Welding Precautions

[Whaler]

I decided to replace and upgrade my house{four} battery rack. A local shop is making a new one and will weld it in place. The location is a fire safe and easy access area. What precautions should I take prior to welding to protect my motorhome systems?

[J-Rooster]

wildmanbaker wrote:

rgatijnet1 wrote:
Disconnect the coach from shore power. Keep the ground connection for the welder as CLOSE as possible to the area to be welded.
Make sure that there are no wiring harnesses, fuel lines, propane lines, air lines, near the area to be welded.
Some people may recommend disconnecting the batteries, or ECM/TCM but I never found that necessary on any of my coaches.

X3.
Your biggest problem will be not starting a fire, or melting something. You can do the disconnecting mentioned by others to make yourself feel good, but it is not necessary. Shore power, ground is ground, do as you want. All TIG welders I have used have HF start in AC and DC. Electricity is like humans and water, it is lazy and will take the path of least resistance. Go forth and create Fusion.

X-4, I agree with the Wildman's post solid advice!

[SCVJeff]

Any good welder with common sense will keep from burning things down. Anyone bragging that they welded the coach without taking provisions to prevent stray current spikes are kidding themselves. Just because you have a return clamp close to the work means nothing. Preventing ground loops are a science with a little luck and there's never any guarantee the return current and welding spikes are heading from the frame and straight to the clamp and not taking an alternate path down low loss copper and through unspecified electronics to stir things up.

[Kayteg1]

I did VERY extensive weldings on my Powerstrokes and never disconnected batteries.
Just made sure to keep the key away from ignition.
Still disconnecting batteries is the safest way.
Without pictures I can only guess, but welding makes lot of things around hot, so protecting sensitive materials from overheating or from the flames is important.
Good welder will know that.

[Jim]

I've read a couple Allison manuals, and those I read had a procedure to follow when welding on a RV. Like cars, newer RVs have computers all over the place. In the tranni, the engine, etc. So at least give your books a read through first.

[SoCalDesertRid1]

Interesting about the Allison control cable.

I did several feet of welding on my truck when I was building it, without disconnecting the Allison tranny from the system. So far, no problems in the past year. All of the welding was DC, electrode negative (self shield flux cored wire).

I'll have to read my Allison manual again to see if there is a notation about disconnecting when welding. I didn't see one before.

[SoCalDesertRid1]

In AC TIG (welding aluminum), continuous HF is needed to keep the arc going, because of the +/- sine wave nature of AC current, as well as HF start.

For DC-only TIG machines (welding steel and stainless), most now days are available with 'lift' or 'touch' start, instead of HF start, in the 'base' model machines, and add HF start in the 'deluxe' models, for a couple hundred dollars more.

There are still some DC Stick/TIG machines made with scratch start only, the cheapest ones. I call these stick machines, that can be used to TIG, in a pinch. These typically don't have a gas valve or remote amptrol connection on the machine.

[SCVJeff]

I had some hitch work done once and the shop went out of their way to pull the control cable plug on the Allison. Apparently it's hyper-sensitive to ground loops, but from where I don't know.

[MrWizard]

unhooking the batteries

i think its safe to say they will be totally removed from the RV and not near the welding

the welding is a NEW battery rack

no way to do that with the batteries in place

[wildmanbaker]

rgatijnet1 wrote:
Disconnect the coach from shore power. Keep the ground connection for the welder as CLOSE as possible to the area to be welded.
Make sure that there are no wiring harnesses, fuel lines, propane lines, air lines, near the area to be welded.
Some people may recommend disconnecting the batteries, or ECM/TCM but I never found that necessary on any of my coaches.

X3.
Your biggest problem will be not starting a fire, or melting something. You can do the disconnecting mentioned by others to make yourself feel good, but it is not necessary. Shore power, ground is ground, do as you want. All TIG welders I have used have HF start in AC and DC. Electricity is like humans and water, it is lazy and will take the path of least resistance. Go forth and create Fusion.

[SoCalDesertRid1]

-Disconnect the batteries (obvious, if you're having the battery trays welded)
-Disconnect the 110vac power from home/shop.
-Unplug any computers you have in RV.

Unless you're having something aluminum welded and using AC TIG HF, you generally don't have to worry about frying something electronic. AC high frequency is what fries sensitive electronics. Steel will be welded using DC low voltage, which is a low risk process (unless you're trying to stick weld it with an AC buzz box).

[10forty2]

All of the above are great precautions to ENSURE that nothing adverse happens. Honestly, anyone who knows what they are doing will be able to do the job without any problems. After a blowout, I had to have the generator tray re-welded, as well as a new tailpipe attached. Both were welded and I didn't do anything but take it to the shop and pick it up later. No problems. Just use good common sense, especially if you're going to try to do it yourself!

[TNGW1500SE]

The safest way to do it is to weld the rack off the RV and then bolt it in. Anytime you weld on a vehicle you take a risk. If that's not possible, you can limit the risk by clamping the ground as close as possible to the weld area. You could also go as far as removing the all the fuses, unhooking the battery and turning off the breakers. Personally, I'd bolt it in. My luck, it seems like if something can go wrong, it does.

[wa8yxm]

rgatijnet1 wrote:
Disconnect the coach from shore power. Keep the ground connection for the welder as CLOSE as possible to the area to be welded.
Make sure that there are no wiring harnesses, fuel lines, propane lines, air lines, near the area to be welded.
Some people may recommend disconnecting the batteries, or ECM/TCM but I never found that necessary on any of my coaches.

I will second this post and make the very same recommendations.

In fact, when I had to do some welding on this rig,,,,,that is exactly what we did.

One other POSSIBLE solution ... I have had this rig welded upon twice, The second time they welded OFF the Rig.. that is the parts needing welding were removed (They bolted on) and the work was done on the bench in the shop, and then bolted back on the Rig.


Battery trays may be doable that way.. Depends on the RV.

[darsben1]

If someone has a pacemaker/defibrillator implant make sure they are not near the welding