding Positive current into the frame of the vehicle, thus into all the electronics, and the positive current is searching for negative polarity (welder).

In MHO in simple terms, hopefully

Rrizz · 08-07-2020, 05:09 PM

I appreciate all the input, folks. I'm considering other options for the repair before I get the MIG out.
After further inspection, what I am dealing with is this:
The Handle is a hollow tube running from one side (stringer) of the step to the other.
One side is still firmly attached, the other snapped off right at the inside of the stringer.
I noticed that on the outside, where I thought the stringer was solid, it actually had a plastic plug through a hole in the stringer, covering what appears to be a hollow tube (the handle itself) slid through the hole in the stringer, and then the tube was flared on the outside to hold it together. both sides are similar.
The inside diameter of the handle tube is just under 5/8". what I was thinking of trying was getting a 5/8" x 3" carriage bolt, filing the inside of the handle clean, and filling the end with some JB weld ( I always have some of that stuff around) then pounding the carriage bolt in through the stringer into the handle. There is ample clearance for the head of the carriage bolt when folding steps to travel position. Hopefully the JB weld will lock that bolt in for good. Its not like the handle takes much abuse or stress after all.
A quick splash of flat black paint, and hopefully all is well. If not, the welder comes out.

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