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Welding on RV frame close to propane bottle

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Dennis van Dam

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Jun 16, 2006, 6:26:53 PM6/16/06
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Most of us have welded on automobile frames at one time or and other and
while I'm immediately leary the closer I get to the fuel tank while
striking an arc, prevalent thinking is that it is not "unsafe" to do
so. Walk into any muffler shop and watch a while. They arc away all
day long on underbodies and I wonder if the weldor performs even a cursory
check for any type of fuel leak before he starts MIG-ing away.

I've got a job to do for a buddy on a small RV camper putting him on a
welded rear bumper suitable to a fix a towing hitch reciever to. Looking
the job over I notice he's got a propane bottle in an enclosed aft
compartment about 18 to 24 inches from where I may have to stike an arc.
The bottle is currently fully charged.

Just wondering what the "rule" is for welding near propane bottles vs
regular automobile fuel tanks. Obviously I would be concerned about
leaks and will make sure no gas is venting before I start but also I'm
wondering about any risks associated with passing current through the
frame to which the bottle is in direct physical contact with.

Is there anything in the nature of propane that makes for greater risk of
explosion compared to regular fuel tank as regards my secondary concern
outlined above?

Dennis van Dam

RoyJ

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Jun 16, 2006, 7:05:47 PM6/16/06
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Most states do not allow the transport of a Propane in an enclosed
space. The thinking is that any leaks will produce an air/fuel mix in a
confined area, good way to have an explosion. With you supplying a nice
ignition source, I'd pull the tank out before doing any welding.

Dennis van Dam

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Jun 16, 2006, 7:26:19 PM6/16/06
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Roy,

Yeah, I thought about that. When I went to look at the job the tank was
located in an aft compartment down low that has an access hatch opening to
the outside. At a glance the opening is too small to pass the bottle so
I'm not sure how it was installed into the enclosure.

When the vehicle shows up for the work I need to look at that again and
see it there is a way to get the bottle out. If not, surely the
enclosure is vented to atmosphere for the very reason you mention. (Is
propane heavier or lighter than air? I'm guessing lighter but I'm not
sure.)

Even if I reasonably establish there are no leaks/fumes I will purge the
enclosure with a fan and put up shielding between the arc and the
enclosure.

But I'm still wondering about any risk associated with passing current
through metal to which that bottle is directly attached.

Thanks for the reply.

Dennis

In article <fPGkg.6703$o4....@newsread2.news.pas.earthlink.net>, RoyJ

Dennis van Dam

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Jun 16, 2006, 7:48:20 PM6/16/06
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In article
<dvandam-1606...@dialup-4.255.243.92.dial1.atlanta1.level3.net>,

dva...@mindspring.com (Dennis van Dam) wrote:

(Is
> propane heavier or lighter than air? I'm guessing lighter but I'm not
> sure.)


And I see after a quick Google that it is *heavier* than air. Good to know.

Dennis

Robert Ball

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Jun 16, 2006, 8:54:45 PM6/16/06
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As long as you are working in an open area and not an enclosed space,
there are no vapors emitted from a propane tank like there is from a
gasoline tank. Propane WILL vent if the tank gets hot and the liquid
propane expands and vents thru the pressure relief valve (I have seen
this where the RV burned and smelled old tanks venting when overfilled
and sitting in the sun but not on newer tanks that can't be overfilled.
I consider it safer to work around propane tank than gasoline tank.
Just close the tank valve and be sure it doesn't get hot enough to need
to release pressure. Even if it does, it will not continue to burn like
gasoline will.

Martin H. Eastburn

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Jun 16, 2006, 10:11:17 PM6/16/06
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Yep -

Don't park a propane tank over a pit to work on. IF there is a leak -
the propane drops down into the pit. It is heavier than air.

I'd have a fan or plenty of ventilation (somewhat standard welding anyway
getting the fumes from you and gas from you as well).

If stick or mig or tig - keep the return between you and the tank and the
work between you and the return clamp. Don't want current through the tank.

Martin

Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH & Endowment Member
NRA Second Amendment Task Force Charter Founder
IHMSA and NRA Metallic Silhouette maker & member
http://lufkinced.com/

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big e lewis

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Jun 16, 2006, 10:49:50 PM6/16/06
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Slightly OT.... I work in an auto salvage yard, and we recently started
to buy scrap steel also, stuff like washers, dryers, ect. Anyway, the
only way we take tanks of any type is if they have a hole or are cut in
half. Several weeks ago, we got in some small propane tanks from a
grill, and they had about a 6x6 inch hole cut WITH A TORCH in the side
of each one... you could see the burn marks on the paint and everything!
You could also still smell the propane smell from the tanks, I don't
know if the odor was imbedded in the steel or what but it was strong. I
can't imagine what kind of idiot would torch on a tank, or how he did it
without blowing himself into next week! I wouldn't have believed it if I
hadn't seen it with my own eyes..... < shakes head > Earl

Leo Lichtman

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Jun 16, 2006, 10:58:29 PM6/16/06
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As others have pointed out, propane is less hazardous than gasoline. I can
see very little risk that the current through the vehicle frame could
produce any ignition hazard.

It is important, however, that you welding ground return fairly close to the
weld, and particularly, don't cause the current to flow through any ball
bearings, or such.


Dennis van Dam

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Jun 17, 2006, 4:53:13 PM6/17/06
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In article <pdKkg.33042$mF2....@bgtnsc04-news.ops.worldnet.att.net>,
"Leo Lichtman" <l.lic...@worldnet.att.net> wrote:

Understood. Thanks Leo and thank you to all who replied. The consenus
appears to be employ all the usual precautions.

The RV is now sitting in my driveway. The bottle is permanently built
into the enclosure so there's no removing it however, commensurate with
the heavier-than-air quality of propane, there is a large hole set in the
floor of the enclosure to keep from accumulating fumes.

Also as Robert indicated the tank is the newer type that can only be
filled to 80% capacity and it's parked in the shade so spontaneous venting
should not be a problem (but I *will* keep the enclosure ventilated with a
fan) and, as a few of you have mentioned, always be aware of where my
ground clamp is set with respect to where the tank is and where I'm
striking an arc.

Thanks again for all the replys, I appreciate the help.

Dennis van Dam

Pete C.

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Jun 17, 2006, 6:13:52 PM6/17/06
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Remove the valves, fill them with water, cut them with plasma. The
"propane" smell is an odorant that really sticks around even if there is
no trace of propane left BTW.

Pete C.

Martin H. Eastburn

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Jun 17, 2006, 9:09:19 PM6/17/06
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Maybe they were full of water when cut. We can only hope.

A guy - native worker - used a cutting torch on a Jet fuel drum overseas.
He tried to cut the end out - for a trash can. He didn't last but for a minute.

Martin

Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH & Endowment Member
NRA Second Amendment Task Force Charter Founder
IHMSA and NRA Metallic Silhouette maker & member
http://lufkinced.com/

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Don Young

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Jun 18, 2006, 12:05:26 AM6/18/06
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"Pete C." <aux3....@snet.net> wrote in message
news:44947E7D...@snet.net...
I recently saw a guy at a scrap yard recycling hundreds of the old 20lb
bottles. He was using a spear point on a log splitter mounted on the back of
a diesel tractor. I moved further away when I realized that many of the
bottles were not empty. There was occasionally a real big cloud when the
bottle was pierced. Apparently no effective ignition source was within range
but it sure looked scary. It amazes me what people sometimes do without
causing a disaster!

Don Young


Pete C.

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Jun 18, 2006, 9:15:51 AM6/18/06
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That propane tank in the car shredder on Monster Garage comes to mind...

Pete C.

JTMcC

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Jun 18, 2006, 12:23:15 PM6/18/06
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"Martin H. Eastburn" <lion...@consolidated.net> wrote in message
news:11505098...@sp6iad.superfeed.net...

> Yep -
>
> Don't park a propane tank over a pit to work on. IF there is a leak -
> the propane drops down into the pit. It is heavier than air.
>
> I'd have a fan or plenty of ventilation (somewhat standard welding anyway
> getting the fumes from you and gas from you as well).
>
> If stick or mig or tig - keep the return between you and the tank and the
> work between you and the return clamp. Don't want current through the
> tank.
>
> Martin
>
> Martin H. Eastburn
> @ home at Lions' Lair with our computer lionslair at consolidated dot net
> NRA LOH & Endowment Member
> NRA Second Amendment Task Force Charter Founder
> IHMSA and NRA Metallic Silhouette maker & member
> http://lufkinced.com/


Nice website Mr. Eastburn.
Have you looked into industrial/commercial work as well?

JTMcC.

Hannah

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Nov 21, 2021, 12:18:04 AM11/21/21
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replying to Leo Lichtman, Hannah wrote:
Thank you for sharing Leo. I was wondering this for welding on a bus with a
100lb tank bolted to the frame.

--
for full context, visit https://www.polytechforum.com/welding/welding-on-rv-frame-close-to-propane-bottle-45224-.htm


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