Welding/ Cutting on smaller gas powered equip

[big bubba]

Looking @ a repair on a smaller 4wd power wheelbarrow about the size of a zero turn mower. need to replace broken ft. axle that will involve cutting/welding, fabrication. the engine is rear mount like a zero turn. so...what are the hazards of doing the above on gas powered equip w/fuel in tank? (in open air)
yes i could drain tank, but still potentially dangerous. & no, not going to upend to weld!!! thx in advance

 

[Shaneard]

The hazard is always there when welding near anything flammable. Without seeing it or being there no one can really give you a green light. You’ll have to use your best judgement.

 

[flyerdan]

If you have access to dry ice through a grocery store or the like, you could put some on top of the engine / fuel tank and tarp it with a trash bag. The CO2 will displace any oxygen so a fire can't start, the down side is it only lasts for a short time so you'll have a small window to do the welding.

 

[RNeumann]

The tank needs to be all the way filled to the brim with cap on or empty with dry ice and cap on. Anything in between has the greatest risk for a poor outcome.

Your level of comfort and the scenario should dictate one or the other.

 

[flyerdan]

If you put dry ice in the tank and put the cap on, you'd better have a really really really good vented cap because that's pretty much how they make dry ice soda bottle bombs.

 

[big bubba]

The tank needs to be all the way filled to the brim with cap on or empty with dry ice and cap on. Anything in between has the greatest risk for a poor outcome.

Your level of comfort and the scenario should dictate one or the other.

hey thanks RNeumann on this & am now reminded that a filled tank is safer than partial.
begin repairs tomorrow, & thanks to both above posters

 

[RNeumann]

LEL and UEL the two principles in play. The gas burns outside the container because inside is above the UEL. But once enough gas burns off to bring the air fuel ratio between the UEL and LEL- boom.

Explosive limits of natural gas - Logic4training - YouTube

So full should keep it above the UEL and empty with something to displace oxygen and or vapors will keep it below the LEL.

 

[radios1]

I'd just remove the fuel tank!. then you know it's safe.. it can't be that involved on something like this..

 

[Gary Fowler]

I'd just remove the fuel tank!. then you know it's safe.. it can't be that involved on something like this..

I would second this action. Other than a little bit of time, no additional expense and the safest option. Be sure to remove the fuel tank to a very secluded spot away from your cutting and welding operation.

 

[Ritothebull]

Sometimes I will wrap a fuel tank with wet rags and cover with fire cloth just to catch stray sparks during a quick fix but for any serious work you need to drain and flush out or remove the tank.