I don't see that being a problem at all. You might need to stop every so often to keep the rubber from getting too hot. It's not rocket science though, the rubber being too hot would be smelling awful before it gets dangerous at all.

cover it with wet rag

How did you break the hub?

hauling wood.....my tractor can make it turn sharper then the hitch will swing so the tire slid and broke. i had to put a solid peice of metal into the hitch to re-inforce it a year ago. is that wet rag dangerous with the welder...ive been told dampness is bad.

Dampness is not a good thing on the material being welded. However, it helps drown sparks on the surrounding parts. Just keep it wet and have some one available with at least a 20 lb BC fire extinguisher.

Wasn`t andyma suggesting that the tire be covered with a wet rag? How would that affect the weld?

There are reasons why moisture in a weld, such as a steam pocket blowing molten metal at you or causing a fisheye, but wet stuff gets welded all the time, welding is even done underwater and overlay welding is done on live steam pipes to stop leaks. Just make sure that you have a good ground and that you are not part of the circuit. Also make sure that the wheel bearings are not part of the circuit or they may also be welded. Like joecool says, the smell from the tire will tell you that it is getting hot before it becomes an issue.

Take the tire off.

to late to take the tire off...i welded it today. mig welded it...didnt even make the rubber smell at all.

thanks for the help tho

barbedwire
The reason for caution is called hydrogen embrittlement where moisture gets broken down by the welding current into hydrogen and oxygen and the hydrogen enters the molten metal causing serious flaws within the weld. This can occur from water, steam or even wet rags giving off steam and even water vapor close to the weld area. It is a REAL problem in that a little bit of hydrogen embrittlement goes a long way towards a dangerous and unpredictable weak weld.

Those welding underwater are probably using a special flux on those welding rods as are the steam fitters welding live steam just as you say. I would then guess that the flux contains some very special hydrogen "getter" chemistry that could make those rods righteously expensive.

Melee,

Thanks for the tutorial but I`m aware of embrittlement, infact when I thought welding would be a good way to make a living I burned hundreds and hundreds of lbs of certified LoHy rod all the way from 7018 up through 11018 and passed certification that qualified me to produce xray quality welds. Most of the rod was burned on a Miller 8 Pack but I`ve used a variety of welders and especially like my Lincoln Square Wave Tig/stick machine. There are weldors who are much more knowledgable and experienced than I but I`m not exactly a babe in the woods.

Now, given that the component to be welded is most likely mild steel and the OP was not attempting an xray quality weld I`m confident that the 10,000 degree electric arc will vaporize any significant amount of water that may be present in the area to be welded.

Also given that the tensile strength of the weakest rod I`m familiar with is 60,000 psi and the most commonly used mig wire for welding mild steel is e70s6, ie; 70,000 psi strength, I`m thinking that he is likely to have plenty of strength for his non-critical application provided that he produces fundamentally decent welds. I`ve burned hundreds of pounds of 6010,6013,7014, and 7018 on field repairs in less than ideal conditions without a failure yet. I store the 7018 in sealed cans, then an oven once the can is opened, and then one of those moisture resistant plastic containers with a gasketed lid when in the field, sometimes rod is in a pastic container for weeks. I can tell if the rod is ok by looking at the bead and if the flux curls off the bead during the weld. My point is, for non-xray welds it doesn`t appear to be crucial that LoHy rod be kept absolutely dry, infact I think that warpage and HAZ are more immediate concerns. IMO a corrolary exists that a little water in the weld area isn`t going to be a problem any more than not keeping LoHy rod in an oven is a problem for non-critical welds.

With all due respect to critical applications I think that we sometimes over think less critical situations at hand.

Just wanted to clarify something else melee. My statement, "Wasn`t andyma suggesting that the TIRE be covered with a wet rag?" was specifically in reference to putting a wet rag on the tire, not the area to be welded, thus I didn`t see how a wet tire could affect the weld?